Дисертації: "Crop residue management Australia"

1

Collins, Shane. "Residue composition influences nutrient release from crop residues." University of Western Australia. School of Earth and Geographical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0171.

Повний текст джерела

Анотація:

[Truncated abstract] A greater adoption of stubble retention, minimum-till and no-till farming practices for the purposes of conserving soil, water and fertility requires a greater understanding of the complexity of physical and chemical interactions between the soil and crop residues. There is currently insufficient knowledge to allow reliable predictions of the effects of different residue types in different environments on soil fertility and crop growth, owing to the many residue characteristics and environmental interactions that have been shown to affect decomposition or nutrient release. The role of fibre and nutrient composition in nutrient release from crop residues, and implications for residue management techniques, were studied. Canola, lupin and field pea residues, obtained from farmland in Meckering and Northam, Western Australia, were separated into upper and basal stems, leaves, and siliques or pods. This was done to provide materials with a wide range of chemical and physical characteristics, and also allowed consideration of differential residue management of plant organs, such as comparing harvested canola siliques and retained canola stubble. Pre-treatment by chopping and/or humidification was applied to residues to provide some information about the processes of nutrient release. Residues were subjected to simulated rainfall to assess nutrient leaching from plant material, and placed on soil in pots in constant-temperature glasshouse conditions to assess decomposition. Amounts and rates of change of residue fibre and nutrients were determined throughout leaching and decomposition. Energy Dispersive X-ray (EDX) microanalysis was used to assess the location of diffusible ions in air-dried residues and the effects of humidification on nutrient positioning and release. ... However, the release of calcium and magnesium depended on the decomposition of the more recalcitrant components such as cellulose and lignin, as supported by microscopy results showing changes in nutrient distribution following humidification. The proportionality of amounts of calcium and magnesium leached and released during decomposition is likely to suggest a similarity of chemical form more than similarity of function or position of the two elements. Management of crop residues for maximising and optimising the timing of release of different nutrients will need to take into account the placement of different plant types and parts, particle sizes distribution and pre-treatment of material to efficiently manage short- and long-term soil fertility to sustain crops, particularly on degraded soils. Significant nutrient release of potassium, sulphur and magnesium from crop residues can be achieved from surface placement, with the release of potassium and sulphur managed by modifying residue particle size through appropriate harvesting, ploughing or sowing implement selection. High nutrient uptake crops and plant parts where they can be economically viable to grow or separated by the harvesting technique are particularly valuable as sources of nutrients and soil organic matter.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Valizadeh, Reza. "Summer nutrition of sheep based on residues of annual crops and medic pastures." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phv172.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Myers, Brian. "Variable crop residue management." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/35271.

Повний текст джерела

Анотація:

Master of Agribusiness
Department of Agricultural Economics
Jeffery R. Williams
Production agriculture is constantly evolving to become more efficient and productive. Crop residue serves as a valuable source of nutrients for the soil, but it is increasingly abundant with today’s enhanced crop genetics. If new technology can effectively provide a way to micro-manage crop residue levels within a field, the benefits will go beyond soil health. Surplus crop residue can be collected for secondary income while leaving the optimum amounts in the field to maintain the environment and soil health as well as promote future crop growth. The main objective of this study is to create a budget model that will determine the economic impact of crop residue removal on a controlled basis. The goals are to determine crop residue removal practices that are sustainable for the long-term, while also enhancing soil quality and increasing grain yield in future years. A sub-objective is to build a business case for producers to invest in variable crop residue management. The hypothesis presented in this study is that the increased complexity and price of a variable rate system is offset by more supplemental profits, increased crop yields, and better management of soil health and nutrients. The negative perceptions of crop residue removal include the fear of soil erosion or loss of soil organic matter. By developing a budget model that is easy to use, takes advantage of existing field data for inputs, and allows producers the ability to look at their operations on a sub-field level, this study aims to provide the necessary motivation to invest in new technology that will increase their productivity. By entering their site-specific crop residue return rate data into a budget model, along with prices and costs related to combine and auxiliary equipment, corn and corn stover, transportation and logistics, and nutrient replacement, they will come up with a return per acre for both constant rate and variable rate collection. The budget model determines whether it is economically viable to harvest crop residue from a continuous corn rotation at a variable rate across a field, rather than at a constant rate, using a producer’s own specific field data. To validate the concept, data from a joint study between John Deere and Iowa State is entered into the model. Prescriptions for corn stover return rates are provided from the study for pre-defined grid areas. Prescriptions are derived from a combination of data including grain yield, soil loss due to wind and water erosion, climate, topography, and soil sample data at time of planting (Nelson, et al. 2004). The average corn stover removal percentage was less for variable rate collection than constant rate collection, 26.05% to 31.85%. However, the assumption that grain yield and corn stover yield are positively correlated did not prove to be true in this case study. The variable rate plots had a lower average grain yield of 158.84 bushel/acre, compared to 160.46 for the constant rate plots, but they had more total corn stover available and therefore a higher return rate of 3.70 tons/acre, compared to 3.05 for the constant rate plots. This case study illustrates that less corn stover can be returned to the field through constant or variable rate collection while sustaining higher grain yields than a conventional harvest that would return all of the corn stover to the field. This case study demonstrates that variable rate collection can be more expensive than constant rate, but not in every situation. Every unique field site will require a specific crop residue management recommendation that is determined by both economic and environmental factors.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

He, Yuxin. "Crop residue management and its impacts on soil properties." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/19043.

Повний текст джерела

Анотація:

Doctor of Philosophy
Agronomy
DeAnn R. Presley
Crop residue removal for livestock feeding and biofuel production at large scales must be evaluated to assess impacts on soil productivity and properties. Among all the potential negative impacts, wind erosion is a major concern in the central Great Plains. We conducted an on-farm study from 2011 to 2013 by removing crop residue at five levels (0, 25, 50, 75, and 100%) to determine the effects of crop residue removal on soil wind erosion parameters such as dry aggregate size distribution including soil wind erodible fraction (EF <0.84 mm aggregates), geometric mean diameter (GMD) and geometric standard deviation (GSD), dry aggregate stability, and soil surface roughness. The sub-model of Wind Erosion Prediction System (WEPS) developed by the USDA-ARS, Single-event Wind Erosion Evaluation Program (SWEEP) is a stand-alone companion software package that can be applied to simulate soil loss and dust emission from a single windstorm event. We applied measured data (i.e. EF, GMD, GSD, and roughness) to SWEEP for predicting wind velocity that can initiate wind erosion and soil loss under each crop residue removal condition with wind velocity at 13 m sˉ¹. The threshold wind velocity to initiate wind erosion generally decreased with increase in crop residue removal levels, particularly for residue removal >75%. The total amount of soil loss in 3 hours ranged from about 0.2 to 2.5 kg mˉ² and depends on soil condition and crop residue cover. On the other hand, high-yielding crops can produce abundant crop residue, which then raises the question that if a farmer wants to reduce residue, what could they do without removing it? The application of fertilizer on crop residue to stimulate microbial activity and subsequent decomposition of the residue is often debated. We conducted wheat straw decomposition field experiments under different fertilizer rates and combinations at three locations in western Kansas following wheat harvest in 2011 and 2012. A double shear box apparatus instrumented with a load cell measured the shear stress required to cut wheat straw and photomicrography was used to measure the cross-sectional area of wheat straw after shearing. Total C and N were also analyzed. The fertilizer rate and timing of application during summer 2012 and Fall 2013 at the Hays site had impacts on wheat straw shear stress at break point. Across site years, earlier (fall) fertilizer application generally resulted in lower remaining aboveground biomass as compared to a spring application. Multivariate and linear regressions suggested that N and C:N ratio partially explain the results observed with respect to treatment effects on winter wheat residue decomposition.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Gherardi, Mark James. "Availability and management of manganese and water in bauxite residue revegetation." University of Western Australia. Soil Science and Plant Nutrition Discipline Group, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0038.

Повний текст джерела

Анотація:

[Truncated abstract] Industrial processing to refine alumina from bauxite ore produces millions of tonnes of refining residue each year in Australia. Revegetation of bauxite residue sand (BRS) is problematic for a number of reasons. Harsh chemical conditions caused by residual NaOH from ore digestion mean plants must overcome extremely high pH (initially >12), saline and sodic conditions. At such high pH, manganese (Mn) is rapidly oxidised from Mn2+ to Mn4+. Plants can take up only Mn2+. Thus, Mn deficiency is common in plants used for direct BRS revegetation, and broadcast Mn fertilisers have low residual value. Added to this, physical conditions of low water-holding capacity and a highly compactable structure make BRS unfavourable for productive plant growth without constant and large inputs of water as well as Mn. However, environmental regulations stipulate that the residue disposal area at Pinjarra, Western Australia, be revegetated to conform with surrounding land uses. The major land use of the area is pasture for grazing stock. Hence, pasture revegetation with minimum requirement for fertiliser and water application is desirable. This thesis investigates a number of avenues with potential for maintaining a productive pasture system on BRS whilst reducing the current level of Mn fertiliser and irrigation input. Emphasis was placed on elucidation of chemical and physical factors affecting Mn availability to plants in BRS

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Gelder, Brian Keith. "Land management database development methods for delineating management units and estimating crop and residue cover /." [Ames, Iowa : Iowa State University], 2007.

Знайти повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Battaglia, Martin. "Crop residue management effects on crop production, greenhouse gases emissions, and soil quality in the Mid-Atlantic USA." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/86483.

Повний текст джерела

Анотація:

Cellulosic biomass-to-bioenergy systems can provide environmental and economic benefits to modern societies, reducing the dependence on fossil-fuels and greenhouse gas emissions while simultaneously improving rural economies. Corn (Zea mays L.) stover and wheat straw (Triticum aestivum L.) residues have particular promise given these crops are widely grown and their cellulosic fractions present a captured resource as a co-product of grain production. Annual systems also offer the ability to change crops rapidly in response to changing market demands. However, concerns exist about residue removal effects on soil health, greenhouse gases emissions and subsequent crop productivity. The carbon footprint and the crop yield productivity and soil health responses resulting from the removal of crop residues has been studied extensively over the last 20 years, but this research has been largely conducted in the Corn Belt. To investigate the impact of crop residue removal in the Mid-Atlantic USA, combinations of corn stover (0, 3.33, 6.66, 10 and 20 Mg ha-1) and wheat straw (0, 1.0, 2.0, and 3.0 Mgha-1) were soil applied in a corn-wheat/soybean (Glycine max L. Merr.) rotation in Virginia's Coastal Plain. Corn stover (0, 3.33, 6.66, 10 and 20 Mg ha-1) was applied in a continuous corn cropping system in the Ridge/Valley province. For each system, residues were applied following grain harvest over two production cycles. Each experiment was conducted as a randomized complete design with four replications. The highest rates of stover retention resulted in greater greenhouse gas emissions in year 1, but not year 2 of these studies and did not affect overall global warming potentials. Stover application also increased soil carbon but had little effect on other measures of soil quality. Stover K levels were greater with high rates of stover retention. Overall, these studies indicate little effect of residue removal or retention (above typical residue production rates) on subsequent crop production, greenhouse gas emissions, or soil health measures in the short term. This study is one of the first to assess residue removal in the Mid-Atlantic USA and is the first study to investigate the impacts that managing more than one crop residue in a multi-crop system. Longer-term research of this type may be warranted both to determine the consequences of residue management and to start building a regionally-specific body of knowledge about these practices.
Ph. D.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Zheng, Baojuan. "Broad-scale Assessment of Crop Residue Management Using Multi-temporal Remote Sensing Imagery." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/19201.

Повний текст джерела

Анотація:

Tillage practices have changed dramatically during the past several decades as agricultural specialists have recognized the unfavorable environmental effects of mechanized tillage. Alternatively, conservation tillage management can mitigate adverse environmental impacts of tillage, such as soil and water degradation. Adoption of conservation tillage has continued to increase since its first introduction, which raises questions of when and where it is practiced. Spatial and temporal specifics of tillage practices form important dimensions for development of effective crop management practices and policies. Because Landsat has been and will continue to image the Earth globally, it provides opportunities for systematic mapping of crop residue cover (CRC) /tillage practices. Thus, the overall objective of this study is to develop methodologies to improve our ability to monitor crop management across different landscapes in a time-efficient and cost-effective manner using Landsat TM and ETM+ imagery, which is addressed in three separate studies. The first study found that previous efforts to estimate CRC along a continuum using Landsat-based tillage indices were unsuccessful because they neglected the key temporal changes in agricultural surfaces caused by tilling, planting, and crop emergence at the start of the growing season. The first study addressed this difficulty by extracting minimum values of multi-temporal NDTI (Normalized Difference Tillage Index) spectral profiles, designated here as the minNDTI method. The minNDTI improves crop residue estimation along a continuum (R2 = 0.87) as well as tillage classification accuracy (overall accuracy > 90%). A second study evaluated effectiveness of the minNDTI approach for assessing CRC at multiple locations over several years, and compared minNDTI to hyperspectral tillage index (CAI), and the ASTER tillage index (SINDRI). The minNDTI is effective across four different locations (R2 of 0.56 ~ 0.93). The third study, built upon the second study, addressed the Landsat ETM+ missing data issue, and devised methodologies for producing field-level tillage data at broad scales (multiple counties). In summary, this research demonstrates that the minNDTI technique is currently the best alternative for monitoring CRC and tillage practices from space, and provides a foundation for monitoring crop residue cover at broad spatial and temporal scales.
Ph. D.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Tao, Hsiao-Hang. "Crop residue management in oil palm plantations : soil quality, soil biota and ecosystem functions." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:ebcc3bd9-45c0-4d22-9fef-71dff4abecd3.

Повний текст джерела

Анотація:

The application of crop residues is one of the most common agricultural practices used to maintain soil ecosystems and crop productivity. This thesis focuses on the oil palm (Elaeis guineensis) agroecosystem, an important tropical crop that has expanded rapidly over the past four decades. Both land conversion and business-as-usual practices within the plantations have contributed to soil degradation. The application of oil palm residues, such as empty fruit bunches (EFB) and oil palm fronds, are thought to have positive effects on the soil ecosystem; yet there is currently a deficit of knowledge on their effectiveness. This thesis aims to examine the effects of oil palm residue application on soil physicochemical properties, soil biota, and ecosystem functions. It reports the results of extensive field trials, sample collection, and statistical analysis of crop residue applications in oil palm plantations in Central Sumatra, Indonesia. Four key results emerged from the thesis. First, in this study site land conversion from secondary forest to oil palm does not affect litter decomposition rate, but positively influences soil fauna activity. Second, there is greater soil fauna activity following EFB application than oil palm fronds or chemical fertilizers, and the fauna activity is highly associated with changes in soil chemical properties and soil moisture conditions. Third, EFB application enhances soil ecosystem functions, through the direct provision of organic matter, and by influencing soil biota. Finally, over 15 years of application, EFB appears to be effective in maintaining or increasing annual crop yield in comparison to chemical fertiliser treatment. Temporal changes in crop yield under EFB application appear to be associated with climatic conditions and soil organic carbon. Overall, these findings improve our understanding of the potential of oil palm residue applications to increase soil quality, soil biota, and ecosystem functions. They also provide useful information for a wider audience of soil ecologists, agricultural managers, and policy makers to improve sustainable management of the oil palm ecosystem.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Montague, Thomas L. "The management of browsing damage caused by wallabies in Australian plantations." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670283.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Ducamp, Fernando Arriaga Francisco J. "Effect of rye residue on soil properties and nitrogen fertiization of cotton." Auburn, Ala, 2008. http://hdl.handle.net/10415/1532.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Cogdill, Todd Joseph. "Investigation of management strategies for the production of sweet sorghum as a bioenergy crop and preservation of crop residue by the ensiling process." [Ames, Iowa : Iowa State University], 2008.

Знайти повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Isaac, Gura. "Crop rotation and crop residue management effects under no till on the soil quality of two ecotopes in the Eastern Cape, South Africa." Thesis, University of Fort Hare, 2016. http://hdl.handle.net/10353/2934.

Повний текст джерела

Анотація:

The degradation of soil quality due to undesirable farming practices has reached alarming scales in the Eastern Cape and this has had negative repercussions on soil productivity and the environment in general. There is growing evidence that conservation agriculture (CA) practices involving minimal mechanical disturbance, maintaining permanent surface cover and embracing diverse crop rotations increase soil organic carbon (SOC) and therefore has potential to mitigate soil quality deterioration. A study was carried out at two sites located in two ecotopes to investigate the effects of crop residue retention and crop rotations in a no till system on overall soil quality using the Soil Management Assessment Framework (SMAF) as the soil quality assessment tool. The CA study trials were laid out in 2012 at two different locations, one at the Phandulwazi Agricultural High school within the Phandulwazi Jozini ecotope and the other one at University of Fort Hare Research Farm within the Alice Jozini ecotope. The experiment was laid out as a split-split plot arrangement in a randomized complete block design with three replicates. Tillage treatments were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). The initial assessment of the overall soil quality of the two ecotopes using the SMAF soil quality index (SQI) revealed that the soils at the Alice site were functioning at 80% while the soils at the Phandulwazi site were functioning at 79 percent of their optimum capacity. The slight difference in the soil quality of the two ecotopes could be attributed to their different soil organic C contents where the Alice Jozini ecotope had significantly higher soil organic C contents than the Phandulwazi Jozini ecotope. After 3 years of continuous treatment application, crop residue retention significantly improved most of the measured soil quality parameters. Generally across the sites, more soil organic C, microbial biomass C (MBC), ß-glucosidase (BG) activity, mineral N, extractable P and K, Cu, Zn, Mn, Fe, and macro-aggregates were recorded in treatments where crop residues were retained. Crop rotations alone did not have a significant impact on most of the measured soil quality indicators. The crop rotations influenced significantly the availability of mineral N across the two sites, highlighting the importance of using a legume in rotations on available N for the subsequent crops. Most of the measured soil attributes were not significantly influenced after 3 years of continuously applying combined treatment of CA components. Mineral N (NO3 + NH4), K, Zn and Fe were significantly impacted on by the interactions of CA components at the Phandulwazi site, while N, Cu, Zn and Mn were significantly increased at the Alice site. Low response of SOC to combined CA treatments in the short-term prompted the need to examine treatment effects on individual soil carbon fractions. The interaction of crop rotation and residue management techniques were significant on the fine particulate organic matter – C fractions and microbially respired C. These soil C fractions were more sensitive to short-term treatments of combined CA components than SOC and MBC, therefore they can be used as short-term indicators of CA effects on SOM. Soil organic carbon, MBC, extractable P and K, soil pH, EC, b, AGS (aggregate stability) and BG activity were measured and the Soil Management Assessment Framework (SMAF) used to calculate soil quality index (SQI) values for each treatment. The combination of the crop rotations with crop residue retention showed the potential to significantly improve SQI values in the long term. The highest soil quality improvement at both sites was achieved by the maize-wheat-soybean (MWS) rotation with crop residue retention.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Suriadi, Ahmad. "Structural stability and Na-Ca exchange selectivity of soils under sugarcane trash management." Title page, Contents and Abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09ASOM/09asoms961.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Burdack, Doreen. "Water management policies and their impact on irrigated crop production in the Murray-Darling Basin, Australia." Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2014/7224/.

Повний текст джерела

Анотація:

The economic impact analysis contained in this book shows how irrigation farming is particularly susceptible when applying certain water management policies in the Australian Murray-Darling Basin, one of the world largest river basins and Australia’s most fertile region. By comparing different pricing and non-pricing water management policies with the help of the Water Integrated Market Model, it is found that the impact of water demand reducing policies is most severe on crops that need to be intensively irrigated and are at the same time less water productive. A combination of increasingly frequent and severe droughts and the application of policies that decrease agricultural water demand, in the same region, will create a situation in which the highly water dependent crops rice and cotton cannot be cultivated at all.
Die ökonomische Folgenanalyse in diesem Buch zeigt, dass insbesondere Landwirte, die stark auf Bewässerung angewiesen sind, von Wasserregulierungsstrategien im Australischen Murray-Darling Becken betroffen sind. Dieses Gebiet ist eines der größten Flussbecken weltweit und zugleich Australiens fruchtbarste Region. Durch den Vergleich von verschiedenen Preisstrategien und anderen Ansätzen konnte mit Hilfe des Water Integrated Market Models herausgefunden werden, dass die Auswirkungen auf hochgradig wasserabhängige Feldfrüchte mit geringeren Wasserproduktivitäten am stärksten sind. Die Kombination von häufigeren und intensiveren Trockenzeiten und einer Regulierungspolitik mit dem Ziel, die Nachfrage nach Wasser zu verringern, führt dazu, dass in ein und derselben Region hochgradig wasserabhängige Feldfrüchte wie Reis und Baumwolle mit geringeren Wasserproduktivitäten nicht mehr angebaut werden können.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Kadango, Tendayi Lovemore. "Farmers' perceptions of insect pests in the Eastern Cape maize-based cropping systems and the effects of crop residue management on insect pest populations." Thesis, University of Fort Hare, 2018. http://hdl.handle.net/10353/6202.

Повний текст джерела

Анотація:

Maize (Zea mays L.) is one of the most important crops in South Africa that is cultivated for food, feed and as a cash crop. Maize in the Eastern Cape is typically grown for consumption and the Province is one of the least producers owing to small landholdings, poor production conditions and pests. This study investigated: (i) the different maize cropping systems smallholder farmers practice in the Eastern Cape (EC), (ii) the major maize insect pests within the identified cropping systems, (iii) the perceptions of Eastern Cape smallholder maize farmers on the effects of insect pests, and (iv) the effects of crop residues on insect pests’ population dynamics. Four major cropping systems namely: maize sole cropping without rotations by government sponsored farmers (GCP) (94 percent), maize intercropping without rotations by independent farmers (IF) (79 percent), maize sole cropping without rotations by IF (67 percent) and maize intercropping without rotations by GCP (61 percent) were identified. The choice of a cropping system by the smallholder farmers was significantly influenced by source of sponsorship, the difference in their district localities, tenure system, availability of inputs and farming equipment, percentage of farmland farmers allocate to maize, maize varieties, farming experience, fallow operations and access to irrigation facilities. The major constraints faced by the farmers in maize production are the attack by insect pests, weeds competition, drought, the lack of fencing around the fields and destruction by mammals. The major insect pests identified were stalk borers (Busseola fusca, Chilo partellus), cutworms (Agrotis spp.), aphids (Rhopalosiphum maidis), bollworms (Helicoverpa armigera) and weevils (Sitophylus spp.). The most popular control measures employed were the use of GM maize and pesticides. Results from the field trial showed that field crickets were the major ground dwelling insect pests observed followed by bollworms and cutworms. However, there were no significant influence of residue retention on the insects’ diversity indices, richness, and evenness. Above ground insects sampling revealed the domination by four major insects namely, cutworms, maize stalk borer, bollworms, and spotted stalk borer. Residue management significantly influenced the infestation by spotted stalk borer only on maize plots. However, the general trend was that there was less infestation by the insects in plots where residues were retained than the ones with residue removed. Results from the study indicate that government sponsorship is significantly influencing the maize cropping systems of the smallholder farmers of the Eastern Cape.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Morris, Jennifer L. "Use of herbicides, tillage, and grazing cattle for establishment of corn in rotation with alfalfa and rye." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/45050.

Повний текст джерела

Анотація:

Six combinations of grazing, tillage, and herbicides were studied during 2 yr in a randomized block design to determine alfalfa (Medicago sativa) survival, corn (Zea mays) plant populations and corn growth in an alfalfa-corn rotation. Alfalfa was overseeded with rye (Secale cereale) in autumn prior to planting corn in spring of each year. Treatments were 1) non-grazed control with standard chemical treatments for no-till establishment of corn, 2) grazing alfalfa, then grazing rye until corn planting followed by dicamba application, 3) alfalfa grazing plus glyphosate prior to corn planting, 4) treatment 3 plus grazing prior to rye jointing, and 5) alfalfa grazing plus autumn application of glyphosate, 6) alfalfa grazing plus autumn disking (no herbicides). Grazing until corn planting decreased (P<0.05) alfalfa stands and rye biomass, but increased (P<0.05) corn plant populations and soil bulk density compared to shorter grazing periods. Grazing prior to rye jointing increased (P <0.05) soil bulk density and corn plant populations, and decreased (P<0.05) rye biomass compared to no spring grazing. Autumn disking decreased (P<0.05) bulk density, but generally provided less (P<0.05) control of alfalfa compared to autumn application of glyphosate. Autumn disking and glyphosate application (Trts. 5 and 6) increased (P<0.05) rye biomass compared to no autumn treatment (Trts. 3 and 4). Applying glyphosate prior to corn planting (Trts. 3 and 4) improved (P<0.05) corn populations and growth compared to autumn glyphosate or disking (Trts. 5 and 6) and was similar to conventional no-till establishment (Trt. 1). Herbicides were necessary to completely kill alfalfa, but grazing reduced TNC in alfalfa roots and alfalfa plant persistence.
Master of Science

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Nishigaki, Tomohiro. "Improvement of Water- and Nutrient-Use Efficiency with Optimum Agricultural Management Practices in Upland Cropping Systems in Morogoro, Tanzania." Kyoto University, 2017. http://hdl.handle.net/2433/228243.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Graham, Michael William. "Evaluating the interactions of crop management, carbon cycling, and climate using Earth system modeling and remote sensing." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102386.

Повний текст джерела

Анотація:

Crop management practices, such as soil tillage and crop residue management, are land management activities with potentially large impacts on carbon (C) cycling and climate at the global scale. Improvements in crop management practices, such as conservation tillage or 'no-till' (NT), have been proposed as climate change mitigation measures because such practices may alter C cycles through increased sequestration of soil C in agricultural soils. Despite their potential importance, regional to global scale data are lacking for many crop management practices, and few studies have evaluated the potential impact of the full range of crop management practices on C cycling and climate at the global scale. However, monitoring of crop management practices is crucial for assessing spatial variations in management intensity and informing policy decisions. Inclusion of crop management practices in Earth system models used for assessing global climate is a key requirement for evaluating the overall effects of different crop management practices on C cycling and their potential to mitigate climate change. Studies in this dissertation seek to address these issues by: (1) evaluating the efficacy of remote sensing methods for monitoring differences in soil tillage and crop residue management practices in Iowa; (2) incorporating soil tillage practices into an Earth system model and assessing the potential for soil C sequestration and climate change mitigation through adoption of NT practices; (3) assessing the historical impact of including the full range of crop management practices (residue harvest, grain harvest, soil tillage, irrigation, and fertilization) on changes in C cycling associated with land use and land cover change (LULCC) to crops in an Earth system model. The remote sensing study found that performance of the minimum Normalized Difference Tillage Index (minNDTI) method for assessing differences in tillage and residue management was below average compared to previous studies, even when using imagery from both Landsat 8 and Sentinel-2A sensors. Accurate assessment of these practices using minNDTI was hindered by issues with image quality and inability to obtain sufficient cloud-free, time series imagery during the critical planting window. Remote sensing research aimed at obtaining regional to global scale data on tillage and residue management practices is likely to continue to face these issues in the future, but further research should incorporate additional sensors and assess the efficacy of the minNDTI method for multiple locations and years. Adoption of NT practices in the Community Land Model, which is the land component of the Community Earth System Model, resulted in a cumulative soil C sequestration of 6.6 – 14.4 Pg C from 2015 – 2100 under a future climate change scenario (Representative Concentration Pathway 8.5), and cumulative soil C sequestration was equal to approximately one year of present-day fossil fuel emissions. Adjusting for areas where NT is already practiced had minor impacts on cumulative soil C storage, reducing gains in soil C from NT adoption by 0.4 – 0.9 Pg C globally. These results indicate that soil C sequestration and potential for climate change mitigation through NT may be more limited than has been anticipated elsewhere. Soil C sequestration via NT adoption was highest in temperate regions of developed countries with high initial soil C contents, indicating these areas should be targeted for NT adoption. Simulating the full range of crop management practices in the Community Land Model resulted in an increase in C emissions due to LULCC of 29 – 38 Pg C compared to scenarios with generic crops and model defaults. Individual crop management practices with the largest impact on LULCC emissions were crop residue harvest (18 Pg C), followed by grain harvest (9 Pg C) and soil tillage (5 Pg C). Although implementation of crop residue harvest and soil tillage was extreme in this study, these results imply that Earth system models may underestimate emissions from LULCC by excluding the full range of crop management practices. Studies in this dissertation corroborate the importance of crop management practices for C cycling and climate, but further research on these management practices is needed in terms of data collection, improving process-level understanding, and inclusion of these practices in Earth system models.
Doctor of Philosophy

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Nafi, Eeusha [Verfasser]. "Interactive tillage & crop residue management effects on soil properties, crop nutrient uptake & yield in different weathered soils of West Africa : measurements, modelling & scenario simulations / Eeusha Nafi." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1235525945/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Dam, Rikke Friis. "Impacts of long term tillage and residue practices on selected soil properties." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=78344.

Повний текст джерела

Анотація:

A two year study was initiated in 2001 on a 2.4 ha site of mostly St. Amable loamy sand and shallow loamy sand at the Macdonald Campus Research Farm. This study sought to assess the effects of long term tillage and residue practices on soil physical properties and to relate these properties to their influence on total carbon, total nitrogen and soil microbial biomass-carbon. The site was set up as a factorial experiment with three tillage practices (no till---NT; reduced till---RT; and conventional till---CT) and two residue practices (with residue (grain corn), +R; without residue (silage corn), -R). Soil physical properties measured were bulk density, macroporosity at -6 kPa, saturated hydraulic conductivity (Ksat ), dry aggregate distribution, soil moisture and soil temperature. Wheel versus non-wheel track bulk density was also determined in the NT plots. Total porosity, soil water characteristic curves and pore volume distribution were derived from field samples. Crop yield was also assessed. Tillage alone had an effect on total porosity, bulk density, pore diameter and macroporosity. No individual physical property was significantly affected by the residue treatments; however, the tillage and residue interaction was significant for Ksat, soil moisture and soil temperature. Dry aggregate distribution was not affected by either tillage, residue or the combination of the two. Tillage affected total carbon and total nitrogen in the 0--0.10 m depth. Soil microbial biomass-carbon was affected by residue inputs. Total carbon and nitrogen were influenced by the bulk density, but none of the other soil physical properties. Soil microbial biomass-carbon was not influenced by any of the physical properties. Tillage and residue practices had no significant effect on crop yield for either year.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Diop, El Hadji Habib Sy. "Biofuel feedstocks: implications for sustainability and ecosystem services." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16994.

Повний текст джерела

Анотація:

Doctor of Philosophy
Department of Agronomy
Charles W. Rice
Biofuel feedstocks such as grains and cellulose are gaining increased attention as part of the U.S. portfolio of solutions to address climate change and improve energy security. As the future of biofuels unfolds, major concerns are emerging, including the sustainability of the soil resource in bioenergy cropping system. With a clear understanding of the sustainability risks that exist within the agricultural soil resources, it is now essential to develop metrics that document the soil health as well as the total biomass production of different cropping system. We tested the effectiveness of eight bioenergy plant species grouped between annual and perennial crops. Our main objective was to determine the sustainability of bioenergy cropping systems. There was significantly greater soil structural stability plus greater root biomass under the perennial crops but greater aboveground biomass in the annual crop. Differences in soil carbon measured to 1.2 m were not significant between energy crops after five years. A transparent, unbiased method to identify possible change in soil characteristics under bioenergy cropping practice was offered. Our next metrics were soil aggregate stability and microbial community structure as indicators of soil ecosystem health and environmental stability. The effects 24 years of differing levels of residue and fertilizer inputs on soil aggregate stability, aggregate C and microbial community structure were evaluated. A native, undisturbed prairie site, located nearby was used as a reference in this study. The results showed that greater inputs of inorganic N and increased returns of crop residues did not cause a proportionately greater increase in SOC. The abundance of microbial parameters generally followed their potential carbon pool in cultivated soils but a strong mismatch was observed in the native prairie site. Our results showed for the first time a clear disconnect between decomposers and macroaggregates; highlighting the role of soil structure in protecting organic matter. Soil carbon sequestration is one of the mechanisms that have been proposed as temporary measure to mitigate global climate change. However, there was a particularly large risk of negative effects of mitigation measures related to the increased removal of crop residues from cropping systems for use in bioenergy, if this means that soil carbon is reduced. Effective measurement of soil C at the field scale requires an understanding of the spatial variability of soil C on a landscape scale. Recent technological advances in soil C measurement offer new opportunities in this area. Our surface measurements of soil C by near infrared spectroscopy (NIRS) provided a quick assessment of soil C and, soil C predicted by NIRS and measured by dry combustion laboratory measurements was correlated with and R-squared of 0.84.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Doole, Graeme John. "Value of perennial pasture phases in dryland agricultural systems of the eastern-central wheat belt of Western Australia." University of Western Australia. School of Agricultural and Resource Economics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0213.

Повний текст джерела

Анотація:

Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Mühlig-Versen, Bernhard. "Effects of crop residue management, phosphorus application and molybdenum supply on yield and nutrient uptake of pearl millet, cowpea and groundnut in Sahelian cropping systems /." Beuren : Grauer, 2001. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=3861863723.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Burdack, Doreen [Verfasser], and Hans-Georg [Akademischer Betreuer] Petersen. "Water management policies and their impact on irrigated crop production in the Murray-Darling Basin, Australia / Doreen Burdack ; Betreuer: Hans-Georg Petersen." Potsdam : Universität Potsdam, 2014. http://d-nb.info/1218861746/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Alfaress, Serine. "Integrated pest management strategies for a terrestrial isopod, Armadillidium vulgare, in no-till soybean production." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13656.

Повний текст джерела

Анотація:

Master of Science
Department of Entomology
Brian P. McCornack
Robert J. Whitworth
No-till management of soybean benefits producers by lowering input costs and retaining soil moisture, but may also provide optimal conditions for increasing populations of soil-inhabiting pests. For Kansas soybean, damaging populations of soil-inhabiting isopods (Malacostraca: Isopoda) have been observed in fields under no-tillage management. To control damage to soybean stands from feeding isopods, current management strategies need to be evaluated. The objectives of my research were to evaluate the effects of chemical and cultural control combinations (seed treatment and planting date, planting date and seed size, seed treatment and natural crop residue removal, and seeding rate and seed treatment) on soybean stand densities exposed to natural isopod populations, and to evaluate the effects of burning crop residue on isopod populations and emergence rates in soybean under no-tillage management. Field studies were conducted in consecutive years (2009 and 2010) in two separate soybean fields within each year. All fields were under no-till management and had a history of damaging isopod populations. In the second chapter, we demonstrated that seed treatment with an insecticide is not a reliable strategy. Doubling normal seeding rates can potentially reduce the number of trips a grower makes across a field (single, high-density versus multiple, low-density plantings). In doing so, growers may save time and money (e.g., fuel). A high seeding rate (563,380/ha), along with a low rate (50 g a.i. / 100 kg seed) of neonicotinoid seed treatment, appears to improve soybean stands (P < 0.05). No other combinations of control methods appeared to affect stand density. In the third chapter, we show burning to be an effective strategy to directly influence isopod populations but its overall effect on soybean stands needs further investigation.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Schreuder, F. A. "An investigation into global distribution systems in the crop protection industry and the development of distribution system managment model for particular application in South Africa and Australia." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/21185.

Повний текст джерела

Анотація:

Thesis (PhD)--Stellenbosch University, 2002.
ENGLISH ABSTRACT: The traditional ways in which manufacturers of crop protection products exercised control over distribution systems have diminished in their impact. Control was based on quality products, the power of the brand, an installed customer base and a broad portfolio of mostly patented products. Manufacturers of crop protection products need to review the manner in which these products are marketed, which distribution system management models are to be used, and the importance that is placed on distribution system management in the marketing mix. The primary aim of this study was defined as: "The development of appropriate distribution system management models for application in South Africa and Australia~. The secondary aim was defined as: "Establishing the key factors which determine the relationship between manufacturers and distributorsn . The dominant economic characteristics of the global crop protection industry are deemed to consist of a global market valued at US $28,090 mio, a mature market in a decline phase, the rapid consolidation of industry players, increased generic product manufacturer activity and an overall decline in manufacturer profitability. In South Africa crop protection product manufacturers use approximately 46 independent distributors to market products on farms through 600 affiliated commissioned sales agents. In Australia the distribution of crop protection products is much more concentrated. Distribution is essentially controlled by five national distributors and their coupled salaried representatives. Manufacturers therefore rely on third parties for the marketing of their products to farmers in both countries. The applicable problem statement has been formulated to select a distribution system management model that will: (i) optimally balance direct distribution related cost and subsequent levels of control over distributors; (ii) maximise the probability that a distributor will buy and actively promote the complete product portfolio of a for high levels of interpersonal relationship maintenance; and (vi) manufacturers have to instill the philosophy that distribution system management is part of a manufacturer's strategic business and marketing focus and not simply a task to be performed by a third party.
AFRIKAANSE OPSOMMING: Die tradisionele maniare waarop die vervaardigers van oesbeskermingsprodukte beheer kan uitoefen oor verspreidingsisteme is nie meer so suksesvol nie. Beheer was gebaseer op kwaliteil produkte, die mag van die handelsmerk:n gevestigde klientebasis en 'n wye produktereeks,bestaande uit gepatenteerde produkte, Vervaardigers van oesbeskermingsprodulcte moet die wyse waarop hierdie produkte bemark word, watter verspreidingsisteem bestuursmodelle gebruik word en die belangrikheid wat geplaas word op die bestuur van die verspreidingsisteme in die totala bemarkingspoging in heroorweging neern. Die primere doelstelling van hierdie studie is: "Die ontwikkeling van toepaslike verspreidingsisteem bestuursmodelle vir toe passing in Suid-Afrika en Australia. "Die sekondere doelstelling is: "Die vas stelling van die sleutelfaktore wat die verhouding tussen velVaardigers (verskaffers) en verspreiders bepaar. Die dominante ekonomiese kenmerke van die globale oesbeskermingsindustrie is 'n markwaarde in VSA $ 28,090 miljoen, 'n stagnante mark in 'n agteruitgang lase, die drastiese konsolidasie van die industrie spelers, 'n toename in die aktiwiteite van die generiese produkvervaardigers en 'n algemene daling in die winsgewindheid van die vervaardigers. In Suid-Afrika gebruik die vervaardigers van die oesbeskermingsprodukte ongeveer 46 onafhanklike verspreiders om die produkte op plaasvlak te bemark met behulp van 600 geaffilieerde kommissie agente. Die verspreiding van oesbeskermingsprodukte is baie meer gekonsentreerd in Australie. Verspreiding word in wese beheer deur vyf nasionale verspreiders en hulle spanne van verkoopsteenwoordigers wat 'n salaris verdien. In beide lande moet velVaardigers van oesbeskermingsprodukte staatmaak op onafhanklike instansies vir die bemarking van hul produkte op plaasvlak. Die probleemsteiling is dus die uitdaging om 'n verspreidingsisteem bestuursmodel t9 ontwikkel wat: (i) . n optima Ie balans sal gee tussen direkte verspreidingskoste en gekoppelde vlakke van beheer oor verspreiders; (ii) die waarskynlikheid dat . n verspreider die betrokke produkreeks van die vervaardiger sal aankoop en aktief sal promoveer; (iii) dit kan bereik in . n mark waar verspreiders talle bronne het van soortgelyke produkte teen kompeterende pryse. Gebaseer op die sekondere navorsing wat gedoen is wit dit blyk dat daar 'n algemene konsensus is dat daar n nei9in9 weg is van transaksie spesifieke besigheidsverhoudings na besigheidsverhoudings gebaseer op vennootskap gebaseerde benaderings in die interaksie tussen vervaardigers (verskaffers) en verspreiders. Hierdie tipe besigheidsverhouding word gekenmerk deur hoe vlakke van onderlinge vertroue, wedersydse verbintenis, konflik hanteringsmeganismes en goeie wedersydse kommunikasie. Primere navorsing is in Suid-Afrika (253 respondente) en Australia (180 respondente) gedoen. Implikasies vir die konstruksie van verspreidingsisteem bestuursmodelle wat voortvloei uit hierdie navorsing sluit in die belangrikheid dat on vervaardiger on wye en gesogte produkreeks het, die vereiste dat produkte beproefde effektiwiteit het, produkte kompeterend geprys is, die vereiste vir hoe vlakke van verskaffer opvolgdiens en die vereiste vir goeie interpersoonlike verhouding tussen werknemers van beide die vervaardigers en die verspreiders. Hierdie elemente moet ondermeer gerugsteun word deur goeie kommunikasiesisteme. Die "idea Ie" verspreidingsisteem bestuursmodelle is vervolgens voorgestel vir beide Suid-Afrika en Australie, gebaseer op die bevindinge van ondermeer die sekondere- en primere navorsing. Hierdie mode lie het ten doel om toepaslike strukture en besigheidsbenaderings vir vervaardigers daar te stel om hulle behulpsaam te wees om die geidentifiseerde behoeftes van die verspreiders aan te spreek.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Choi, Suk-won. "The potential and cost of carbon sequestration in agricultural soil empirical study of dynamic model in the midwestern U.S /." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1095676113.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xiii, 133 p.; also includes graphics (some col.). Includes bibliographical references (p. 125-133).

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Landzela, Besule. "Effects of BT Maize (MON810) crop and its residues on selected soil biological properties and N and P release in a sandy loam soil from Alice, Eastern Cape, South Africa." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1007542.

Повний текст джерела

Анотація:

There are apprehensions that genetic modification of maize with Bacillus thuringiensis (Bt) may have negative effects on soil biodiversity, ecosystem processes and functions. This study aimed at determining the effect of Bt maize crop, Bt maize residues and its genetic modification on microbial biomass carbon (MBC), selected enzyme activities, vesicular arbuscular mycorrhizal (VAM) fungi and N and P release patterns. The study was conducted under field, glasshouse and laboratory conditions. In 2010/2011 season, four maize cultivars; DKC 61-25B (Bt), DKC 61-24 (non-Bt), PAN 6Q-321B (Bt) and PAN6777 (non-Bt) were planted. Determination of MBC, enzyme activities and fungal spore count was done at 42, 70, and 105 days after planting (DAP). A loam soil amended with Bt or non-Bt maize leaf residues from a study of 2009/2010 season was incubated to investigate effects of Bt maize residues on MBC and soil enzyme activities. Leaf residues of Bt and non-Bt maize cultivars (DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777) were used and soil without residues was used as a control. Samples were collected at 7, 28 and 56 days of incubation (DOI). An incubation study was also carried out in the laboratory to determine the effect of Bt maize residues (i.e. leaf, stem and root) and its genetic modification on N and P release patterns. Residues of DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777and soil without residues as a control were incubated in the laboratory. After destructive sampling at 0, 7, 14, 28, and 56 DOI, N in the form of NH4-N and NO3-N and P mineralisation were determined. Amendment of soil with residues enhanced MBC (p < 0.05) at all the sampling dates. For example MBC increased from 95 in the control to 146.3 mg/kg in the DKC 61-25B treatment at the end of the glasshouse trial. In the field DKC 61-25B had 9.1 mg/kg greater MBC than DKC 61-24, while PAN 6Q-321B had 23.9 mg/kg more MBC than PAN6777 at the end of the trial. However, no differences (p < 0.05) were observed in enzyme activities under field and glasshouse conditions except for dehydrogenase that had greater activity where DKC 61-25B and PAN 6777 were grown. There were no differences between the type of residues (Bt and non-Bt) on enzyme activities tested. However, differences were observed among the sampling dates. No effects of Bt maize crop on fungal spore count were observed. Similarly no differences were observed in leaf, stem and root tissues composition between Bt and non-Bt maize cultivars. Net N and P mineralisation from Bt maize cultivars did not differ from that of non-Bt maize cultivars. However, differences were observed among the cultivars. The results of this study suggested that Bt maize with Bt MON810 event can be grown in the central region of the Eastern Cape (EC), South Africa without affecting MBC, soil enzyme activities, VAM, and release of N and P nutrients from its residues.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Martins, Bianca Assis Barbosa. "Biologia e manejo da planta daninha Borreria densiflora DC." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-25072008-122909/.

Повний текст джерела

Анотація:

A planta daninha vassourinha-de-botão (Borreria densiflora DC.) está apresentando aumento na sua infestação em áreas cultivadas com cana-de-açúcar e soja, respectivamente nos estados do Maranhão, Goiás e Tocantins. Observações de campo têm relatado a deficiência de controle químico sobre esta espécie, quando ocorre em estádio de crescimento avançado. Sendo assim, este trabalho objetivou classificar botanicamente B. densiflora DC., analisar a influência da luz e da temperatura na germinação desta espécie, seu crescimento, desenvolvimento e estruturas reprodutivas, sua susceptibilidade a herbicidas em condições de pré e pósemergência, e a influência da interação entre a profundidade de enterrio e a presença de palha em diferentes quantidades sobre a superfície do solo sobre a emergência desta planta daninha. A classificação botânica foi realizada na Facultad de Ciencias Exactas y Naturales y Agrimensura - UNNE / IBONE, Argentina; o experimento que analisou a germinação sob diferentes condições foi realizado no Laboratório de Análise de Sementes, do Departamento de Produção Vegetal da USP / ESALQ, e todos os demais experimentos foram conduzidos em casa-de-vegetação, do mesmo departamento. Todos os trabalhos foram conduzidos entre 2006 e 2007. Constatou-se que a planta daninha vassourinha-de-botão se trata da espécie Borreria densiflora DC., pertencente à família Rubiaceae. Com relação à germinação, constatou-se que a vassourinha-de-botão é fotoblástica positiva preferencial, uma vez que sua germinação é favorecida na presença de luz, respondendo diferentemente às condições de luz e temperatura estudadas. As maiores taxas de germinação e índices de velocidade de germinação foram alcançados em condição de fotoperíodo (12h) sob as temperaturas constantes de 30ºC e 35ºC e alternada de 20-30ºC. Praticamente, não houve germinação no escuro constante. Sobre o crescimento e desenvolvimento, observou-se que a planta daninha Borreria densiflora DC. é uma espécie com desenvolvimento inicial lento, de ciclo de vida perene simples, apresentado grande incremento nas variáveis massa seca total, taxa de crescimento relativo e de assimilação líquida entre os 26 e 36 dias após transplante (DAT). Ao final do experimento, os ramos se mostram como os compartimentos mais participativos na partição de fotoassimilados pela vassourinha-de-botão. Esta espécie é capaz de produzir, em média, 93.090 sementes por planta. Com relação ao manejo químico de Borreria densiflora DC., a maioria dos herbicidas promoveram controles considerados adequados, com exceção ao clomazone e MSMA, em condições de pré e pós-emergência, respectivamente. Sendo assim, várias opções de herbicidas e de misturas destes podem ser recomendadas para o manejo da planta daninha B. densiflora DC., tanto em condições de pré-semeadura quanto pré e pós-emergência. O estudo sobre a influência da interação entre profundidade da semente no solo e presença de palha de cana-de-açúcar na superfície do solo sobre a emergência desta espécie demonstrou haver interação entre os dois fatores testados, sendo que quanto maior a profundidade da semente no solo e a quantidade de palha sobre a superfície, menor é a porcentagem de emergência e biomassa fresca de B. densiflora DC. Tais resultados são importante na medida em que favorecem o entendimento da dinâmica populacional da B. densiflora DC., auxiliando o manejo integrado desta espécie.
The weed vassourinha-de-botao (Borreria densiflora DC.) has been presenting increase in its infestation in areas cultivated with sugarcane and soybean, respectively in Maranhao and Goias states and north of Tocantins state, Brazil. Field observations have reported the control deficiency of this species, when it occurs in advanced growth stage. Thus, this research was conducted with the objective of classify botanically the weed, analyze the light and temperature influence on the germination of this species, its growth, development and reproductive structures, its susceptibility to herbicides in pre and post conditions, as well as the influence of the interaction between seed burial and the presence of crop residue in different amounts in the soil surface on the emergence of this weed. The botanical classification of vassourinha-de-botao was done in the Exact and Natural Sciences College - UNNE / IBONE, Argentina; the experiment that evaluated germination under different conditions was conducted in the Seeds Analyzes Laboratory, of the Crop Science Department of USP / ESALQ, and all the other experiments were carried out in the same department, between 2006 and 2007. It was concluded that the weed vassourinha-de-botao is the species Borreria densiflora DC. and it belongs to Rubiaceae family. Related to germination, it was observed that B. densiflora DC. is preferencial positive photoblastic, since its germination is favored by presence of light, responding differently to the studied light and temperature conditions. The highest germination rates and speeds of germination were reached in presence of photoperiod condition (12h), under the constant temperatures 30ºC and 35ºC and the alternated 20-30ºC. Basically, there was not germination in the constant dark condition. About the growth and development, it was observed that the weed Borreria densiflora DC. is a species with slow initial growth, with a simple perennial life cycle, presenting a big increment in the variables total dry biomass, relative growth and liquid assimilation rates between 26 and 36 days after transplanting (DAT). At the end of the experiment, the stems appear as the most participative compartments in the photosynthate partition by Borreria densiflora DC. This species is able to produce, in average, 93,090 seeds per plant. Related to the chemical management of Borreria densiflora DC., the majority of the herbicides provided controls considered adequate, except clomazone and MSMA, in pre and post-emergence conditions, respectively. Therefore, many herbicide options and mix of herbicides can be recommended to the management of the weed Borreria densiflora DC., since in pre-plant to pre and post-emergence. The study about the influence of the interaction between seed burial and presence of dry sugarcane residue in the soil surface on the emergence of this species demonstrated to exist interaction between those two tested factors, being that the bigger depth in the soil and amount of dry sugarcane residue in the soil surface, the lower is the percentage of emergence and fresh biomass of B. densiflora DC. Those results are important since they favor the understanding of the population dynamics of Borreria densiflora DC., aiding the integrated management of this weed species.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Morais, Maristela Calvente. "Efeito da remoção de quantidades de palha de cana-de-açúcar na biomassa e na comunidade microbiana do solo." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-15122016-105828/.

Повний текст джерела

Анотація:

O esforço global em diversificar a matriz mundial de combustíveis líquidos, busca substituir as fontes fósseis por renováveis. A produção de bioenergia derivada da biomassa assume importante papel neste cenário. A biomassa gerada após a colheita da cana-de-açúcar ganha destaque como matéria prima pela grande quantidade de material que pode ser usado para geração direta (queima) e indireta (biocombustíveis) de bioenergia. No entanto, ainda pouco se sabe sobre os efeitos da remoção de quantidades de palha de cana-de-açúcar voltado à produção de bioenergia sobre os atributos biológicos do solo. Assim, o objetivo deste estudo foi avaliar o efeito da remoção da palha de cana-de-açúcar no carbono e nitrogênio microbiano e na comunidade microbiana do solo. O estudo foi conduzido em duas áreas cultivadas com cana-de-açúcar (Saccharum spp. L.) nos municípios de Capivari, SP (Usina Bom Retiro) e Valparaíso, SP (Usina Univalem). Em Bom Retiro o experimento foi instalado em um Latossolo Vermelho distrófico típico de textura franco-argilo-arenosa e, em Univalem foi um Argissolo Vermelho-Amarelo distrófico de textura arenosa. Em ambos locais, o delineamento experimental utilizado foi blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos testados corresponderam a diferentes intensidades de remoção de palha de cana-de-açúcar (i.e., 100%; 75%; 50%; 0 de remoção; e aleiramento da quantidade remanescente na área após colheita), sendo 0; 3,4; 7,8; 16,6; 15,6 Mg ha-1 de palha em massa de matéria seca na Usina Bom Retiro e 0; 4,2; 8,7; 18,9; 23,3 Mg ha-1 na Usina Univalem. Um ano após a instalação do experimento, foram coletadas amostras de palha e de solo na camada 0-10 cm e, passados quatro meses após o segundo manejo de remoção da palha nos tratamentos foram coletadas amostras de palha e de solo nas camadas 0-5 e 5-10 cm. Os atributos avaliados foram: carbono e nitrogênio total da palha e do solo, fração mais oxidável do carbono do solo, carbono e nitrogênio da biomassa microbiana da palha e do solo e, quantificação de genes microbianos no solo. Os resultados mostraram que as quantidades de C e N totais no solo não apresentaram resposta em função das quantidades de palha, no entanto, a fração de C mais facilmente oxidável e o C e N microbiano apresentaram tendência de redução em função de maiores níveis de remoções de palha, sendo a resposta da biomassa microbiana mais expressiva no solo de textura arenosa (i.e., Univalem). Da mesma forma, as comunidades microbianas foram mais sensíveis às diferentes remoções de palha, apresentando maior abundância com menor remoção de palha. Desta forma, a remoção de elevadas quantidades da palha de cana-de-açúcar do campo, ao alterar a microbiologia do solo, pode ter consequências nas específicas funções exercidas por este compartimento, que garantem o bom funcionamento do solo e podem prevenir contra a degradação. Estes resultados podem servir de base para avaliações mais amplas que buscam uma estratégia sustentável de manejo da palha de cana-de-açúcar que garanta o bom funcionamento do solo
The global effort to diversify the global matrix of liquid fuels seeks to replace fossil sources by renewable ones. Bioenergy production derived from biomass plays an important role in this scenario. The biomass generated after the harvest of sugarcane stands out by the large amounts of straw that can be used for direct generation (burning) and indirect (biofuels) of bioenergy. However, little is know about the effects of sugarcane straw removal to bioenergy production on biological soil properties. The objective of this study was to evaluate the effect of the straw removal on soil microbial carbon and nitrogen as well as on soil microbial community. The experiments were conducted in two areas cultivated with sugarcane (Saccharum spp. L.) in Capivari, SP (Bom Retiro) and Valparaíso, SP (Univalem). The soils studied were an Oxisoil with clay texture in Bom Retiro and an Ultisoil with sandy texture in Univalem. In both sites, the experimental designer was a randomized blocks with five treatments and four replications. The treatments tested were decreasing intensities of sugarcane straw harvest (i.e., 100%; 75%; 50%; 0 removing of the original straw deposition) : i) Bom Retiro: 0; 3,4; 7,8; 16,6; 15,6 Mg ha-1 of dry matter of straw kept on soil surface; ii) Univalem: 0; 4,2; 8,7; 18,9; 23,3 Mg ha-1 of dry matter of straw kept on the soil surface. One year after experiment installation, straw and soil (0-10 cm layer) samples were collected. A new sugarcane straw and soil (0-5 and 5-10 cm) sampling was performed four months from the second deposition of sugarcane straw on the field. The attributes evaluated were: total and microbial C and N of straw and soil, soil easily-oxidizable C, straw and soil microbial genes quantification using qPCR method. Our results showed that soil C and N contents were not impacted by sugarcane straw removal. However, the fraction of easily-oxidizable C and microbial C and N tended to decrease due to increased straw removal, with a more significant microbial biomass response for the sandy soil site (Univalem). Likewise, microbial communities were also sensitive to straw management, resulting in a significant decrease in the number of gene copies with increasing intensities of sugarcane straw harvest. Therefore, we can concluded that the large amounts of sugarcane straw removal from field as affects soil microbiology, may have consequences in specific functions performed by microorganisms, which ensure the soil functioning and can prevent soil degradation. These results can serve as a basis for more comprehensive assessments that seek a sustainable crop residue management strategy for sugarcane, to ensure the proper functioning of the soil

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Meyer, Christin Verfasser], and Jürgen [Akademischer Betreuer] [Scheffran. "Climate Change Impacts and Risk Management : Improving farm resilience through adaptation in the crop-livestock zone of the Corangamite catchment in Victoria (Australia) with a Case Study of the ´Mount Hesse´ farm / Christin Meyer ; Betreuer: Jürgen Scheffran." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1151322385/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Callum, Ian R. "Long-term effects of tillage and residues on selected soil quality parameters." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31202.

Повний текст джерела

Анотація:

A two year study was initiated in 1999 at the Macdonald Campus Farm, on a 2.4 ha site consisting mainly of St-Amable sand to shallow loamy sand (Typic Endoaquent; Humic Gleysol). The site was planted to alfalfa ( Medicago sativa) prior to the establishment of the experimental design and has been planted to corn (Zea mays L.) since 1991. The experiment was set up as a randomized complete block design and consisted of three tillage levels (NT, no-till; RT, reduced tillage; and CT, conventional tillage) and two residue levels (-R, no residues; +R, with residues). This study was performed in order to ascertain the effect of these management systems on soil organic carbon (SOC), particulate organic matter carbon (POM-C), microbial biomass carbon (MBC) levels and soil physical properties. Soil physical properties measured included bulk density, saturated hydraulic conductivity (Ksat), dry and wet aggregate stability, total porosity, macroporosity at -1 kPa and -6 kPa of matric potential, and moisture content. Crop yield was also measured. Results indicated that lower rates of mineralization of POM-C under NT+R in the surface 0--10 cm led to significantly higher SOC at the same depth. There were no significant differences between treatments at the 10--20 cm depth. The MBC was not a good indicator of the differences in soil organic matter levels between treatments. No-till treatments had higher bulk densities, reduced total porosity and macroporosity, increased moisture content, and increased constant-head measured Ksat. Differences in Ksat as measured with the Guelph permeameter, were not significant between treatments, most likely due to increased earthworm activity in NT. There were no significant differences in crop yield in 1999, but a significantly wetter year in 2000 caused lower grain yields in NT+R compared to NT-R and CT+R.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Vasconcelos, Ana Luisa Soares de. "Emissão de gases de efeito estufa do solo devido à remoção de quantidades de palha de cana-de-açúcar e à adubação nitrogenada." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-19122016-163327/.

Повний текст джерела

Анотація:

A palha de cana-de-açúcar tem sido uma importante matéria prima para aumentar a produção de bioenergia no Brasil. Porém a dinâmica das emissões de gases de efeito estufa no campo devido à prática de remoção de palha ainda não é totalmente compreendida. O objetivo deste trabalho foi quantificar as emissões de GEE do solo devido à remoção da palha de cana-de-açúcar com e sem adição de nitrogênio. Foram realizados dois experimentos com câmaras amostrais de gás mantidas em condições naturais com quatro tratamentos: sem palha, 3, 6 e 12 Mg ha-1, os quais equivalem as intensidades de 100, 75, 50 e 0% de remoção. O primeiro foi conduzido por 180 dias sem adição de N e o segundo experimento conduzido por 100 dias, foi adicionado 80 kg ha-1 de N no sulfato de amônio e 32 kg ha-1 de N na vinhaça. Conjuntamente ao experimento 1, foi conduzido um ensaio de decomposição com as mesmas quantidades de palha limitadas por caixas plásticas sem fundo (0,3 x 0,5 m). No Experimento 1 a presença de palha aumentou 35 - 45% os fluxos acumulados N2O e CO2 em relação ao solo descoberto. O influxo de CH4 aumentou 40% na presença total de palha (12 Mg ha-1) em relação ao sem palha. O fator de emissão de N2O encontrado para a palha em decomposição foi de 0,02%. No Experimento 2 ocorreu uma intensificação das emissões devido à adubação nitrogenada, com isso as emissões em razão das quantidades de palhas não foram significantes. O fator de emissão médio foi de 0,42%. Os resultados indicam que a palha, sem N, possui um efeito na emissão de GEE e, que para manter o estoque de C do solo, é necessário a manutenção de pelo menos 6 Mg ha-1 para compensar as perdas de CO2 por respiração. Este trabalho contribuirá para os cálculos de pegada de carbono do bioetanol e na decisão da usina sobre a intensidade de remoção de palha de cana-de-açúcar para a produção de energia e etanol 2G
Sugarcane straw has been point out as an important feedstock to increase bioenergy production in Brazil However, the field greenhouse gas (GHG) emission dynamic due straw removing management is not completely understood yet. Two experiments were conducted with gas sampling chambers that was kept under natural conditions with four treatments: bare soil, 3, 6 and 12 Mg ha-1, which is approximately the equivalent of the 100, 75, 50 and 0 % intensities of removing. The first was conducted for 180 days without the N addition and the second experiment was conducted for 100 day and its was added 80 kg ha-1 N in ammonium sulfate and 32 kg ha-1 N in the vinasse. Parallely to the experiment 1, a decomposing trial was conducted with the same straw amounts in a side limited bottomless plastic boxes (0.3 x 0.5 m). In Experiment 1, the presence of straw increased 35-45% the N2O and CO2 accumulated flux compared to the bare soil. While the influx of CH4 increased by 40% in the maximum straw amount (12 Mg ha-1) compared to zero. The N2O emission factor found for the straw decomposition was 0.02%. In Experiment 2 occurred an intensification of emissions due to nitrogen fertilization which raised the average emission factor for 0.42%. Thus emission due straw quantities were not significant. The results indicate that the straw without N has an effect of GHG emissions, and in order to maintain the C stock in soil is need keep at least 6 Mg ha-1 of straw to compensate for the loss of CO2 thru respiration. This work will contribute to the bioethanol carbon footprint calculation and in the grower decision taking of straw removing intensity for energy and 2G ethanol

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Marx, Peggy. "Untersuchungen zur Vermehrbarkeit und zur Wachstumsregulierung von neu in den europäischen Markt einführbaren australischen Pflanzen." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2004. http://dx.doi.org/10.18452/15032.

Повний текст джерела

Анотація:

Die vorliegende Arbeit zeigt die Möglichkeiten einer Kultur australischer Akazien als Topfpflanzen. Im ersten Teil werden in einer umfangreichen Literaturübersicht ökologische Standortbedingungen und bisherige nationale und internationale Veröffentlichungen über australische Akazien und zur Kultur weiterer australischer Pflanzen dargestellt. Untersuchungen zur generativen Vermehrung an 12 Akazienarten beinhalten verschiedene Saatgutvorbehandlungsmethoden: mechanische Beschädigung, Vorquellen, Behandlung mit konzentrierter Schwefelsäure, dem Seed Starter "Smoky Water" sowie die Behandlung mit hohen Temperaturen. Die mechanische Beschädigung des Saatgutes erzielt bei der Mehrzahl der untersuchten Akazienarten eine hohe Keimrate bei kurzer Keimdauer. Die Behandlung mit Seed Starter zeigt dagegen keine keimungsfördernde Wirkung. Praktische Versuche zur vegetativen Vermehrung durch Stecklinge beziehen sich auf unterschiedliche Stecklingsarten, Vermehrungstermine, Alter der Mutterpflanzen sowie verschiedene Stecklingsbehandlungen mit Bewurzelungshormonen und die Lagerung der Stecklinge. Es wird gezeigt, dass diese bisher problematische Vermehrungsmethode durch die Verwendung juvenilen Mutterpflanzenmaterials deutlich verbessert werden kann. Ferner konnte ein positiver Einfluss der Lagerung von Stecklingen auf die Bewurzelungsraten dargestellt werden. Vorteile bei der Bewurzelung und teilweise im weiteren Wachstum erzielte die Anwendung von IBS als Bewurzelungshormon. Versuche zur In-vitro-Kultur zeigen die Möglichkeit der In-vitro-Vermehrung und In-vitro-Bewurzelung der Akazienarten sowie die unproblematische Überführung in vivo für Acacia retinodes. Der Einfluss der Vermehrungsmethoden und -arten auf die weitere Entwicklung der Akazien wird im Teil der Wachstumssteuerungsmöglichkeiten untersucht. Es erfolgt die Darstellung der klimatischen Ansprüche und die Wirkung einiger kulturtechnischer Maßnahmen, beispielsweise die Anwendung von Hemmstoffen, Stutzen und Wurzelkürzen. Entscheidend für eine zeitige Blütenknospenbildung ist die Vermehrung über adultes Stecklingsmaterial. Die Kultur unter Zusatzlicht führt zu einem kompakten Habitus und einer verbesserten Blühinduktion. Die Blütenentwicklung kann durch das Absenken der Temperatur gefördert werden. Das Kürzen der Wurzeln beeinträchtigt die weitere Entwicklung der Pflanzen nicht. Durch Stutzen kann der Austrieb nicht gefördert werden; die Wirkung auf die Pflanzenhöhe erfolgt in Abhängigkeit vom Stutztermin. Abschließend werden Kulturschemata ausgewählter australischer Akazien als Blattpflanzen und blühende Topfpflanzen dargestellt.
This study was conducted to examine the suitability of the Australian acacias species for pot plant production. A comprehensive overall review of national and international literature was first carried out on ecological conditions of the habitat and cultivation of some Australian plants. The seed germination of 12 Acacia species was studied following a manual chipping treatment, exposure to hot water, concentrated sulphuric acid, the seed starter "Smoky water" and high temperature scarification. The manual chipping treatment resulted in a faster and improved germination rate. The seed treated with "Smoky water" showed no increase in germination rate. In-vitro-culture of acacia species was examined. In-vitro-propagation and in-vitro-rooting of acacia species was carried out. Acacia retinodes is adaptable to resettlement from in vitro to in vivo. Practical examinations of propagation included different types of cuttings, times of propagation, age of mother plants, treatment with root hormones and the storage of cuttings. The use of juvenile plant material for cuttings resulted in increased rooting percentages. Storage of cuttings had a positive influence on rooting rates. Treatment with indole butyric acid (IBA) promoted rooting and future plant growth. The portion of the study on growth manipulation examined the effects of using differing kinds and methods of propagation, different environmental conditions and technical manipulations such as growth regulator applications and the pruning of stems and roots. The propagation of cuttings from adult plant material is decisive for inflorescence bud formation. Increasing light intensity and day length produced a compact plant and improved floral initiation. Lowing temperatures can increase flower development. The development of the plants is not affected by root pruning. Pruning stems can not stimulate branching, however, depending on the time of application, pruning stems does promote plant growth. The crop management of special Australian acacia species as pot plants or flowering pot plants is described on charts in conclusion of the study.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Melapi, Aviwe. "Investigation into the characteristics and possible applications of biomass gasification by-products from a downdraft gasifier system." Thesis, University of Fort Hare, 2015. http://hdl.handle.net/10353/d1020174.

Повний текст джерела

Анотація:

Biomass gasification has attracted the interest of researchers because it produces zero carbon to the atmosphere. This technology does not only produce syngas but also the byproducts which can be used for various application depending on quality.The study conducted at Melani village in Alice in the Eastern Cape of South Africa was aimed at investigating the possible applications of the gasification byproducts instead of being thrown away. Pine wood was employed as the parent feedstock material for the gasifier. Biomass gasification by-products were then collected for further analysis. The studied by-products included tar(condensate), char, soot and resin. These materials were also blended to produce strong materials.The essence of the blending was to generate ideal material that is strong but light at the same time.The elemental analysis of the samples performed by CHNS analyser revealed that carbon element is in large quantities in all samples. The FTIR spectra showed almost similar results for all the studied samples, since the samples are end products of lignocellulosegasification. SEM gave the sticky images of resin as well as porous char structures. Char showed a higher heating value of 35.37MJ/Kg when compared to other by-products samples.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Qureshi, Maqsood Hassan. "Tall fescue growth and nitrogen uptake as influenced by non-thermal residue management." Thesis, 1994. http://hdl.handle.net/1957/35322.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Graham, Martha Helena. "The effect of various crop residue management practices under sugarcane production on soil quality." Thesis, 2003. http://hdl.handle.net/10413/10163.

Повний текст джерела

Анотація:

This study examined the influence of different management practices under sugarcane production on soil chemical, biological and physical properties on a long-term (59yr) field experiment in KwaZulu-Natal. These management practices included conventional post-harvest burning of crop residues, with the tops either left on the soil surface or with tops removed, and green cane harvesting with the retention of crop residues on the soil surface as a trash blanket. Each of these treatments were either fertilized or did not receive fertilizer. The data collected was used to evaluate the effect of crop residue management on soil quality under sugarcane production. Soil organic matter content increased from 39 g C kg¯¹ soil, under conventional burning to 55 g C kg¯¹ soil in the surface 10 cm under green cane harvesting where crop residues are returned to the soil. It also resulted in greater recycling of nutrients and increases in exchangeable K and Ca and extractable P. Fertilizer application resulted in a build-up of soil nutrients in combination with trash retention. Fertilizer application induced increases in exchangeable P and also some accumulation in soil organic P. Exchangeable and non-exchangeable K concentrations were also higher in fertilized than non-fertilized treatments. However, nitrogen fertilizer application and, to a lesser degree, organic matter mineralization, resulted in soil acidification to a depth of 30 cm. Acidification in the fertilized treatments resulted in a concomitant increase in exchangeable acidity and exchangeable Al, due to the increase in H⁺ ions and solubilized Al species on exchange sites. Base cations moved into soil solution and were leaching to lower soil layers. The decrease in soil pH resulted in the surface charge conferred on the variable charge surfaces on soil colloids becoming less negative and as a result there was a decrease in ECEC. Acidification in fertilized treatment not only increased exchangeable Al but also the buffering reserve of non-exchangeable al; both that complexed with soil organic matter (CuCl₂- extractable) and that present as hydroxy - Al associated with mineral colloids (ammonium acetate - extractable). The increased organic matter content under trash retention resulted in an increase in ECEC. This enabled the soil to retain greater amounts of Ca²⁺, Mg²⁺ and K⁺ which were returned to the soil in the trash. Both residue retention and fertilizer application had a positive effect on the microbial biomass C and N and the microbial quotient increased from 0.39% to 0.86% as organic C increased from 39 g C kg¯¹ soil under burnt treatments to 55 g C kg¯¹ soil under trashed, fertilized treatments. This increase was associated with increased concentrations of labile organic material (K₂S0₄₋extractable) present as well as increased amounts of nutrients being cycled through the plant-soil system. The light fraction organic matter also increased with increasing returns of organic residues. However, the large active microbial biomass under the trashed, fertilized treatment resulted in an increased turnover rate of this fraction and consequently resulted in lower LF dry matter, C and N than in the unfertilized treatment. Aggregate stability increased with increasing amounts of organic material returned due to trash retention. Nevertheless, fertilized treatments induced a lower aggregate stability than unfertilized ones, despite the tendancy for the latter to have higher organic C and microbial biomass values. This was attributed to an increase in the proportion of exchangeable cations present in monovalent form (due to application of fertilizer K and leaching of Ca and Mg) favouring dispersion and a decline in aggregate stability. Green cane harvesting resulted in an increase in microbial activity (basal respiration, FDA hydrolytic activity, arginine ammonification rate and dehydrogenase activity) and in the activity of specific soil enzymes involved in turnover of C, N, P and S to a depth of 30 cm. Increased activities of these enzymes reflect a higher rate of turnover of C, N, P and S. The metabolic quotient decreased with increasing residue return, indicating a more metabolically efficient microbial community. Fertilizer application resulted in a variable effect on enzyme activity. Long-term fertilizer application resulted in an increase in invertase and acid phosphatase, a decrease in L-histidase and arylsulphatase and had little effect on protease and alkaline phosphatase. These variable effects were explained in terms of an interaction between fertilizer - induced increases in Corg and soil nutrient status and fertilizer - induced soil acidification. The size and activity of the soil microbial biomass was studied in the plant row and in the inter-row of a sugarcane field under burning or green cane harvesting. Soils were sampled to 30 cm depth in (i) the centre of the plant row, (ii) 30 cm out from the row centre and (iii) 60 cm out from the row centre (i.e. the middle of the inter-row area). Under burning, the only substantial input of organic matter to the soil was from root turnover in the row area where the root biomass was concentrated. As a consequence, the size (microbial biomass C) and activity (basal respiration of the soil microbial community were concentrated in the row. However, under green cane harvesting there was a large input of organic matter in the inter-row area in the form of the trash blanket itself and through turnover of crop roots that were concentrated in the surface 10 cm of the soil below the blanket. As a result, soil microbial activity was considerably higher in the interrow area under green cane harvesting than under burning. Phospholipids are essential membrane components of microorganisms and a good correlation was found between the total PLFA's extracted from soils and the microbial biomass C, indicating that phospholipids are an accurate measurement of living biomass. Mutivariate statistical analysis (PCA) was used to separate different PLFA profiles under burning versus trash retention and under different land uses (sugarcane, maize, annual and perennial pasture and undisturbed veld). Soil organic matter content contributed the greatest variance in the data along the first axis. That is increasing soil organic matter return not only increased the size of the microbial biomass, but also affected the composition of the microbial community. There was a shift in the different sub-fractions under different management practices. MUFA's are general biomarkers of Gram negative bacteria and were found to be a sensitive indicator of higher substrate availability (i.e they increased under green cane harvesting). Fungal biomarkers indicated an increased fungal biomass associated with surface application of residues. Soil physical conditions were considered to be a contributing factor to the shift in microbial community structure. Increased organic matter content improved soil physical conditions and preferentially stimulated the growth of aerobic microorganisms. In addition to this, the proportion of SATFA (gram positive bacteria) was found to increase in response to burning. This increase was attributed to the survival mechanisms of these microorganisms (i.e. endospore formation). It was found that the conversion from burning to trash management changes the composition of the soil microbial community. The effect of management practices on soil functional diversity was also evaluated using two methods (i.e. Biolog plates and substrate induced respiration (SIR)). Biolog plates are a selective technique that stimulate growth of a small proportion of the soil microbial community whereas the SIR technique measures the activity of the metabolically active microbial community in situ. As a result the SIR method separated treatments more effectively than Biolog plates (i.e. annually tilled treatments, permanent grassland sites and fertilized and unfertilized treatments). The quantity and the quality of organic C supply influenced the catabolic diversity. Conversion from burning to green cane harvesting greatly increased catabolic evenness and richness and therefore presumably also tended to increase the resilience of the soil to stress and disturbance particularly in relation to decomposition functions. It was concluded that conversion from preharvest burning to green cane harvesting results in an increase in soil organic matter content, an improvement in soil structure and soil nutrient status, an increase in the size, activity, taxonomic and functional diversity of the soil microbial community. The practice should therefore be promoted to the South African sugar industry.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Azooz, Rahman Hassan. "Influence of crop residue management and tillage on soil thermal and moisture regimes and corn growth." 1991. http://catalog.hathitrust.org/api/volumes/oclc/25645876.html.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--University of Wisconsin--Madison, 1991.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Meints, Paul David. "Physiological responses of creeping red fescue to stubble management and plant growth regulators." Thesis, 1997. http://hdl.handle.net/1957/33990.

Повний текст джерела

Анотація:

Legislation to reduce open field burning in grass seed fields within the Willamette valley of western Oregon changed established production practices. In the creeping grasses such as Kentucky bluegrass (Poa pratensis L.) and creeping red fescue (Festuca rubra L.) non-thermal management resulted in reduced yield. Studies were conducted to examine the effects of three stubble height treatments in comparison to open field burning in creeping red fescue seed production. The effects of light quality on characteristics of plant development were investigated in field and controlled environments. Exogenous applications of plant growth regulators (PGR's) were made to elucidate the causes of low seed yields observed without burning. Field plots were prepared in fall of 1994, and 1995 in creeping red fescue commercial production fields as well as at Hyslop research farm in 1995. Three cultivars were included in the trial; Shademaster and Hector, which produce many rhizomes, and Seabreeze which produces few rhizomes. The effects of stubble height, PGRs, and field burning were measured during fall regrowth and flowering. Non-structural carbohydrates available for early regrowth were reduced when stubble was removed below 5.0 cm, particularly in first-year stands. Fall tiller height was increased by stubble remaining and was negatively correlated with flowering. Rhizome development was reduced when stubble was removed mechanically or burned to the crown, whereas yield potential was increased. Fall ethylene application reduced fall tiller height, fall tiller number, and percent fertile tillers the following spring and was similar to control treatment compared with burn. Other PGRs did not produce consistent results in this study. Excess ethylene produced by decaying stubble may impact floral induction and reduce yield potential in creeping red fescue seed crops. Light quality as measured by red:far-red ratio (R:FR) was reduced by canopy closure during regrowth but not by the presence of stubble. In controlled environment studies, red light (R) promoted taller tillers, greater stage of development, and greater tiller number than far-red (FR) light. Sunlight enriched with FR completely inhibited rhizome formation. Results suggest that environments with excess reflected FR may negatively impact early development of creeping red fescue seed crops.
Graduation date: 1998

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Schumacher, Derek David. "Residue management and yield characteristics of fine fescue seed crops." Thesis, 2005. http://hdl.handle.net/1957/29436.

Повний текст джерела

Анотація:

Chewings fescue [Festuca rubra L. subsp. fallax (Thuill.) Nyman] is a desired turfgrass with dense sod forming capabilities and superior shade tolerance. Thermal residue management (open-field burning) has traditionally been used to remove post-harvest residue and maintain seed yield over the life of the stand. However, alternative non-thermal residue management practices have been observed to produce adequate seed yields dependent upon cultivar. Strong creeping red fescue (F. rubra L. subsp. rubra) is desired for its prolific tillering capacity and creeping rhizomatous growth habit. In contrast to Chewings fescue, maintenance of seed yield in strong creeping red fescue has only been profitably produced under thermal residue management. Slender creeping red fescue [F. rubra L. var. littoralis (Vasey)] is a desired turfgrass with a compact, less rhizomatous growth habit, similar to Chewings fescue in desirable turf attributes. However, little is known about the effects of post-harvest residue management in slender creeping red fescue. The objectives of this study were: 1) to evaluate seed yield and yield components among different cultivars to thermal (open-burning), and non-thermal (flail low and flail high) post-harvest residue management; 2) to evaluate harvest index and percent cleanout to thermal and non-thermal residue management in different cultivars; and 3) and to provide an economic analysis of thermal and non-thermal residue management in all cultivars based on partial budgeting. Three post-harvest residue management treatments (burn, flail low and flail high) were applied over the course of two years. Seed yield components measured included: total dry weight, fertile tiller number, spikelets per panicle, florets per spikelet, and panicle length. Final seed yield in each cultivar and residue management treatment method was determined after seed harvest and conditioning. Seed yield component analysis was conducted over three production seasons. Chewings fescue, strong creeping red fescue, and slender creeping red fescue cultivars responded differently to residue management as indicated by a residue management by cultivar interaction. In 2003 and 2004, residue management by cultivar interactions were evident in seed number, seed weight, fertile tiller number, percent cleanout, harvest index, and seed yield. Residue management by cultivar interactions occurred in spikelets per panicle in 2003, whereas in 2004 a residue management by cultivar interaction occurred in panicle length and florets per spikelet. In 2004, non-thermal flail low, and thermal residue management resulted in significantly greater spikelets per panicle in all cultivars. Thermal residue management resulted in the greatest number of spikelets per panicle. Results indicate that thermal residue management best maintained seed yield in most subspecies and cultivars across both years. However, in 2003, non-thermal flail low residue management produced profitable seed yield in only Marker slender creeping red fescue. In contrast, thermal residue management resulted in poor seed yields in Marker slender creeping red fescue and enhanced yields in Seabreeze slender creeping red fescue in 2003. However, following the second year of thermal treatment in 2004, Marker and Seabreeze both had lower seed yields, thus exhibiting the only negative impact of thermal management among the cultivars tested in this study. Moreover, upon review of an economic analysis, Marker slender red fescue was the only cultivar that produced a positive net return of $78 and $4 ha⁻¹ under non-thermal residue management in 2003 and 2004, respectively. Furthermore, in 2003, thermal residue management net return increases ranged from $104 ha⁻¹ to -$996 ha⁻¹ in Barnica and Shademark, respectively. In 2004, thermal residue management net return increases ranged from $115 ha⁻¹ and $1,332 ha⁻¹ in Seabreeze and Shademark, respectively. Poor seed yields were observed in all strong creeping red fescue cultivars under non-thermal residue management across both years of the study. This may be attributed to an observed reduction in fertile tiller number and seed yield. In addition, percent seed cleanout was increased with non-thermal residue management. In 2004, as stand age increased, thermal residue management resulted in greater seed yields in all cultivars and species, except both cultivars of slender creeping red fescue. Thus, this study provided substantial evidence that thermal residue management has the potential to maintain or increase fine fescue seed yield as stands age as well as to maintain stand profitability.
Graduation date: 2005

Стилі APA, Harvard, Vancouver, ISO та ін.

42

McKeown, Steven. "Discrimination of Agricultural Land Management Practices using Polarimetric Synthetic Aperture RADAR." Thesis, 2012. http://hdl.handle.net/10214/3901.

Повний текст джерела

Анотація:

This thesis investigates the sensitivity and separability of post-harvest tillage conditions using polarimetric Synthetic Aperture RADAR in southwestern Ontario. Variables examined include: linear polarizations HH, HV, and VV and polarimetric variables: pedestal height, co-polarized complex correlation coefficient magnitude, left and right co-polarized circular polarizations and co-polarized phase difference. Six fine-quad polarimetric, high incidence angle (49°) RADARSAT-2 images acquired over three dates in fall 2010 were used. Over 100 fields were monitored, coincident with satellite overpasses. OMAFRA’s AgRI, a high-resolution polygon network was used to extract average response from fields. Discrimination between tillage practices was best later in the fall season, due to sample size and low soil moisture conditions. Variables most sensitive to tillage activities include HH and VV polarizations and co-polarized complex correlation coefficient magnitude. A supervised support vector machine (SVM) classifier classified no-till and conventional tillage with 91.5% overall accuracy. These results highlight the potential of RADARSAT-2 for monitoring tillage conditions.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Schuster, Matthew D. "Annual bluegrass (Poa annua L.) emergence under different residue management practices in perennial ryegrass and determination of resistant and susceptible annual bluegrass germination under controlled temperature and moisture." Thesis, 1999. http://hdl.handle.net/1957/29112.

Повний текст джерела

Анотація:

With the loss of field burning the amount of crop residue that remains in perennial ryegrass fields has increased. As the amount of crop residue remaining in the field increases so does annual bluegrass. This has resulted in the increased use of herbicides to control annual bluegrass. However, this increased use has also resulted in herbicide-resistant annual bluegrass. Field experiments were initiated in 1997 to investigate residue management options available to growers and their impacts on annual bluegrass emergence. Two sites, Glaser and Wirth, were established with three residue management treatments replicated four times. The treatments included full-straw, bale/flail, and vacuum sweep. Perennial ryegrass seed yield and annual bluegrass seed contamination were evaluated. The vacuum sweep treatment had lower annual bluegrass emergence than the full-straw or the bale/flail treatments during the 1997-98 growing season, for both sites. The fall of 1998 was much drier than the fall of 1997. Annual bluegrass emergence in all plots was lower in 1998 than in 1997 because of the dry conditions. Fall emergence in 1998 was higher in the vacuum sweep treatment than in the other two treatments, which may have been the result of better soil-seed contact in the vacuum sweep treatment. Lower emergence in the spring at the Wirth site compared to the Glaser site may have been due to narrow crop row spacing and cultivar selection, which shaded the annual bluegrass. When growing seasons were combined, there were no treatment differences. However, more emergence was observed in the spring at the Glaser site compared to the Wirth site. Yield was highest for the vacuum sweep treatment at the Glaser site in the 1998-99 growing season. However, competition from volunteer perennial ryegrass in the full-straw and bale/flail treatments could have accounted for this increase. No other differences in yield and no difference in contamination among treatments were observed. However, contamination at the Glaser site was higher in the 1998-99 growing season than in the 1997-98 growing season. Experiments were conducted in growth chambers to determine how differing environmental conditions affect seed germination of diuron-susceptible and diuron-resistant annual bluegrass. Cumulative germination for the susceptible-biotype decreased from 96% to 88% while the resistant-biotype remained above 95% as temperature decreased from 3 0/20 C to 10/2 C. The susceptible-biotype germinated sooner than the resistant-biotype regardless of temperature. The susceptible-biotype had a higher rate of germination than the resistant-biotype at 30/20 C, but not when the temperature decreased to 10/2 C. Germination response to differing matric potentials did not vary much within a biotype for a given soil type and temperature. Therefore, parameters estimated at -1.03 MPa were chosen to contrast susceptible- and resistant biotypes, and soil types, for each temperature. Maximum cumulative germination was greater than 96% for all treatments. When germination on a given soil type was contrasted, differences were only seen for the susceptible biotype vs. resistant biotype on Dayton soil; and the resistant biotype on Dayton soil vs. resistant biotype on Woodburn soil at both temperatures. The lag in onset of germination was shorter for the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil than the resistant biotype on Dayton soil at 30/20 C. At 18/5 C, the lag in onset of germination was shorter for the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil than the resistant biotype on Dayton soil (P = 0.000 1 and 0.0001, respectively). But the rate of germination was faster for the resistant biotype on Dayton soil than both the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil at 18/5 C (P = 0.02 and 0.0004, respectively). The rate of germination did not differ at 3 0/20 C. When just the soils were contrasted, at 18/5 C all annual bluegrass seeds on the Woodburn soil germinated sooner and the rate of germination was higher than on the Dayton soil. These results indicate that the hydraulic properties of the soils may influence germination. However, this was not observed at 30/20 C. The results suggest that the susceptible-biotype was more sensitive to temperature while the resistant-biotype was more sensitive to moisture. Changing crop management in ways that will reduce annual bluegrass emergence and establishment is needed. By altering management strategies, growers may obtain more efficient and effective use of herbicides, while reducing the selection of herbicide-resistant annual bluegrass.
Graduation date: 2000

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Rietz, Diana Nicolle. "The effects of compaction and residue management on soil properties and growth of Eucalyptus grandis at two sites in KwaZulu-Natal, South Africa." Thesis, 2010. http://hdl.handle.net/10413/726.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Christ, Robert A. "Effects of long-term residue management and nitrogen fertilization on availability and profile distribution of nitrogen, phosphorus, and sulfur." Thesis, 1992. http://hdl.handle.net/1957/36465.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Zapiola, Maria Luz. "Trinexapac-ethyl and open-field burning in creeping red fescue (Festuca rubra L.) seed production in the Willamette Valley." Thesis, 2004. http://hdl.handle.net/1957/29428.

Повний текст джерела

Анотація:

Open-field burning has been an effective, economical, and widespread method of post-harvest residue management in creeping red fescue seed production in the Willamette Valley since the late 1940s. However, the use of field burning has been legislatively restricted due to air quality and safety issues. The foliar-applied plant growth regulator trinexapac-ethyl (TE), commercialized in the USA as Palisade, has been accepted by producers as a yield enhancing agent and is considered here as an alternative to open-field burning over a four-year period. The effects of open-field burning versus mechanical removal (flailing) of post-harvest residue, and spring versus fall applications of TE on seed yield, dry matter partitioning, and seed yield components were evaluated in a split-plot design. The response to the different treatment combinations differed across years. The young stand responded with a seed yield increase to spring TE applications, regardless of residue management treatment. However, as the stand aged, field burning became critical for maintaining high yields and, in 2003 and 2004, only spring TE applications resulted in seed yield increases in burned plots. The higher potential seed yield achieved in burned plots over flailed plots, as a result of a higher number of panicles per unit area and spikelets per panicle, was critical for maintaining high seed yields as the stand aged. Spring applications of TE, further increased seed yield over the untreated check by increasing the number of florets per spikelet, reducing fertile tiller height and lodging and consequently, favoring pollination and fertilization of the florets. Late spring TE applications also increased 1000-seed weight in 2003 and 2004. Although spring applications of TE were a promising alternative to open-field burning early during the life of the stand, as the stand aged they did not increase seed yield on flailed plots. Fall TE applications did not have a consistent effect on seed yield, dry matter partitioning or seed yield components, and were found not to be a viable management practice.
Graduation date: 2005

Стилі APA, Harvard, Vancouver, ISO та ін.

Дисертації з теми "Crop residue management Australia"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями