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Kufimfutu, Bakelana ba. "Crop planting pattern effects on crop and weed growth /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487778663287222.
Pełny tekst źródłaÅström, Petter. "Cash crops vs food crops : A case study of household's crop choices in Babati District". Thesis, Södertörn University College, School of Life Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-2605.
Pełny tekst źródłaAccording to earlier research farmer's crop orientation in developing countries mainly depends on farm size, large-scale farmers prefer cash crop while small-scale farmers prefer subsistence crops. The first aim of this study is to see if this hypothesis can be applied on six households in Babati District in rural Tanzania. The second aim is to investigate if other factors than farm size affect crop portfolio choice and the final aim is to see if those crop portfolio models can be improved. A case-study research design and qualitative interviews are used. The primary data is based on a fieldwork that took place from the 18th of February until the 7th of March 2009 in the study area.
From a theoretical perspective the underlying assumptions of the Marcel Fafchamp's model Crop portfolio choice under multivariate risks is discussed in connection to the result of the study.
Interviews were made with six households of different farm size. The result of the study indicates that both small-scale and large-scale farmers are using cash crops. The fact that all crops can be used for selling, gives also small-scale farmers in season with higher prices, an opportunity to sell a large share of their crops. It's thereby not possible to state that large-scale farmers devote a larger share of their land for cash crop than small-scale farmers do.
Subedi-Chalise, Kopila. "Impacts of Crop Residue and Cover Crops on Soil Hydrological Properties, Soil Water Storage and Water Use Efficiency of Soybean Crop". Thesis, South Dakota State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10265200.
Pełny tekst źródłaCover crops and crop residue play a multifunctional role in improving soil hydrological properties, soil water storage and water use efficiency (WUE). This study was conducted to better understand the role of crop residue and cover crop on soil properties and soil water dynamics. The study was conducted at the USDA-ARS North Central Agricultural Research Laboratory, located in Brookings, South Dakota. Two residue removal treatments that include low residue removal (LRR) and high residue removal (HRR) were established in 2000 with randomized complete block design under no-till corn (Zea mays L.) and soybean (Glycine max L.) rotation. In 2005, cover crop treatments which include cover crops (CC) and no cover crops (NCC) were integrated into the overall design. Soil samples were collected in 2014, 2015 and 2016. Data from this study showed that LRR treatment resulted in lower bulk density (BD) by 7 and 9% compared to HRR in 2015 and 2016, respectively, for 0-5 cm depth. Similarly, LRR treatment significantly reduced soil penetration resistance (SPR) by 25% in 0-5 cm depth compared with HRR treatment. In addition to this, LRR treatment significantly increased soil organic carbon (SOC) concentrations and total nitrogen (TN) by 22 and 17%, respectively, in 0-5 cm. Similarly, CC treatment resulted in lower BD and SPR by 7% and 23%, respectively, in 0-5 cm depth in 2015 compared with NCC treatment. The LRR significantly increased soil water infiltration by 66 and 22% compared to HRR in 2014 and 2015, respectively. Similarly, the CC treatment significantly increased infiltration by 82 and 22% compared to the NCC in 2014 and 2015, respectively. The significant impact of a crop residue was observed on soil water retention (SWR) in 2014 and 2015 for the 0-5 cm depth. The LRR and CC treatments increased the soil volumetric moisture content (VMC) and soil water storage (SWS) on the surface 0-5 cm depth. However, the trend was not always significant during the growing season. The CC treatment significantly impacted the soybean yield by 14% and WUE by 13% compared with NCC treatment. Some interaction of residue by cover crops was observed on BD, SPR, VMC, and SWS, which showed that the use of cover crops with LRR can be beneficial in improving the soil properties.
Ramirez, Almeyda Jacqueline <1985>. "Lignocellulosic Crops in Europe: Integrating Crop Yield Potentials with Land Potentials". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7854/1/Tesi_J.Ramirez_2017_Lignocellulosic%20crops%20potentials%20in%20EU.pdf.
Pełny tekst źródłaMurphy, Donal Patrick Lee. "Crop structure and crop productivity in winter barley, (Hordeum sativum)". Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262202.
Pełny tekst źródłaPerkins, Seth A. "Crop model review and sweet sorghum crop model parameter development". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14037.
Pełny tekst źródłaDepartment of Biological and Agricultural Engineering
Kyle Douglas-Mankin
Opportunities for alternative biofuel feedstocks are widespread for a number of reasons: increased environmental and economic concerns over corn production and processing, limitations in the use of corn-based ethanol to 57 billion L (15 billion gal) by the Energy Independence and Security Act (US Congress, 2007), and target requirements of 136 billion L (36 billion gal) of renewable fuel production by 2022. The objective of this study was to select the most promising among currently available crop models that have the potential to model sweet sorghum biomass production in the central US, specifically Kansas, Oklahoma, and Texas, and to develop and test sweet sorghum crop parameters for this model. Five crop models were selected (CropSyst, CERE-Sorghum, APSIM, ALMANAC, and SORKAM), and the models were compared based on ease of use, model support, and availability of inputs and outputs from sweet sorghum biomass data and literature. After reviewing the five models, ALMANAC was selected as the best suited for the development and testing of sweet sorghum crop parameters. The results of the model comparison show that more data are needed about sweet sorghum physiological development stages and specific growth/development factors before the other models reviewed in this study can be readily used for sweet sorghum crop modeling. This study used a unique method to calibrate the sweet sorghum crop parameter development site. Ten years of crop performance data (Corn and Grain Sorghum) for Kansas Counties (Riley and Ellis) were used to select an optimum soil water (SW) estimation method (Saxton and Rawls, Ritchie et al., and a method that added 0.01 m m [superscript]-1 to the minimum SW value given in the SSURGO soil database) and evapotranspiration (ET) method (Penman-Montieth, Priestley-Taylor, and Hargraeves and Samani) combination for use in the sweet sorghum parameter development. ALMANAC general parameters for corn and grain sorghum were used for the calibration/selection of the SW/ET combination. Variations in the harvest indexes were used to simulate variations in geo-climate region grain yield. A step through comparison method was utilized to select the appropriate SW/ET combination. Once the SW/ET combination was selected the combination was used to develop the sweet sorghum crop parameters. Two main conclusions can be drawn from the sweet sorghum crop parameter development study. First, the combination of Saxton and Rawls (2006) and Priestley-Taylor (1972) (SR-PT) methods has the potential for wide applicability in the US Central Plains for simulating grain yields using ALMANAC. Secondly, from the development of the sweet sorghum crop model parameters, ALMANAC modeled biomass yields with reasonable accuracy; differences from observed biomass values ranged from 0.89 to 1.76 Mg ha [superscript]-1 (2.8 to 9.8%) in Kansas (Riley County), Oklahoma (Texas County), and Texas (Hale County). Future research for sweet sorghum physiology, Radiation Use Efficiency/Vapor Pressure Deficit relationships, and weather data integration would be useful in improving sweet sorghum biomass modeling.
Schmitz, Austin. "Row crop navigation by autonomous ground vehicle for crop scouting". Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36237.
Pełny tekst źródłaDepartment of Biological & Agricultural Engineering
Daniel Flippo
Robotic vehicles have the potential to play a key role in the future of agriculture. For this to happen designs that are cost effective, robust, and easy to use will be necessary. Robotic vehicles that can pest scout, monitor crop health, and potentially plant and harvest crops will provide new ways to increase production within agriculture. At this time, the use of robotic vehicles to plant and harvest crops poses many challenges including complexity and power consumption. The incorporation of small robotic vehicles for monitoring and scouting fields has the potential to allow for easier integration of robotic systems into current farming practices as the technology continues to develop. Benefits of using unmanned ground vehicles (UGVs) for crop scouting include higher resolution and real time mapping, measuring, and monitoring of pest location density, crop nutrient levels, and soil moisture levels. The focus of this research is the ability of a UGV to scout pest populations and pest patterns to complement existing scouting technology used on UAVs to capture information about nutrient and water levels. There are many challenges to integrating UGVs in conventionally planted fields of row crops including intra-row and inter-row maneuvering. For intra-row maneuvering; i.e. between two rows of corn, cost effective sensors will be needed to keep the UGV between straight rows, to follow contoured rows, and avoid local objects. Inter-row maneuvering involves navigating from long straight rows to the headlands by moving through the space between two plants in a row. Oftentimes headland rows are perpendicular to the row that the UGV is within and if the crop is corn, the spacing between plants can be as narrow as 5”. A vehicle design that minimizes or eliminates crop damage when inter-row maneuvering occurs will be very beneficial and allow for earlier integration of robotic crop scouting into conventional farming practices. Using three fixed HC-SR04 ultrasonic sensors with LabVIEW programming proved to be a cost effective, simple, solution for intra-row maneuvering of an unmanned ground vehicle through a simulated corn row. Inter-row maneuvering was accomplished by designing a transformable tracked vehicle with the two configurations of the tracks being parallel and linear. The robotic vehicle operates with tracks parallel to each other and skid steering being the method of control for traveling between rows of corn. When the robotic vehicle needs to move through narrow spaces or from one row to the next, two motors rotate the frame of the tracks to a linear configuration where one track follows the other track. In the linear configuration the vehicle has a width of 5 inches which allows it to move between corn plants in high population fields for minimally invasive maneuvers. Fleets of robotic vehicles will be required to perform scouting operations on large fields. Some robotic vehicle operations will require coordination between machines to complete the tasks assigned. Simulation of the path planning for coordination of multiple machines was studied within the context of a non-stationary traveling salesman problem to determine optimal path plans.
Watt, J. "3D crop modelling". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1421425/.
Pełny tekst źródłaPotter, Mark. "Biochemical studies of tissue glucosinolates for improvement of canola (Brassica napus) as a disease break within the southern Australian cereal rotation /". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09php8678.pdf.
Pełny tekst źródłaThesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1999? Bibliographical references: leaves 112-125.
Arnet, Kevin Broc. "Cover crops in no-tillage crop rotations in eastern and western Kansas". Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4086.
Pełny tekst źródłaEss, Daniel R. "Cover crop residue effects on machine-induced soil compaction". Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-164819/.
Pełny tekst źródłaBalnytė, Skirmantė. "Agroecosystem Optimization by Crop Rotation, Catch Crop and Manure in Organic Farming". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20110902_143932-39161.
Pełny tekst źródłaAgroekosistemų optimizavimo augalų kaita, tarpiniais pasėliais ir organinėmis trąšomis ekologinėje žemdirbystėje tyrimai vykdyti 2004–2009 m., Lietuvos žemės ūkio universiteto Bandymų stotyje, sertifikuotame ekologinės žemdirbystės lauke, karbonatingame sekliai glėjiškame išplautžemyje (IDg8-k) – Calcari-Epihypogleyic Luvisol (LVg-p-w-cc). Tyrimų hipotezė. Optimizuoti agroekosistemas ekologinėje žemdirbystėje galima taikant priemonių kompleksą: parenkant sėjomainas su skirtinga azotą fiksuojančių augalų dalimi, auginant tarpinius pasėlius bei tręšiant organinėmis trąšomis. Tyrimų tikslas – įvertinti agroekosistemų optimizavimo galimybes ekologinėje žemdirbystėje derinant sėjomainas su skirtinga azotą fiksuojančių augalų dalimi, auginant tarpinius pasėlius ir tręšiant organinėmis trąšomis. Tyrimų uždaviniai: Ištirti sėjomainų su skirtinga azotą fiksuojančių augalų dalimi, tarpinių pasėlių ir tręšimo organinėmis trąšomis įtaką: 1. dirvožemio fermentų aktyvumui; 2. dirvožemio agrocheminėms savybėms ir azoto balansui; 3. pasėlių piktžolėtumui; 4. dirvožemio armens užteršimui piktžolių sėklomis; 5. augalų derlingumui ir bendrosios energijos kiekiui. Mokslinio darbo naujumas. Ekologinės žemdirbystės sąlygomis kompleksiškai įvertintas sėjomainų su skirtinga azotą fiksuojančių augalų dalimi, tarpinių pasėlių bei tręšimo organinėmis trąšomis poveikis agroekosistemoms. Tai suteikia naujų žinių apie potencialaus dirvožemio derlingumo palaikymo, pasėlių ir dirvos piktžolėtumo kontrolės... [toliau žr. visą tekstą]
Key, Georgina. "Cross-crop benefits : developing crop combinations to promote conservation biological pest control". Thesis, Lancaster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658572.
Pełny tekst źródłaGayam, Narsi Reddy. "Risk in agriculture : a study of crop yield distributions and crop insurance". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35537.
Pełny tekst źródłaIncludes bibliographical references (leaves 52-53).
Agriculture is a business fraught with risk. Crop production depends on climatic, geographical, biological, political, and economic factors, which introduce risks that are quantifiable given the appropriate mathematical and statistical methodologies. Accurate information about the nature of historical crop yields is an important modeling input that helps farmers, agribusinesses, and governmental bodies in managing risk and establishing the proper policies for such things as crop insurance. Explicitly or implicitly, nearly all farm decisions relate in some way to the expectation of crop yield. Historically, crop yields are assumed to be normally distributed for a statistical population and for a sample within a crop year. This thesis examines the assumption of normality of crop yields using data collected from India involving sugarcane and soybeans. The null hypothesis (crop yields are normally distributed) was tested using the Lilliefors method combined with intensive qualitative analysis of the data. Results show that in all cases considered in this thesis, crop yields are not normally distributed.
(cont.) This result has important implications for managing risk involving sugarcane and soybeans grown in India. The last section of this thesis examines the impact of crop yield non normality on various insurance programs, which typically assume that all crop yields are normally distributed and that the probability of crop failure can be calculated given available data.
by Narsi Reddy Gayam.
M.Eng.in Logistics
Lena, Bruno Patias. "Crop evapotranspiration and crop coefficient of jatropha from first to fourth year". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-06012017-111443/.
Pełny tekst źródłaA determinação de coeficiente de cultivo (Kc) com metodologia adequada é essencial para quantificar o consumo hídrico de cultivos em diferentes regiões. Valores de Kc do pinhão-manso (Jatropha curcas L.) ainda não foram determinados e essa informação é muito importante para auxiliar o manejo de irrigação de maneira adequada. O objetivo desse estudo foi determinar a evapotranspiração (ETc) e Kc do 1º ao 4º ano de cultivo do pinhão-manso, e correlacionar Kc com o índice de área foliar (IAF) e a soma da unidade térmica (SUT). O experimento foi realizado de março de 2012 à agosto de 2015 na Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ)/Universidade de São Paulo (USP), na cidade de Piracicaba, SP, Brasil. O experimento foi divido nos tratamentos irrigados por pivô central, gotejamento e sem irrigação. Foram utilizados dois lisímetros de pesagem (12 m2 de superfície em cada lisímetro) por tratamento para realizar a determinação de ETc (uma planta por lisímetros). A evapotranspiração de referência (ET0) foi determinado pelo método de Penman-Monteith a partir de dados meteorológicos coletados na estação meteorológica localizada ao lado do experimento. Valores diários de Kc foram determinados nos tratamentos irrigados pela razão entre ETc e ET0 (Kc=ETc/ET0). IAF foi determinado utilizando o equipamento LAI-2200 Plant Canopy Analyzer, que foi previamente calibrado para adequar as características do dossel do pinhão-manso. Em todos os anos avaliados, o IAF foi quase zero durante o início do período vegetativo, aumentando os valores conforme a planta começou a se desenvolver até atingir valores máximos durante o período produtivo, decrescendo os valores até zero no estádio de desenvolvimento de senescência foliar. A variação anual de ETc no 2º, 3º e 4º ano foi muito similar, explicado pelos diferentes períodos de desenvolvimento da cultura e a variação de IAF no ano. No 1º ano, Kc foi 0,47 para os dois tratamentos irrigados. No 2º, 3º e 4º ano, Kc variou de 0,15 a 1,38 no tratamento irrigado por pivô central e de 0,15 a 1,15 no tratamento irrigado por gotejamento. A média dos valores de Kc no 2º, 3º e 4º ano durante os períodos vegetativos e produtivos foi de 0,77, 0,93 e 0,82 no tratamento irrigado por pivô central, respectivamente, e 0,69, 0,79 e 0,74 no tratamento irrigado por gotejamento, respectivamente. A relação entre Kc e IAF mostrou, para o tratamento irrigado por pivô central, um ajuste logaritmo com coeficiente de determinação (R2) e somatória do erro médio ao quadrado (SEMQ) de 0,7643 e 0,334, respectivamente, e 0,8443 e 0,2079 para o tratamento irrigado por gotejamento, respectivamente. Nos três anos analisados, Kc correlacionado com SUT mostrou o melhor ajuste à equação polinomial de 2ª ordem para os dois tratamentos.
Alexander, Peter Mark William. "Modelling the UK perennial energy crop market". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9645.
Pełny tekst źródłaMyers, Brian. "Variable crop residue management". Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/35271.
Pełny tekst źródłaDepartment 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.
Silvertooth, Jeffrey C. "Early Season Crop Management". College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/558539.
Pełny tekst źródła2 pp.
The approaches and techniques used to produce a cotton crop in Arizona can vary to some degree from county to county, or from farm to farm. However, one of the objectives that has become increasingly common across Arizona is that of achieving earliness with a crop.
Watson, J., i M. Sheedy. "Crop Water Use Estimates". College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/210312.
Pełny tekst źródłaJones, Jennifer S., John C. Palumbo i Peter C. Ellsworth. "Arizona Crop Information Site". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/215239.
Pełny tekst źródłaMallory, Ellen B. "Crop/Livestock Integration Effects on Soil Quality, Crop Production, and Soil Nitrogen Dynamics". Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/MalloryEB2007.pdf.
Pełny tekst źródłaMditshwa, Sithembele. "Estimating maize grain yield from crop growth stages using remote sensing and GIS in the Free State Province, South Africa". Thesis, University of Fort Hare, 2017. http://hdl.handle.net/10353/6016.
Pełny tekst źródłaCastellazzi, M. S. "Spatio-temporal modelling of crop co-existence in European agricultural landscapes". Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/3747.
Pełny tekst źródłaIsaac, 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.
Pełny tekst źródłaZhen, Chen. "Celestial satellite and earthly crop yield: informational content of satellite-based crop yield forecasts". Thesis, Montana State University, 2001. http://etd.lib.montana.edu/etd/2001/zhen/ZhenC2001.pdf.
Pełny tekst źródłaAl-Shammari, Dhahi Turki Jadah. "Remote sensing applications for crop type mapping and crop yield prediction for digital agriculture". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29771.
Pełny tekst źródłaDodds, Paul Edward. "Development of a crop model to examine crop management and climate change in Senegal". Thesis, University of Leeds, 2010. http://etheses.whiterose.ac.uk/1121/.
Pełny tekst źródłaPing, Zhang. "The partitioning of water loss between crop transpiration and soil evaporation in potato crops". Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303926.
Pełny tekst źródłaChristenson, Andi Marie. "Cover crops for horseweed [Conyza canadensis (L.)] control before and during a soybean crop". Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19230.
Pełny tekst źródłaDepartment of Agronomy
J. Anita Dille
Kraig Roozeboom
Increasing numbers of herbicide-resistant weed species require alternative methods of weed suppression to be examined. This study quantified the interaction between various cover crop or herbicide systems and horseweed [Conyza canadensis (L.)] growth. Fall cover crops of winter wheat [Triticum aestivum (L.)], winter rye [Secale cereal (L.)], barley [Hordeum vulgare (L.)] and annual ryegrass [Lolium multiflorum (L.)] were seeded in November 2012 and 2013. Spring cover crop of oat [Avena sativa (L.)] was seeded in April 2013 or rye was seeded in March 2014. All cover crops were no-till seeded into grain sorghum stubble [Sorghum bicolor (L.) Moench]. Four herbicide treatments were fall or spring applied, with and without residual. The spring non-residual treatment was also applied to plots of winter rye. Cover crop plots were split and terminated with a roller crimper or glyphosate application prior to soybean [Glycine max (L.) Merr.] planting to determine the effect of termination method on treatment performance. Soybean was planted in June 2013 and May 2014 and mechanically harvested in October of both years. Horseweed density, biomass accumulation, and soybean yield data were quantified. Horseweed height, whole plant seed production, and seed subsamples were recorded in the untreated fallow control, winter wheat, and winter rye plots in 2014. Horseweed suppression by winter rye approached 90%, levels similar to suppression by herbicide systems. In both years, herbicide plots had less than half the horseweed biomass than any of the cover crop systems. In 2013, soybean yields in herbicide plots were at least 1,500 kg ha[superscript]-1, nearly more than double yields in cover crop plots. Soybean yields in 2014 were more consistent across treatments; barley and spring rye plots achieved yields equal to or greater than 2,000 kg ha[superscript]-1. Winter rye and winter wheat reduced horseweed seed production by 60% compared to the untreated fallow control, with no effect on individual seed weight. Seed production varied across plants, with the untreated control producing the greatest number of seeds. Cover crops were successful at reducing horseweed biomass, suppressing horseweed pressure, preserving soybean biomass, and protecting soybean yields when compared to a fallow untreated control.
Addala, Venkata Krishna Raju. "Mining genes from crop genebanks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/MQ52868.pdf.
Pełny tekst źródłaLi, Bo. "Studies of weed-crop competition". Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262269.
Pełny tekst źródłaSongjang, Khemika. "Peptides to inhibit crop predation". Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428155.
Pełny tekst źródłaEndacott, Christopher John. "Studies on electrodynamic crop spraying". Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47423.
Pełny tekst źródłaHerse, Maria. "Crop improvement using synthetic variation". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607892.
Pełny tekst źródłaGelt, Joe. "Wanted: A Viable Biofuel Crop". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2007. http://hdl.handle.net/10150/622106.
Pełny tekst źródłaMunda, Bruce, Tim C. Knowles, Art Meen, Vic Wakimoto i Bill Worthy. "Winter Forage Cover Crop Trials". College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/208283.
Pełny tekst źródłaSilvertooth, J. C., P. W. Brown i J. E. Malcuit. "Basic Cotton Crop Development Patterns". College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208324.
Pełny tekst źródłaOppong-Konadu, Eden Y. "Evolution in genetically diverse populations of barley (Hordeum vulgare L.)". Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336773.
Pełny tekst źródłaWang, Dong. "Reducing the environmental risks and hazards of crop production by biosafe use of transgenic crops". Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511191.
Pełny tekst źródłaÖdegaard, Knut. "Cash crop versus food crop production in Tanzania an assessment of the major post-colonial trends /". Lund : [Dept. of Economics, University of Lund], 1985. http://catalog.hathitrust.org/api/volumes/oclc/18958128.html.
Pełny tekst źródłaHumble, Shauna Marie. "Weeds and ground beetles (Coleoptera: Carabidae) as influenced by crop rotation type and crop input management". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62758.pdf.
Pełny tekst źródłaAtkinson, Ross G. "Molecular approaches to horticultural crop improvement". Thesis, University of Auckland, 1993. http://hdl.handle.net/2292/1911.
Pełny tekst źródłaJagbrant, Gustav. "Autonomous Crop Segmentation, Characterisation and Localisation". Thesis, Linköpings universitet, Institutionen för systemteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-97374.
Pełny tekst źródłaEftersom fruktodlingar kräver stora markområden är de ofta belägna långt från större befolkningscentra. Detta gör det svårt att finna tillräckligt med arbetskraft och begränsar expansionsmöjligheterna. Genom att integrera autonoma robotar i drivandet av odlingarna skulle arbetet kunna effektiviseras och behovet av arbetskraft minska. Ett nyckelproblem för alla autonoma robotar är lokalisering; hur vet roboten var den är? I jordbruksrobotar är standardlösningen att använda GPS-positionering. Detta är dock problematiskt i fruktodlingar, då den höga och täta vegetationen begränsar användandet till större robotar som når ovanför omgivningen. För att möjliggöra användandet av mindre robotar är det istället nödvändigt att använda ett GPS-oberoende lokaliseringssystem. Detta problematiseras dock av den likartade omgivningen och bristen på distinkta riktpunkter, varför det framstår som osannolikt att existerande standardlösningar kommer fungera i denna omgivning. Därför presenterar vi ett GPS-oberoende lokaliseringssystem, speciellt riktat mot fruktodlingar, som utnyttjar den naturliga strukturen hos omgivningen.Därutöver undersöker vi och utvärderar tre relaterade delproblem. Det föreslagna systemet använder ett 3D-punktmoln skapat av en 2D-LIDAR och robotens rörelse. Först visas hur en dold semi-markovmodell kan användas för att segmentera datasetet i enskilda träd. Därefter introducerar vi ett antal deskriptorer för att beskriva trädens geometriska form. Vi visar därefter hur detta kan kombineras med en dold markovmodell för att skapa ett robust lokaliseringssystem.Slutligen föreslår vi en metod för att detektera segmenteringsfel när nya mätningar av träd associeras med tidigare uppmätta träd. De föreslagna metoderna utvärderas individuellt och visar på goda resultat. Den föreslagna segmenteringsmetoden visas vara noggrann och ge upphov till få segmenteringsfel. Därutöver visas att de introducerade deskriptorerna är tillräckligt konsistenta och informativa för att möjliggöra lokalisering. Ytterligare visas att den presenterade lokaliseringsmetoden är robust både mot brus och segmenteringsfel. Slutligen visas att en signifikant majoritet av alla segmenteringsfel kan detekteras utan att felaktigt beteckna korrekta segmenteringar som inkorrekta.
Artus, Sally. "VEGIGRO: a crop growth teaching model". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484201.
Pełny tekst źródłaAshby, Alison Mary. "Agrobacterium tumefaciens : chemotaxis and crop protection". Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6723/.
Pełny tekst źródłaAfreh-Nuamah, K. "Spray distribution in a tree crop". Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38212.
Pełny tekst źródłaAl-Azri, Masoud. "Modelling crop diseases for food security". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/44777/.
Pełny tekst źródłaBurns, James Ian. "Agricultural Crop Monitoring with Computer Vision". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/52563.
Pełny tekst źródłaMaster of Science
Shakoor, Arif. "Crop rotation planning using simulated annealing". Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-02232010-020018/.
Pełny tekst źródłaHusaker, Douglas, i Dale Bucks. "Crop Yield Variability in Irrigated Wheat". College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/200484.
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