Journal articles on the topic 'Soil treatment unit'
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1
Elkayam, R., M. Michail, O. Mienis, T. Kraitzer, N. Tal, and O. Lev. "Soil Aquifer Treatment as Disinfection Unit." Journal of Environmental Engineering 141, no. 12 (December 2015): 05015001. http://dx.doi.org/10.1061/(asce)ee.1943-7870.0000992.
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Kambulov, Sergey Ivanovich, and Igor Vladimirovich Bozhko. "AGGREGATE FOR COMBINED TREATMENT OF SOIL APK-4." Agrarian Scientific Journal, no. 9 (September 24, 2020): 78–82. http://dx.doi.org/10.28983/asj.y2020i9pp78-82.
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The article presents the results of experimental studies of the aggregate of tillage combined APK-4. During the research it was found that in terms of quality indicators, the unit at a working speed of 9.8 km/h withstands an installation processing depth of 12-14 cm. According to energy indicators, the traction resistance of the APK-4 machine in the unit with the K-701 tractor was 48.2 kN, and the specific energy consumption amounted to 123.5 MJ/ha. According to operational and technological indicators, the productivity per hour of the main time is 3.82 ha with the operating speed of the unit 2.72 m/s (9.8 km/h). The replaceable productivity in this case amounted to 2.10 ha/h, while the operational productivity of the unit at the same time amounted to 2.07 ha/h.
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Салахов, Ильнур, and Ilnur Salakhov. "AGROTECHNICAL ASPECTS OF THE WORKING UNIT APPLICATION FOR UNDERGROUND SOIL TREATMENT." Vestnik of Kazan State Agrarian University 12, no. 3 (January 11, 2018): 82–85. http://dx.doi.org/10.12737/article_5a1d9aa31ec6e6.52700948.
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Abstract. The subsoiling tillage is aimed at weakening the surface runoff of water and transferring it to the subsurface. The main methods of non-plowing treatment are subsoiling, flat and chisel processing, milling, chinking, deepening of the arable layer of the soil. However, the working units of existing tools for subsoiling tillage do not provide sufficient accumulation and preservation of moisture in the soil, its optimum density for the development of the root system of plants, and are characterized by increased energy intensity. This article presents the agrotechnical aspects of subsoiling, which contributes to a decrease in the development of erosion processes and an increase in moisture accumulation in the soil in conditions of a deficiency in soil moisture. The description of the soil-cultivating tool with working units of drive action is given. The results of the influence of the proposed treatment method on the agrotechnical indices of the soil are obtained.
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Kaplan, Christopher W., and Christopher L. Kitts. "Bacterial Succession in a Petroleum Land Treatment Unit." Applied and Environmental Microbiology 70, no. 3 (March 2004): 1777–86. http://dx.doi.org/10.1128/aem.70.3.1777-1786.2004.
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ABSTRACT Bacterial community dynamics were investigated in a land treatment unit (LTU) established at a site contaminated with highly weathered petroleum hydrocarbons in the C10 to C32 range. The treatment plot, 3,000 cubic yards of soil, was supplemented with nutrients and monitored weekly for total petroleum hydrocarbons (TPH), soil water content, nutrient levels, and aerobic heterotrophic bacterial counts. Weekly soil samples were analyzed with 16S rRNA gene terminal restriction fragment (TRF) analysis to monitor bacterial community structure and dynamics during bioremediation. TPH degradation was rapid during the first 3 weeks and slowed for the remainder of the 24-week project. A sharp increase in plate counts was reported during the first 3 weeks, indicating an increase in biomass associated with petroleum degradation. Principal components analysis of TRF patterns revealed a series of sample clusters describing bacterial succession during the study. The largest shifts in bacterial community structure began as the TPH degradation rate slowed and the bacterial cell counts decreased. For the purpose of analyzing bacterial dynamics, phylotypes were generated by associating TRFs from three enzyme digests with 16S rRNA gene clones. Two phylotypes associated with Flavobacterium and Pseudomonas were dominant in TRF patterns from samples during rapid TPH degradation. After the TPH degradation rate slowed, four other phylotypes gained dominance in the community while Flavobacterium and Pseudomonas phylotypes decreased in abundance. These data suggest that specific phylotypes of bacteria were associated with the different phases of petroleum degradation in the LTU.
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Gaybaryan, Mikhail A., Vladimir S. Teterin, Vladimir I. Sidorkin, and Natalya N. Gapeeva. "Modification of the unit for subsurface injection of organomineral fertilizers." Tekhnicheskiy servis mashin, no. 2 (June 10, 2020): 12–20. http://dx.doi.org/10.22314/2618-8287-2020-58-2-12-20.
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Subsurface injection of liquid organomineral fertilizers provides activation of soil microflora, increased nutrient adsorption by plants, improved physical and agrochemical properties of soil, adsorption of harmful contaminants, pesticides and radioactive nuclides from soils. Subsurface injection of liquid fertilizers is usually carried out locally in planting or feeding seedlings, using sowing and planting units, plant nourishing cultivators, fertilizing systems, cultivators with feeding devices. (Research purpose) The research purpose is in increasing the efficiency of using liquid fertilizers, including organomineral fertilizers, by upgrading the developed technical means for their intra-soil application. (Materials and methods) The article presents the designed, manufactured and tested a technical tool for continuous intra-soil application of liquid organomineral fertilizers during pre-sowing soil treatment. Authors proposed the design of a combined device that includes a vertical milling cultivator, a system for injecting liquid organomineral fertilizers and a rolling drum and allows to carefully loosen the soil, grind root and crop residues, conduct a continuous intra-soil application of liquid organomineral fertilizers to a depth of 20 centimeters, as well as create a compacted seedbed. (Results and discussion) The authors identified a number of design flaws during the tests of the developed machine, and therefore decided to modernize some of them. Authors have upgraded the design of the cutter and coulter and changed the injection system of liquid fertilizers. (Summary) As a result of the modernization, authors have increased the charge productivity of the unit, improved the quality of soil treatment and increased the efficiency of fertilizer application by increasing the uniformity of their application.
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Braunack, M. V., and T. C. Peatey. "Changes in soil physical properties after one pass of a sugarcane haulout unit." Australian Journal of Experimental Agriculture 39, no. 6 (1999): 733. http://dx.doi.org/10.1071/ea98026.
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Summary. Field trials were established at different locations within the Herbert River area near Ingham in North Queensland to assess the ratooning ability and yield of sugarcane after a wet harvest. Treatments consisted of harvesting under dry conditions and then applying 50 mm of irrigation, followed by no traffic (control), traffic of a haulout unit directly over the harvested row (traffic treatment), and traffic as above with the application of further irrigation to maintain wet soil conditions (traffic + water treatment). Undisturbed soil cores were collected from the row before harvest and after treatment imposition to assess the change in soil physical properties due to traffic. Soil cone resistance was also measured. Soil physical properties changed significantly after traffic with increases in soil bulk density and soil cone resistance and decreases in saturated hydraulic conductivity. The greatest change occurred in the top 20 cm of the profile. Yield at one site was significantly reduced after traffic and the effect was enhanced in the presence of water after traffic. It is suggested that to maintain good soil conditions in the row all traffic should be restricted to the central part of the inter-row. One way to achieve this is to match crop row spacing with equipment track widths.
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Casarini, D. C. P., R. C. A. Cunha, M. I. Z. Sato, and P. S. Sanchez. "Evaluation of Toxicity Test Procedure To Define Loading Rates in a Land Treatment System." Water Science and Technology 24, no. 12 (December 1, 1991): 183–88. http://dx.doi.org/10.2166/wst.1991.0383.
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Land treatment is categorized as an option to treat hazardous organic waste in soils. This treatment relies on detoxification, degradation, and immobilization of hazardous wastes constituents within the defined treatment zone to ensure the protection of surface water, groundwater and soil. The use of an appropriate battery of acute toxicity screening tests provides an acceptable method to estimate the initial application rates to be used in subsequent land treatment systems. This paper describes the Microtox acute toxicity test that has been developed and proposed by EPA - Environmental Protection Agency, to estimate the initial loading rates in a land treatment unit (EPA, 1986). The procedure involves conducting a sequence of Microtox tests on the water-soluble fraction of the soi], the waste, and selected waste-soil combinations. The results are used to establish a range of loading rates, which graphically are correlated with the EC50 or TU (toxic unit) to define the test loading rate which does not impact the biological activities of soil microorganisms.
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Nazarenko, Ihor, and Oleksandr Kovalov. "ENERGY EFFICIENT ELECTROMECHANICAL SOIL TREATMENT SYSTEM BASED ON ELECTRIC MOTORBLOCK." Bulletin of the National Technical University "KhPI". Series: Energy: Reliability and Energy Efficiency, no. 1 (2) (July 2, 2021): 71–78. http://dx.doi.org/10.20998/2224-0349.2021.01.10.
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In Ukraine, the number of farms, private land users and protected soil structures has increased significantly in recent years. To increase the efficiency of vegetable production, small-sized mobile units in the form of motoblocks with internal combustion engines of domestic and foreign production have been widely used. However, during the operation of mobile units with internal combustion engines in greenhouses and hotbeds, the noise level and air pollution increase, which negatively affect not only people but also plants. The disadvantages of motoblocks with internal combustion engines should also include a fairly high specific consumption of liquid fuel, which has a high cost, difficulties in starting and stopping the unit, as well as the relatively low reliability of the internal combustion engine. More promising for work in protected soil structures are mobile units with traction motors, called electric motors, as environmentally friendly units that do not have these shortcomings. The main technical characteristics of the experimental sample of a small-sized electrified soil-cultivating motoblock are given in the work. The structural scheme of the power energy channel of the electric motor unit is substantiated, which clearly demonstrates the processes of energy conversion in it. The equation of energy balance of the electric motor unit and the main energy ratios that determine the properties of the traction motor in the drive of the electric motor unit are obtained. The algorithm of optimal control of a direct current traction motor by the maximum efficiency for direct current motors of serial and mixed excitation is substantiated. The results of field tests of the prototype of the electric motor unit are presented. The analysis of the obtained results of experimental researches of the electrified tillage motor-drive driven by the direct current motor of sequential excitation testifies to the reduction of specific energy consumption for the main types of tillage by 12-15%.
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Jeksen, Julianus, Wayan Diara, and Wiyanti Wiyanti. "PREDIKSI EROSI DAN PERENCANAAN KONSERVASI TANAH PADA DAERAH ALIRAN SUNGAI JANGA KABUPATEN KARANGASEM, BALI." AGRICA 1, no. 1 (July 21, 2020): 14–23. http://dx.doi.org/10.37478/agr.v1i1.476.
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Erosion prediction on Janga flow river area at Karangasem district used USLE ( Universal Soil Loss Equation ). This research conducted to know the large erosion on Janga flow river area and conservation treatment on unit larger erosion area of permitted erosion to concern on the class of ability area. Based on slope map compilation, used area map and soil variety map on research area was founded L6 unit area. The large erosion predicts on Janga flow river area between 0,829 to 1.109,208 ton/ha/th. Low erosion in area unit 1,3,5,6,7, and 9 located on downstream of the flow river area. Be on the process of erosion on area unit 11 and 13 located on mid-flow river area. High erosion in area unit 14 and 16 located on upper reaches flow river area. Lowest erosion found in area unit 1,3,5,6,7,9,11 and larger erosion of permitted erosion located in area unit 10,13,14,15,and 16 need to soil conservation treatment. Applicable Soil conservation treatment is increasing the density of crops and improve terrace construction and by added used organic substance and cultivation crop
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Bulgakov, Volodymyr, Pavol Findura, Volodymyr Nadykto, Volodymyr Kyurchev, and Mikola Tikhovod. "Experimental Study of Two Fallow Field Treatment Influence Methods on Soil Moisture Dynamics." Acta Technologica Agriculturae 25, no. 4 (November 1, 2022): 176–82. http://dx.doi.org/10.2478/ata-2022-0026.
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Abstract The yield of any crop depends on soil moisture. One of the moisture conservation technological methods is fallow in the form of soil mulch with a layer not exceeding a thickness of 5–6 cm. To create this, a harrow utilizing special working devices was designed. This paper presents the results obtained on the dynamics of changes in soil moisture in a fallow field treated with a new harrowing unit compared to a serial cultivator operating at a depth higher than 6 cm. It was observed that the soil moisture in the harrowed area of the fallow field was 1.4 times higher, while the moisture reserves were 2.2 times higher in contrast to the field with the agrotechnical environment, treated with the sweeps of a serial cultivator. The actual soil tillage depth uniformity reached with the new harrowing unit is higher in comparison to that of the basic cultivator unit because, according to the F-test, the dispersion of fluctuations in the field tillage depth by the former (0.64 cm2) is significantly less than that for the latter (3.24 cm2).
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Mamadaliev, M. K., and R. V. Sabirov. "ESTABLISHING AN ADJACENT AGGREGATE SOFTENER TO THE SOIL FOR MINIMAL PROCESSING OF SOIL." RUSSIAN ELECTRONIC SCIENTIFIC JOURNAL 35, no. 1 (March 27, 2020): 101–7. http://dx.doi.org/10.31563/2308-9644-2020-35-1-101-107.
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The tillage process in agriculture is the main process, which consumes about 40% of all energy. Currently, in order to save energy costs, a number of research projects are being conducted to reduce the number of units. For example, in the article, the angle of entry of the cultivator of the combined unit for minimal tillage is justified. It was found that for high-quality soil crushing with minimal energy consumption, the angle of entry of the working body into it must be within 30-35º. The use of a combined unit equipped with rippers with the recommended angle of entry of the Ripper of the combined unit makes it possible to reduce the cost of soil treatment by 12.7%.
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Bútorová, Jana. "Príspevok k problematike určovania špecifickej hmotnosti subhorizontov opadu lesných pôd." Forestry Journal 59, no. 1 (March 1, 2013): 38–43. http://dx.doi.org/10.2478/forj-2014-0021.
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Abstract According to national and international laboratory methods, the density of soil samples is determined by pycnometer in heated samples crushed by ultrasound. In mineral soils, the elementary unit of density is represented by a mineral grain of quartz, granite, andesite, etc. On the other hand, in organic soils, the elementary unit is represented by a leaf (or just a part of it), needles, stems and roots. Heating of the mineral grain causes its release from the soil aggregate. Organic parts of the soil are losing air vacuoles by heat treatment while in the same time, carbohydrates, proteins, oils and resins create new chemicals which are heavier than water. That is a reason why density determination of litter subhorizons in forest soils needs to have different rules in comparison with mineral soil samples. Samples with more than 50 volume per cent of organic matter are not treated by heat and do not decompose. In case of high mineral soil content, mineral parts are removed from the sample and their density is determined. The final density is based on mathematically processed data.
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Qiu, Qinli, Dongmei Fan, Yinmao Wang, Danyi Huang, Yu Wang, Junhui Ma, and Xiaochang Wang. "Effect of Calcium Cyanamide on Soil Fungal Community in Successive Tea-Cuttings Nursery." Agriculture 11, no. 8 (July 29, 2021): 716. http://dx.doi.org/10.3390/agriculture11080716.
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The effects of calcium cyanamide on the soil fungal communities in successive tea-cuttings nursery soils were investigated based on Illumina high-throughput sequencing. The field experiment was carried out with three treatments, including control (CK), flooding (F) and calcium cyanamide (CC). The treatment with calcium cyanamide increased pH (~1 unit) and reduced the accumulation of phenols (~50%), available phosphorus (~28%) and exchangeable Al (~90%) significantly, and improved soil quality. The predominant phylum in all treatments was Ascomycota. FUNGuild revealed that the dominant trophic mode was saprotrophy in tea-cuttings nursery soil. Plant pathogens had a low abundance in the calcium cyanamide treatment. Alpha diversity analysis showed lower richness in the calcium cyanamide than the other treatments. Network analysis showed a poorly connected but highly modularized network in the calcium cyanamide treatment, with the crucial OTUs functions related to anti-pathogenicity. The results showed that calcium cyanamide should be recommended for improving long-term tea nurseries by increasing the survival rate of tea seedlings due to increasing soil pH value, reducing aluminum toxicity, decreasing the accumulation of polyphenols, diminishing pathogenic fungi and making the taxa related to anti-pathogenicity occupy a more important niche.
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Vujinović, Tihana, Timothy J. Clough, Denis Curtin, Esther D. Meenken, Niklas J. Lehto, and Michael H. Beare. "Quantity and biodegradability of dissolved organic matter released from sequentially leached soils, as influenced by the extent of soil drying prior to rewetting." Soil Research 57, no. 4 (2019): 374. http://dx.doi.org/10.1071/sr18172.
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Soil rewetting can induce a flush of organic matter mineralisation, but the factors underpinning this mineralisation response are poorly understood. We investigated the effects of antecedent soil water content, before rewetting, on the quantity, quality and biodegradability of dissolved organic matter present in the leachate pore volumes from a soil under two different management histories: arable and grassland. Soils were collected at field capacity (FC) and dried to give four soil gravimetric water contents (θg): 22% (not dried, left at FC), 15%, 8% and <2% (air dry, AD). Soils were repacked to the same bulk density (1.1 g cm–3) and each core was sequentially leached, with four pore volumes collected. The total amount of dissolved organic carbon (DOC) leached increased (P < 0.001) only in the soils that had been air-dried before rewetting (3.8 and 5.3 mg g–1 soil C, for arable and grassland respectively), while among the other θg treatments differences were relatively small (1.6–2.4 mg g–1 soil C). The pre-rewetting θg treatment affected the DOC content of the pore volume leached (P < 0.001): in the grassland soil, the DOC of the AD treatment was consistently twice as high as the other θg treatments, but this trend was not as consistent in the arable soil. For all θg treatments and both soils, specific ultraviolet absorbance at 254 nm increased as leaching progressed. Biodegradability, expressed as cumulative CO2 produced per unit of DOC in leachates, was significantly lower in the first pore volume of all treatments in the grassland soil and increased with sequential leaching. In the arable soil, differences were small or insignificant across the pore volumes leached, but were large and inconsistent across the θg treatments. These findings improve our understanding of how antecedent soil water content affects the quantity and quality of dissolved organic matter released when soils are rewetted, and the potential for soil carbon losses.
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Mirzaev, Bakhadir, Farmon Mamatov, Ikromjon Avazov, and Sherzod Mardonov. "Technologies and Technical Means for Anti-Erosion Differentiated Soil Treatment System." E3S Web of Conferences 97 (2019): 05036. http://dx.doi.org/10.1051/e3sconf/20199705036.
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This paper highlights the necessity of system modification of the main soil slopes processing by developing new technologies of processing eroded soils and technical means to protect a soil from wind and water erosion, reduce processing energy costs, improve moisture accumulation and preservation, and increase the aggregate productivity. An improved differentiated system of slopes soil tilling is proposed, including a crest-stepped ploughing with complete alternation (at 180° within the range of own furrow) and incomplete turnover of the layers and mouldboardless two-tier tilling. During the first year, a crest-stepped ploughing was carried out on slope fields affected by water and wind erosion. Thus, stratum’s subsurface layers are strip loosened. To implement this technology, an improved plough for crest-stepped ploughing developed on the basis of a stepped plough for furrowless smooth tillage is proposed. The rotation was carried out with mould boardless two-tier soil tilling by a ripper with inclined posts. Further, it is recommended to develop and implement combined machines able to simultaneously conduct mould boardless and mouldboard soil tilling, strip subsurface loosening, fertilizer application and other manipulations to prepare soil for sowing and the sowing per one passage of the unit to protect soil from wind and water erosion.
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Riskawati, R., Dwi Putro T. Baskoro, and Latief M. Rachman. "Analysis of soil physical quality index (case study: groundnut/ Arachis hypogeal L.)." E3S Web of Conferences 306 (2021): 02052. http://dx.doi.org/10.1051/e3sconf/202130602052.
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Physical properties of soil are good for plant growth is closely related to the management of the soil, so it will need to integrate of physical properties to get an overall assessment with making soil physical quality index (SPQI). This study aims to an evaluation of physical properties and determines the physical quality index using several unit treatments to produce various physical qualities on Groundnut/Arachis hypogeal L. The location of the research was carried out in a farmer's garden in Cimaung Village, Cikeusal District, Serang Regency, Banten Province (Coordinates 6o12’14’’ S dan 106o11’52’’E). To analyze the SPQI using several physical properties of the soil such as texture, bulk density, porosity, permeability, and aggregate stability. Each indicator has a scoring parameter to assess the soil physical quality index with a score range of 0-5. An assessment SPQI in a land unit is able to describe the various physical qualities of the soil which are represented by several physical properties of the soil. The unit treatment which class categorization of soil physical quality index indicated slightly good (U2), medium (U1, U3-U6), and slightly poor (U7) as a control.
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Chen, Xiaochen, and Kensuke Fukushi. "Development of a natural treatment system consisting of red ball earth and alfalfa for the post-treatment of anaerobically digested livestock wastewater." Water Science and Technology 70, no. 5 (June 28, 2014): 795–802. http://dx.doi.org/10.2166/wst.2014.297.
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With the objective of developing a post-treatment process for anaerobically digested livestock wastewater, an innovative natural treatment system composed of two units is proposed. The first trickling filter unit further reduced biochemical oxygen demand and achieved a certain degree of nitrification. The second soil-plant unit was targeted at the removal and recovery of nutrients N, P and K. For the feasibility study, a bench-scale soil column test was carried out, in which red ball earth and alfalfa were utilized for treating synthetic nutrient-enriched wastewater. Through long-term operation, the nitrification function was well established in the top layers, especially the top 20 cm, although a supplementary denitrification process was still required before discharge. P and K were retained by the soil through different mechanisms, and their plant-available forms that remained in the soil were considered suitable for indirect nutrient reuse. As for alfalfa, with wastewater application it fixed more N from the atmosphere, and directly recovered 6% of P and 4% of K input from wastewater. More importantly, alfalfa was verified to have an indispensable role in stimulating the soil nitrifying microorganisms by sustaining their abundance during substrate (NH3) and oxygen scarcity, and enhancing cell-specific nitrification potential during substrate (NH3) and oxygen sufficiency. The proposed system is expected to be further improved, and adopted as a sound countermeasure for livestock wastewater pollution.
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Aghajani Shahrivar, A., D. Hagare, B. Maheshwari, and M. Muhitur Rahman. "The effect of irrigation using recycled waters obtained from MBR and IDAL wastewater treatment systems on soil pH and EC under kikuyu grass (Pennisetum clandestinum) production." Water Supply 20, no. 4 (March 27, 2020): 1313–20. http://dx.doi.org/10.2166/ws.2020.049.
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Abstract The main objective of this study was to determine the effect of irrigation using three different types of waters, namely treated wastewater through membrane bioreactor (MBR) system, treated wastewater via intermittently decanted aerated lagoon (IDAL) process and tap water (TW) on soil pH and electrical conductivity (EC) under kikuyu grass production. No fertilizer was added during the study period (1 year). Irrigation waters and water and soil samples extracted from different soil depths were analysed in laboratory. Considerable changes occurred in soil characteristics over the study period under various treatments. Soil pH increased more than 1 unit under irrigation with treated wastewater produced by the IDAL system while soil irrigated with treated wastewater from the MBR treatment system showed little change and TW irrigated soil evidenced a slight decrease when compared to pH at the beginning of the study. There was also a remarkable increase recorded for EC1:5 of top soils irrigated with treated wastewaters compared to the initial EC of the soil. The results from this study highlighted the benefits of irrigation with treated wastewater from the MBR system due to its lower cost of treatment compared to the IDAL process while providing additional nutrients such as nitrogen and phosphorus from the wastewater for plant growth.
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Gomes, D. C., R. C. de A. Cunha, and E. Gloeden. "Evaluation of a Petroleum Refinery Land Treatment Unit Using Unsaturated-Zone Monitoring Data." Water Science and Technology 24, no. 12 (December 1, 1991): 217–27. http://dx.doi.org/10.2166/wst.1991.0388.
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The difficulties in calculating degradation rates of the residues based on theoretical equations and parameters, together with the natural wide soil variability, make the “in situ” monitoring of land treatment units a fundamental management step to both ensure that the residues are being treated by the soil, and to guarantee no risk of groundwater deterioration. Among the methods usually employed, monitoring the unsaturated zone is one of the most promising, since it is inexpensive, easy to use and to maintain, and can detect failures in the treatment system before the aquifer becomes polluted. This paper reviews existing methods for unsaturated-zone monitoring, analysing recent monitoring results of a land treatment unit located at the recharge area of an important aquifer of the State of S8o Paulo, Brazil. Recommendations are made in terms of sampling, operational arrangements and management follow-up actions, so as to reduce pollution migration to the subsurface.
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Nguyen Thi Ngoc, Yen, Viet Tran Trung, and Giang Nguyen Hoang. "Establishment the program and mathematical diagrams of embankment stability analysis on soft soil reinforced by soil cement columns." Transport and Communications Science Journal 72, no. 1 (January 25, 2021): 107–16. http://dx.doi.org/10.47869/tcsj.72.1.12.
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In the calculation of improvement of embankments on soft soils, the geometrical parameters of soil cement columns such as the length L, diameter d, the distance between the columns D, greatly affect to the stability of embankments (settlement S, coefficient of stability Fs) and treatment efficiency. On the basis of the multivariate correlation equation predicting total settlement (S), residual settlement after treatment (DS) based on the unit weight of soil , the height of embankments H, the length L, diameter d, the distance between the columns D after statistical analysis on p_value index and R2 with the following models: Linear, Quadratic combined with the Bishop method on slope stability analysis, the authors have built the code of stability analysis for the embankment on soft ground reinforced with soil cement columns system. At the same time, we have developed mathematical diagrams for the analysis of the influence of each pair of column geometry factors on the settlement of the roadbed.
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Rahayu, Rahayu, Jauhari Syamsiyah, and Laila Nikmatus Sa'diyah. "Aggregate stability of Alfisols root zone upon turfgrass treatment." SAINS TANAH - Journal of Soil Science and Agroclimatology 17, no. 1 (June 29, 2020): 50. http://dx.doi.org/10.20961/stjssa.v17i1.40455.
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<p>Soil degradation mostly occurs on land where a lack of surface coverage results in soil-aggregate destruction due to heavy rainfall. Turfgrass is an ornamental plant and covers the soil surface and, thus, potentially improves soil-aggregate stability. This study determined the potential of some summer grasses to improve soil-aggregate stability and was a pilot experiment using six turfgrass species: <em>Paspalum vaginatum</em>; middle-leaf <em>Zoysia sp.</em>; <em>Cynodon dactylon</em>; coarse-leaf <em>Zoysia sp.;</em> <em>Axonopus compressus</em>; <em>Zoysia matrella</em>. Turfgrasses were planted using stolons in a 0.6 m<sup>2</sup> plot unit with 5 cm x 5 cm space. Lawn maintenance included irrigation, fertilizing, and weeding. Soil characteristics were observed six months after planting and showed that turfgrass increased the soil-aggregate index from 42.3% to 83.0% in control, and carbon particles measuring 6.4 μm from 28.3% to 63.0%.</p>
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Widowati, Ladiyani Retno, and Sukristyonubowo. "Dynamics of pH, Ferrum and Mangan, and Phosphorus on Newly Opened Paddy Soil having High Soil Organic Matter on Rice Growth." JOURNAL OF TROPICAL SOILS 17, no. 1 (May 28, 2019): 1. http://dx.doi.org/10.5400/jts.2012.v17i1.1-8.
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Research had been carried out at the Research and Soil Testing Laboratory and Greenhouse of Soil Research Institute, Bogor using newly opened paddy soil from Pesisir Selatan districts, West Sumatra (one year old). Total treatments tested were 12 which were combination of farmer rate, NPK recommendation (½×; ¾×; 1½×), straw compost (½×; ¾×; 1½×), and dolomite. The trial was conducted using a completely randomized design with three replications. This research had been prepared in two units, one unit for observing plant response to nutrient management and another unit for incubation trial with the same treatment placed in the greenhouse. Rice cultivar used was IR-42 in accordance to the preferred varieties of local farmers. The sampling method for measuring the solubility of Fe2+ and Mn2+, as well as the availability of PO43- was by centrifuge 50 g mud samples from the incubation pots then separated clear extract using filter paper. The observation results on dynamics of pH, Fe2+, Mn2+ and PO4-3 mainly occured in 1 to 14 days after submerging (incubation). After 14 days soil reaction had reached thermodynamic sequence of oxidation-reduction processes, the PO43- more available and pH of the soil reached the peak. The optimum dose of NPK fertilizer obtained 0.875 NPK or equal to 175 kg of urea, 87.5 kg of SP-36 and 87.5 kg KCl ha-1. The highest number of hills achieved from straw compost treatment 1½ organic matter (OM) or 3 tons with an increase of 20%. Application of ameliorant dolomite increased the number of tillers about 2-3%, but insignificantly different with no dolomite treatment.
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Watson, Gary W., Gary Kupkowski, and Kerstin von der Heide. "Pin Oak Root Injury from Soil Acidification with Sulfuric Acid." Journal of Environmental Horticulture 9, no. 2 (June 1, 1991): 102–5. http://dx.doi.org/10.24266/0738-2898-9.2.102.
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Abstract Sulfuric acid soil treatments that have been used to reduce soil pH in the landscape can cause root damage. When 5 cm (2 in) diameter holes were filled with 33% (4 N) sulfuric acid, pH reduction of one-half unit or greater was limited to soil within 5 cm (2 in) of the treatment hole and persisted less than 2 years. Fine root density was significantly reduced and root tip injury was significantly increased within 15 cm (6 in) of the treatment hole. Cambium of woody roots greater than 3 mm (0.1 in) diameter was killed up to 25 cm (10 in) from the application hole. Destruction of the cambium would result in the death of the roots beyond the point of cambium injury and may be responsible for crown dieback which sometimes develops following acid treatments in the landscape.
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Coventry, D. R., W. J. Slattery, V. F. Burnett, and G. W. Ganning. "Longevity of wheat yield response to lime in south-eastern Australia." Australian Journal of Experimental Agriculture 37, no. 5 (1997): 571. http://dx.doi.org/10.1071/ea96146.
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Summary. A long-term experiment in north-eastern Victoria has been regularly monitored for wheat yield responses to a range of lime and fertiliser treatments, and the soil sampled for acidity attributes. Substantial grain yield increases have been consistently obtained over a period of 12 years with a single lime application. Lime applied at 2.5 t/ha in 1980 was still providing yield increases of 24% with an acid-tolerant wheat (Matong, 1992 season) and 79% with an acid-sensitive wheat (Oxley, 1993 season) relative to no lime treatment. The 2 wheat cultivars responded differently to phosphorus fertiliser, with the acid-sensitive wheat less responsive to phosphorus fertiliser in the absence of lime. The use of a regular lime application applied as a fertiliser (125 kg lime/ha) with the wheat seed gave only a small grain yield increase (8% Matong, 16% Oxley), despite 1 t/ha of lime applied over the 12-year period. Liming the soil at a rate of 2.5 t/ha (1980) initially raised the soil pH by about 1.0 unit and removed most soluble aluminium (0–10 cm). However, after 12 years of crop–pasture rotation after the initial 2.5 t lime/ha treatment the soil pH had declined by 0.7 of a pH unit and exchangeable aluminium was substantially increased, almost to levels prior to the initial application of lime. Given the continued yield responsiveness obtained following the initial application of lime, this practice, rather than regular applications of small amounts of lime, is recommended for wheat production on strongly acidic (pHw < 5.5) soils in south-eastern Australia.
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VOLOZHANINOV, SERGEY S. "APPLICATION OF PHYSICAL TREATMENT METHODS FOR SOIL DISINFECTION." Agricultural engineering, no. 6 (2022): 32–37. http://dx.doi.org/10.26897/2687-1149-2022-6-32-37.
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To reduce the chemical load on the soil, plants and fruits, it is important to use alternative methods of soil and plant cultivation, which include irradiation with non-ionizing radiation. To establish the range of technological parameters and operating modes of the developed machines for tillage with non-ionizing radiation, the authors developed a technique and an experimental installation capable of providing infrared and ultraviolet radiation. To study the soil intended for use as protected greenhouse ground, standard methods for determining the physical, microbiological, and qualitative properties of the soil were applied. In the course of research, fi ve modes of soil cultivation were implemented: infrared radiation for three hours with and without the mechanical mixing of the soil; ultraviolet radiation for one hour; exposure for one hour to one infrared and one ultraviolet emitters with the mechanical mixing of the soil; processing for one hour with three infrared emitters and one ultraviolet with the mechanical mixing of the soil. Microbiological studies of the soil treated at the experimental unit were carried out within one hour after the selection of the material according to the presented method. It has been experimentally established that, depending on the modes of soil cultivation, the number of microorganisms decreases by 14…98%. The combination of infrared and ultraviolet radiation with a simultaneous threefold increase in the thermal power of radiation for one hour helps to reduce the number of microorganisms up to 98%. The decrease in the content of microorganisms in the soil due to non-ionizing radiation is the fi rst step to establish the design and technological parameters and operating modes of the developed machines used for tillage in protected greenhouse conditions.
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Bui, Son Truong, Nu Thi Nguyen, Tho Duc Pham, and Duong Thanh Nguyen. "Study on the consolidation properties of soft soil distributed in the North Center coastal area of Vietnam." Journal of Mining and Earth Sciences 61, HTCS6 (December 31, 2020): 116–22. http://dx.doi.org/10.46326/jmes.htcs2020.16.
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Consolidation parameters of soft soil play an important role in calculating settlement and soft soil improvement by vertical drainage method (distance, quantity, treatment time). In this study, using oedometer tests, consolidation parameters of some soft soils in the North Central coastal region, Vietnam are clarified. The research results show that the compression index Cc has a strong relationship with the natural water content, liquid limit, dry unit weight, and void ratio of the soil. The consolidation coefficient significantly depends on the applied pressure level, at the over-consolidation stage (normal stress is less than pre-consolidation pressure), the consolidation coefficient is high. By contrast, at the normal consolidation stage (normal stress is greater than pre-consolidation pressure), the coefficient of consolidation is small. The pre-consolidation pressure of soil changes with the distribution depth.
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Tsai, Chen-Chi, and Yu-Fang Chang. "Carbon Dynamics and Fertility in Biochar-Amended Soils with Excessive Compost Application." Agronomy 9, no. 9 (September 5, 2019): 511. http://dx.doi.org/10.3390/agronomy9090511.
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In Taiwan, farmers often apply excessive compost to ensure adequate crop yield in frequent tillage, highly weathered, and lower fertility soils. The potential of biochar (BC) to decrease soil C mineralization and improve soil nutrient availability in excessive compost application soil is promising, but under-examined. To test this, a 434-day incubation experiment of in vitro C mineralization kinetics was conducted. We added 0%, 0.5%, 1.0%, and 2.0% (w/w) woody BC composed of lead tree (Leucaena leucocephala (Lam.) de. Wit) to one Oxisol and two Inceptisols in Taiwan. In each treatment, 5% swine manure compost was added to serve as excessive application. The results indicated that soil type strongly influences the impact of BC addition on soil carbon mineralization potential. Respiration per unit of total organic carbon (total mineralization coefficient) of the three studied soils significantly decreased with increase in BC addition. Principal component analysis suggested that to retain more plant nutrients in addition to the effects of carbon sequestration, farmers could use locally produced biochars and composts in highly weathered and highly frequent tillage soil. Adding 0.5% woody BC to Taiwan rural soils should be reasonable and appropriate.
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Ахалая, Бадри, Badri Ahalaya, Юрий Шогенов, Yuriy Shogenov, Сергей Старовойтов, Sergey Starovoytov, Юлия Ценч, Yuliya Cench, Анзор Шогенов, and Anzor Shogenov. "THREE-SECTION SOIL PROCESSING UNIT WITH UNIVERSAL REPLACEABLE WORKING UNITS." Vestnik of Kazan State Agrarian University 14, no. 3 (October 30, 2019): 92–95. http://dx.doi.org/10.12737/article_5db9656e2ade23.01560949.
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A three-section tillage unit has been developed that allows several operations to be performed in one pass: slotting to a depth twice as deep as cultivation, cultivation, crushing the soil and harrowing. At the same time, the grip width of the chopper and harrow of the first and third sections is equal to the width of three cultivating points, and the second base section is five, the operation of the unit with the proposed arrangement of working units improves the quality of the soil treatment. The design of a universal cultivating point of a new sample is presented, containing a chisel located in the bow and slotting machines in the form of two disks with teeth. Using the proposed universal cultivator point of a new sample provides improved soil cultivation by achieving more stable cultivator progress, increasing the unhindered access of irrigation water to the underlying layers of the root zone of plants, improving the water-air regime of the soil environment, increasing the operational reliability of the slotting machine and reducing the consumption of fuels and lubricants to 15 % A promising direction in the development of combined units with removable working units is the creation of combined working units for both sowing seeds, applying mineral fertilizers and herbicides, with the aim of conducting direct sowing of row crops in both dotted and combined ways. The combination of tillage operations with the placement of several working units on one rack allows you to reduce the number of frames in the unit while reducing the metal consumption of the structure by 10 ... 15%, which leads to an increase in the economic efficiency of the tillage unit.
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Lavanya, S., and V. Krishna Murthy. "Suitability of Electronic Nose as a Reflective Tool to the Measurement of Soil Fertility Factors." Kathmandu University Journal of Science, Engineering and Technology 13, no. 2 (October 8, 2018): 39–47. http://dx.doi.org/10.3126/kuset.v13i2.21282.
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Humic Acid (HA) and Fulvic Acid (FA) contribute prominently to soil fertility. They are aromatic in nature and hence can be determined by sensory array. This is apparently the first report on the employment of Electronic nose (E-nose) to detect HA and FA extracted from soil. The aim was to evaluate the E-nose sensor response to HA and FA chemically extracted from different agricultural soils. Humic acid and Fulvic acid were extracted from collected agricultural soils and the aroma was measured by E-nose from each of the seven soils. Their presence was confirmed by fluorescence spectroscopy. The Norm Aroma Index (NAI) was measured for: soil, soil after heat treatment, heat treated soil amended with extracted HA, heat treated soil amended with extracted FA, extracted HA and extracted FA. The NAI values were descending in the order: heat treated soil amended with extracted HA/FA, extracted HA/FA, soil (untreated) and heat treated soil. This indicates that HA and FA are detected by E-nose. It was also observed that the most sensitive sensors were 2, 3, 4, 8 and 5 for all agricultural soils tested. Out of the eight sensors in the sensory array of E-nose, above mentioned sensors consistently exhibited high response and these sensors when customized into a small unit may act as a soil fertility tester.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page: 39-47
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GUNADI, I. GUSTI ALIT, and I. KETUT SUMIARTHA. "Pertumbuhan Bibit Anggur Prabu Bestari Asal Okulasi pada Berbagai Campuran dan Kandungan Air Media Tanam." Agrotrop : Journal on Agriculture Science 9, no. 1 (July 24, 2019): 42. http://dx.doi.org/10.24843/ajoas.2019.v09.i01.p05.
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The Growth and Development of the Prabu Bestari Grape Seedling on Various Compositions and Water Content of Growing Media. The growth and development of the grape seedling influenced by the presence of solar and ground water energy. Prabu Bestari is a originally variety introduced by Balitjestro from Australia after being assembled with the selection process. The need for this variety of agroclimates is in accordance with the North Bali region as a production center. The bud break in grape plant can be affected by condition of plant media during the seedling procession. Shoot failure in grapes can be caused by the condition of the planting medium in the nursery process. This study aims to determine the growth of grape seedlings that are treated with the use of planting media (soil, soil, chaff, soil + cocopeat, and soil compost) 1: 1 (v / v) mixture ratio. The planting media treatment will be combined with different water content (100%, 75%, and 50% of the field capacity conditions). The study was conducted in a green house at the Experimental Station of Faculty of Agriculture Udayana University from May to August 2018. The research used factorial method (4 x 3) which was designed randomly in groups with three replications. The results showed no interaction on all parameters observed. Increasing length of tendrils (148.16 cm) and number of leaves (26.58 strands) looks better with increasing groundwater content up to 100% of field capacity, whereas the resistant mixture + compost gave the highest increase in tendril length (131.91 cm) and the number of leaves (26.56 pieces). The highest chlorophyll content of the leaves reached 28.68 SPAD unit in a mixture of soil + compost treatment and the lowest was in land use + cocopeat with 18.99 SPAD unit. While the highest leaf chlorophyll content due to water content treatment was shown in 100% of field capacity treatment of 27.84 SPAD unit.
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Leech, Fiona J., Alan E. Richardson, Michael A. Kertesz, Beverley A. Orchard, Samiran Banerjee, and Phillip Graham. "Comparative effect of alternative fertilisers on pasture production, soil properties and soil microbial community structure." Crop and Pasture Science 70, no. 12 (2019): 1110. http://dx.doi.org/10.1071/cp19018.
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Different fertiliser products are commonly promoted for use on pastures in order to improve pasture productivity and support a more ‘healthy’ soil microbial environment. However, minimal field research has been conducted to validate such claims. A 6-year study (2009–14) was conducted on phosphorus (P)-deficient soils at three sites near Yass, New South Wales, to investigate the effect of topdressing perennial native-based pastures with a range of alternative fertilisers compared with single superphosphate and an unfertilised control treatment. The alternative fertiliser products included manures, composts, crushed rock, rock-phosphate-derived products, concentrated ash and microbial products. Annual measurements were made of soil chemical properties, botanical composition and pasture yield during spring and/or winter + spring, as well as the relative effectiveness of products per unit of pasture grown. Soil microbial community structure under each fertiliser treatment was also analysed in the sixth year of the study. Fertiliser products with substantial quantities of P increased extractable soil P and resulted in significantly higher pasture growth and clover content compared with the unfertilised control. Superphosphate was found to be the most P-effective fertiliser for increasing pasture growth, along with a range of other products that showed differential responses. However, the cost and P-effectiveness of the products in relation to pasture growth varied considerably and was a function of rate and frequency of application as well as amount and solubility of the P applied. Despite large differences in pasture growth across the various fertiliser treatments, there was no significant effect of the alternative fertiliser products on microbial community structure compared with either the superphosphate or unfertilised control treatments. The observed variation in bacterial, fungal and archaeal community structures across all fertiliser treatments was best explained by soil pH or aluminium (Al) concentration, which was influenced differentially by the fertiliser products. Fungal community structure was also correlated with pasture-productivity parameters (i.e. spring pasture yield, clover content and soil-available P). Our findings reveal a highly resilient soil microbial community that was influenced minimally by use of the alternative fertiliser products, thus highlighting that on-farm management decisions regarding fertiliser product choice should primarily focus on pasture response and cost-effectiveness.
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Sparling, G. P., L. Barton, L. Duncan, A. McGill, T. W. Speir, L. A. Schipper, G. Arnold, and A. Van Schaik. "Nutrient leaching and changes in soil characteristics of four contrasting soils irrigated with secondary-treated municipal wastewater for four years." Soil Research 44, no. 2 (2006): 107. http://dx.doi.org/10.1071/sr05084.
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Land treatment is the preferred option for the disposal of wastewater in New Zealand. We applied secondary-treated municipal wastewater to 4 contrasting soils (a Gley, Pumice, Recent, and Allophanic Soil) at the rate of 50 mm per week, for 4 years. Amounts of N and P in applied wastewater, leachates, and removed in herbage were measured every 1–4 weeks, and a range of soil chemical, biochemical and physical characteristics measured by destructive sampling after 2 and 4 years. After 4 years, leaching losses amounted to 290–307 kg N on the Gley and Recent Soils, representing approximately 22% of the N applied. Leaching losses from the Allophanic and Pumice Soils were 44 and 69 kg N/ha, respectively, representing <5% of that applied. More than half of the N leached was in organic forms. Leaching losses of P were <5 kg P/ha on the Pumice and Allophanic Soils (< 1% of that applied), 41 kg P/ha from the Recent Soil and 65 kg P/ha from the Gley Soil (8% and 13% of that applied, respectively). After 4 years, the total C and microbial C content in the A horizon of the irrigated Recent Soil were, respectively, 47% and 44% less than non-irrigated cores. All irrigated soils showed a rise in pH of up to 1 unit, and all had a marked increase in the exchangeable Na+ which reached 4–22% ESP. After 4 years, the saturated and near saturated hydraulic conductivity of the Gley Soil had declined from 567 and 40 mm/h to 56 and 3 mm/h, respectively. Allophanic and Pumice Soils are to be preferred over the Recent and Gley Soils for effective treatment of wastewater and to minimise the loss of nutrients to the wider environment.
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Maslov, G. G., E. M. Yudina, and I. A. Zhurij. "Efficiency of surface treatment of soil by a stubble multifunctional cultivator." Traktory i sel hozmashiny 85, no. 3 (June 15, 2018): 7–11. http://dx.doi.org/10.17816/0321-4443-66365.
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The effective application of the stubble cultivator on surface tillage is justified simultaneously with the introduction of solid mineral fertilizers. The atomization of the soil in comparison with the disk tools decreases in 1,5...2 times. Using the example of the proposed multifunctional stubble cultivator with the device for simultaneous application of mineral fertilizers, the possibility of using the cost and loss function (the cost of carrying out the amount of work and the loss of the future crop due to a violation of the optimal duration of work) is proved to optimize the duration of work. A block diagram of the algorithm for optimizing the parameters and operating conditions of a multifunctional stubble cultivator is presented based on the criterion of the optimal value of the traction factor of a given tractor, taking into account its traction characteristics and the dependence of the coefficient of the resistivity of the cultivator on the working speed of movement, the depth of processing and the specific material consumption, with consideration of the mass of fertilizers applied. In the objective function of optimizing the duration of the work performed, the cost of the cost includes the operating costs for the specified unit for the planned scope of work. With an increase in the duration of these works, costs are reduced, and the cost of future crop losses, on the contrary, increases. The sum of costs and losses has an extremum, which determines the optimality of the solution. The dependence of the cost of losses of the future corn grain crop on the duration, the amount of work, the purchase price of the harvested crop and the intensity of losses for each day of the violation of the optimal period of stubble cultivation of the soil with simultaneous application of mineral fertilizers is given. With the help of the obtained cost and loss function, the optimum duration of stubble cultivation of the soil was established with the simultaneous introduction of solid mineral fertilizers using the example of the machine-tractor unit as part of the MTZ-1221 tractor and the stubble cultivator KSU-3 with the device for simultaneous application of solid mineral fertilizers.
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Caixeta, Matheus Ramos, Saul Jorge Pinto de Carvalho, Poliana Coste e. Colpa, Márcio Donizetti de Andrade, and Breno Régis Santos. "Soil microbial activity and hairy beggarticks’ germination after application of crude glycerin." Revista Ceres 64, no. 2 (April 2017): 151–58. http://dx.doi.org/10.1590/0034-737x201764020007.
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ABSTRACT Biodiesel stands out as an alternative for petroleum-based products, but its production generates a large amount of by-products. This study was carried out at the Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais, Campus Machado, with the objective of evaluating the impacts of the disposal of crude glycerin on agricultural soil and its microbial activity as well as in plant development. An experiment with a completely randomized design, five treatments, and five replicates was developed in the laboratory to analyze microbial activity. Soil samples of 100 g were incubated for 36 days with concentrations of crude glycerin, namely: 0; 48.7; 146.1; 292.2 L ha-1. Besides these four treatments, flasks without soil and glycerin have composed one more treatment. During this period, the CO2 volume released in each sample was evaluated 11 times. Another experiment was developed in the laboratory with hairy beggarticks’ achenes to evaluate crude glycerin effects on plant development. A randomized complete block design was used in a 4x2 factorial scheme, with five replicates, the same glycerin concentrations, and two glycerin sources (laboratory and biodiesel plant-unit). Crude glycerin stimulated soil microbial activity for doses of up to 143.83 L ha-1, being a positive indicative for future studies on its application to agricultural soils. Glycerin applications reduced the hairy beggarticks’ root protrusion, even at the lowest doses. Residues have Na+ contents that limit their application in agricultural soils.
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Osu, S. R., N. U. Ndaeyo, and G. E. Udofia. "Effect of soil amendments on leaf pigmentation and N status in cassava (Manihot esculenta crantz) grown in crude oil contaminated soil." Journal of Applied Sciences and Environmental Management 24, no. 12 (February 16, 2021): 2113–19. http://dx.doi.org/10.4314/jasem.v24i12.17.
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Growth studies on TMS 30572, NR8082 and Local cassava cultivars grown on previously crude oil polluted soil were conducted to assess effects of oil palm bunch ash (OPBA), dried poultry manure (DPM) on Leaf pigmentation and N2 status of test crops. In addition, physical and chemical properties of soils were determined. The pH was raised from 5.62±1.50 in control soil to values that ranged between 6.97±1.23 to 9.24±1.89 in soil treated with organic amendment. The result of organic amendment ensures reduction of C: N ratio from 50:1 in control to critical threshold that ranged between 8:1 – 10:1 for improved decomposition and soil quality. SPAD measurement revealed no significance (P≤ 0.05) in readings for both treatments and control experiments. However, the interactive effect of both cassava variety and type of amendments were significant. Cultivar TMS 30572 was found to be brought to high productivity under treatment with combined OPBA + DPM and recorded highest chlorophyll content per unit area of leaf surface with Chl. a/Chl.b ratio of 2.13 and thicker leaf blade. While Leaf chlorophyll is directly associated with the efficiency and capacity of the photosynthetic apparatus and hence chlorophyll content in this study was found to be directly related to good health status of the test crops. Results revealed that quality of crude oil contaminated soil was greatly enhanced by organic amendment.
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Bristow, KL. "The role of mulch and its architecture in modifying soil temperature." Soil Research 26, no. 2 (1988): 269. http://dx.doi.org/10.1071/sr9880269.
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Both the quantity and architecture of a surface mulch affect its performance in modifying the soil microenvironment. In this paper, temperature under two simple mulch architectures is compared and contrasted with that of bare soil in a tropical environment. In mulch treatments the quantities of mulch per unit area were similar, but elements in one treatment were horizontal (forming a 5 cm layer) while in the other they were vertical (forming a 22 cm layer). Temperatures were recorded for several days as the soil dried following a storm which saturated the mulch and surface soil. The bare soil dried more rapidly than that with mulch, so that by the fourth day its hourly maximum surface temperature was 8�C higher, and that at 2 5 cm depth was 3�C higher, than soil temperatures under the mulch. Significant differences in soil temperatures under the two mulch treatments only appeared several days later, as subtle differences in the partitioning of energy by the two mulch canopies became more apparent with drier conditions. By the twelfth day, the maximum surface temperature under the vertical mulch was 7�C higher than that under the horizontal mulch. Minimum soil temperatures were never more than 2.5�C different between the bare and mulched treatments and converged with drying. In both mulch treatments, the mulch elements near the soil surface experienced greater temperature extremes than those at the top of the mulch layer. The range in element temperature was slightly greater in the horizontal mulch treatment than in the vertical mulch treatment, where the element temperatures were more closely tied to air temperatures. The first few days following rain are crucial for seedling establishment in the semi-arid tropics and it appears from this study that mulch architecture is of minor importance during this period.
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Shedlosky, M. E., and J. W. White. "Growth of Bedding Plants in Response to Root-zone Heating and Night Temperature Regimes." Journal of the American Society for Horticultural Science 112, no. 2 (March 1987): 290–95. http://dx.doi.org/10.21273/jashs.112.2.290.
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Abstract Nine bedding plant vegetable and flower cultivars were grown in each of 10 night air and root media temperature regimes. Generally, fresh and dry weights were greater at 16°C than at 7° night air temperature when root-zone (RZ) heating was not used. Soil warming increased fresh and dry weights of all cultivars grown at 16° night air temperatures. When air temperatures were below 16°, soil warming maintained fresh and dry weights equivalent to or better than plants grown at 16° without soil warming. Two split-night (SN) air temperature regimes were as effective as a constant 16° night temperature, ranking first and 3rd in fresh and dry weight per unit of energy consumption. All soil warming treatments had higher energy productivity than the 16° air temperature treatment with no RZ heating.
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Duarte, I. M., M. P. Amador, S. Dias, T. Vasconcelos, and J. M. Gonçalves. "Farm Wastewater Treatment with Microalgae: A Living-lab Experimental Unit." Agrociencia 19, no. 3 (December 2015): 23. http://dx.doi.org/10.31285/agro.19.252.
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Wastewaters from farms, agro-industrial activities and urban grey waters are residues that can be valued, through their reuse for several purposes within the farm, for example, irrigation or facilities washing. This practice saves conventional water and preserves the environment from contaminations, namely the water resources. This paper presents a research project planning an experimental study to be carry out in a wine farm aiming, through the settlement of a microalgae reactor, the wastewater treatment and the microalgae production. The farm has a vineyard, a winery and a rural tourism unit. Wastewaters are mainly generated from washing the equipment and the fermentation tanks and from the house (grey waters, with low organic loads). According to their characteristics a wastewaters pre-treatment might be required. The outdoor bioreactor uses those wastewaters, solar radiation and is supplied with CO2 conducted from wine fermentation and from the composting unit, reducing the emission of this greenhouse gas. Prokaryotic cyanobacteria, as well as mono- and oligocellular species of eukaryotic algae species will be tested and applied. The performance of the outdoor cultivation systems will be assessed with respect to their light utilization (photosynthetic efficiency), growth yields (productivity), the economic aspects for the cultivation of phototrophs and the quality of treated wastewater.The biomass produced will be used as animal feed, for example for aquaculture, or as soil fertilizer. Treated wastewater will be temporarily stored, for later use, particularly for vineyard drip irrigation.The experimental unit of this project will be set in a living-laboratory to revitalise the environmental education, benefits for knowledge extension to other farmers of the Region. It will also provide deeper knowledge of this type of units to enable its optimization for a larger scale application and extension.
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Hidayat, Nur, Sri Suhartini, and Dian Indriana. "Horizontal Biofilter System in Tapioca Starch Wastewater Treatment: The Influence of Filter Media on the Effluent Quality." Agroindustrial Journal 1, no. 1 (May 15, 2012): 1. http://dx.doi.org/10.22146/aij.v1i1.23243.
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The aim of this research was to analyse the use of different filter media at laboratory scale under a horizontal biofilter system treating tapioca starch wastewater (TSW) to improve the effluent quality that met the national standard. The completely randomized design was used in this study. A horizontal biofilter system was designed and filled with filter media, include sand, gravel, soil (entisol type), coconut fibre and bamboo plait, in each unit. Prior feeding to the biofilter unit, TSW was inoculated with Bacillus sp. N-09. The TSW flow rate was maintained at 6 l d-1 and operated for 1-month period. The results showed that the use of sand as filter media gave a better performance in improving the TSW effluent quality followed by gravel, coconut fibre, soil and bamboo plait. The horizontal biofilter system packed with sand filter media removed 98.53 % BOD, 98.71 % COD, 88.96 % TSS, and increased pH to 8.0.
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Collinson, S. T., S. N. Azam-Ali, K. M. Chavula, and D. A. Hodson. "Growth, development and yield of bambara groundnut (Vigna subterranea) in response to soil moisture." Journal of Agricultural Science 126, no. 3 (May 1996): 307–18. http://dx.doi.org/10.1017/s0021859600074864.
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SUMMARYStands of bambara groundnut (Vigna subterranea (L.) Verde.) were grown in five controlledenvironment glasshouses at the Tropical Crops Research Unit, University of Nottingham, Sutton Bonington Campus, in 1990. Five soil moisture regimes were imposed (one per house), from fully irrigated each week (treatment A), to no irrigation after crop establishment at 35 days after sowing (DAS) (treatment E). Decreasing the amount of water applied resulted in a decline in total dry matter production and harvest index, and a reduction in pod yield from 412 (treatment B) to 0·041 ha-1 (treatment E) at 125 DAS. A maximum leaf area index of 5–4 was achieved by treatments B and C at 90 DAS, resulting in a fractional interception of c. 0·8 of incoming radiation. Total accumulated radiation interception values were 749, 693, 688, 618 and 554 MJ m-2 for treatments A, B, C, D and E, respectively. The efficiency of conversion of the radiation intercepted into dry matter was reduced from 1·41 to 0·50 g MJ-1 by drought.
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Almeida, Thayná, Abelardo Antônio de Assunção Montenegro, Ailton Alves de Carvalho, and José Nildo Tabosa. "Soil and crop spatial variability in maize irrigated with domestic effluent." DYNA 88, no. 219 (November 22, 2021): 111–17. http://dx.doi.org/10.15446/dyna.v88n219.92874.
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Wastewater use in agriculture is a high-potential alternative for coping with water scarcity. The present study aimed to evaluate the impact of using wastewater and sewage sludge on soil attributes in an irrigated maize plantation in the Brazilian northeastern semi-arid region, at an experimental reuse unit. Two experimental plots were installed with the following treatments: wastewater and sludge, and irrigation with wastewater only. The presence of sludge reduced the salt content and promoted an increase in the soil organic matter content, reducing the salinization risk. Biometric parameters showed no spatial dependence. On the other hand, soil moisture, electrical conductivity, sand content, clay content and sodium and potassium contents showed strong spatial dependence for the treatment with sludge application.
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Mataa, Mebelo, and Shigeto Tominaga. "Effects of Root Restriction on Tree Development in Ponkan Mandarin (Citrus Reticulata Blanco)." Journal of the American Society for Horticultural Science 123, no. 4 (July 1998): 651–55. http://dx.doi.org/10.21273/jashs.123.4.651.
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The effects of root restriction, induced by root restriction bags, was evaluated on `Yoshida' Ponkan mandarin (Citrus reticulata Blanco). Trees were planted in 0.02-m3 volume root wrap bags (RWBs), which were made from woven polystyrene fiber, or root control bags (RCBs) made from nonwoven UV-stabilized Duon polystyrene fibre with plastic bottoms. A direct soil planted, nonrestricted root treatment (DPC) was included as a control. After 3 years, reductions in height (14% to 29%), canopy volume (66% to 43%), girth (10% to 22%), and leaf area (8% to 12%) were recorded in both of the root restriction treatments. Greater reductions occurred in the RWB treatment. Photosynthesis, transpiration, water potential, and leaf carbohydrate content were not affected by root restriction although soil moisture content was lower in the root restricted treatments. Fruiting efficiency (i.e., number of fruit per unit volume of tree canopy) improved only in the RWB treatment over the control. Total soluble solids and the fruit color index were enhanced by root restriction.
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DJAJADI, DJAJADI, MASTUR MASTUR, and A. S. MURDIYATI. "TEKNIK KONSERVASI UNTUK MENEKAN EROSI DAN PENYAKIT LINCAT PADA LAHAN TEMBAKAU TEMANGGUNG." Jurnal Penelitian Tanaman Industri 14, no. 3 (June 25, 2020): 101. http://dx.doi.org/10.21082/jlittri.v14n3.2008.101-106.
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ABSTRAK<br />Masalah utama pada budidaya tembakau temanggung adalah erosi yang<br />mencapai 42,75 ton/ha dan serangan penyakit lincat yang dapat mematikan<br />tanaman sampai 80%. Untuk menekan erosi dan penyakit lincat tersebut telah<br />dilakukan penelitian yang dilaksanakan pada tahun 2002 di Desa Glapansari,<br />Kecamatan Parakan, Kabupaten Temanggung. Tujuannya adalah untuk<br />mengetahui pengaruh penerapan teknik konservasi lahan yang dikombinasikan<br />dengan pengendalian penyakit lincat terhadap erosi, kadar unsur hara tanah<br />tererosi, sifat fisik tanah, populasi patogen, persentase kematian tanaman, serta<br />hasil tembakau. Perlakuan yang diuji adalah teknologi konservasi lahan yang<br />meliputi penanaman rumput setaria pada bibir saluran pemotong lahan selebar<br />4 m, dan tanaman flemingia pada bidang vertikal saluran pemotong setinggi 0,5<br />m, serta pembuatan rorak di dasar saluran pemotong lahan yang mempunyai<br />kemiringan 43%. Perlakuan tersebut dikombinasikan dengan teknologi<br />pengendalian penyakit “lincat”, yaitu penanaman galur tahan (BC3-C51),<br />pemberian mikrobia antagonis A. fumigatus, penyemprotan dan pemberian<br />pestisida kimiawi. Mikrobia antagonis dan pestisida kimia disemprotkan pada<br />lubang tanam sehari sebelum tembakau ditanam. Penanaman bibit rumput<br />setaria dan flemingia serta pembuatan rorak dilakukan pada tahun 2000, yaitu<br />dua bulan sebelum penanaman tembakau musim tanam tahun 2000. Rancangan<br />yang digunakan adalah rancangan acak kelompok yang diulang 6 kali. Di<br />setiap petak perlakuan yang berukuran 22 m x 4 m dipasang sebanyak dua unit<br />bak penampung erosi, yaitu 1 unit bak penampung erosi untuk perlakuan<br />kontrol dan 1 unit untuk perlakuan teknik konservasi yang diletakkan di tengah<br />petak bagian bawah. Hasil penelitian menunjukkan bahwa penerapan teknik<br />konservasi pada lahan tembakau temanggung dapat menekan besarnya erosi<br />dari 30,22 menjadi 16,67 ton/ha/thn atau sebesar 44,84%. Penyemprotan<br />mikrobia antagonis pada lahan dengan teknik konservasi dapat menekan<br />perkembangan populasi patogen lincat dan mengurangi persentase kematian<br />tanaman tembakau. Hasil tembakau yang ditanam pada lahan dengan teknik<br />konservasi dan aplikasi pengendalian penyakit “lincat” ternyata lebih tinggi<br />42% dibanding hasil tembakau yang ditanam pada lahan kontrol.<br />Kata kunci : Konservasi lahan, erosi, tembakau temanggung, penyakit lincat<br />ABSTRACT<br />Soil conservation technique to reduce erosion and soil<br />pathogens of temanggung tobacco land<br />Mostly area cropping of temanggung tobacco is located in hilly land, so<br />that erosion and accumulation of disease are the main problems. To minimize<br />erosion and disease attacks, research had been done in Glapansari Village,<br />Parakan District, Temanggung in 2002 at site with slope of 43%. The aim was<br />to know the effect of soil conservation which was combined with soil disease<br />control techniques on soil erosion, eroded soil element, soil physics, soil<br />pathogens population, percentage of dead tobacco plant, and tobacco yield.<br />The treatments are soil conservation technique, planting of setaria grass and<br />flemingia in ridge terrace and digging of ditch pitch on the base of ridge<br />terrace. All of the treatments was established in 2000. The soil conservation<br />treatments were combined with application of antagonistic microbes (A.<br />fumigatus) and cropping of resistant tobacco line (BC3-C51). Randomized<br />Block Design with 6 replicates was used in this research. In each treatment of<br />22 m x 4 m plots, two units soil erosion collector were set, one unit was for<br />control treatment (without soil conservation and soil disease control techniques<br />or local farmer technology treatment) and the other for soil conservation<br />techniques. Results showed that soil conservation technique reduced soil<br />erosion from 30.22 to 16.67 tones/ha/year or 44.84%. Tobacco land that was<br />treated with soil conservation and soil pathogen control techniques had less soil<br />pathogen population and death tobacco plant than tobacco land without<br />treatments (control). Tobacco yield planted in land with soil conservation was<br />higher 42% than that planted in control land.<br />Key words : Soil conservation, erosion, temanggung tobacco, soil pathogen
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Guo, Zhen, Jichang Han, Yan Xu, Yangjie Lu, Chendi Shi, Lei Ge, Tingting Cao, and Juan Li. "The mineralization characteristics of organic carbon and particle composition analysis in reconstructed soil with different proportions of soft rock and sand." PeerJ 7 (September 16, 2019): e7707. http://dx.doi.org/10.7717/peerj.7707.
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The organic carbon mineralization process reflects the release intensity of soil CO2. Therefore, the study of organic carbon mineralization and particle composition analysis of soft rock and sand compound soil can provide technical support and a theoretical basis for soil organic reconstruction (soil structure, materials and biological nutrition). Based on previous research, four treatments were selected: CK (soft rock:sand=0:1), C1 (soft rock:sand=1:5), C2 (soft rock:sand=1:2) and C3 (soft rock:sand=1:1), respectively. Specifically, we analyzed the organic carbon mineralization process and soil particle composition by lye absorption, laser granulometer, and scanning electron microscope. The results showed that there was no significant difference in organic carbon content between C1, C2 , and C3 treatments, but they were significantly higher than in the CK treatment (P < 0.05). The organic carbon mineralization rate in each treatment accords with a logarithmic function throughout the incubation period (P < 0.01), which can be divided into a rapid decline phase in days 1 to 11 followed by a steady decline phase in days 11 to 30. The cumulative mineralization on the 11th day reached 54.96%–74.44% of the total mineralization amount. At the end of the incubation, the cumulative mineralization and potential mineralizable organic carbon content of the C1, C2 and C3 treatments were significantly higher than those of the CK treatment. The cumulative mineralization rate was also the lowest in the C1 and C2 treatment. The turnover rate constant of soil organic carbon in each treatment was significantly lower than that of the CK treatment, and the residence time increased. With the increase of volume fraction of soft rock, the content of silt and clay particles increased gradually, the texture of soil changed from sandy soil to sandy loam, loam , and silty loam, respectively. With the increase of small particles, the structure of soil appear ed to collapse when the volume ratio of soft rock was 50%. A comprehensive mineralization index and scanning electron microscopy analysis, when the ratio of soft rock to sand volume was 1:5–1:2, this can effectively increase the accumulation of soil organic carbon. Then, the distribution of soil particles was more uniform, the soil structure was stable (not collapsed), and the mineralization level of unit organic carbon was lower. Our research results have practical significance for the large area popularization of soft rock and sand compound technology.
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Majumder, Dip, Manabendra Ray, and Dilip Kumar Khan. "Effect of crop management and weed control systems on the native soil microbial population." INTERNATIONAL JOURNAL OF EXPERIMENTAL RESEARCH AND REVIEW 21 (April 30, 2020): 1–9. http://dx.doi.org/10.52756/ijerr.2020.v21.001.
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The soil quality in a paddy field is the most crucial element for the supply and the production of rice in India. However, the pressure on the paddy field creates a challenge for preventing soil degradation. Soil microflora are most vulnerable to soil pollution, and a decrease or increase of the soil bacteria may reflect the health of soil. In this study, we try to understand the effect of crop management and weed control systems on the native soil bacterial colony. Our study consists of three types of crop management systems, such as zero-tillage, the system of rice intensification (SRI), brown manuring, and three types of weed removal processes, i.e. chemical, integrated and mechanical. In the chemical and integrated treatment, two herbicides were used for weed removal, but in mechanical weeding, a conoweeder was used. The colony forming unit (CFU) of different soil bacteria (nitrogen fixing and phosphate solubilizing) were measured during different stages of the crop growth. It was observed that the mechanical weeding has the least impact for both soil bacteria, but the chemical treatment showed a decrease of PSB count in all three systems. Whereas, the integrated treatment produced a better result in crop management and soil microbial population.
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Oyebamiji, N. A., D. O. Adelani, and O. O. Ojekunle. "Breaking Seed Dormancy of Prosopis africana Seeds and its Effects on Seedlings Growth under Two Different Savanna Soils Conditions." Journal of Applied Sciences and Environmental Management 26, no. 11 (November 30, 2022): 1765–70. http://dx.doi.org/10.4314/jasem.v26i11.5.
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Forest trees across the tropics can be effectively domesticated and conserved for afforestation programmes after successful overcoming by breaking the dormancy of their seed coats. The study was conducted at Forest Nursery Unit of Federal University Dutsin-Ma to assess the breaking dormancy of Prosopis africana seeds and its effects on seedlings growth under two different savanna soils conditions. A 2x5 factorial in Randomized Complete Block Design was used for this experiment in four replicates. The factors were savannah soils locations; (ZA: Zaria soil and DS: Dutsin-ma soil) and pre-sowing treatments; Seeds soaked in 60% diluted Tetraoxosulphate (VI) acid (H2SO4) (A); seeds soaked in hot water at 1000C (HW); seeds soaked in water for 24 hours (W); mechanical scarification (MS); control (C). The data were analyzed using analysis of variance at (P=.05). Zaria soil had significantly higher values (8.55cm, 12.65cm and 17.65cm, 0.15cm and 0.17cm, and 262.05, and 0.12) on seedling heights (SH) at 4-8 weeks after sowing (WAS), collar diameters (CD) at 4-6 WAS, and leaflet areas (LA) at 4 WAS respectively. Mechanically scarified seeds (MS) had consistent significantly higher values (6.54cm, 13.79cm, 19.90cm, 25.13cm and 29.15cm, 0.15cm, 0.19cm, 0.21cm, 0.25cm and 0.29cm, and 0.14, 0.16, 0.19, 0.20 and 0.23) on SH, CD, and LA at 2-10 WAS respectively. It is concluded that seeds sowed in Zaria soil performed better than Dutsin-ma soil, while, mechanical scarification was the best pre-sowing treatment for improved seedlings growth of P. africana seeds.
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Wang, H., F. Clarke, D. Curtin, and R. Lemke. "Optimizing sampling allocation for detecting management effects on soil CO2 emissions." Canadian Journal of Soil Science 85, no. 2 (May 1, 2005): 203–11. http://dx.doi.org/10.4141/s04-050.
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Measurement of soil CO2 flux is an important tool for detecting management induced changes in soil C. The objective of this study was to analyze sources of variability of a recently published CO2 flux dataset to identify a sampling protocol with optimal allocation of replication, sub-sample and treatment numbers for detecting treatment differences. The dataset comprised daily CO2 flux measurements from a long-term study with treatments of conventional tillage (CT) and no-till (NT) under continuous wheat (CONT) and fallow-wheat rotation (F-W) in a randomized complete block design (RCBD) with four blocks. PROC MIXED in SAS was used to estimate variances. The standard error of the difference (SED) between two treatment means was used as the precision indicator. Although increasing the number of replications effectively reduced SED, sub-sampling also often improved detection of treatment differences because sub-sample variance (σ2δ) was higher than experimental unit variance (σ2ε) on most sampling days. When treatments with small CT vs. NT difference were excluded, degrees of freedom for treatment effects were reduced and both variances were generally increased or unchanged, resulting in increased requirement for sub-sampling. Based on the selected dataset, we produced graphs showing the number of days on which a CT vs. NT difference of 0.3 µmol CO2 m-2 s-1 could be detected at P < 0.10 as a function of replication, sub-sample and treatment numbers. This approach may be used as a guide to optimize sample allocation in similar studies, though site- and experiment-specific factors (e.g., spatial and temporal variability of CO2 flux, size of treatment difference to be detected, the required confidence level) should also be considered. Key words: Carbon dioxide emissions, tillage, variance, wheat
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Demshin, S. L., D. A. Cheremisinov, V. P. Ostal’tsev, and V. V. Ilyichev. "Results of the research of the basic model of multifunctional tillage unit." Agricultural Science Euro-North-East 20, no. 2 (April 28, 2019): 172–82. http://dx.doi.org/10.30766/2072-9081.2019.20.2.172-182.
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The analysis of equipment for basic boardless plowing and surface tillage revealed the absence in the market of agricultural machinery of multifunctional units capable of reliable and efficient performing both types of tillage by means of one machine. The constructive-technological scheme is offered and the basic model of the unit with replaceable working bodies is developed: flat hoes for performance of the basic processing of soil at 14-25 сm with the creation of a mulch layer and cultivator hoes for carrying out the surface and shallow tillage at 5-14 cm. To assess the effectiveness of the basic model of the unit in 2018 in field conditions a research was carried out, during which the main agrotechnical indicators of the quality of soil treatment were determined. Studies have shown that the degree of crumbling of the soil at the basic boardless plowing of sod-podzolic medium loamy soil at a speed of more than 6.5 km/h exceeded 80 %. For shallow tillage to a depth of 12 cm in the range of operating speeds above 7.0 km/h the amount of a soil fraction up to 25 mm was not less than 70 %. The unit stably sustains the working coverage width and the installation depth of tillage. The variant of the unit with a set of working bodies for the basic boardless plowing in the entire range of operating speeds provides an average tillage depth of 19.5-21.0 cm at an installation depth of 20 cm, with working bodies for shallow tillage - of 11.5-12.0 cm at an installation depth of 12 cm. The height of roughness of the field surface after the basic boardless plowing was 20.7-23.0 mm, for shallow tillage – 12.5-17.0 mm. The results of the research showed that the basic model of the multifunctional unit can perform the basic boardless plowing and shallow tillage in compliance with the basic agrotechnical requirements without the use of replaceable adapters for additional tillage of the top layer of soil. The use of additional working bodies will make it possible to form more highly specialized versions of the machine based on the basic model of the unit.
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Hin, Sarith, Veasna Touch, Vanndy Lim, Jochen Eberhard, Alice R. Melland, John McPhee, Suzie Jones, Stephen Ives, and Vang Seng. "Lime and Fertiliser Applications Increase Yield of Leafy Vegetable Crops in Cambodia." Proceedings 36, no. 1 (April 7, 2020): 179. http://dx.doi.org/10.3390/proceedings2019036179.
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Growing vegetables after rice harvest allows Cambodian farmers to use land that would otherwise be unproductive between rice crops. Producing vegetables on these soils is limited by low soil pH, low cation exchange capacity and limited nutrient retention capacity. Soil pH in the top 20 cm is generally low (pH 5.5 H2O) and may limit the availability of nutrients. Farm-based trials in Siem Reap and Kampot provinces assessed the effect of lime and fertiliser on leafy vegetable crop growth and yield. At lime-only sites, lime was applied at rates of 0.5, 1.0 and 2.0 tonnes per hectare (t/ha) in conjunction with farmer practice fertiliser rates. For sites with lime and fertiliser treatments, combinations of farmer practice and optimal fertiliser rates, no lime and 2.0 t/ha of lime were applied. Two consecutive crops were planted at one site to examine the residual effect of lime on soil pH and crop yield. At lime-only sites, all crops responded to lime application with yield increases of up to 100%. For sites that assessed combinations of lime and fertiliser, the treatment of lime and optimum fertiliser rates showed the highest yield increase (92%). Application of 2.0 t/ha lime increased soil pH by approximately 1.0 unit. This effect was still evident after a second crop of Bok Choy. For the 0.5 t/ha lime treatment, an initial soil pH increase of 0.4 units had reduced to 0.2 units after the second crop. The first crop yield was higher than the second crop yield. Long-term field trials are needed to examine residual lime effects.
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Knappe, Jan, Celia Somlai, and Laurence W. Gill. "Assessing the spatial and temporal variability of greenhouse gas emissions from different configurations of on-site wastewater treatment system using discrete and continuous gas flux measurement." Biogeosciences 19, no. 4 (February 18, 2022): 1067–85. http://dx.doi.org/10.5194/bg-19-1067-2022.
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Abstract. Global emissions linked to wastewater treatment are estimated to account for up to 1.5 % of total greenhouse gas (GHG) emissions globally. However, few studies have measured GHG emissions from domestic on-site treatment systems (DWWTSs) directly. In this study, two DWWTSs were monitored for 446 d and > 42 000 gas flux measurements were conducted using both discrete spot measurements and continuous flux chamber deployments. The observed GHG fluxes from biological activity in the soil and water phase were found to be highly spatially and temporally variable and correlated to environmental factors, water usage patterns and system design. In total, the results show that a septic tank discharging effluent into a well-designed soil treatment unit is estimated to emit a net 9.99 kg-CO2eq.cap-1yr-1, with approximately 63 %, 27 % and 10 % of the total CO2-equivalent net emissions in the form of CO2, CH4 and N2O, respectively. Emissions from the septic tank surface contributed over 50 % of total emissions and tended to be strongly underestimated by one-off discrete measurements, especially when episodic ebullitive events are to be considered. Fluxes from the soil treatment unit (STU) stemmed from both the soil surface and the vent system. Soil fluxes were mostly influenced by temperature but peaked regularly under conditions of rapidly changing soil water content. Vent fluxes were mostly governed by effluent, quality and a low number of high-emission events were responsible for the majority of total observed vent emissions. Owing to the strong overall spatial and temporal heterogeneity of observed fluxes from DWWTSs across all modules, future studies should focus on continuous deployments of a number of flux chambers over discrete measurements to accurately assess GHG emissions from on-site systems. This study also provided insights into managing GHG emissions from DWWTSs by different system configuration design, as well as indicating that the current IPCC emission factors for CH4 and N2O significantly overestimate emissions for on-site wastewater treatment systems.