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| Filter results9 paper(s) found. |
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1. Compaction - K Fertility Interactions in Corn ProductionSoil compaction is recognized as a significant factor affecting yield in crop production today. The pressure to produce crops profitably has often led gruwers to farm greater acreages, with larger equipment under soil conditions which favor compaction. Effects of compaction are not limited to the surface lay- of a soil but often may be apparent cut much of the root zone. With the interest in soil compaction and its effects on crop growth, a research project was initiated to accomplish the fol lowing... |
2. Economic Perspective on Variable Rate FertilizationSoils form a continuum across every farmer's field, constantly changing in both physical and chemical characteristics. Sometimes these changes are visible; sometimes they are completely masked to the eye. Variables such as organic matter, water-holding capacity, pH, and soil nutrient levels differ, and combined, they affect crop yield goals. In either case, these differences should result in different management practices, including fertilizer applications, being recommended for different soils within... |
3. Alfalfa Responses to PotassiumThe potassium requirement of alfalfa is greater than that for any other nutrient. Potassium influences several systems within alfalfa plants including enzyme activity, carbohydrate production and transport, stornatal activity, photosynthesis through chlorophyll content and C02 exchange rate, and nitrogen fixation. Excellent reviews on the role of K in physiological processes are provided in the most recent potassium monograph (Munson, 1985). Potassium also markedly influences alfalfa agronomically... |
4. Grid Soil Sampling for Precision and ProfitSite specific management of plant nutrients for crop production begins with an inventory of soil test levels in a field. Fertilizer recommendations are based on the expected response to addition of fertilizers as a function of soil test levels. Therefore, the accuracy of site specific fertilizer applications depends on the precision of the soil test map from which the fertilizer recommendations are based. Precision usually increases as fields are divided and sampled as smaller areas. Mapping accuracy... |
5. Assessing Nitrogen Use Efficiency Of Maize On Highly Productive Irrigated Sandy Soils As Affected By Three Nitrogen SourcesIrrigated soils in Minnesota account for only 500,000 acres, but these acres are some of the most productive and environmentally sensitive areas in the state. Ground water is the major source of drinking water in the sandy areas of Minnesota, so obtaining information on nitrogen use efficiency is critical for corn (Zea mays L.) grown on these soils. Slow release urea products have the potential to increase nitrogen (N) use efficiency by releasing N at a time when crop demands are highest. Two such... |
6. The Effects of 40 Years of Tillage and Fertility Practices on Soil Organic Carbon and Fungal PopulationsSoil organic carbon plays an integral role in long-term soil productivity. In cultivated systems, potential productivity is directly related to soil carbon concentrations, highlighting the need to protect current organic matter levels and develop management practices that will enhance soils with declining soil carbon contents. There have been variable responses in soil carbon levels to both tillage and fertility treatments. Tillage alters the physical and chemical properties of the soil environment... |
7. Field Correlation of Tissue Testing for Phosphorus and Potassium in Corn and SoybeanInterest in tissue testing as a method of guiding fertilization and detecting nutrient deficiencies in corn and soybean in the upper Midwest is increasing. Tissue testing may be a helpful diagnostic tool for assessing in-season crop nutrients deficiencies. No current yield-response based interpretations for tissue test results are available in Iowa, although previous reports based on limited data collected during the 1990s and 2000s suggested that the value of tissue testing for phosphorus (P) and... |
8. Active-Optical Reflectance Sensing Evaluated for Red and Red-Edge Waveband SensitivityUncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Active-optical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency. However, various sensors utilize different wavebands of light to calculate N fertilizer recommendations making it difficult to know which waveband is most sensitive... G. Bean, N. Kitchen, J. Camberato, R. Ferguson, F. Fernandez, D. Franzen, C. Laboski, E. Nafziger, J. Sawyer, P. Scharf, J. Schepers, J. Shanahan |
9. Enhancing Nitrogen Fertilizer Efficiency in Sorghum to Boost Yields and Reduced Nitrogen LossNitrogen management is crucial in modern farming as it plays a major role in achieving higher yields. This study aimed to identify the optimal nitrogen application rate and best management practices to prevent over-application, nitrogen losses, and nitrogen deficiency in crops. Kansas, a leading state in sorghum production, served as the study's setting. Research was conducted at four sites during 2021 and 2022 on rain-fed fields in North-East and North-West Kansas. The objectives... M. Platero, P. Morinigo ferreira, D. Ruiz diaz, P. Tomlinson |