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1. Accuracy of Credits and Soil Indicies for Predicting Nitrogen Response in Corn Following AlfalfaCorn is the most frequent first- and second-year crop following alfalfa in the upper midwestern United States. In the majority of reported cases, there is little need for additional fertilizer N to optimize yield of first-year corn following alfalfa. For second-year corn following alfalfa, fertilizer N is needed in about one-half of cases and the economically optimum N rate (EONR) has varied greatly in responsive fields. The objective of this research was to use literature data to evaluate the accuracy... |
2. Stand Age Affects Fertilizer Nitrogen Response in First-Year Corn Following AlfalfaThrough a symbiotic relationship with soil bacteria, alfalfa can acquire nitrogen (N) from the atmosphere, use the N for its own growth, and contribute large amounts of N to subsequent crops. To estimate this N contribution, most land-grant universities use book-value N credits based on alfalfa stand density at termination. However, a recent literature analysis indicated that alfalfa stand density is not a reliable predictor of grain yield response to fertilizer N in first-year corn. That analysis... |
3. Tolerance to Low pH- Soluable Aluminum by Winter Wheat Grown in KansasThe majority of Kansas soils are relatively young ic terms of geologic development. Low pHs and the need for liming are not common in other than the eastern third of Kansas. In South Central Kansas, isolated very low pK's have been reported in fields predo~inantly cropped to continuous wheat since the late 1970s. However, in the past three to four years, an increasing number of low pH soils have been reported. A summary of the soil test results from the KSU Soil Testing Lab by year shows a dramatic... |
4. Phosphorus Management on Extremely Acid Soils in South Central KansasResearch was conducted to evaluate the effectiveness of phosphate fertilizer in reducing the toxicity of soluble aluminum (Al) on very acidic soil for production of winter wheat. Banded P fertilizer increased wheat grain yields significantly with the response being greater on unlimed compared to lime conditions. Based on the findings of this research coupled with Oklahoma State University research, banded P is an alternative to liming for wheat production on extremely acidic soils with considerable... |
5. Crop Residue and Fertilizer Management Effects on Soybean, Wheat, and Grain Sorghum in Eastern KansasRemoval of crop residue is being considered for many non- agricultural uses. The agronomic consequences of these practices are not fully known, especially for different levels of fertilizer management. An experiment was begun in eastern Kansas in 1980 to determine the effects of returning different levels of crop residue on soil properties and crop yields in a soybean-wheat-grain sorghum rotation, fertilized with different amounts of N-P-K fertilizer. Crop residue treatments included residue removed,... |
6. Fertilizer Recommendations- Fact or FictionFertilizers are all important and expensive part of the crop production systenl in Indiana. Indiana farmers spend nearly a half billion dollars each year on fertilizer and lime. The question is. is this expense really nccessary? Farmers obtain fertilizer reconlmendations from a number of sources. Soil testing labs. fertilizer dealers. crop consultants and extension all make fertilizer reconunendations. In many cases the reconlmendations are quite different. Is there a valid reason for these differences... |
7. Early Season Nutrient Uptake from Combinations of N itrogen, Phosphorus, and Potassium Applies in Starter Fertilizer in Two Corn HybridsConventional small plot field trials were establ ished to study the effect nitrogen (N), phosphorus (P), and potassium (K) applied as starter ferti lizer on early season growth and nutrient uptake of two corn hybrids with a nd without the Bt-rootworm gene. Ei ght locations were studied over two years comparing a non-starter check, N only, K only, NP, NPK, and NK starter fertilizer combinations on early season growth and nutrient uptake. Sites tested High initially in both P and K. One or more starter... |
8. Response of Corn to Residue Management and Nitrogen FertilizationInterest in the production of cellulosic fuel production for bioenergy has identified corn (Zea mays L.) as a suitable option. However, residue removal can affect the growth and yield of a following corn crop and its response to N fertilizer. Residue removal may also influence the optimal tillage system with regard to yield and N-use efficiency. In southern Minnesota, concern about yield reductions due to cool, wet soil conditions, partially attributed to high amounts of crop residue, have limited... |
9. Response Surface Models Of Subsoil K Concentration For Loess Over Till Soils In MissouriCrop uptake of potassium (K) has demonstrated sensitivity to subsoil variation in K content. This fact has not been sufficiently considered in K management strategies in part due to logistical difficulties in sampling spatially variable subsoil K. We propose a simplified soil factorial model, a response surface, to enable site-specific accounting of whole root zone K supply for loess over till soils. We compared the performance of two peak functions and a non-parametric local regression procedure... |