Proceedings
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| Filter results10 paper(s) found. |
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1. Topsoil Thickness Effects on Phosphorus and Potassium Dynamics on Claypan SoilsDue to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) could be used to improve P and K management for corn (Zea mays L.) and soybean (Glycine max [L.]). Research was conducted on a claypan soil at the University of Missouri’s... L. Conway, M. Yost, N. Kitchen, N. Kitchen, K. Sudduth |
2. Small Grain Response to Potassium and Chloride AdditionsStudies have been conducted over a three-year period to determine the frequency and the cause of small grain response to KC1 additions on high K soils. During the first two years responsiveness of hard red spring wheat, spring barley, and oats were compared at six locations in eastern South Dakota. Broadcast applications of 167 lbs/A of KC1 caused grain yield increases significant at the 0.05 probability level at four sites for wheat and two sites for barley while no oat yield increases were measured.... |
3. Credibility of soil Testing- Results os the Iowa Task ForceSeveral factors led to the convening of the Iowa Soil Testing Task Force: (1) The Iowa legislature passed the 1987 Groundwater Protection Act; (2) The Big Spring study in northeast Iowa in a Karst topography region revealed presence of pesticides and nitrates in groundwater; (3) Public awareness of contaminants in public water supplies was enhanced by influential newspapers and other publications; (4) Influential publications did major stories on the results of soil test comparison studies of several... |
4. Certified Crop Adviser (CCA) ProgramThe Certified Crop Adviser (CCA) Program is being developed under the auspices of the American Society of Agronomy (ASA). The ad hoc steering committee is comprised of industry and university agronomists, state dealer associations, independent crop consultants, several organizations (including T.F.1, P.P.I., ARA, TVA) and ASA staff. This is a broad group representing wide geographic parts of the U.S., and has also included USDA officials, representing SCS and Extension. The purpose of the CCA program... |
5. Estimating Second- and Third Year Nitrogen Availability from Dairy manure: It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of rnanure nutrients, it is necessary to account for the nutrients remaining in soil fiom previous years applications. A corn (Zea mays) field experiment has continued since 1998 on a Plano silt loam. Residual manure N availability was estimated for two and three years after a single rnanure application fiom differences in whole-plant N uptake using 1) fertilizer N equivalence... |
6. Induced Manganese Deficiency in GM SoybeansGlyphosate resistance in soybean and corn reduced manganese uptake and physiological efficiency. Applicatior~ of glyphosate immobilized manganese applied before, concurrent with, or within 6-8 days after the glyphosatc event. Inorganic sources of manganese (Cl, CO,, SO,) tank-mixed with gly-phosate were antagonistic and reduced herbicidal efficacy: ho~vever, antagonism was significantly influenced by glypllosate fonnulation. Glyphosate root exudates and plant deconlposition products can alter the... |
7. Evaluation of Sulfur Fertilizers In Corn ProductionSulfur deficiencies and corn yield increases from S fertilization have been documented in Iowa since the mid-2000’s. Therefore, S fertilization management is an important component of high yield corn production. Many S fertilizers are available for use in correcting deficiencies. However, specific product evaluations have not been widely conducted in Iowa. In addition, a new S fertilizer has recently become available in the Midwest U.S., the mineral polyhalite. The research objectives were... J. Sawyer, M. Castellano, A. Sassman, J. Lundvall |
8. No-till corn nitrogen recommendation using precision soil management practicesIn long-term no-till fields, South Dakota (SD) farmers reported a reduced fertilizer-nitrogen (N) requirement compared to conventional tillage to obtain optimum corn yield. Reduced fertilizer recommendation may be due to improved soil health resulting from increasing soil organic matter, higher soil microbial activities, and improved water and nutrient use efficiency over the years the no-till system is used. However, the impact of soil health measurements on fertilizer-N requirement has not been... D. Bhattarai, J. Clark, D. Clay |
9. Implications of Clay Mineral Analysis for Improved Calibration of Corn Potassium Fertilizer RecommendationsEastern South Dakota has seen an increase in soil potassium (K) deficiencies. To correct those deficiencies and avoid yield reductions, corn producers rely on accurate K fertilizer recommendations (KFRs). Among the various parameters used to estimate a KFR, clay mineralogy has significant potential to increase KFR accuracy. The study has two objectives: first, to determine the relationships among clay mineralogy, K uptake by corn, and KFRs, and second, to calibrate KFRs in South Dakota to incorporate... A. Ahlersmeyer, J. Clark, D. Clay, K. Osterloh |
10. Consideration of Clay Mineralogy for Enhanced Prediction of Optimal Corn Potassium Fertilizer RatesProperly calibrated potassium (K) fertilizer recommendations (KFRs) are critical for improving crop yields and maintaining environmental stewardship. Recent innovations in soil and crop management suggest that certain soil factors, including clay mineralogy, can be used to predict optimal K requirements in corn. The objectives of this study include 1) correlate soil K levels to corn yield, 2) calibrate KFRs with clay mineralogy data, and 3) determine the relationships among clay mineralogy, K... A. Ahlersmeyer, J. Clark, K. Osterloh, D. Clay |