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1. The Conservation Reserve Program- Changes on the HorizonTen years ago, Congress passed the foundation of current conservation programs--the Food Security Act of 1985. Today, one program in particular, has exceeded many peoples' expectations. The Conservation Reserve Program (CRP) yas designed to take 40 - 45 million acres of highly erodible cropland out of production for a 10 - 15 year period. As the first CRP contracts begin to expire, Congress and the Administration are grappling with the program's future in the context of the 1995 farm bill. Will the... |
2. Changes in Iowa's Soil Test P and K Interpretations and RecommendationsResearch results from long-term and short-term experimentation in Iowa have been consistent in the response or lack of response of Iowa field crops to applications of fertilizer phosphorus (P) and potassium (K) at various soil test levels for P and K. Analyses of the research data have established critical soil test values for P and K and the most economic soil test range for P and K to maintain (Mallarino, Webb, and Blackmer, 1991a and 1991 b; Mallarino and Blackmer, 1992 and 1994; Webb, Mallarino,... |
3. Corn and Soybean Grain Yield and Concentration of Potassium in Plant Tissues and Soil as Affected by Potassium FertilizationResearch in the Midwest has shown that K fer tilization tends to increase plant K uptake by corn and soybean and the K concentration of vegeta tive tissues. Several studies found that K fertilization usually increases the K concentrati on of vegetative plant parts, often regardless of the soil-test K (STK) level a nd grain yield response (Malla rino et al., 1999; Borges and Mallarino, 2000; Yin and Vyn, 2002a, 2002b; Borg es and Mallarino, 2003; Yin and Vyn, 2003). It is well known that the K concentration... |
4. Using Soil and Tissue Testing to Predict Soybean Yield Response to Foliar Applied Micronutrients in IowaPrior research with foliar application of micronutrients for soybean has shown inconsistent yield responses in Iowa and the western Corn Belt. Iowa has no interpretations for soil or tissue tests for micronutrients in soybean. This study's objectives were to evaluate soybean plant-tissue and grain yield responses to foliar application of boron (B), copper (Cu), manganese (Mn), and zinc (Zn) in Iowa. There were 22 field trials in 2012 and 21 in 2013, which were established in 20 counties and included... |
5. Evaluation of Macronutrient Uptake and Partitioning in Winter WheatA better understanding of nutrient uptake patterns during the growing season for winter wheat (Triticum aestivum) can help to improve nutrient management decisions at the farm level. The objective of this study was to evaluate the effect of macro and micronutrient fertilization on nutrient uptake and partitioning for a Kansas wheat variety. This study was conducted during the 2014-2015 growing season at the Manhattan North Farm research station, Kansas State University. The experimental design was... |
6. Evaluation of Fertilizer Placement for Corn with Contrasting Rooting SystemCorn genetic improvements in recent year⤙s generated hybrids adapted for water limited conditions (drought tolerant-DT). Drought tolerant hybrids were developed with conventional breeding selection process, and therefore selected based on certain characteristics such as growth habits and root system. New transgenic DT corn hybrids are also becoming available to producers. A previous study demonstrated that corn response to starter fertilizer application can vary by hybrid (Gordon et al, 1997).... |
7. Identification of Reasons for High Temporal Soil-Test Potassium VariationExtensive research has focused on potassium (K) fertlization and soil K testing during several decades in the Corn Belt. IN Iowa, more t han 200 conventional or on-farm strip trials were conducted since the iddle 1990s until the early 2000s. Results of this research were used to update Iowa State University (ISU) K recommendations in 1999 and in 2002. In spite of increasd knowledge about soil-test K calibration, K fertilizer placement meethods, and needed K fertilizer rates, this research demonstrated... |
8. Phosphorus and Potassium Removal and Leaching from Residue in Corn and SoybeanResearch is continually being conducted to adjust and update recomm endations for phosphorus (P) and potassium (K), and to be tter understand relationships betw een nutrient application, grain yield, nutrient removal with harvest, and soil-test values. Studies in Iowa and other states of the north central region have been used to develop guidelines about P and K removal rates in corn and soybean for use together with soil testing information to manage P and K. There is very large temporal variability... |
9. Soil pH and Lime Management for Corn and Soybean: An Ongoing On-farm ProjectSoil acidity can affect plant growth directly and indirectly by affecting the plant-availability of nutrients, levels of phytotoxic el ements, microbial activity, and ot her soil properties. Soils may become acidic in the long term as a result of several natural processes. In the short term, however, soil acidity develops mainly due to application of N fertilizers or manure, primarily those having high concentrations of ammonium or urea because nitrification releases hydrogen (H) ions. Soil pH decreases... |
10. Deep Banding Phosphorus and Potassium for No-till Corn and SoybeanThe information presented is part of ongoing research to identify effective fertilizer placement methods and diagnostic tools lor phosphorus (P) and potassium (K) in no-till corn and soybeans. There is uncertainty about soil test interpretations and cost-effective methods of fertilizer application for the no-till systcni. Moreover, producers are uncertain about the value of soil testing in conservation tillage because of large variability and lack of knowledge concerning techniques for collection... |
11. No-till and Cover Crops Influence Soil Health and Nitrogen Rate and Timing Recommendations: Early ResultsThe idea of improving soil health has become increasingly more talked about by researchers, agronomists, and farmers in the past five years. Management practices such as no- or reduced-tillage and planting cover crops are recommended to improve soil health because of their potential to improve organic matter and soil structure leading to a greater capacity to hold water and nutrients needed for plant growth. Research in South Dakota has been occurring these past two years to determine the influence... J.D. Clark, A. Bly, D. Karki, D. Sanyal, J. Wolthuizen, P. Kovacs |
12. Nitrogen Fertilizer Management for Wheat Under Dual Purpose Grazing and Grain ProductionDual purpose winter wheat is a common system used in many regions of the Southern Great Plains. The objective of this study was to i.) evaluate the interaction of wheat grazing management and soil and fertilizer nitrogen requirements with emphasis on dual purpose wheat. This study was established at three locations during the 2015-2016 growing season. Experimental design was a randomized split block design with 16 treatments including simulated grazing and grain only treatments and varying rates... T. Gardner, D. Ruiz diaz, C. Edwards |
13. Sensor-Based Fertigation Management for Production-Scale ApplicationsFertigation, the practice of applying fertilizer through irrigation water, offers many benefits as an in-season nitrogen application technique for irrigated corn production systems. Most notably, fertigation offers growers the opportunity to make multiple applications throughout the growing season, including late season applications during corn reproductive growth stages. Growers have traditionally determined the timing and number of fertigation applications using visual observations, irrigation... J. Stansell |
14. Effect of Phosphorus and Potassium Application on the Growth and Yield of a 14 Year Old Miscanthus X Giganteus StandMiscanthus x gigantues (miscanthus) is a perennial C4 grass grown for renewable bioenergy and bioproducts. Despite its known low nutrient requirements, the specific fertilization needs of miscanthus remain poorly constrained, especially for older stands. This study aims to guide nutrient management practices for miscanthus by determining the demand for phosphorus (P) and potassium (K) fertilization and identifying the soil testing values at which these nutrients optimize yields. To address this... A. Larson, E. Heaton, N. Boersma, J. Studt, S. Emran, M. Mcdaniel, A. Vanloocke |