Proceedings
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| Filter results7 paper(s) found. |
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1. Relationship Between Response Indices Measured In-Season and at Harvest in Winter WheatCurrent methods for making nitrogen recommendations in winter wheat (Triticum aestivurn L.) do not adjust for in-season temporal variability of plant available non-fertilizer nitrogen (N) sources. The purpose of this study was to compare the use of different nitrogen response indices determined in-season @INDVI and RIPLANTHEIGkm) to the nitrogen response index measured at harvest (RIHARvEST). In addition, this study evaluated the use of the in-season response indices for determining topdress nitrogen... |
2. Cropping Systems Management Effects on Soil N Mineralization DynamicsChanges in soil organic matter (SOM) content due to cultivation also impacts the amount of indigenous soil nitrogen (IN) supply. Crop management practices designed to achieve high yields also result in high residue inputs, which can contribute to SOM build up and enhanced indigenous N supply. The objective of this study was to evaluate the long term effect of crop rotation and nutrient management in conventional and intensive maize based systems on the change in soil N supply. Soil samples fiotn... |
3. Overview of Manure Handling on Steroid Movement in Agricultural Fields from Beef Cattle SystemsManure generated from concentrated animal feeding operations may serve as a source of steroids in surface water and potentially in groundwater. The objectives of this research were to determine the amount of steroids and metabolites in runoff from beef cattle production pens, and from runoff and leaching from crop production fields. Cattle were fed a synthetic progestagen, MGA or melengestrol acetate and treated with zeranol, trenbolone acetate, and estradiol implants, while a second group was not... |
4. Efficacy of Variable-Rate Application Technology for Phosphorus, Potassium, and Lime ManagementVariable-rate (VR) application technology may improve P and K fertilizer and lime use efficiency, increase crop yield and the profitability of crop production, and reduce within-field soil-test variability. On-farm research assessed the potential of VR P or K fertilization and liming for corn and soybean in Iowa. Replicated strip-trials evaluated one to three cycles of the two-year rotation. Treatments for areas 10-30 acres in size were a non-fertilized or unlimed control, VR based on dense grid-point... A.P. Mallarino |
5. Role of Postemergence Sidedressed Fluid Potassium Fertilizer to Complement Preplant Fertilization in Corn-Soybean RotationsRole of Postemergence Sidedressed Fluid Potassium Fertilizer to Complement Preplant Fertilization in Corn-Soybean Rotations Antonio P. Mallarino and Louis B. Thompson-Ansorena Iowa State University ABSTRACT Farmers and crop consultants of non-irrigated areas of the north-central region have been asking questions about possible use of post-emergence fluid potassium (K) fertilization to complement preplant fertilization. Sidedressing N for corn is common,... A.P. Mallarino, L.B. Thompson-ansorena |
6. Pelleted Lime Application Strategies for Iowa Corn and Soybean ProductionResearch has shown inconsistent results about the efficiency of pelleted lime at increasing soil pH or crop yield compared with aglime. Our previous Iowa research (2015-2016) showed that pelleted lime manufactured with limestone from northern Iowa quarries attained maximum soil pH with the same rate and at the same time than finely ground calcium carbonate, but more time was needed for aglime. However, there were no yield differences between the sources for corn-soybean rotations when one-time... A.P. Mallarino, M.U. Haq |
7. Iowa Phosphorus and Potassium Soil-test Interpretations Were Updated in 2023: Changes and ReasonsNew field research is conducted as issues or questions arise to assure that nutrient management guidelines are kept current. The Iowa State University phosphorus(P) and potassium (K) soil-test interpretations for crops were updated in 2023 because the previous update had been in 2013 using data until 2012 and research since then indicated a need for some changes. Field-response trials with corn and soybean from 2013 until 2020 involved 799 site-years for P and 724 site-years for K, encompassed... A.P. Mallarino |