Proceedings
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| Filter results4 paper(s) found. |
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1. Do Soil Nitrogen Tests Relate to Nitrogen Mineralization in First-year Corn Following Alfalfa?Corn (Zea mays L.) is the most frequent first-year crop grown following alfalfa (Medicago sativa L.) in the Upper Midwest. In the majority of cases, first-year corn does not respond to fertilizer N, but sometimes large amounts are needed to optimize yield. The pre-sidedress and Illinois soil N tests (PSNT and ISNT, respectively) are early-season tests used to predict corn yield response to fertilizer N. These tests measure specific fractions of soil N and define a critical concentration to separate... |
2. 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... |
3. Carbon Sequestration: The Lack of Initial Measurement Could Bias Interpretation of Management Effect on Soil CarbonMuch research has been done in the last decades to determine the effect of management practices on the rate of soil carbon (C) seque stration over time. Generally paired fields are sampled and soil organic carbon (SOC) content under each manage ment system is determined. Conclusions about the effectiveness of different management systems in sequestering soil C are established based on the SOC difference and le ngth of the experiment. However, properly archived historic samples are often unavailable.... |
4. Design, Wrangling and Analysis of an On-farm Strip Trial. Iowa Soybean Association MethodologiesIowa Soybean Association (ISA) has conducted over 4,000 replicated on-farm trials over the past 15 years. During this time, we have developed our own methodologies and approaches to the data. In this talk we review step by step ISA approaches to a replicated strip trial involving 5 nitrogen rates including trial design, data wrangling, data analysis and machine learning approaches. The talk concludes with discussion on some difficulties in on-farm research with an appeal to the science community... S. Nelson |