Proceedings
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| Filter results4 paper(s) found. |
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1. Iowa Soil-Test Field Calibration Research Update- Potassium and the Mehlich-3 ICP Phosphorus TestIowa soil-test interpretations and fertilizer recommendations for phosphorus (P) and potassium (K) were last updated in 1999. The only change from previous recommendations (Voss et al., 1996; Voss and Mallarino, 1996) was to add interpretations for the Mehlich-3 (M3) P and K tests to existing interpretations for the Bray-1 P, Olsen P, and ammonium-acetate K tests (Voss et al., 1999). The interpretations for the ammonium-acetate and M3 K tests are similar because comparisons of amounts of K extracted... |
2. Soil-Test Potassium Field Calibrations for Soybean Iowa Interpretations and Research UpdateThere is a long history of potassium (K) fertilization research for soybean and other crops in the North-Central Region. Sustained Iowa field research efforts focused on developing soil-test K (ST10 interpretation and on studying impacts of K fertilization strategies on grain yield and STK. Because of changes in the soil-test K method used in Iowa, this information collected over time should be evaluated separately. The field crop response and STK calibration research conducted Erom the late 1960s... |
3. Nitrification Inhibitor Value in Irrigated Corn: Insights From a Long-term StudyProper nitrogen (N) nutrition is key to optimizing corn yields. Due to its dynamic behavior in soils, N can be lost through different pathways and negatively impact corn production. Nitrification inhibitors (NI) decrease the rate of ammonium transformation to nitrate in the soil, potentially decreasing denitrification and leaching potential. However, NI only has a positive effect on yield if environmental conditions are conducive to loss to the point of N becoming limiting to crop performance.... L. Bastos |
4. Recalibration of Potassium Requirements for Corn in North DakotaThe previous North Dakota potassium recommendations for corn were borrowed from central Corn Belt states, where the dry soil-based 1 M ammonium acetate extraction for soil test K was utilized with a critical K value of 150 ppm. This value was adequate before 2000 because corn production was limited to only a few counties in southeastern North Dakota, and soil test K values were commonly above 300 ppm. However, the intensification of corn production in these counties and an increasing acreage around... D. Franzen, J. Breker, M. Rakkar, A. Chatterjee |