Proceedings
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| Filter results3 paper(s) found. |
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1. Spacial Variability of Soil Test Phosphorus in a Northern Corn Belt FieldFor some time, an increasing number of fertilizer dealers, crop consultants, and farmers have reported substantial year-to- year variability in soil test values for phosphorus (P) and potassium (K). Frequently, this variation could be explained by such factors as extremes in soil moisture content at the time of sample collection. In many situations, however, this variation was due to the fact that soil samples were not collected from the same location in the field in two consecutive years. The introduction... |
2. Effect of Time of N Application for CornThe economic benefit associated with the application of N fertilizers for corn has been known for over 5 decades. As a result, over 99 % of the farmers in Illinois apply N fertilizers when corn is grown. Unlike phosphorus and potassium, there is no good soil test to predict the amount of N needed, instead, farmers use a factor times yield potential with appropriate credits for legume and other N sources to set N rates. While this works well over a number of years, there are years when less N will... |
3. An Overview of On-Farm Nitrogen Rate ResearchBecause crop advisors, farmers, and some in the fertilizer industry questioned the University's N recommendations as being too low and raised concerns that the N calibration research had been done primarily in small plots on University Experiment Station land. numerous N calibration studies for corn after soybeans were conducted on farmers' fields in southern Minnesota and northeastern Iowa from 1989 through 2002 to validate present N recommendations. On-farm replicated trials were conducted by University... |