Soils

We hope that we’ve seen the last of the snow by now, but both air and soil temperatures remain below average in Illinois heading into the second half of March. According to the Illinois State Water Survey (http://www.isws.illinois.edu/warm/soiltemp.asp) minimum temperatures 4 inches deep under bare soil ranged from the low 30s in northern Illinois to the mid-30s in southern Illinois the morning of March 17, and with some sunshine on that day, reached the upper 40s to low 50w in southern Illinois but did not get above the low 30s in the northern part of the state.…

With 85 percent of soybean and 74 percent of corn acres harvested by October 27, the annual process of deciding when and how to supply nitrogen fertilizer for the 2014 corn crop is underway.
Lessons from this past year
Following the very dry first half of 2012 and low corn yields, soil sampling last fall revealed an average of about 80 lb N present as nitrate in the top foot of soil in Illinois. With a lot of rain in late winter and early spring,…

Corn and soybean harvest continues to move along in Illinois, and as the 2013 crops come off, thoughts turn to fall fertilization. In this article we’ll discuss nutrients other than nitrogen. This will be followed soon by an article on nitrogen.
P and K
In areas with dry soils, we have in recent years had reports of lower than expected soil test K values. There might be some of this in 2013, but we’re also hearing some reports of soil test P and K levels higher than expected.…

Last fall, with funding provided through the Illinois Council for Best Management Practices (C-BMP), GROWMARK, C-BMP, and the University of Illinois initiated the N-Watch soil sampling program to see how much inorganic N remained in the soil following the drought of 2012.
Fall sampling revealed fairly high amounts of soil N, with 151 samples statewide averaging 19.5 ppm of nitrate-N in the top foot of soil. We multiply this time 4 to get lb of N per acre,…