By Hans Schmitz, Technical Assistance Specialist
Indiana Ag Nutrient Alliance
The best word to describe Indiana weather this summer – let’s go with whiplash. All around the state, talk continues about that July or August multiple inch event that blew down corn by Arcadia, submersed ears around Connersville, carried a tornado that blew barns apart near Boswell, or pulled tile apart in St. Phillips. Meanwhile, the intervals between rainfall have been plenty hot, dry, and windy, pulling us close to drought before the next flash flood.
The ability of the topsoil to hold on to nutrients in such conditions is tenuous at best. Nitrogen and phosphorus are water-soluble, more so in certain forms than others, and their abundant need by plants makes those two the most problematic. We know a lot of corn has matured and dried down a little earlier than expected this season. Some of that rush to maturity can be chalked up to early planting in areas of the state not including Northeastern Indiana. At least a portion is due to nitrogen depletion in the soils and late season deficiencies. Water soluble forms of nitrogen are nitrate, ammoniacal, and urea. Of the three, nitrate is most readily taken by plants or by water. Ammoniacal forms of nitrogen are the most likely to cling to soils rather than water and leave the field in gully washers rather than leaching.
Phosphorus, along a similar vein, tends to leave fields with soil rather than water, although recent research into dissolved organic phosphate suggests that the leaching potential is far from negligible. In the last decade, the harmful algal blooms on Lake Erie, caused by phosphorus applied to watersheds where no-till is considered common practice, have further emphasized that some amount of phosphorus is traveling with water and not soil.
Stalk nitrate sampling this fall may not return reliable results given the year we have had and the way nitrates accumulate in the lower portion of the stalk. Conversely, in the Plains states, some southern areas, and areas of Minnesota and Wisconsin, the extent of the drought has stalk nitrates being tested as too high even to harvest for livestock feed. Indiana livestock producers this year may want to focus on sourcing feedstocks from as close to home as possible. For the crop or pasture owner, getting soil testing done and basing nutrient recommendations off the results, as well as the planned crop for 2027, is important BOTH because of the variable weather this year and the economic/supply issues associated with fertilizer application this fall or next spring.