Sampling soil this fall following the dry conditions this past summer, and in some places continuing up to this time, may result in lower than expected soil-test results for phosphorus (P), potassium (K), and pH. Especially if soil samples are collected before any significant rainfall. Therefore, farmers and crop consultants should interpret those soil-test results with caution.
Integrated Crop Management News
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Fall is an ideal time to collect soil cores from fields to determine if the soybean cyst nematode (SCN) is present and to assess the population densities (numbers). There are reasons to sample fields in which soybeans and corn were grown in 2020. Multiple private soil testing laboratories can process samples for SCN as can the ISU Plant and Insect Diagnostic Clinic. Guidelines for fall SCN soil samples are provided in this article.
Wind damage or stalk rots can cause lodged corn that is difficult to gather with standard corn harvesting equipment. Powered attachments for corn heads are available to assist the gathering process and reduce the number of missed stalks and ears. These attachments assist the flow of corn stalks up and over the snouts and into the gathering chains and cross augers. While required travel speed may still be significantly reduced from normal, these attachments can greatly reduce head plugging and field gathering losses.
A monitoring network was established this year to monitor corn rootworm adults in Iowa cornfields, similar to the moth trapping network we manage in the spring each year. The goal was to help farmers and agronomic professionals monitor populations of northern corn rootworm (NCR) and western corn rootworm (WCR) in their fields and assess management decisions. A secondary goal was to estimate the ratio of NCR to WCR throughout the state and describe changing ratios into the future. The sampling protocol used is detailed at the end of the article.
The August 10 derecho left portions of Iowa with broken, uprooted, and damaged corn across a significant portion of the state. Paired with drought conditions across the state, especially in west central Iowa, growers should be on the lookout for mycotoxin issues in this years’ crop, especially aflatoxins and fumonisins, as discussed in “Drought and Derecho Increase Mycotoxin Risk in 2020 Iowa Corn Crop-Scouting and Monitoring Fields”. For fields that are intended to be harvested, considerations for harvest, mycotoxin testing, and storage are presented below.
The majority of Iowa is currently in moderate to severe drought, with west central Iowa under the most extreme drought. As if drought were not enough, we were dealt another blow with extreme and widespread wind damage on August 10, some of which overlapped the drought area. With these events come an increased risk for ear rots and associated mycotoxins. This article will address ear rots and mycotoxins of particular concern this year, in addition to scouting methods and monitoring considerations while grain is still in the field.
The Derecho storm on August 10 left fields with varying degrees of downed corn. In the weeks following the storm, the condition of the corn plants has worsened and the quality of the corn grain appears to be deteriorating. This deterioration in quality is expected to increase with time.
The dry conditions throughout large areas of Iowa during 2020 reminds us of Iowa’s last significant drought in 2012 and the subsequent impacts on nitrate-N levels in subsurface drainage the following spring. This article will address concerns for water quality in drought conditions and opportunities to reduce nutrient losses from fields this fall.
Many fields have been ravaged by adverse weather this year in Iowa. On top of drought and hail we had a devastating derecho steam-roll a wide swath of Iowa starting in Sac County and progressing eastward along Highway 30. Along with the decision of how to handle this year’s crop, consideration for protecting the soil and preparing for next year’s crop should include cover crops.
Extreme weather events may lead to a decision to make corn silage rather than harvest corn for grain, or to harvest acres that will exceed current silage storage capacity. Before harvesting for silage, make sure you have a market for the silage or a sufficient number of livestock to feed it to. It may be difficult to harvest good quality corn silage if the crop has weather damage and the economic value of the silage will likely be lower than silage from non-damaged fields.