Tips for Fall Nutrient and Lime Applications

The fall season is a common time for application of fertilizer and manure. Here are a few tips to consider as you plan those applications.

  • Use current soil sample test results to guide need for phosphorus and potassium applications.
  • Monitor soil pH and consider lime applications in the fall to give time for soil pH correction before next years’ crop.
  • Avoid surface phosphorus applications immediately before heavy rainfall events.
  • Incorporate phosphorus fertilizer and manure to lessen surface runoff. However, avoid tillage if erosion is a concern, especially in low residue situations. Or, subsurface band fertilizers if using tillage systems such as strip till.
  • Inject manure to avoid nitrogen volatilization losses, reduce odors, and place phosphorus away from the soil surface.
  • Wait until soil temperatures are below 50F and trending colder before making fall anhydrous ammonia applications.
  • If possible, wait for cold soil temperatures (see above) before applying manure that has high ammonium-N content, like liquid swine manure.
  • While fall is a nice time to make fertilizer applications, spring or sidedress is preferable for applying nitrogen.

Late Season Warmth and Dryness

Much of the Cornbelt experienced conditions warmer and drier than average in recent weeks. Temperatures for the first 25 days of September have been above average in the western two-thirds of the region with the departures becoming stronger moving from east to west. Meanwhile, much of Ohio and Indiana as well as parts of Illinois and Wisconsin have been close to average. After planting delays this spring and the cooler than average conditions that prevailed through mid-August, this late season warmth gave corn an opportunity to at least partially catch up in its development. In addition, it has served as an aid in drydown in those fields that have already reached maturity.

Based on the September 24, 2013, US Drought Monitor, the US Department of Agriculture estimates that 54 percent of the US corn production is in some stage of drought. At this late stage of the growing season, additional precipitation will have little impacts on yields. In fact, any significant precipitation at this point is more likely to be a hindrance as the harvest continues.



Click to enlarge. Map courtesy of the US Department of Agriculture

Cover crop seeding into standing crops or after harvest?

Cover crops have gained in popularity in the Corn Belt over the last few years, and now is the time of year they are being seeded.  Some producers have already flown on cover crop seed into their standing corn or soybean crops, while others are waiting to drill or seed the cover crops after harvest.  With the delayed crop maturity and later harvest in some areas of the Corn Belt this year, it could be a good year to try seeding by air or with ground-based high clearance equipment, especially if seed is already purchased for species needing several months of moderate temperatures to grow.  Brassicas, legumes, and oats, for example, should be seeded no later than the third week in September for much of the Corn Belt, and flying them on now could still give some benefit to the soil.  Cereal rye is the most hardy of the cover crops grown in the region and can be successfully seeded after harvest throughout the region, and would be a good choice after corn harvest this year, particularly if next year’s crop will be soybeans.  Producers should consult the Cover Crop Selector Tool from the Midwest Cover Crops Council ( for recommended seeding dates for their state and county, as well as seeding rates, depths, and other tips.  It is important for producers to do their homework on fitting cover crops into their overall systems, however, including choice of cover crop based on next year’s cash crop and the method and timing of termination in the spring.

Video: Cover Crops – Fall Seeding … This short video features an aerial seeding
demonstration at a field day in Iowa on September 11, 2013.  Aerial
seeding of cover crops has been in full swing for the past two weeks in Iowa
and will continue as crops mature across the state.

Drought issues returning


The most recent US Drought Monitor map shows drought returning to larger parts of the Corn Belt in the last few weeks. This has been driven by warm temperatures over the last part of August. Dryness has existed across parts of IA, MN and SD over the middle part of the summer. But cool temperatures during that same period had reduced the stress on crops. With the return of warm temperatures in the latter part of August, the dry areas began showing stress quickly.

Areas of Iowa and Missouri have degraded to D2-Severe Drought with surrounding areas of SD, MN, and IA with D1 – Moderate Drought.

In some ways the heat in the latter part of August was welcomed in pushing crops along to development. But the extended period of heat without moisture is stressing crops, pushing some to early maturity and browning.

Large parts of the central part of the corn belt are watching for freezing conditions because of the late development. We will post more about that as information becomes available.