Jarrod Miller, Extension Educator, Somerset County
With the weather this spring, planting windows and excessive soil moisture have made for some variable corn heights. There can be a lot of reasons for short corn, including soil compaction, lack of nitrogen and the weather.
Early planted fields may be shorter since corn is growing during cooler, wetter periods, creating an entire field that is shorter than normal. Fields with ponding or sidewall compaction may have variable growth across the field, with drier areas having normal heights. Some of this can be related to lack of nitrogen, either from denitrification in wet soils, or limited uptake from poor root growth. In some cases ponding in lower parts of the field simply kills the plant altogether. Alternatively, during drought periods, those drier parts of a field may have shorter corn due to the lack of water.
Whether or not shorter corn plants have lower yields depends on canopy cover. If you walk into the rows and see minimal sunlight (<10%) on the soil, this indicates good canopy cover and yields probably won’t suffer. However, short corn with short leaves may also not intercept enough light for optimal yields. If you can see your own shadow walking through a field at tassel, you might expect some yield reductions at harvest time.
The only way to get an idea of what to expect is to walk along the rows and look for spots of sunlight on the ground. While there isn’t much you can do about it at this point, you may know what to expect. As Dr. Bob Nielsen (Purdue) has pointed out, corn in soggy areas may both pollinate and mature later. This later maturity may lead to increased moisture at harvest, compared to the upland portions of the field. You should account for this at harvest and make sure your load will average out to the moisture you desire.
Nielsen: Soggy Soils Severely Stunt Stands of Corn. https://www.agry.purdue.edu/ext/corn/news/articles.00/WetFeet2-0629.html
Larson: Will Short Corn Limit Your Yield Potential? http://www.mississippi-crops.com/2016/06/09/will-short-corn-limit-your-yield-potential/
