Soybean Harvest Considerations During Dry Weather

Currently, most of Ohio is experiencing abnormal dryness due to exceptional drought conditions (U.S. Drought Monitor), which can bring along additional challenges during harvest.

Pod Integrity. When dry pods are re-wetted, they may split and shatter, resulting in soybean seeds on the ground (Figure 1). At harvest, shatter losses are less likely to occur when grain moisture is approximately 13%. As grain moisture decreases, shatter losses can increase. In previously conducted field trials, we measured 8% loss when harvesting at 9% grain moisture content. At 13% grain moisture content, we still measured some loss, but at a much lower level (1-2%). If possible, harvest soybeans in time to avoid pod shatter and harvest losses. The loss of four soybean seeds per square foot equals about one bushel per acre in loss. These losses may not always be easily visible as the seeds are often covered by soybean residue and chaff, which need to be brushed away from the soil surface.

Figure 1. Pod splitting and shattering in Clark County, 2017. Pod damage in Pickaway County associated with extreme drought conditions in 2024.

Green stem. Green stem occurs when soybean stems remain green while the pods have reached their mature color (Figure 2). Green stem may be the result of a source/sink problem. If there are a limited number of pods (sink), there are fewer places for the plant’s photosynthates (source) to go. Seasonal environmental stress is commonly associated with green stem syndrome. Premature loss of pods and/or seeds during mid-reproductive growth stages inhibits the sink strength.

Green stem syndrome does not appear to limit yield; however, it can severely reduce harvest efficiency. The presence of green stems will require operators to reduce their combine speed, and the green stems may plug harvest equipment. For more information about green stems, please see this Science for Success FactSheet: https://soybeanresearchinfo.com/wp-content/uploads/2024/02/20240123_Factsheet_GreenStem_V1.pdf.

Figure 2. Green stem syndrome in Clark County, 2024.

Originally Published in C.O.R.N Newsletter