May rainfall, averaged across all of Missouri, was greater than any May on record. In fact, it was 6 inches above normal. This wet weather across all of the crop-producing areas of Missouri greatly delayed corn planting. This delay in corn planning has had a ripple effect on soybean planting. Figure 1 presents soybean planting progress for Missouri in 2019 and the 5-year average. According to the latest information from NASS/USDA only 37% of Missouri's intended soybean acres has been planted. We've made some progress the past week with Missouri soybean farmers planting one million acres in seven days. But, we are well behind the 5-year average of 73% planted.
Figure 2 presents soybean yield response to planting date averaged over 12 experiments conducted in central Missouri. Soybean yield is highly related to weather conditions during August, and yield variability among years for June planted soybean in this dataset was large. Average yield for soybean planted in the second week of June is 16% less than when soybean was planted in early May. This year's intended soybean acreage in Missouri was estimated to be 5.5 million acres. Over 4.5 million acres are yet to be planted. A majority of Missouri's soybean crop will be planted more than a month past the optimum planting date. The ultimate effect on yield is yet to be determined, but the upper limit of yield potential has been diminished. Missouri farmers are experiencing a triple whammy of prevented corn planting, reduced soybean yield from delayed planting, and poor crop vigor of emerged corn and soybean plants.
REVISED: February 21, 2017