Soil temperatures from around the state are finally approaching optimum planning but still on the cool side for soybean. From the weather stations at the branches, these are the soil temperatures at 2.5 inches, from April 20 and on May 4:
County Research Branch Temperature (F) April Temperature (F) May 4
Jackson Jackson 51.1 55.9
Noble Eastern 51.8 55.6
Piketon Piketon 49.3 54.2
Clark Western 50.6 54.2
Huron Muck Crops 45.5 52.8
Ashtabula Ashtabula 32.1 49.9
Sandusky North Central 47.0 52.2
Wood Northwest 40.8 51.8
Wayne OARDC, Wooster -- 56.0
Before heading to the field, consider the conditions you will be planting into. Soybean germination begins when soil temperatures reach 50°F and moisture is present at the planting depth of 1-1.5 inches. In these conditions, emergence can typically be expected 2-3 weeks after planting. Do not plant early if the soil is excessively cold or wet. Slower germination and compaction can negate the benefits of the earlier planting date. Soybean yield tends to decrease when planting after May 10; however, any benefits of earlier planting may not be realized if soil conditions are not adequate (too wet/too cold).
I’m an optimist…So, keep in mind soybeans are an incredibly flexible crop. In 2011, only 4% of the Ohio soybean acres were planted by May 22. Last year, 45% of the soybean acres were planted by May 19. However, the state average soybean yield in 2011 was only 1 bushel/acre less compared to 2013. Clearly, the weather in the remainder of the growing season is also important.