The time to make changes if you're still trying to plant first-crop soybeans or spot in and replant areas where soybeans didn't come up or were washed out has arrived.
Shaun Casteel, Purdue University Extension soybean specialist, offers several suggestions. Many of them also apply to those getting ready to plant double-crop soybeans after wheat. Casteel also writes 'Soybean Success' in the Indiana Prairie Farmer magazine.
"If you're planting now increase the seeding rate," Casteel says. He has been a proponent of backing off seeding rates, but only when soybeans are planted on time.
He suggests upping rates 10% to 20%, especially as the calendar moves later in June. The goal is to get quicker canopy closer and higher pod height with fewer days to flowering. If you're still planting or replanting and there is heavy corn residue, up the planting rate there as well, he says. Much of the corn residue didn't break down like it normally does because of the super cold winter.
Since we're now in the third week of June, if you typically plant 140,000 seeds per acre, Casteel recommends 185,000 in 20-inch rows. If you go into the fourth week of June, up the rate to 200,000 seeds per acre. Soybeans planted later produce fewer main-stem nodes. Planting more plants helps offset that trend.
Next, abandon 30-inch rows if that's still your method of choice. The 15-inch or narrower rows really pay late in the season. The advantage for 15 over 30-inch rows could be 5% to 10% more yield per acre. The later it gets, the more likely that that percentage increase will go higher, the specialist adds.
He calculates that wide rows will take 25 days longer to canopy compared to 15-inch rows, and 40 days longer than 7.5 inch rows. Canopy is about getting a factory out there to collect sunlight.
Stay with full-season varieties for your area in the northern quarter of the state, but as it gets later, back off half a group, say from 3.5 to 3.0. You can ride full-season varieties to June 20 in central Indiana and June 25 in southern Indiana before backing off."