The size of grain sorghum seed varies among hybrids and from situation to situation, depending on growing conditions. Some lots will have 12,000 seeds or less per pound and others 16,000 seeds or more. Seed number and spacing are important. Pounds per acre is not appropriate for determining planting rate. Yield goal populations and seed spacing in various row widths for sorghum.
Soils are cooler under residue than bare soils.
Early plantings generally yield higher than later plantings, but the cooler soils early in the season must be kept in mind. If you want to plant corn in late April or early May, pay particular attention to the five day weather forecast. If the weather reporter says the forecast is for normal or above normal temperatures and sunny days, it probably will be fine to plant corn. If the prediction is for cloudy days and cool temperatures, you probably should leave the seed in the bag until more favorable weather occurs. By mid-May, plant corn regardless of the predictions, since the periods of warmer temperatures are ahead and the cool soil shouldn't last long enough to damage germination too badly.