Corn (Zea mays L.) Planting Density and the Effect on Dryland Yield in Mississippi.

The heat and drought of Mississippi summers often limits corn production.  Corn requires moisture during tasselling and reproductive phases to get superior yields.  By planting corn earlier, we will shift the production window of corn forward by several weeks potentially limiting the detrimental effects of heat and drought and thereby improving yield.  If moisture is more plentiful and temperatures are lower, we hypothesize that higher planting densities will result in improved yields. We investigated three commercial hybrids at three locations with population densities ranging from 20- to 40-thousand plants per acre.  We conducted this research at three locations, two of which we included a planting-date component.  In summary, we think that by planting corn earlier we can stabilize and improve corn yields, and because moisture is more plentiful and temperatures cooler, raising plant populations might improve yields even further. This growing season was wet and cool, and raising the dryland populations up to 35K plants per acre produced favorable results.  Dryland yield at Verona, MS ranged from approximately 150 to 230 bu/A.  At Brooksville, MS, yield ranged from 130 to 180 bu/A.  By planting earlier, we decreased the probability of corn exposure to heat and drought stress during the critical window of tasselling and reproduction phases, and increased the likelihood of having weather like we experienced this season: wetter and cooler.  In summary, the newer, stress-tolerant hybrids appear to tolerate high populations quite well; however, we must note that this was a wet growing season.  We need to conduct this study over additional locations and site years to determine how well these early planting dates and elevated populations respond to a warm spring and periods of drought.