Long Term Trend Of Soybean Yield Potential In South-Central Nebraska.

Quantification of the magnitude and trends in soybean yield response to changing climatic variables is needed to determine adaptive soybean management practices. A long-term simulation of soybean yield will be carried out to determine the contribution of factors (e.g., weather variables – temperature and radiation, steady rise in atmospheric CO₂, planting date, and soybean maturity groups MG II, MG III, and MG IV) with the documented yearly increase of on-farm irrigated soybean yield in Nebraska. A 110 years of daily weather variables (measured air temperature and precipitation; estimated incoming shortwave radiation, wind speed, relative humidity, and vapor pressure deficit) will be used to simulate the impact(s) of aforementioned factors on soybean yields. Annual CO₂ rise and planting dates prior to year 1959 and 1980, respectively, will be regressed using the recorded CO₂ and planting dates. This study will demonstrate a centurial or generational influence of yield-driving factors on soybean yields.