Crop-climate link in the southeastern USA: A case study on oats and sorghum

Recognizing the crop and region-specific irreversible effects of climate change on agriculture is unavoidable. The Southeastern United States region (SE-US) contributes significantly to the United States (US) economy through its diverse agricultural productivity. Climatically, this region is more vulnerable than the rest of the country. This study was designed to quantify the effect of changing climate, i.e., daily maximum temperature (Tmax), daily minimum temperature (Tmin), and precipitation, on oats (Avena sativa L.) and sorghum (Sorghum bicolor L. Moench) in SE-US. The panel data approach with a fixed effects model was applied by creating a production function on a panel dataset (1980-2020) of climate and yield variables. The required diagnostic tests were used to statistically confirm that the dataset was free of multi-collinearity, unit root (non-stationarity), and auto-correlation issues. The results revealed asymmetric warming (Tmin increase > Tmax increase) over the region. Tmax and Tmin significantly increased during the oats growing season (OGS) and sorghum growing season (SGS). Precipitation increased during OGS and decreased during SGS. The growing season average values of Tmax, Tmin, and Tavg (daily average temperature) have shifted by 1.08 degrees C (0.027 degrees C/year), 1.32 degrees C (0.033 degrees C/ year), and 1.20 degrees C (0.030 degrees C/year) in OGS and by 0.92 degrees C (0.023 degrees C/year), 1.32 degrees C (0.033 degrees C/year), and 1.12 degrees C (0.028 degrees C/year) in SGS. However, precipitation had shifted by 23.2 mm (0.58 mm/year) in OGS and shifted (decreased) by-5.2 mm (-0.13 mm/year) in SGS. Precipitation had a non-significant effect on oats and sorghum yields. With every 1 degrees C increase in Tmin and Tmax, oats yield was reduced by (-5%) and (-4%), respectively, whereas sorghum yield was increased by (+13%) and decreased by (-7%), respectively. Taken together, a 1 degrees C net rise in overall temperature reduced oats yield (-9%) while increased sorghum yield (+6%).