Impact of planting date on CO2 fluxes, evapotranspiration and water-use efficiency in peanut using the eddy-covariance technique

The combination of increased climate variability with changing weather patterns heightens the importance of the role of planting date on water use in peanut production. Experiments addressing different peanut planting dates were conducted over three years and daytime ecosystem water-use efficiency was determined using the eddy-covaraince method. Results suggest that during the early growing stage in all three planting dates, a late planting date presented by far the highest CO2 fluxes and daytime ecosystem water-use efficiency. Of immediate significance, the latest planting date was also found to exhibit the highest yield in two of the three years in the experiment. Furthermore, an examination of the last 20 years (2001-2020) of climatological records suggests that a late planting date carries a risk of 40% chance of sub-optimal low temperatures in early fall, potentially reducing the yield in those years. In addition, the late planting date carries 15% probability of ten or more consecutive rainy days in the narrow harvest window, potentially impacting a timely harvest.