Transformational agronomy by growing summer crops in winter: Crop establishment in cold soils

Abstract

Winter sown sorghum reduces the impact of heat and water stresses around flowering and increases cropping intensity, though, achieving uniform plant establishment remains challenging. Sowing sorghum in winter will require crops to uniformly germinate and emerge in soils which are cooler than the recommended >16ºC minimum daily temperature, during the driest time of the year. Prolonged emergence periods and reduced total emergence can decrease canopy uniformity with negative impacts on yield, crop management and cropping system intensity. Acceptable establishment percentages (>80%) were achieved for some site by seedlot combinations, though large differences in establishment rate between seedlots were observed. The differences in seedlot emerge rate were related to final establishment. This calls for seed vigour testing, novel seed production technologies, management of seedbed hydrothermal conditions and breeding programs for cold tolerance.