The effect of different sowing dates on dry matter and nitrogen dynamics for winter wheat: an experimental simulation study

Abstract

Our results showed that grain yield declined by 0.97 ± 0.22% with each one-day change (either early or delayed) in sowing beyond the normal sowing date. The yield loss could be explained by the inhibition of crop growth, yield components, biomass and nitrogen (N) production. The negative effects of delayed sowing were caused by environmental limitations including adverse weather factors such as low temperature during vegetative growth, shortened duration of various phases of crop development, and increased temperature during the grain-filling period. The grain yield gap decreased between the late and normal sowing periods owing to a compensatory effect between the highest average rates (<i>V_t</i> ) and the rapid accumulation period (<i>T</i>) of DMA and NA for single stem wheat. The grain yield was maintained at 6,000 kg ha^-1 or more when the ratio of DMA at the mature-to-jointing stage (M_D/J_D) and the ratio of NA at the mature-to-jointing stage (M_N/J_N) was 4.06 (<i>P</i> < 0.01) and 2.49 (<i>P</i> < 0.05), respectively. The compensatory effect did not prevent the impact caused by delayed sowing, which caused biomass and N production to decrease. Physiological development reached a maximal accumulation rate (<i>T_m</i> ) of NA earlier than DMA.