Optimum planting date and cultivar maturity to optimize potato yield and yield stability in North China

Abstract

Potato (Solanum tuberosom L.) is one of most important food crops in North China. Optimizing potato planting date and cultivar maturity is of great importance for increasing yield and reducing yield variability in North China. The APSIM-Potato model was calibrated and validated with field experimental data from a 2-year х 3-planting dates х 3-cultivars study, and used to determine the optimal combinations of planting date and cultivar maturity for rainfed potato production in North China. APSIM-Potato performed well in simulating phenology (mean RMSE = 3.6 days), soil water content in the 0–100 cm soil profile (mean RRMSE = 23.5 %), total dry matter (mean RRMSE = 26 %), and fresh potato yield (mean RRMSE = 22.5 %) under different combinations of planting date and cultivar maturity. Simulated rainfed fresh potato yield in North China was 16,407 ± 6432 kg ha−1. Late planting coupled with middle- to late-maturing cultivars could increase rainfed potato yield in North China. To achieve high yield and yield stability, later planting coupled with early-maturing cultivars is recommended along a ‘N-S’ transect, while a later planting coupled with late-maturing cultivars should be selected along a ‘W-E’ transect. Growth period and growing season precipitation explained 90 % and 85 %, respectively, of the variation in high-stable index of potato yield. Within the potential planting window, the onset of the optimal planting window was negatively correlated with March-May precipitation (R2 = 0.82, P < 0.05), and corresponding optimal potato cultivars could be determined based on the onset of the optimal planting window and mean growing season thermal time (R2 = 0.92, P < 0.01). Study results determined a simple but feasible rule for farmers to use in selecting the optimal combination of planting date and cultivar maturity to increase rainfed potato yield and yield stability in North China.