Safe and optimal transplanting windows for high yield of potato in China

Context Although China ranks first globally in planting area and total production of potato, the suboptimal transplanting date is one of the limiting factors for high yield of potato. Aims This study aimed to determine the safe transplanting window (SPW) and optimal transplanting window (OPW) across China’s potato planting regions. Methods The APSIM-Potato model was used to simulate potato yields under different transplanting dates in China. The SPW and OPW were defined as the periods during which potato yield surpassed the medium and the 90th percentile of all simulated yields respectively, during 1961–2023. Key results The 30°N line could be regarded as the boundary for determining whether potato can be transplanted at certain dates. The OPWs of potato in the North Single planting region, Central Double planting region, Southwest Mixed planting region, and South Winter planting region were early to late May, late April to late May, late July to late August, and early April to middle May respectively. Within the OPWs, potato yields were 8–136% higher than those under the conventional transplanting dates. Conclusions The decrease in latitude leads to an advancement and widening of SPW and OPW of potato. The southern China had a greater potential for increasing potato yields through selecting the optimal transplanting date, than did northern China. Implications These results not only help increase high stability of potato yield in China, but also provide theoretical reference for other regions or crops in optimizing planting dates in the context of climate change.