Diverging water-saving potential across China's potato planting regions

Abstract

China ranks the first in total planting area and production of potato (Solanum tuberosum L.) over the world. However, high potato yield depends on a large amount of irrigation that raises a series of environment problems. Assessing the water-saving potential across China’s potato planting regions is of importance for maintaining sustainable development of potato production. In this study, we firstly evaluated the potential yields, rainfed yields, and their gaps of potato across different potato planting regions, and then presented optimal agronomic management options (planting date, cultivar maturity, and irrigation schedule) by considering both yield and water use efficiency of potato under the limitation of available water resources with validated APSIM-Potato model. Along the distribution of growth period solar radiation, potential yield of potato was highest in the North Single planting region (NS), followed by the Central Double planting region (CD), Southwest Mixed planting region (SWM), and South Winter planting region (SW). However, rainfed yield of potato was highest in CD followed by NS, SW, and SWM along the distribution of the reproductive growth period precipitation. Under the limitation of available water resources, most potato planting regions should select middle−late maturing cultivars while optimal planting dates varied among regions with earlier planting in north China and later planting in south China compared with normal planting date. Based on the optimization of planting date, cultivar maturity, and irrigation schedule, there is a large water-saving potential in China’s potato planting regions. Average irrigation amount could be decreased by 66% in SW, 49% in SWM, 40% in NS, and 29% in CD, respectively, relative to irrigation quota. Our study suggests that optimizing planting date, cultivar maturity, and irrigation management could realize win-win of yield and water use efficiency and provide a scientific support for water-saving irrigation of potato production in China.