Crop water requirements for rainfed and irrigated rice (Paddy) in China

Abstract

A parametric crop water use and yield model was used to calculate temporal and spatial water consumption for rice for the region of China and Korea. The objective was to investigate evapotranspiration (ET) demand and associated irrigation water application strategies for irrigated and rainfed crop production. A network of 241 stations provided the seasonal climatic input consisting of data averaged over approximately a 20 year period. Highest ET under full irrigation (first harvest) was observed in the northwestern, northcentral, and southwestern inland sections of China, whereas least ET occurred in son hcentral China. In order to achieve optimum crop yields, over 1000 mm of irrigation water was needed in the northwest and southwest, in contrast to about 500 mm in southcentral China. The number of required irrigations exceeded eight per growing season in the western and central interior, the edges of the Tibetan Plateau, and the south China littoral. A brief sensitivity analysis was conducted to determine the degree of error introduced by faulty or uncertain station input data.