Potential Paddy Rice Yields for Rainfed and Irrigated Agriculture in China and Korea

Abstract YIELD, a water-balance and crop-yield model that calculates production and water consumption variables for a variety of major crops, was applied specifically for wetland rice to China and Korea in order to estimate the region's potential and actual yields for irrigated and rainfed rice production. A network of 241 stations provided the climatic data averaged over approximately a 25-year period. Highest potential yields under full irrigation for a single rice crop occurred in Kansu-Niangsia, the Yangtze River plain, Yunnan-Szechwan-Kweichow, coastal China and Korea, and the islands of Hainan and Taiwan. The yields ranged from 6,000 to 10,000 kg/ha. Smallest yields were found for the western interior and the northeast. In areas where multiple cropping was possible, total yields exceeded 16,000 kg/ha in the south. Under rainfed conditions, only the central and southern China region retained a viable production. In order to achieve optimum crop yields, about 1.000 mm of irrigation water was needed in northcentral China, whereas similar yields could be attained with 500 mm in southern China. The calculated rice production could potentially support between 560 and 860 million people, depending on the irrigation, multiple-cropping strategies, and dietary assumptions adopted.