Grain Production Potential And Irrigation Water’s Contribution In China

Researches about grain production potential are significant to nation’s grain security Global climate has been changing rapidly since the industrial revolution and it has a huge impact on the ecological system, so it is indispensable to quantitatively and accurately evaluate grain production potential and irrigation water’s contribution in thus a climatic environment in China. In this study, according to the remote sensing date of arable land spatial distribution, average meteorological data from 1981 to 2010, including terrain elevation, soil, and farmland distribution data in 2010, were used to calculate the production potentials and suitable areas in rain-fed and irrigated scenarios of rice, wheat, maize and soybean in various regions of China based on the Global Agro-Ecological Zone (GAEZ)model, which takes multiple factors into consideration, including light, temperature, moisture, CO2 fertilization, pests, diseases, soil, and topography. Subsequently, we analyzed the spatial characters of the four crops’production potentials and the contribution of irrigation water.Results:(1)In term of national total potential production, maize ranks first both under rain-fed scenario and irrigated scenario, then it’s wheat and rice, the last one is soybean. (2) There exsit differences of grain suitable areas between two scenarios. Rice potential production shows tremendous heterogeneity in spatial pattern under two scenarios:rice suitable areas are only 57.82 million hectares and distributed in the South China while not in the large North China under rain-fed scenario. High rice yield areas under rain-fed scenario are mainly distributed along the Yangtze River in Middle-lower Yangtze Plain, Jianghan-Dongting-Lake Plain and Poyang lake plain; while under irrigated scenario, high rice production areas expand markedly into north China, especially into Northeast China Plain and Huang-Huai-Hai Plain, making the two regions to be high yield and high yield areas reach 152.31 million hectares. The spatial difference of suitable areas of maize, wheat and soybean between two scenarios is not obvious. Under rain-fed scenario, south Huang-Huai-Hai Plain, the north part of Middle-lower Yangtze Plain along the Yangtze River and parts of Northeast China Plain is the common place where high yield areas of wheat, maize and soybean concentrate in, and the three crops’suitable areas expand by 10 million hectares more or less and mostly concentrate in Northern arid and semiarid region under irrigated scenario. Thus, we can find that the reason for national total potential productions of the four crops except for rice under irrigated scenario are much higher than that under rain-fed scenario is the increasing of potential productions at current suitable areas but not increasing of suitable areas. (3) Among four crops, irrigation water contributes the most to rice production potential (373.55 million tons) and the least to soybean production potential. The spatial pattern of contribution of irrigation water to rice is different to it to the other three crops. The regions where irrigation water contributes the most to rice production potential are Northeast China Plain and Huang-Huai-Hai Plain, areas that irrigation water has no contribution to rice production potential means these places are not influenced by water deficit are mainly distributed in the part of Hunan, Jiangxi, Zhejiang that in Middle-lower Yangtze Plain and the north part of Southern China; the regions where irrigation water contributes the most to maize, wheat and soybean are more or less the same, primarily distributed in north China and present a tendency of increase from southeast to northwest, in oasis of Xinjiang, Hexi Corridor, Hetao Plain, the foot of Yinshan Mountain and Keerqin sandy land, irrigation water’s contributions reach a maximum. Areas that irrigation water has no contribution to production potential of wheat, maize and soybean means these places are not influenced by water deficit are roughly consistent:the east foot of Changbai Mountain, Sichuan Basin, or Guizhou and Guangxi, Guangdong, Dongting lake plain and Poyang lake plain. (4) On the whole, the top three regions of grain potential productions and suitable areas in China are Middle-lower Yangtze Plain, Huang-Huai-Hai Plain and Northeast China Plain under both rain-fed scenario and irrigated scenario, low-ranking areas are Southern China and Qinghai-Tibet Plateau. It is in Northern arid and semiarid region that irrigation water’s contributions to four crops are the most, and the largest areas that irrigation is needed are Huang-Huai-Hai Plain, Northeast China Plain and Northern arid and semiarid region.Our results reveal China’s primary grain crops’production potentials and the contribution of irrigation water, this information will help to optimize grain crops’layout, perform agricultural irrigation infrastructure, make management policies and even population policies and Land policies, agricultural practices, it is influential to national food security and economy sustainable development in China.