Adaptability between agricultural water use and water resource characteristics

Based on analysis of characteristic of agricultural water, water requirement characteristic of main water-intensive crops and effective precipitation throughout each city in Henan Province, agricultural water deficit and crop irrigation water productivity under the condition of natural precipitation and manual irrigation are calculated and the adaptability between agricultural water and water resources characteristic are revealed. The results show that under the condition of natural precipitation, water deficit in Henan Province is 240.5mm and falls to 76.3 mm after manual irrigation. The deficit period is concentrated mostly in March ~ June, accounting for more than 65% of annual water deficit. Spatially water deficit is gradually decreasing from north to south, and agricultural irrigation water productivity is relatively high in central China and relatively low in the south and north. Thereby, the region with full irrigation (the south) and the region with large crop water deficit (the north) have a relatively low irrigation water productivity; a certain degree of water deficit (in central China) is conductive to improvement of crop irrigation water productivity. And then the adaptability between regional agricultural water and water resource characteristic shall not be balanced simply based on the degree of crop water deficit, instead, it shall be closely combined with irrigation water productivity