Agricultural precipitation and thermal resources use efficiency and potential resources management measures in the context of global climate change in Northeast China

Northeast China is one of the most important regions for food production in China, with its cropping system being significantly affected by the climate change and vulnerable with water and heat stress. For annual harvest in Northeast China, agricultural precipitation and thermal resources were the primary environmental factors for crops growth from May to September. Therefore, its temporal and spatial change, distribution and use efficiency become important to the crops growth. We choose annual mean precipitation (AP) and annual accumulated temperature 10°C (AAT10) in the growing season to represent the water and thermal resources. And we use Agricultural Precipitation Resources Use Efficiency (APUE) and Agricultural Thermal Resources Use Efficiency (ATUE) to reflect the water and heat utilization. The results showed that 1) AAT10 increased slightly from 1971 to 2006 with distribution of decreased from southwest to northeast, AP trends was decreased and with regional variation that concentrated on the southeast of Northeast China, 2) APUE was 6.6-6.8 kg/mm · hm2 higher than the national level (5.25 kg/mm · hm2) and lower than the world level (7-7.8 kg/mm · hm2). ATUE was 1.13-1.72 kg/hm2 · d · °C, which was higher than the national level, 3) Annual mean precipitation and thermal resources use efficiency in growing season was not distribute as the natural resources distributed which meant the potential of water and heat use was not insufficient. We propose the potential resources measures as follows: 1) Prevented chilling damage and be fit for the temperature increased and make water conservation, 2) Choosing systematic irrigation management measures according to water spatial and temporal allocated changed, 3) Improving the multiply cold and arid tolerance varieties technology and adjusting crops planting structure and varieties distribution to adapt climate change impacts.