Climate Change and High Quality Development of Agriculture in Water Limited Regions

The concept of high-quality development was put forward in China in 2017, so, agriculture development enters the new stage of the high-quality development. The high-quality development of agriculture is to take some measures and methods to make the land produce the maximum output and services to meet people's yearning for a better life and the needs of agricultural production services. However, because of climate change, overuse of fertilizer and pesticide, introduction of un-native plant species or varieties and exotic plant species or varieties, unbalance plant water relationship often happens, resulting soil and vegetation degradation and crop failure or waste of nature resources, which are unfavorable for the sustainable utilization of soil water resources and crops high-quality production. Therefore, it is necessary to adjust the plant water relationship and obtain the maximum yield and services to realize the sustainable utilization of nature resources by plants and crops high-quality management. Here we show that the theoretical foundations of sustainable use of soil water resources includes the soil water resources use limit by plants (SWRULP), soil water vegetation carrying capacity (SWVCC) and the critical period of plant soil relationship regulation in water-limited regions. The SWRULP is the soil water resources in the maximum infiltration depth (MID) in which the soil water content in every soil layer equal to wilting coefficient. The wilting coefficient is expressed by the wilting coefficient of indicate plant in a plant community. SWVCC is the population or density of indicator plants in a plant community when the soil water supply is equal to soil water consumption in the root zone in the critical period of plant water relationship regulation (CPPWRR, which changes with plant community type, site condition and time. When soil water resources in the MID is lower than SWRULP, the plant water relation enters the CPPWRR. The ending time of CPPWRR is the ineffective time of plant soil relationship regulation. In order to get the maximum yield and service, we have to select best plant species or varieties, take Suitable initial planting density and effective measures or methods to ensure plant normal grow and get the cultivate goal. If in the process of plant growth, the plant density in the critical period of plant soil relationship regulation is more than the SWVCC, plant water relationship must be regulated based on SWVCC to get the maximum yield and service and realize sustainable use of soil water resources and high-quality production. As for some fruit or crops, the leaf and fine fruit must be regulated according to the suitable quantity of leaf when the plant density is equal to the SWVCC in the critical period of plant soil relationship regulation and the fine fruit is the fruit for goal market.