Appropriate Canopy Depth and Distance Among Plant

Agriculture development had entered new stage of Agriculture high-quality development. Agriculture high-quality development is to take some measure and method to make land produce maximum yield and service to meet people's needs for better life and agriculture production and services. Because overuse of fertilizer, pesticide and introduction of un-native plant species or varieties n modern agriculture. As plant grows, plant water relationship has altered, resulting in soil dryness, soil degradation and crop failure in dry years or waste of soil water resources in wet year in water-scarce areas, which is unfavorable for the sustainable utilization of soil water resources and crops high-quality development. Therefore, it is necessary to adjust the plant water relationship and obtain the maximum yield and services to realize the sustainable utilization of soil water resources by plants and crops high-quality management. However, there is not a universally accepted theory to provide guidance of regulation of plant water relationship in practice. Here we show that the theory of sustainable use of soil water resources includes the soil water resources use limit by plants (SWRULP) soil water vegetation carrying capacity (SWVCC) and critical period of plant soil relationship regulation. 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. The soil water vegetation carrying capacity (SWVCC) is the ability of soil water resources to support vegetation. 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 CPPSRR, 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 critical period of plant soil relationship regulation (CPPSRR). The ending time of CPPSRR is the ineffective time of plant soil relationship regulation, such as fruit stopping expanding, vegetation stop serve. We have to keep appropriate canopy depth and distance among plant in the process of plant growth to get the maximum yield and service. For example, perennial prickly ash forest with about 2 meter in high in Yilong, China. Because leaf of prickly ash tree is a compound leaf. According to the investigation of prickly ash forest on March 14, 2025, if there is no flower bud at the base of the leaf bud at the top of the canopy, the top bud at the top of the canopy should be removed to control the vegetative growth of new bits. If there is no flower bud at the lower part of the canopy, inferior leaves should also be removed to maintain the thickness of the canopy depth at 80-100 cm. The appropriate canopy depth is 80-100 cm. The appropriate canopy depth and distance among plant is good control index.If present plant density in the critical period of plant soil relationship regulation is more than SWVCC, plant soil relationship must be regulated based on SWVCC to get the maximum yield and service to realize sustainable use of soil water resources and agriculture high-quality development.