COMPARATIVE STUDY ON WATER USE CHARACTERISTICS AND PRODUCTIVITY OF SOYBEAN AND MAIZE INTERCROPPING SYSTEM UNDER DRY FARMING CONDITIONS

Quantitative investigation of the utilization characteristics of precipitation resources and the production capacity of the intercropping production system under the soybean maize intercropping mode in northern China is of great significance for improving the resource utilization rate of dryland agriculture and regional sustainable development. This study adopted a completely randomized block design, and six planting modes were set up: soybean monoculture, maize monoculture, and four soybean maize intercropping modes. Plant height and grain yield data were observed, and precipitation resource utilization efficiency was calculated. Based on the FAO-56 recommended crop coefficients, the crop coefficients were corrected according to the actual growth of crops in the experimental area; combined with meteorological data, the crop water demand under different planting modes was estimated based on the Penman-Monteith principle. The results showed that crops' daily growth water demand under different planting modes was generally deficient in water in the early and middle stages of growth, and surplus in the later stages. Compared with the monoculture mode, there were significant differences in precipitation resource utilization efficiency under different intercropping modes (P < 0.05), with soybeans reduced by 67.50% ~ 89.56%, and corn reduced by 43.99% ~ 61.05%. Based on the semi-humid and semi-arid area of the eastern Loess Plateau, an appropriate irrigation system needs to be designated for soybean and corn intercropping systems in the early and middle stages of crop growth. Under a certain proportion of water resource supply, different modes have different water resource utilization efficiency and final production capacity for the intercropping system.