Reseach On Interspecific Relationship In Apple-Crop Intercropping System Of Western Shanxi Province

Agroforestry management is widely applied in Loess Plateau as one of the effective measures to reduce soil and water loss, restore ecological balance, raise land utilization rate and increase economic benefits. However, interspecific competition exists in agroforestry system to some extent, the study on the relationship among different species in agroforestry system could contribute to intensively understanding the stability of ecosystem structure and function, explore reasonable and efficient utilization ways of resource, provide theoretical basis for managing agroforestry system with high-yield, high-efficiency and stabilization. In order to find suitable intercropping models and managements in Loess Plateau, two typical apple-crop intercropping models were selected as research objects. Combined with effects of fruit trees and crops on light, soil moisture, soil nutrients and other ecological factors, the dynamic changes of light, soil moisture and soil nutrients in the system interface were quantitative analyzed. Coupling effect of water and fertilizer and the different management techniques of apple-crops intercropping systems also been studied. The objectives of the paper are:1) to minimize the competition between trees and crops and maximize resource utilization,2) to provide a theoretical basis for the agroforestry control and management in this region. The results showed that:(1) Light distribution characteristics and crop photosynthetic responses in economic tree and crop intercropping system showed that:the change trend of net photosynthesis effect and light effect in the intercropping system were almost the same, both were negative. With the increase distance from tree line, the negative trend gradually eased. Intercropped peanuts can obtain better light conditions than intercropped soybeans, but owing to the influence of tree shading, the net photosynthetic rate of intercropped peanuts had a greater reduction than intercropped soybeans. Compared with soybeans, peanuts were more vulnerable to the effects of fruit light stress.(2) Soil moisture distribution in economic tree and crop intercropping system showed that:In temporal, the soil moisture was significant different in different phenological phases. In spatial direction, the soil moisture in both of the intercropping systems and the corresponding monoculture systems was increasing with soil depth, showing a significant gradient characteristics. In horizontal direction, soil moisture content was related to distance from tree line. The closer to tree line, the lower soil moisture was. Within the range1.5m of apple tree line was the main competition area between apple trees and crops for soil moisture in the current tree age. On the perspective of soil moisture, apple-soybean intercropping system was superior to apple-peanut intercropping system.(3) Soil nutrient distribution in economic tree and crop intercropping system showed that:In vertical direction, similar patterns were found in both intercropping systems that soil nutrient decreased with increasing soil depth and showed significant differences. In horizontal direction, the soil nutrient content showed the same distribution characteristics of high-low-high with the distance increasing from the tree line. The minimum value was the area1.5m from the apple line. In both intercropping systems, soil nutrient showed negative effect. The relationship between intercropping species mainly performanced as competition. However, for different soil nutrient elements, there were difference between the two intercropping systems. On the perspective of soil nutrient, the results showed that apple-peanut intercropping system was superior to apple-soybean intercropping system.(4) The water and fertilizer coupling orthogonal test of apple-peanut and apple-soybean intercropping systems showed that:water was still the most important factor influencing the tree growth and crop yield in the intercropping system in loess region.(5) Different management measures had significant differences on the growth of different species. The plastic film mulching and root barrier measures could effectively raise the yield of crops and increase the income of farmers. But, the root barrier would cause adverse effects on apple trees. Therefore, from the overall consideration of the intercropping systems, the plastic film mulching measures should be taken as the primary choice of field management measures in economic tree and crop intercropping systems.In the research of economic tree and crop intercropping, long-term experiment observation should be carried to achieve the functions of economic tree and crop intercropping system, thus better realize the function of economic tree and crop intercropping system, improve ecology, economy and social benefits in the maximal degree, and make better use of the advantages of economic tree and crop intercropping system.