Study On Interactions Among Species Of Walnut-peanut Intercropping System In Loess Area Of West Shanxi Province

In this paper, microclimate, photosynthetic, soil moisture, soil nutrient and roots of walnut-peanut intercropping system in loess region of western Shanxi Province was researched to find suitable intercropping models and management in Loess Plateau. 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 were as following:(1)Micro-climatic effect and light distribution in walnut-peanut intercropping system showed that: walnut-peanuts farm intercropping system had the micro-climatic effects in improving the farmwater conditions; The crops were influenced by trees, the photosynthetic active radiation and net photosynthetic rate of crops were significantly decreased by trees, and the decreasing degree is decreased with the increasing of distance from tree rows.(2) Soil moisture distribution in walnut-peanut intercropping system showed that:In temporal, soil moisture of different layer in walnut-peanut intercropping system increased first and decreased then in 2008 and 2009; Compared with other layer, change of soil moisture of surface soil is more severe, then, soil moisture change remained stable with increasing soil depth. In spatial, soil moisture increased and the variation coefficient of soil moisture decreased with increasing soil depth; In horizontal direction, soil moisture was related to distance from tree row. The closer to trees sampling points, the lower the soil moistures. In comparison with peanut monoculture, soil moisture of different layer in walnut-peanut intercropping system is more than peanut monoculture and increased with increasing soil depth in flowering-pod period of peanut. It is relative in seedling- flowering period and pod- maturity period.(3) Soil nutrient distribution in walnut-peanut intercropping system showed that:soil organic matter, total nitrogen, phosphorus and potassium of Walnut-peanut intercropping System have the highest content in surface soil; In vertical direction, soil nutrient decreased with increasing soil depth; In horizontal direction, soil nutrient decreased with the decrease of the distance from the tree row in 1.5 meters from walnut trees and soil nutrient increased with the increase of the distance from the tree row in 1.5-3.5 meters from walnut trees. In comparison with peanut monoculture, soil nutrient of different layer in walnut-peanut intercropping system is less than peanut monoculture. It is rich in potassium and is lacking in nitrogen and phosphorus in research area.(4) Roots distribution in walnut-peanut intercropping system showed that:walnuts roots is most in 20cm～40cm soil layer. In horizontal direction, peanut roots is most in 0cm～10cm soil layer of walnut-peanut intereropping system and in 10cm～20cm soil layer of peanut monoculture in 1.5 meters from walnut trees:In vertical direction.the peanut were influenced by walnut trees in walnut-peanut intercropping system in 0cm～10cm soil layer in 1 meters from walnut trees. Total root length, total root length density and total root surface area of peanut monoculture were more than that in walnut-peanut intercropping system in 10cm-40cm soil layer.