Interspecific Interaction And Soil Phosphates In Mulberry/Soybean Intercropping System

Intercropping of mulberry and soybean is a new planting system of agroforestry in Northeast China. In this system, mostly intercropped mulberry cultivars are used own-root mulberry varieties to intercrop or mix soybean. The own-root mulberry in one year old will grow into a shrub about 1.5 metre high to pick up its leaves for silkworms and to cut branches for medicine materials. The own-root mulberry species used in intercropping system can overwinter in northeast China, at same time mulberry intercropped crop can avoid continuous cropping. In the co-grown stage of intercropping plants, interspecific plants exist competition in the resources of light, heat, water and nutrients, but interspecific plants can exist apparent facilitation in soil nutrients and light using. In this paper, using mulberry/soybean intercropping system grown in saline-alkali soil and meadow black soil as object, interspecific interaction of belowground and aboveground indices in mulberry/soybean intercropping system in the field were investigated during co-grown stage of mulberry/soybean intercropping system.The results showed that above ground biomass, net photosynthetic rate in leaves, nitrogen content, root dry weight, root length density and nitrate reductase activity in leaves of intercropped mulberry increased 65.9%,11.8%,17.8%,24.8%,139.8%and 116.2% compared to sole mulberry during the co-growth stage in mulberry/soybean intercropping system, but the value of these were reduced in intercropped soybean indicating interspecies competition between component crops. Soil microbial biomass C and dehydrogenase activity increased in intercropped soybean compared to sole soybean indicating interspecies facilitation between component crops. It suggested that interspecific competition and interspecific facilitation coexisted in mulberry/soybean intercropping systemThe innovation in this paper through mulberry/soybean intercropping in saline-alkali soil and meadow black was found that interspecific facilitation and interspecific competition co-exist in mulberry/ soybean intercropping system, while interspecific facilitation stronger than interspecific competition in mulberry/ soybean intercropping system in adversity soil(saline-alkali soil).The root phosphates activity and soil phosphates activity enhanced in mulberry/ soybean intercropping system in saline-alkali soil, Phosphates play a important role in enhancing Phosphates activity in adversity soil, especially in forming oecology system advantage in intercropping in saline-alkali soil.