| Weibei loess plateau is the major grain producing area, but the ecological environment is weak and the farmers’income is low. Walnut (Juglans regia L.) is one of the representatively economic tree species in this area. Relay intercropping walnut with grain crops can play a role in agriculture and forest depending and promoting each other. The goals of harvesting both grain and walnut can be achieved, and it is significant in stabilizing food production and promoting the development of local characteristic industry and increasing farmers’ income. In this study, the microclimate and benefit of relay intercropping walnut of6-8years and wheat (Triticum aestivum L.) was investigated. Pure stand of6-8years walnut was the control. The walnut cv."LiaoHe No.1" was planted in autumn2003. There were eight planting densities and they were divided into planting belts and relay intercropping belts along the row space direction. The growing zone of relay intercropped crops was two meters wide and the side was one meter distance from walnut zone. The atmospheric temperature, soil moisture, soil temperature, soil humidity, evaporation capacity, wind speed and illumination intensity, etc. in relay intercropping region were measured when the walnut was about ten years old. Results showed that, under the same site conditions, plant height and the average diameter at breast height of walnut under relay intercropping were respectively16%and26%higher than control. The yield of walnut dry fruit was150kg/667m2,21%higher than control. The income of relay intercropping system was3000Yuan/667m2, increasing doubled compared to control.After relay intercropping with wheat, the enhanced field management indirectly created good conditions for walnut growth.The reasons of the advantage of walnut/wheat relay intercropping system are as follows. One side, the76%absorbing roots of walnut intensively distribute in the40-100cm soil layer, but the roots of wheat mainly distribute in the0-40cm plough layer, only12%of depth compared to walnut; roots of the two crops distributed basically staggered, so the conflict of the two crops for utilizing water and fertilizer was little, making them suitable for relay intercropping. Another side, the changes of microclimate factors, such as environment temperature, wind speed, light intensity, soil moisture, soil temperature, soil humidity and evaporation capacity, etc. in relay intercropping system indicated the regulating effect of walnut to agricultural microclimate, which created advantageous growth environment for wheat. |
