The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intercropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.