华北农牧交错带退耕区榆树幼林-南瓜间作的农田生态效应

Farmland Ecological Effect of Young Elm Forest–Pumpkin Strip Intercropping in De-farming Area in the Agriculture-Animal Husbandry Ecotone of North China

【目的】针对华北农牧交错区退耕林地大面积荒芜资源无效流失的问题,通过榆树幼林-南瓜带状间作,达到林地高效利用与生态-经济效益协同增进的目的。【方法】采用田间试验和室内理化分析相结合的方法。【结果】榆树幼林与南瓜间作后,瓜蔓覆盖地面,显著提高了南瓜行间和榆树林地的土壤水分含量,林-瓜间作地水分的利用效率较单作提高了23.7%～163.3%;间作改变了南瓜行间杂草群落自然演替的方向,一年生杂草成为优势物种,其饲用营养物质的含量和产量较林带间杂草显著提高。间作比单作南瓜增产24.4%,榆树生物量累积提高28.4%,杂草增产144.4%,南瓜的经济效益也提高了23.2%。林-瓜间作比单作土地利用效率提高了132%。监测表明,榆树幼林-南瓜间作地的土壤输沙量与南瓜单作地、退耕榆林地间的差异均不显著,没有因南瓜地的土壤耕作而提高土壤的风蚀量。【结论】华北农牧交错带退耕区榆树幼林-南瓜带状间作是区域生态-经济效益兼顾、综合利用林地资源的有效技术模式。

[Objective] In accordance with the actual problem of large area of barren lands and resource loss resulted from returning land for farming to forestry in agricultural and pastoral areas of North China, by using young elm forest-pumpkin strip intercropping, the purpose wanted to be achieved to realize the effective utilization of barren lands and ecological improvement and economic development. [Method] Field experiments combined with laboratory experimental estimation and analysis were adopted. [Result] With young elm forest-pumpkin strip intercropping, since the branch tendril covered the gap between pumpkin planting-ditches and elm forest land, the soil moisture was remarkably increased. And the water use efficiency under intercropping increased by 23.7%-163.3% compared with the sole cropping. Elm-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-ditch, annual grasses became the dominant vegetation, and the feeding nutrient matter content and yield of the annual grasses increased significantly. The biomasses of pumpkin, elm and grass under intercropping were increased by 24.4%, 28.4% and 144.4%, respectively, compared with those under sole cropping. The land use efficiency was increased by 132%. Results also indicated that the soil erosion from the intercropping land was not increased by planting pumpkin, the difference in soil erosion among intercropping land, elm forest land and pumpkin land with sole cropping was not remarkable.[Conclusion] Young elm forest-pumpkin strip intercropping is an effective technical way to utilize the barren lands between the young forest elm belts effectively and realize synergistic enhancement of ecological benefit and economic profit.