甘草种植对西北风蚀区农田土壤养分及风蚀的影响

    Effects of Glycyrrhiza uralensis Plantation on Soil Nutrients and Wind Erosion in Wind Erosion Stricken Region of Northwest China

    • 摘要: 为了探讨甘草(Glycyrrhiza uralensis)植被对农田土壤风蚀和土壤养分的影响及植被覆盖措施减少土壤养分损失的机理,以甘草植被及其下部土壤为研究对象,对甘草植被的特征指标及其下部0~5 cm土层的风蚀和土壤养分含量进行分析。结果表明,随甘草生长年限的增加,甘草植被的覆盖度、高度、地上生物量和下部表土层的有机碳,速效N、P、K含量呈显著升高趋势,而表土层风蚀量及容重却呈下降趋势(P<0.05);相关分析显示,甘草植被的特征指标与土壤养分间均呈显著正相关关系(P<0.05),其中土壤养分与植被覆盖度间相关系数最大,其后依次为植被高度和地上生物量;回归分析显示,甘草植被的覆盖度每提高1%,可使农田表土的有机碳,速效N、P、K含量分别提高0.038 g·kg-1、0.052 mg·kg-1、0.113 mg·kg-1和0.971 mg·kg-1。风蚀区农田若采取植被覆盖措施一方面可降低表层土壤的风蚀,从而减少土壤养分的流失,另一方面可增加枯枝落叶进入土壤的几率,从而提高土壤养分的输入;通过两方面共同作用最终可使植被覆盖农田的养分流失变小。

       

      Abstract: To explore effects and mechanisms of liqorice (Glycyrrhiza Uralensis) vegetation conserving soil nutrients and reducing wind erosion, analysis was done of the liqorice vegetation cover for characteristic indices and of the soil 0-5 cm under the cover for soil nutrient conservation and effect on wind erosion reduction. Results show that with the liqorice vegetation growing on, coverage, height and above ground biomass of the vegetation, and organic carbon(OC), available N, P and K contents in the topsoil all increased, while wind erosion and bulk density decreased (P<0.05). Correlation analysis indicates that characteristic indices were significantly and positively related to soil nutrients (P<0.05), showing an order of vegetation coverage> height> aboveground biomass in terms of correlation coefficient. Regression analysis demonstrates that for every 1% of increase in vegetation coverage, the content of OC, available N, P and K in the topsoil increased 0.038 g·kg-1, 0.052 mg·kg-1, 0.113 mg·kg-1 and 0.971 mg·kg-1, respectively. Obviously, the adoption of the practice of maintaining vegetation coverage on farmlands of wind erosion stricken regions of Northwest China, may on the one hand, reduce wind erosion of the surface soil and hence the loss of soil nutrients, and on the other hand, increase the amount of litters and hence content of soil nutrient, of which the joint effects will eventually reduce the loss of soil nutrients correspondingly.

       

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