平茬对毛乌素沙地飞播杨柴林土壤养分与颗粒组成的影响

Effects of Stumping on Soil Nutrients and Particle Size of Aerial-seeding Hedysarum mongolicum Shrubs in Mu Us Sandy Land

本文以毛乌素沙地飞播杨柴林为研究对象,对4种平茬强度(预留盖度10%、20%、30%、40%)及未平茬杨柴林(对照)的土壤有机质、全氮、速效氮、速效磷、速效钾及粒径组成进行研究,了解平茬对土壤理化性质的影响,为杨柴林分结构调控提供依据。结果显示:(1)预留盖度10%~30%平茬可提高0~20 cm土层土壤全氮含量,预留盖度20%较对照提高了137.50%;预留盖度30%土壤有机质含量较对照提高6.29%;4种预留盖度平茬处理样地土壤速效氮、速效磷、速效钾含量均显著低于对照;杨柴林土壤养分表现出一定的表聚效应,主要集中在0~5 cm土层。(2)平茬提高了土壤黏粒和粉粒含量,降低了砂粒含量,对0~10 cm土层影响较大,预留盖度20%较对照0~20 cm土层黏粒和粉粒含量提高了205.68%和144.97%,砂粒含量降低了7.65%。(3)基于改善土壤理化性质考虑,建议飞播杨柴林在平茬抚育时选择20%~30%的预留盖度为宜。

The aerial-seeding Hedysarum mongolicum shrubs in Mu Us Sandy Land was taken as the research object,the soil organic matter,total nitrogen,available nitrogen,available phosphorus,available potassium and particle size composition of four stumping intensities(reserved coverage at 10%,20%,30%,40%)and non-stumping forest(control)were studied.It could provide the basis for regulating the structure of Hedysarum mongolicum shrubs to understand the influence of stumping on soil physical and chemical properties.The results showed:(1)The soil total nitrogen content in 0-20 cm soil layer was increased with the reserved coverage at 10%-30%,it was increased by 137.50%with the reserved coverage at 20%compared with the control.The soil organic matter content was increased by 6.29%with the reserved coverage at 30%,compared with the control.The contents of soil available nitrogen,available phosphorus and available potassium were significantly lower than those of the control in the plots of stumping with four reserved coverage.The soil nutrients in Hedysarum mongolicum shrubs showed a certain aggregation effect,mainly concentrated in 0-5 cm soil layer.(2)Stumping increased the content of soil clay and silt and decreased the content of sand,which had a great influence on 0-10 cm soil layer.The content of soil clay and silt in 0-20 cm soil layer with the reserved coverage at 20%was 205.68%and 144.97%higher than that in the control,and the content of sand was reduced by 7.65%.(3)In view of improving the soil physical and chemical properties,it was suggested that the reserved coverage at 20%-30%was suitable for stumping tend of the aerial seeding Hedysarum mongolicum shrubs.