黄土区冰草和柳枝稷草地土壤分离生长季变化

Growing Season Variations of Soil Detachment under Wheatgrass and Switchgrass Lands in the Loess Area of China

以黄土区的黄绵土为材料,研究了退耕还草3年和17年条件下,黄绵土的土壤分离能力生长季的变化。结果表明:两种退耕草地黄绵土的土壤分离能力在整个生长季均呈下降趋势,其中,冰草地的土壤分离能力具有明显的生长季变化(P<0.05),柳枝稷草地无明显生长季变化(P>0.05)。土壤硬化、水稳性团聚体和根系生长是影响两种退耕草地土壤分离能力生长季变化的主要因素。两种退耕草地黄绵土的土壤分离能力在生长季的变化可以用土壤容重、根系密度和水流剪切力很好地模拟(R2>0.82,ME>0.82)。

After 3 years of switching farmland to grassland with wheatgrass and 17 years with switchgrass grass in Loess Plateau of China, the variations of soil detachment with growing season were studied. Results showed that soil detachment of these two rehabilitated grasslands exhibited declined trend during the growing season. Soil detachment of wheatgrass land showed obvious change with growing season （P 〈 0.05）; One of switchgrass lands had no obvious change with growing season （P 〉 0.05）. The variations of soil detachment with growing season under two rehabilitated grasslands were affected by soil consolidation, water-stable aggregates, and root growth. Soil detachment of two rehabilitated grasslands could be estimated using soil bulk density, root density, and flow shear stress （R2〉 0.82, ME 〉 0.82）.