利用年限对农牧交错带退耕还草地土壤物理性质的影响

Effects of utilization years on soil physical properties in the agro-pastoral transitional zone after cropland’s being transformed into grassland

在农牧交错带以小麦为对照,比较研究不同利用年限对退耕还草种植的老芒麦草地土壤物理性质的影响.结果表明,随利用年限增加,在0～30 cm范围内,老芒麦草地土壤体积质量呈现先降低后增加,土壤含水量、孔隙度呈现先增加后降低的趋势.利用第2年的老芒麦草地土壤体积质量最小、孔隙度最大,利用第3年的老芒麦草地土壤含水量最大.利用年限对0～120 min内的老芒麦草地土壤渗透性影响不大.不同利用年限老芒麦草地首30 min渗透率大小顺序为:第2年>第1年>第3年>第4年,利用第2年的老芒麦草地通过渗透截留降水的能力较强.一个生长季后,不同利用年限的老芒麦草地土壤含水量、孔隙度和体积质量分别比小麦地平均提高3.86%、1.53%和降低6.07%.

The study investigated the effects of different utilization years on soil physical characteristics of Siberian wildrye grassland after transformed from wheat cropland in the agro-pastoral transitional zone. it revealed that: (1) With the utilization years increasing, soil bulk density presented a trend of reducing firstly then raising but soil total porosity and soil water content took an opposite trend in the 0~30 cm depth; (2) Siberian Wildrye grassland had the smallest soil bulk density and the biggest soil total porosity on the second year, and the biggest soil water content on the third year; (3) Utilization years had no significant influence on soil permeability rate and the order of first 30 minute soil permeability rate of grassland with different utilization years is: the second year >the first year >the third year>the fourth year; (4) After a growing season, soil bulk density reduced 6.07%, soil water content and soil total porosity raised 3.86% and 1.53% respectively in different utilization years Siberian wildrye grassland when compared with those in the field planted with wheat.