北方土石山区不同土地利用方式下土壤质量综合评价

摘要

为了确定不同土地方式对土壤质量的影响,以北方土石山区不同土地利用方式(人工林地、封山育林、坡改梯、谷坊、撂荒地)土壤为研究对象,采用室内土壤理化性质分析等手段研究土壤蓄水能力、土壤养分特征差异性,采用层次分析法对各样地土壤质量进行综合评价.结果表明:各个样地土壤容重在1.24～1.37g?cm-3之间,撂荒地最大,人工林地最小;土壤容重随着土层深度的增加而呈现增大的趋势;不同土地利用方式下土壤毛管孔隙度依次为人工林地>坡改梯>谷坊>封山育林>撂荒地,土壤有效含水率依次为人工林地>坡改梯>封山育林>谷坊>撂荒地.土壤总库容和土壤最大有效库容均以人工林地最好,其数值分别为1459.29t?hm-2和1339.5t?hm-2;土壤死库容表现为封山育林(134.03t?hm-2)>谷坊(126.14t?hm-2)>人工林地(119.79t?hm-2)>坡改梯(102.52t?hm-2)>撂荒地(100.44t?hm-2),撂荒地的土壤水分利用效率低;土壤兴利库容和滞洪库容在1127.06～1241.78t?hm-2和58.28～167.21t?hm-2之间.封山育林、人工林地、坡改梯、谷坊土壤有机质相比于撂荒地(9.39g?kg-1)分别提高59.42％、49.09％、36.74％、24.07％;不同土地利用方式条件下土壤全氮、有效磷和速效钾含量有所不同,表现为封山育林>人工林地>坡改梯>谷坊>撂荒地,说明通过采取水土保持措施能够有效地提高土壤养分含量.人工林地、封山育林、坡改梯、谷坊土壤质量综合指数比撂荒地(0.421)分别提高31.83％、31.59％、17.58％、17.34％;采取水土保持措施后能提高土壤质量,以人工林地和封山育林效果最佳.%In order to determine the effects of different land types on soil quality, taking the soil of rocky mountain areas of Northern China as examples, we mainly analyzed the differences in soil water storage capacity and soil nutrient characteristics of different land use types (artificial woodland, closing hillsides to facilitate afforestation, slope change ladder, valley square, fallow land) by using soil physical and chemical properties analysis indoor. The comprehensive evaluation of soil quality was carried out by analytic hierarchy process. The soil bulk density of all samples was 1.24 -1.37 g?cm -3, the maximum for fallow land and the minimum for the artificial woodland. The soil bulk density increased with the depth of soil layer. The soil capillary porosity of all samples was artificial woodland > slope change ladder > valley square > closing hillsides to facilitate afforestation > fallow land, and soil effective water content was artificial woodland > slope change ladder > closing hillsides to facilitate afforestation > valley square > fallow land. The soil total reservoir storage and maximum available storage were 1459.29 t?hm -2 and 1339.5 t?hm -2, respectively, with artificial woodland the best. The soil dead storage of all samples was closing hillsides to facilitate afforestation (134.03 t?hm-2 ) > valley square (126.14 t?hm-2 ) > artificial woodland (119.79 t?hm-2)> slope change ladder (102.52 t?hm-2 ) > fallow land (100.44 t?hm-2 ) and the lowest soil water use efficiency was fallow land. The usable storage and flood control storage were 1127.06-1241.78 t?hm-2 and 58.28-167.21 t?hm-2, respectively. Compared with the fallow land (9.39 g?kg-1 ), the soil organic matter in closing hillsides to facilitate afforestation, artificial woodland, slope change ladder, valley square increased by 59.42％, 49.09％, 36.74％, and 24.07％, respectively. The total N, available P and available K with different land use types were different and the orders were closing hillsides to facilitate afforestation > artificial woodland > slope change ladder > valley square >fallow land. Soil and water conservation measures could effectively improve the soil nutrient content. Compared with the fallow land (0.421), the soil quality composite index of artificial woodland, closing hillsides to facilitate afforestation, slope change ladder, valley square increased by 31.83％, 31.59％, 17.58％, and 17.34％, respectively. Soil and water conservation measures can improve soil quality, and artificial woodland and closing hillsides to facilitate afforestation are the best.