土壤侵蚀因素对紫色丘陵区坡耕地耕层质量影响  

Effects of soil erosion factors on cultivated-layer quality of slope farmland in purple hilly area

作　　者：史东梅[1] 蒋光毅 蒋平 娄义宝 丁文斌[1] 金慧芳[1] Shi Dongmei Jiang Guangyi Jiang ping Lou Yibao Ding Wenbin Jin Huifang(College of Resources and Environment, Southwest University, Chongqing 400715, China Chongqing Eco-environment Monitoring Station of Soil and Water Conservation, Chongqing 401147, China Chongqing Surveying and Design Institute of Water Resources Electric Power and Architecture, Chongqing 400020, China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]重庆市水土保持生态环境监测总站,重庆401147 [3]重庆市水利电力建筑勘测设计研究院,重庆400020

出　　处：《农业工程学报》2017年第13期270-279,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项经费项目"坡耕地合理耕层评价指标体系建立(201503119-01-01)";重庆市水利局科技项目"重庆市水力侵蚀监测点背景侵蚀环境调查(2016)"研究成果

摘　　要：土壤侵蚀是导致坡耕地耕层土壤质量退化和土壤生产力不稳定的关键因素。该文以紫色丘陵区坡耕地为例,对坡耕地不同地力等级耕层土壤质量、渗透性能及耕层类型进行聚类分析,讨论了土壤侵蚀对坡耕地耕层厚度影响及合理耕层土体构型。结果表明:(1)紫色土坡耕地耕层土壤质量具有中等程度变异性,有效土层厚度(15~80 cm)和耕层厚度(15~25 cm)变异系数分别为12.18%和37.26%,土壤有效磷变异系数可达94.51%,说明土壤物理指标变异性小于化学指标变化;三级以下地力耕层构型为近似全虚或全实剖面结构,五等地力坡耕地产量下降50%左右。(2)紫色土坡耕地不同坡位、不同垂直深度的耕层土壤物理性质、持水性能及耕作性能差异显著(P<0.05),土壤容重为上坡>下坡>中坡,土壤抗剪强度为上坡>中坡>下坡,土壤稳定入渗为下坡>中坡>上坡,土壤贯入阻力表现为中坡>上坡>下坡;除土壤入渗外,土壤容重、抗剪强度、贯入阻力均表现为底土层>心土层>耕层;坡耕地0~40 cm土层中蓄存降水可被农作物利用70%左右。(3)中度侵蚀程度坡耕地,年均耕层厚度薄化值为1.04~3.04 mm,坡耕地合理耕层建立可选择有效土层厚度、耕层厚度、土壤容重、土壤抗剪强度、土壤有机质、土壤渗透性为坡耕地合理耕层评价最小数据集,耕层构型总体保持上虚下实型、耕层厚度20~25 cm、有效土层厚度50~60 cm。(4)紫色土坡耕地可分为四种耕层类型,其障碍耕层主要表现为有效土层厚度限制型(第II类)、耕层厚度限制型(第III类)和土壤养分限制型(第IV类),分别占耕层总量30%、10%、3%;紫色土坡耕地合理耕层建立应重点关注有效土层厚度和耕层厚度调控。研究结果可为客观认识土壤侵蚀与紫色土坡耕地耕层退化关系、合理耕层构建提供理论依据和技术参数支持。Cultivated layer soil quality is highly sensitive to both soil erosion and artificial farming tillage in Purple Hilly Area. Soil erosion is a key factor that causes soil degradation and soil productivity instability of cultivated layer for slope farmland. Taking slope farmland in purple hilly area as an example, this paper has conducted cluster analysis on soil quality, permeability and cultivated layer type of slope farmland with different land productivity grades, and further discussed the effect of soil erosion on thickness of cultivated layer and the soil body configuration with reasonable cultivated layers of slope farmland. Results indicated that： （1） The soil quality of cultivated layer for purple soil slope farmland presented a moderate variability, the variation coefficients were 12.18% and 37.26% for the effective soil layer thickness （15-80 cm） and the cultivated layer thickness （15-25 cm）, respectively, and the variation coefficient was 94.51% for the soil available phosphorus, indicating that the variability of soil physical properties was weaker than that of chemical properties. The cultivated layer configuration below the third grade of land productivity was almost full virtual or full real profile structures, and meanwhile, the production of slope farmland with the fifth grade of land productivity fell by about 50%. （2） There were significant （P〈0.05） differences in soil physical properties, water-retention properties and tillage performances of cultivated layer at different slope position and different vertical depth of purple soil slope farmland, in which the soil bulk density showed upper slope 〉 lower slope 〉 middle slope, and soil shear strength showed upper slope 〉 middle slope 〉 lower slope, the soil stable infiltration rate showed the contrary order, and the soil penetration resistance was middle slope 〉 upper slope 〉 lower slope. The soil bulk density, shear strength and penetration resistance all presented bottom soil layer 〉 subsoil layer 〉 cultiv

关 键 词：土壤 侵蚀 养分 耕层 坡耕地 土壤质量 最小数据集 紫色丘陵区 

分 类 号：S157.1[农业科学—土壤学]