三峡库区植物篱模式对土壤理化性质和可蚀性的影响

为探究不同植物篱模式对土壤理化性质及土壤可蚀性空间上的影响,以三峡库区秭归县张家冲水土保持试验站为研究区,选取经济林地小区(H1)和农耕地小区(H3)分别为"植物篱+经济林地小区"(H2)和"植物篱+农耕地小区"(H4)对照小区,对其3个坡位(上、中、下坡)和2个土层(0—20,20—40 cm)进行土壤理化性质对比分析,探讨2种植物篱配置下对土壤理化性质和可蚀性的影响。结果表明:(1)同一小区,土壤机械组成和土壤养分含量空间分异较明显,上坡与中坡、下坡差异显著(p0.05),其中土壤机械组成以砂粒为主(59.01%～63.51%),且分布于上坡,而土壤细颗粒主要分布在中、下坡,0—40 cm土层土壤养分均表现为下坡中坡上坡,全钾含量均值较其对照小区分别高3.75%～19.61%。(2)不同小区,土壤细颗粒和土壤养分含量表现为植物篱小区高于无植物篱小区,其中土壤细颗粒占比表现为H4小区(39.94%)H2小区(38.92%)H1小区(38.34%)H3小区(37.84%);土壤可蚀性K值大小与土壤细颗粒含量呈反比,即土壤细颗粒占比越大,K值越小,越不易被侵蚀,"农耕地+植物篱"(H4)较"经济林+植物篱配置"(H2)更不易被侵蚀。(3)随着土壤有机质、黏粒、全氮和全钾含量的增加,可以有效增强土壤抗侵蚀能力。土壤可蚀性K值与粉粒、黏粒分别呈极显著正相关和负相关关系(相关系数分别为1.000,-0.708),而与砂粒、有机质、全氮和全钾均无显著相关关系(p0.05)。

Effects of Hedgerow Patterns on Soil Physical and Chemical Properties and Erodibility in Three Gorges Reservoir Area

In order to explore the spatial effects of different hedgerow patterns on soil physical and chemical properties and soil erodibility, this study took Zhangjiachong Soil and Water Conservation Experimental Station in Zigui County of the Three Gorges Reservoir Area as the research area, and selected the economic woodland plot (H1) and agricultural land plot (H3) as the control plot of "hedgerow and economic woodland plot" (H2) and "hedgerow and farmland plot" (H4) respectively. The soil physical and chemical properties were compared and analyzed in three slope positions (up, middle and down slope) and two soil layers (0-20 and 20-40 cm). The results showed that:(1) In the same plot, the spatial variations of soil mechanical composition and soil nutrient content were obvious, and the difference was significant (p<0.05). The soil mechanical composition was mainly composed of sand (59.01%~63.51%) and distributed in the upper slope, while the soil fine particles mainly distributed in the middle and lower slopes. The soil nutrients in 0-40 cm soil layer were downhill > middle slope > upper slope, and the average content of total potassium was 3.75%~19.61% higher than that of the control plot. (2) In different plots, the contents of soil fine particles and soil nutrients in hedgerow plot was higher than those in non hedgerow plot, and the proportion of soil fine particles was as follows:H4 plot (39.94%) > H2 plot (38.92%) > H1 plot (38.34%) > H3 plot (37.84%). There was a negative relationship between the K values of soil erodibility and the fine particles contents. The larger proportion of soil fine particles, the smaller the K value, the more difficult soil erosion occurred. The soil of H4 was less likely to be eroded than that of H2. (3) With the increase of soil organic matter, clay, total nitrogen and total potassium contents, soil erosion resistance could be effectively enhanced. Soil erodibility K value of soil erodibility was significantly positively and negatively correlated with silt and clay (correlation coefficients were 1.000, -0.708), but not with sand, organic matter, total nitrogen and total potassium (p>0.05).