黄土丘陵区柠条种植带状结构对坡面土壤水分的影响

(山西师范大学 生命科学学院, 山西 临汾 041000)

黄土丘陵区; 种植年限; 柠条条带; 土壤水分

Effects of Strip Caragana korshinskii Plantation on Soil Moisture at Hillslope Scale in the Loess Hilly Region
DU Yujia, ZHAO Yonggang, LIU Xiaofang, ZHANG Xingxing, REN Zeying, JIA Jiayu

(College of Life Science, Shanxi Normal University, Linfen, Shanxi 041000, China)

loess hilly region; plantation age; shrub-grass band; soil moisture

备注

为了探明柠条种植对坡面土壤水分的影响,选择黄土丘陵区等高线带状种植15 a,25 a和35 a柠条(Caragana korshinskii Kom.)坡地,以撂荒草地为对照,分析了不同种植年限、坡位以及灌草部位(柠条带间、带前、带内和带后)下0—100 cm土层水分变化。结果 表明:(1)与撂荒草地相比,柠条种植15,25,35 a后,土壤含水量分别降低了7.76%,44.30%,48.42%。不同坡位的土壤含水量表现为坡顶最高,坡中和坡下次之并显著高于坡上。(2)研究区灌草部位土壤含水量在带间、带前和带内无显著差异(p>0.05),但均显著高于带后(p<0.05)。灌草部位显著差异主要出现在坡上、坡中、坡下。(3)冗余分析(RDA)结果表明:柠条种植年限对坡面尺度土壤含水量影响最大,海拔和坡度次之。变异分割分析(VPA)检测结果显示:年限、海拔、坡度对土壤含水量的解释量分别为4.8%,3.6%,2.3%,各环境因子综合效应的解释量为65.2%。总体来看,黄土丘陵区长时间柠条种植已显著降低了坡面土壤水分含量及其异质性,年限是坡面尺度土壤含水量的主控因素,而柠条带状结构种植也对小尺度土壤水分产生了明显的影响。

To further understand the effect of Caragana korshinskii plantation on soil moisture at hillslope scale in the loess hill region, the soil moisture contents were analyzed at three selected slope positions and four shrub-grass band positions(inter-band, front-band, inner-band and behind-band)under four transects: 15-, 25-, and 35-years old Caragana korshinskii plantations and native grassland as control. The results showed that:(1)compared with barren grassland, the soil moisture content of Caragana korshinskii reduced by 7.76%, 44.30% and 48.42% after 15-, 25-, and 35-years old, respectively; the soil moisture content at different slope positions was the highest on the top-slope, and the soil moisture contens of the mid-slope and lower-slope were significantly higher than that of the upper-slope;(2)there was no significant difference in soil moisture content among the inter-, front- and inner-band(p>0.05), but it was significantly higher than that of behind-band(p<0.05); significant differences of shrub-grass band mainly occurred in upper-, mid-, and lower-slope;(3)the redundant analysis showed that the plantation ages of Caragana korshinskii had the greatest effect on soil moisture content at hillslope scale, followed by altitude and slope gradient; variation partitioning analyses showed that the explanation variance of soil moisture by age, altitude and slope gradient was 4.8%, 3.6%, 2.3%, respectively, and the integrated explanation variance of all environmental factors reached to 65.2%. In general, long-time plantation of Caragana korshinskii in the loess hilly region significantly reduced the soil moisture content and heterogeneity along slope and depth. The plantation age and altitude were the main controlling factors at hillslope scale, while shrub-grass band also had significant impacts on soil moisture at small-scale.