桂西北喀斯特区石灰土与红壤坡地幼龄橘园降雨侵蚀特征

为探究桂西北喀斯特区石灰土与红壤坡地幼龄橘园的降雨侵蚀特征,通过室内人工模拟降雨试验,研究3种降雨强度(30,60,90 mm/h)下,石灰土与红壤坡地幼龄橘园的产流产沙特征。结果表明：(1)降雨强度为30,60 mm/h时,红壤橘园的产流总量分别为石灰土橘园的2.46,1.83倍,且红壤橘园主要以地表产流为主,石灰土橘园主要以壤中流产流为主;当降雨强度为90 mm/h时,二者产流总量无显著性差异(p>0.05),均以地表产流为主。(2)石灰土橘园与红壤橘园地表径流强度随降雨强度增大而增大;但随着降雨强度增大,石灰土橘园的壤中流径流强度呈先增大后减小趋势,红壤橘园壤中流径流强度却在减小。(3)降雨强度为60 mm/h时,红壤橘园产沙总量为石灰土橘园的3.74倍,当降雨强度为90 mm/h时,石灰土橘园产沙总量为红壤橘园的2.86倍;在降雨过程中,石灰土橘园产沙量随着降雨历时增大上下波动较为剧烈,红壤橘园产沙量随降雨历时增大波动幅度较小。(4)当降雨强度≥60 mm/h时,石灰土橘园与红壤橘园累积产沙量与累积产流量存在显著线性关系,且降雨强度越大线性关系越明显。研究结果可为喀斯特地...

Rainfall Erosion Characteristics of Young Citrus Orchards on Calcareous Soil and Red Soil Slopes in Karst Areas of Northwest Guangxi

In order to investigate the characteristics of rainfall erosion of young citrus orchards on calcareous soil and red soil slopes in karst areas of northwestern Guangxi, an indoor artificial simulated rainfall experiment was conducted to study the runoff and sediment yield characteristics of young citrus orchards on calcareous soil and red soil slopes under three rainfall intensities (30, 60, and 90 mm/h). The results showed that: (1) When the rainfall intensity was 30 and 60 mm/h, the total runoff yield of red soil citrus orchards was 2.46 and 1.83 times that of calcareous soil citrus orchards, respectively, and the red soil citrus orchards was dominated by surface runoff yield, while the calcareous soil citrus orchards was dominated by subsurface flow yield; when the rainfall intensity was 90 mm/h, there was no significant difference in the total amount of runoff between the two (p>0.05), and both of them were mainly by surface runoff. (2) The surface runoff intensity of calcareous soil citrus orchards and red soil citrus orchards increased with the increase of rainfall intensity. However, with the increase of rainfall intensity, the subsurface flow intensity of calcareous soil citrus orchards showed a trend of first increasing and then decreasing, while the subsurface flow intensity of red soil citrus orchards was decreasing. (3) When the rainfall intensity was 60 mm/h, the total sediment yield of red soil citrus orange orchards was 3.74 times that of the calcareous soil citrus orchards, and when the rainfall intensity was 90 mm/h, the total sediment yield of the calcareous soil citrus orchards was 2.86 times that of red soil citrus orchards. During the rainfall process, the sediment yield of calcareous soil citrus orchards fluctuates sharply with the increase of rainfall duration, while the sediment yield of red soil citrus orchards was relatively small with the increase of rainfall duration. (4) When the rainfall intensity was more than 60 mm/h, there was a significant linear relationship between the cumulative sediment yield and cumulative runoff yield of calcareous soil and red soil orchards, and the greater the rainfall intensity, the more obvious the linear relationship was. The research results can provide reference and reasonable suggestions for the prevention and control of soil erosion in young citrus orchards on calcareous soil and red soil slopes in karst areas.