亚热带低丘地巨尾桉幼林地径流特性研究与评价

Research and Evaluation on the Surface Runoff Characteristics of Young Eucalyptus grandis × E.urophylla Forest Land in the Low Hilly District of Subtropical Zone

[目的]揭示生长于不同环境的桉树幼林地径流特性。[方法]通过在广西钦州市低丘地区选择不同更新方式的巨尾桉幼林地建立径流小区,进行水土流失量及其养分流失量的定位对比监测研究。[结果]不同植被类型年均地表径流量为灌草坡(215.930 mm)>萌芽林(168.499 mm)>实生林(122.455 mm),地表径流量的季节变化为夏季(395.043 mm)>春季(96.343 mm)>秋季(19.452 mm)>冬季(0 mm),与该区降雨量的季节分配相吻合。不同植被类型年土壤侵蚀量依次为实生林(7.220 kg/hm2)>灌草坡(6.345 kg/hm2)>萌芽林(6.285 kg/hm2),土壤侵蚀量的大小主要取决于降雨强度。水土主要养分流失量为实生林(0.095 5 kg/hm2)>灌草坡(0.084 0kg/hm2)>萌芽林(0.083 0 kg/hm2),与土壤侵蚀量大小规律相一致,并显示出K>N>P。[结论]该地区不同植被类型幼林地表径流差异显著,其养分流失量各有差异。

[ Objective ] The study aimed to reveal the surface runoff characteristic for forest land in young Eucalyptus grandis x E. urophylla grown in the different environment. [ Method] Through select different regeneration patterns of young E. grandis x E. urophylla forest to set up runoff plot in the low hilly district of Qinzhou in Guangxi Province and the location contrast and monitoring research was conducted on the amount of soil loss as well as nutrient loss. [ Result ] The annual surface rainfall amount of different vegetation types were ： shrub-herb forest （215. 930 mm） 〉 sprouted forest （ 168. 499 mm） 〉 seedling forest （ 122. 455 mm） and the seasonal variation of the rainfall amount were ： summer （395. 043 mm） 〉 spring （96. 343 mm） 〉 autumn （19. 452 mm） 〉 winter （0 mm） , which was identical with the seasonal distribution of precipithtion in this region. The amount of soil erosion of different vegetation types were as follows： seedling forest （7. 220 kg/hm2） 〉 shrub-herb forest （6. 345 kg/hm2 ） 〉 sprouted forest （6. 285 kg/hm2 ） and the amount of soil erosion mainly lied on rainfall intensity. The amount of soil nutrients loss were：seedling forest （0.095 5 kg/hm2 ） 〉 shrub-herb forest （0. 084 0 kg/hm2 ） 〉 sprouted forest （0. 083 0 kg/hm2 ） ,which coincided with the law of the amount of soil erosion and the soil nutrient showed as K 〉 N 〉 P. [ Conclusion] The surface rainfall amount of young forest with different vegetation types had significant difference in this region and their soil nutrients loss amount was also differentiated.