桉树人工林水土流失及养分损耗研究

目的]研究广西国有七坡林场内桉树人工林水土流失及养分损耗情况。方法]利用径流小区进行定点连续监测研究,分析了间种牧草对桉树林水土流失及其养分损耗的影响。结果]不同植被类型年平均地表径流量为桉树纯林(2 919.50 m3/hm2)>桉树林+桂牧1号象草(2 219.42 m3/hm2),地表径流量季节变化为夏季>春季>秋季>冬季,与该地区同期降雨量的季节分配基本一致。土壤侵蚀量为桉树林+桂牧1号象草(4.125 t/hm2.a)>桉树纯林(3.835 t/hm2.a),桉树间种牧草流失的泥土比例高,而桉树纯林流失的径流比例大。水土养分流失量为桉树林+桂牧1号象草(4.388 5 kg/hm2.a)>桉树纯林(4.303 1 kg/hm2.a),与土壤侵蚀量大小规律相一致,并得出养分流失大小为有机质>Ca>K>N>P>Mg>Zn>B>Cu。结论]该地区不同植被型桉树林的地表径流量差异明显,土壤侵蚀量和养分流失量差异不显著。

Study on Soil Erosion and Nutrient Loss in Eucalyptus Plantation

Abstra-ct Objective] To study water, soil and nutrients loss of ~Eucalyptus plantation in Qipo forestry station in Guangxi Province. Meth- od] Based on location and continuous observation with a runoff plot, effects of the intercropped herbage on soil erosion and nutrient loss in Eu- calyptus plantation were analyzed. Result] The results showed that the annum surface runoff amount of different vegetation types were Euca- lyptus plantation（2 919.50 m^3/hm^2） 〉 Eucalyptus ＋ Guimu No. 1 grass（2 219.42 m^3/hm^2） and the seasonal variation of surface runoff a- mount were summer 〉 spring 〉 autumn 〉 winter , which is basically coincided with the seasonal distribution of precipitation in this region. The amount of soil erosion were Eucalyptus ＋ Guimu No. 1 grass（4. 125 t/hm^2·a） 〉Eucalyptus plantation（3. 835 t/hm^2·a）, Eucalyptus grass was high proportion on soil erosion, and Eucalyptus plantation loss in surfaced runoff. The amount of soil nutrients loss were Eucalyptus grass（4. 388 5 kg/hm^2· a） 〉 Eucalyptus plantation（4. 303 1 kg/hm^2·a）which coincided with the law of the amount of soil erosion and the soil nutfiet~t showed as organic matter 〉 Ca 〉 K 〉 N 〉 P 〉 Mg 〉 Zn 〉 B 〉 Cu. Conclusion] It was concluded that the surface runoff amount of Eucalyptus plantation with different vegetation types had significant difference in this region, but their soil nutrients and nutrient loss amount have no significant difference.