桂东丘陵不同造林模式水土流失监测研究

The Study on Observation for Soil and Water Losses of Different Afforestation Models in Hills of East Guangxi

关键词:  水土流失  造林模式  土壤养分  水土保持

Key words:  soil and water losses  forestation pattern  soil nutrient content  soil and water conservation

摘要:

1997~2000年在广西苍梧县林业科学研究所的3年生湿地松林中,按相同坡向、坡位、坡度设置20m×5m的集雨区、集水槽、蓄水池构成3个地表径流场,其中为马占相思(Acacia mangium)纯林,为马占相思×湿地松(Pinus elliotii Engelm)异龄混交林,为湿地松纯林(对照)。再在2年生黄皮(Clausena lansium)果园设置4个地表径流观测场,设置方法同上,其中,径流场A内种扶芳藤(Euonymusf ortunei)、B内种花生(Arachis hypogaea),C内种鸡骨草(Abrus mollis)、D未间种植物(对照)。测定径流场的地表径流量,径流的含沙量、淤泥量及其样品中的全N、全P₂O₅、全K₂O、有机质和pH值,分析土壤养分的流失,评价不同造林模式的水土保持效益。结果表明,马占相思纯林和马占相思与湿地松的异龄混交林,水土流失量分别比对照(湿地松纯林)减少50.70%和17.77%,年平均含沙量分别比对照减少50.35%和42.06%,黄皮果园间种扶芳藤模式的水土流失量和含沙量分别比对照减少90.36%和65.78%。

Abstract:

Three ground surface runoff constructions made up of 20 m×5 m watershed,waterslot and reservoir were set up on the basis of the same slope aspect,site and gradient in 3-year-old Pinus elliotii Engelm forest in Cangwu Forestry Department from 1997 to 2000.Among them,I refers to Acacia mangium pure forest;Ⅱ refers to mixed uneven aged forest of Acaicia mangium×Pinus elliotii Engelm;Ⅲ refers to Pinus elliotii Engelm pure forest (control).Also,four ground surface runoff observation constructions were set up in 2 year old clausena lansium orchard based on the same method mentioned above.Among them,Euonymus fortunei was planted in runoff construction A;Arachis hypogaea in B;Abrus mollis in C and nothing was intercropped in D (control).The trial is to survey the ground surface runoff volume,the silt content,the warp clay content and in the samples the content of entire N,entire P₂O₅,entire K₂O,organic matter and pH value;to analyse the losses of soil nutrient content and to assess the soil and water conservation benifits of different forestation pattern.The results show that Acacia mangium pure forest and Acacia mangium×Pinus elliotii mixed unevened forest reduced the soil and water losses by 50.70% and 17.77% respectively as compared with the control (Pinus ellotii pure forest);the annual mean silt content was reduced by 50.35% and 42.06% respectively as compared with the control;the soil and water losses content and silt content of the clausena lansium orchard intercropped with Euonymus fortunei were reduced by 90.36% and 65.78% respectively as compared with the control.