桂南红壤区多代连栽桉树对土壤肥力的影响

Effects of Multi-generation Continuous Planting on Soil Fertility Quality of Eucalyptus Plantation in Red Soil Area of Southern Guangxi

以桂南红壤区4个代次桉树人工林土壤为研究对象,采用空间替时间的方法,对新造林(Ⅰ)、萌芽一代林(Ⅱ)、萌芽二代林(Ⅲ)、萌芽三代林(Ⅳ)土壤的15个指标进行测定,通过显著性比较分析3种综合指标评价法(模糊数学法、内梅罗指数法和灰色关联度分析法)对不同代次桉树人工林土壤肥力质量进行评价,并进行回归性验证。结果表明:土壤pH值在多代连栽后有所降低,Ⅳ林(4.41)比Ⅰ林(4.71)低,呈现出一定的酸化趋势,而有机质和有效磷、锌等元素含量也均有所下降;内梅罗指数法和模糊数学法的评价结果趋势一致,而灰色关联度分析法的评价结果则和前2种方法不一致;进一步通过回归性验证发现,内梅罗指数法和模糊数学法的综合评价结果符合实际生产情况,而灰色关联度分析法反映的结果失真。连栽土壤肥力质量变化为Ⅱ>Ⅰ>Ⅲ>Ⅳ,土壤肥力从Ⅲ林开始出现衰退现象,需要及时补充缺失养分,维持土壤肥力质量稳定。

Taking the soil of Eucalyptus plantation in the red soil area of southern Guangxi as the research object,15 indexes of the soil of generations 1,2,3 and 4 were measured by the method of space replacing time.The soil fertility quality of Eucalyptus plantation of different generations was evaluated by means of significance comparative analysis and 3 comprehensive index evaluation methods(fuzzy mathematics method,Nemero index method and grey correlation analysis method),Finally,the regression verification is carried out.These results indicated that the soil pH value decreased after several generations of continuous planting.Forest Ⅳ 4.41 was lower than forest Ⅰ 4.71,showing a certain acidification trend,and the contents of organic matter,available phosphorus and zinc also decreased;the evaluation results of Nemero index method and fuzzy mathematics method are consistent,while the evaluation results of grey correlation analysis method are inconsistent with the first 2 methods;further through the regression verification,it is found that the comprehensive evaluation results of Nemero index method and fuzzy mathematics method are in line with the actual production situation,while the results reflected by grey correlation analysis method are distorted.The change of soil fertility quality after continuous planting:Ⅱ>Ⅰ>Ⅲ>Ⅳ,soil fertility began to decline from forest Ⅲ,and it is necessary to supplement the missing nutrients in time to maintain the stability of soil fertility quality.