基于Nemerow法和隶属度函数的湖北杉木人工林土壤肥力评价

Soil fertility evaluation of Chinese fir planted forest based on Nemerow method and membership function in Hubei

【目的】对湖北省杉木人工林土壤肥力进行评价,为该区域杉木人工林立地选择、土壤管理及合理经营提供理论依据。【方法】采集保康、谷城、阳新、咸安、通城5个县市31个杉木人工林样点0~100 cm的土壤样本,检测有机质、全氮、全钾、全磷、水解性氮、速效钾、速效磷、有效铁、交换性钙、交换性镁及pH值共11个土壤肥力指标,分别采用改进Nemerow法和主成分分析与隶属度函数相结合的模糊综合评价方法对土壤单项肥力和综合肥力进行评价。【结果】1)各县市土壤单项肥力指标均存在极显著差异,不同土层间除交换性阳离子(钙、镁)、全钾、全磷外,其它指标均存在显著或极显著差异。2)两种评价方法对单项肥力和综合肥力的评价结果基本一致,单项肥力指数Pi和隶属度值Fi分别为0.02~3.68和0.10~0.92,均反映出土壤富氮缺磷钾且交换性阳离子贫乏的状况,而平均综合指数和FQI分别为0.656和0.358,说明土壤肥力总体处于较低水平。3)各县市土壤肥力综合指数和FQI分别为0.412~0.783和0.231~0.392,均存在极显著差异,两种评价方法均表明谷城土壤肥力相对最好,咸安最差,可能与后者林分年龄小、密度大及其短周期经营模式有关。【结论】湖北杉木人工林林地土壤处于低肥力水平,杉木栽培应以中小径材为主要经营目标,栽培过程中补充磷、钾肥十分必要。

【Objective】In order to provide basis for site selection,soil management and reasonable management of Chinese fir plantation in Hubei province,the soil fertility of Chinese fir planted forest was evaluated.【Method】Soil samples of 31 sites from Baokang,Gucheng,Yangxin,Xian’an and Tongcheng were collected and a total of 11 soil fertility indexes were tested including organic matter,total nitrogen,total potassium and total phosphorus,hydrolysable nitrogen,available potassium,available phosphorus,available iron,exchangeable calcium,exchangeable magnesium and pH value.Nemerow method and fuzzy comprehensive evaluation method combined with principal component analysis and membership function were used to analyze the single soil fertility and integrated soil fertility.【Result】1)There were extremely significant differences in soil fertility indexes in different counties and significant or extremely significant differences in different soil layers except total potassium,total phosphorus,exchangeable calcium and exchangeable magnesium.2)The evaluation results of single fertility and comprehensive fertility by the two methods were basically consistent.The values of single fertility index Pi and membership value Fi were 0.02-3.68 and 0.10-0.92,respectively,which reflected the situation of soil rich in nitrogen and deficient in phosphorus and potassium and exchangeable cation.The average composite index and FQI were 0.656 and 0.358 respectively,indicating that the overall soil fertility was at a low level.3)The soil fertility composite index and FQI were 0.412-0.783 and 0.231-0.392,respectively,with extremely significant differences in counties.Both evaluation methods showed that Gucheng had the best soil fertility and Xian’an had the worst soil fertility,which may be related to the small age,high density and short cycle management mode of planted forest of the latter.【Conclusion】Chinese fir plantation in Hubei province has low soil fertility,so the cultivation of Chinese fir should take medium and small size timber as the main management target,and it is necessary to supplement phosphorus and potassium fertilizer in the cultivation.