摘要:
文章以喀斯特峰丛洼地的核桃(J uglans regia )人工林为研究对象,采用野外与室内相结合的方法,分析了不同林龄核桃生物量与土壤养分的变化规律,比较了土壤养分与环境因子(坡度、坡向、坡位和裸岩率)的相关性,探讨了土壤养分对生物量的影响作用。结果表明:(1)核桃林生物量随林龄的增大而增大;不同林龄均以树干和根系比重为主,占整个生物量的60%以上;(2)除速效钾外,土壤养分表现为盛产期(33年)>幼苗期(2年)>初果期(10年),不同林龄之间的土壤养分差异显著;(3)相关分析表明,土壤养分与坡位、裸岩率无相关性,与坡度、植被覆盖率呈负相关;(4)主要影响核桃幼苗期生物量的是全磷,初果期的是速效磷,盛果期的是速效氮。因而土壤肥力状况是喀斯特地区核桃人工林培育需要考虑的重要因素之一。
关键词:
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核桃
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峰丛洼地
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林龄
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生物量
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土壤养分
Abstract:
The objective of this study is to explore the change process and the relationships between biomass and soil nutrients for different-aged J uglans regia plantation in karst peak-cluster depression in the north-west of Guangxi Province.Based on a combination of field investigation and laboratory analysis,this study analyzed the change in biomass and soil nutriens and the influence of soil nutrients on the biomass of the J uglans regia trees in different stand ages.It also discussed the biomass of the J uglans regia trees and asso-ciated soil nutrients;and established relationship between soil nutrients and environmental factors (e.g. slope aspect,gradient and position and bare rock rate).The biomass of the J uglans regia trees increases a-long with the stand age,of which the trunk and root accounted for more than 60% of the total biomass.Ex-cept for the available potassium,the soil nutrients have such a trend as rich fruiting period (33 years)>seedling stage (2 years)> early fruiting (10 years).The result of correlation analysis showed that there was no significant relationship between soil nutrient,slope position and bare rock rate.However,there was neg-atively significant correlation between soil nutrient,slope,and vegetation coverage.The biomass of the J uglans regia trees is a result of the combined influence of various factors and their growth at different sta-ges is affected by different factors.For example,in seedling period the biomass of the J uglans regia trees is controlled by total phosphorus;but that is controlled by available phosphorus in early fruiting and by availa-ble nitrogen in rich fruiting.Based on these findings,soil nutrient should be considered as one of key factors in the J uglans regia plantation cultivation in karst regions.
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