摘要
马尾松是西南地区的主要造林树种之一,对酸沉降比较敏感,在生产实践中常常在受酸沉降影响严重的针叶林地进行林分改造来应对酸沉降.为了解酸雨区马尾松纯林改造对土壤性质的影响及科学指导经营管理,本研究以重庆铁山坪马尾松纯林及改造后的马尾松-香樟混交林以及香樟纯林为对象,分不同季节采集腐殖质层(Ah层)和淋溶层(E层)的样品进行分析,探讨林分改造对土壤酸化及养分的影响.结果表明:(1)林型对Ah层土壤性质影响显著(P＜0.05),且Ah层土壤养分显著高于E层,季节对两个土层的土壤性质影响均显著(P＜0.05).(2)当马尾松纯林改造后,Ah层土壤各季节平均pH表现为马尾松纯林＜马尾松-香樟混交林＜香樟纯林;马尾松纯林改造后显著降低了土壤NH4+∶N(3-,可缓解土壤酸化.(3)虽然马尾松林改造后显著降低了土壤有机碳和全氮含量,但明显增加了土壤全磷和全钾含量(P＜0.05),可以为缺磷缺钾的铁山坪酸性土壤提供更多的磷和钾,从而缓解磷、钾限制对植物生长的抑制作用.(4)通过模糊综合法评价3种林型的土壤综合肥力指数,在0.585～0.664,马尾松纯林改造成马尾松-香樟混交林、香樟纯林,可以提高土壤肥力水平.
Abstract
Pinus massoniana is one of the main afforestation species in southwest China,which is sensitive to acid deposition.To cope with acid deposition,stand transformation is often carried out in coniferous forests that have been seriously affected.In this study,we explored the effects of transformation of P.massoniana pure plantation on soil acidification and nutrients by comparing P.massoniana-C.camphora mixed plantation,C.camphora pure plan-tation,and P.massoniana pure plantation in Tieshanping of Chongqing.Soil samples of humus(Ah)and leachate(E)horizons were collected in different seasons.The results showed that:(1)Forest type had significant effects on soil properties in Ah horizon(P＜0.05).Soil nutrient concentrations in Ah horizon were significantly higher than those in E horizon.Soil properties in both horizons varied greatly across seasons(P＜0.05).(2)After the transfor-mation of P.massoniana pure plantation,soil pH in Ah horizon was in order of P.massoniana pure plantation＜P.massoniana-C.camphora mixed plantation＜C.camphora pure plantation.Soil NH4+:NO3-ratio was significantly reduced after the transformation of P.massoniana pure plantation,which could alleviate soil acidification.(3)Soil organic carbon and total nitrogen concentrations were significantly reduced after the transformation of P.massoniana pure plantation,while soil total phosphorus and total potassium concentrations were significantly increased(P＜0.05),which could provide more phosphorus and potassium and thus alleviate the phosphorus and potassium limi-tation on plant growth in the acidic soils.(4)The comprehensive soil fertility index evaluated by the fuzzy compre-hensive method was 0.585-0.664.Our results suggested that the transformation of the P.massoniana pure planta-tion into P.massoniana-C.camphora mixed plantation and C.camphora pure plantation could improve soil fertility.
基金项目
国家自然科学基金面上项目(31971630)
中央级公益性科研院所基本科研业务费专项(CAFYBB2018SZ004)
国家科技期刊平台
NSTL
万方数据