摘要
以立地条件和营林方式相同的约30a林龄油松与云杉人工纯林为对象,测定地表微气候、土壤理化性质以及微生物生物量C、N、P(MBC、MBN、MBP),揭示林分结构、土壤性质与微生物生物量间的关系,以及两林分间的差异性。结果表明:两个林分地表环境荫湿,土壤肥力较低,土壤微生物生物量低,林地土壤碳积累低,土壤生态服务功能不强。相对而言,云杉林比油松林相对湿度大而地表温度低、林地土壤肥力高、土壤微生物生物量高,因此更有利于林地土壤生态服务功能的恢复。综合分析发现,林分结构、土壤养分状况及地表小气候影响着土壤微生物生物量与肥力转换过程,降低乔木冠层密度可以改善地表小气候,为有机物分解与养分归还创造良好的条件,从而改善土壤肥力与林地土壤生态服务功能。
Pinus tabulaeformis and Picea asperata plantations are extensively distributed in the upper Minjiang River,western Sichuan.They became representative low-benefit forests at present which display low biodiversity and productivity,poor soil fertility,vulnerable to forest disturbances and difficult for new species to immigration. We selected two typical plantations with about 30-year-old and uniform in habitats and afforestation management to investigate microclimate under forest,stand structure,soil properties and soil microbial biomass.Through comparing the differences in microclimate under forest,soil properties and soil microbial biomass between pine and spruce plantations,we aimed to illustrate whether there are different effects on soil quality and forest microclimate bwteen pine and spruce plantations.It is well known that microbial biomass is clearly important to a series of soil process and sensitive to change in soil texture and environmental conditions,and forest microclimate and soil properties are very important factors controlled microbial biomass.Therefore,we examined the correlation between soil microbial biomass,forest microclimate,soil properties and stand structure to find out the key factors which control soil microbial biomass in pine and spruce plantations in the upper Minjiang River.The present study provides foundational data for management and promotion of soil function restoration under forest plantations,especially low efficiency forest as pine and spruce plantations in the upper Minjiang River. Air temperature and relative humidity were measured at 5 cm above ground on three plots separately in the two forest plantations.Stand structure including tree DBH,height,tree density,tree cover,shrub cover,herb cover,litter cover and so on was investigated in nine pine plantation plots（10m×12m） and twelve spruce plantations plots（10m×12m）.Soil samples were collected at different layer（0-10 cm,11-20 cm,21-30 cm） in nine plots under pine plantation and twelve plots under spruce plantation.Soil properties including organic carbon（TOC）,total nitrogen（TN）,total phosphorus（TP）,total potassium（TK）,dissolved organic carbon（DOC）,dissolved organic nitrogen（DON）,ammonium（NH＋4-N） and nitrate（NO-3-N）,pH,cation exchange capacity（CEC）,particle composition ratio,bulk density were determined in this study.Fresh soil,which was sieved（2mm） and stored at 4℃,was used for DOC,DON,NH＋4-N and NO-3-N,microbial biomass carbon,nitrogen and phosphorus（MBC,MBN and MBP） measuration,and all fresh soil analyses were finished in ten days.Assays of other indexes were conducted using dry soil. The results were as follows：（1） Both the two forest plantations displayed humid ground environmental condition,low soil fertility,low soil carbon accumulation and low soil microbial biomass（microbial biomass C,N and P ranged from 190.99 to 608.90 mg/kg,37.76 to 99.79mg/kg,and 7.04 to 11.14mg/kg,respectively）.While compared with the pine plantation,the spruce plantations presented better microclimate status and soil quality,implying that spruce plantation could promote soil function restoration better than the pine plantation;（2） Stand structure,soil nutrient condition and microclimate operated soil microbial biomass and nutrient turnover process together.Owing to high afforestation density,the high tree cover of pine and spruce plantations at present resulted in humid microclimate and inhibited the regeneration of species under canopy.It was concluded that canopy tree thinning could improve soil nutrient cycling and accelerate ecological function restoration for those pure dense plantation forests by promoting microclimate and microbial activity.
出处
《生态学报》
CAS
CSCD
北大核心
2011年第3期801-811,共11页
Acta Ecologica Sinica
基金
中国科学院西部行动计划项目(KZCX2-XB2-02)
国家自然科学基金(40701181
30972350)
中国科学院山地生态恢复与生物资源利用重点实验室以及生态恢复与生物多样性保育四川省重点实验室共同资助
