不同经营模式对毛竹土壤活性有机碳的影响

以起始于1984年的长期不同经营模式毛竹林为研究对象,探讨了夏季毛竹林集约经营后土壤有机碳的变化。结果表明:(1)集约经营后0~80 cm土层毛竹林土壤总有机碳平均增加了5.48%,易氧化碳含量平均增加了15.14%,水溶性有机碳含量平均下降了3.98%,三者均未达到显著差异。(2)两种毛竹林土壤总有机碳、易氧化碳、水溶性有机碳的剖面特征均随土层深度的增加而呈现下降趋势,但下降速度不同。集约经营在一定程度上影响毛竹土壤易氧化碳剖面特征。(3)土壤总有机碳、易氧化碳与土壤养分之间相关性均达到极显著水平,而水溶性有机碳与土壤养分之间相关性不显著。(4)集约经营提高了土壤易氧化碳占总有机碳的比例、土壤碳库活度,并在土壤剖面部分土层差异达到显著水平。但其水溶性有机碳占总有机碳的比例3.74%,低于粗放经营毛竹林的4.10%。因此,集约经营的毛竹林,通过配施恰当比例的有机无机肥,结合土壤垦复、除草、合理的竹株留养和采伐等综合竹林经营技术,以达到改善土壤质量和实现毛竹林可持续经营的目的,也可改善土壤生物化学活性。

Effects of Different Management Models on Soil Active Organic Carbon of Bamboo Forests

Increasing problems concerning the environmental quality in forest land and the long-term productivity of forest emphasized a need to develop and improve management strategies that maintain and protect soil function and resources.Changes in forest management may lead to changes in soil organic carbon(SOC) quantity and quality.The maintenance of a high SOC status was desirable for long-term land use due to the multiple beneficial effects of SOC on the soil nutrient status,its structure and water holding capacity etc.The effects of different silvicultural practices on soil organic carbon were still poorly known.The changes were studied in SOC during the long-term conversion of extensively managed Moso(Phyllostachys pubescens) stands to intensively managed ones in Fuyang County,Zhejiang Province,where Moso were widely distributed.Bamboo stands of different management types started in 1984 were designed to investigate the effects of intensive management on SOC.The results showed:(1)The average of total organic carbon(TOC) and readily oxidation carbon(ROC) in 0-80 cm soil layer was increased by 5.48% and 15.14% respectively,while water soluble organic carbon(WSOC) was averagely decreased by 3.98% after intensive practice.(2) The vertical features of different fractions of organic carbon under two management models of bamboo stands were observed in decline trends with increasing of soil depths,while both of the drop speeds were different.Intensive practice affected the profile distribution of soil ROC to a certain extent.(3) TOC and ROC were extremely significantly correlated with soil nutrients,while WSOC wasn′t significantly related to soil nutrients.(4) The percentage of ROC to TOC and activity of carbon pool was increased significantly after intensive management in part of soil layers,but the percentage of WSOC to TOC was 3.74%,was below the extensive practice that was 4.10%.Therefore,to improve soil quality and achieve sustainable management of bamboo stands,a mixture of organic and inorganic manures with the proper ratio in bamboo stands under intensive management should be applied,combined with ploughing,weeding,reasonable bamboo leaving and bamboo cutting,which could fulfill a high yield of bamboo shoot and bamboo culm,maintain the ecological function of bamboo stands and improve the soil activities of biology and chemistry.