毛竹林集约经营过程中土壤活性有机碳库的演变

为了探讨不同集约经营历史毛竹林的土壤有机碳库演变规律,在浙江省安吉县分别采集了集约经营5、10、20和40年的毛竹林土壤样品,与粗放经营毛竹林进行比较.结果表明:毛竹林集约经营的前5年里,土壤总有机碳、微生物量碳、水溶性碳和矿化态碳含量均明显下降(P＜0.05);土壤总有机碳持续下降至20年后趋于稳定,土壤水溶碳、矿化态碳含量集约经营5年后一直到第40年无明显变化;随着集约经营措施的实施,土壤活性有机碳占总有机碳的比例变化不大(除矿化态碳在0～5年以及微生物量碳在10～20年明显下降外).集约经营20年后,土壤总有机碳下降了34.70%,微生物量碳下降了49.35%.相关分析表明,各活性碳之间显著或极显著相关.比较不同经营类型的毛竹林发现,集约经营并未改变土壤各类碳含量的剖面特征.集约经营会导致土壤碳的大量损失,并使土壤生物学性质明显下降.

Changes in Soil Active Organic Carbon with History of Intensive Management of Phyllostachy pubescens Forest

Soil organic carbon approved affected by intensive practice. phyllostachy pubescens forest has been managed in intensive way for long term in order to get higher economic profits. Soils under intensive management (IM) for 5, 10, 20 and 40 years respectively were compared with the soil of extensive practice. The result showed: Soil total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC) and mineralize carbon(MC) decreased greatly (P<0.05) after 5_year intensive practice; Soil TOC was continuing going down until 20_year, however, WSOC and MC kept constant after 5_year till 40_year. Soil TOC and MBC decreased by 34.70% and 49.35% respectively with the intensive practice in 20 years.The vertical distribution feature of different soil organic carbon were not altered by intensive practice in the soil section, the amount of organic carbon have decreased in the similar soil layer. Intensive practice caused a big loss of soil carbon and degradation of soil biological properties. It is recommended to amend the amount of organic matter or fertilizer annually to sustain the soil quality.