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目前,人工林普遍存在土壤退化、生物多样性降低等生态问题.人工抚育间伐,营造混交林是人们经营和管理人工林的主要方式之一.为了了解这种经营方式对人工林生态系统中养分循环的影响,本文研究了位于长江上游低山丘陵区的42年生马尾松人工林7种林窗(G_1:100 m~2、G_2:225 m~2、G_3:400 m~2、G_4:625 m~2、G_5:900 m~2、G_6:1225 m~2、G_7:1600 m~2)中马尾松和红椿凋落叶分解过程中微生物生物量碳和氮的动态变化.结果表明:中小型林窗(G_1~G_5)有利于凋落叶分解过程中微生物生物量碳(MBC)和生物量氮(MBN)的增加.马尾松凋落叶中的MBC和MBN以及红椿凋落叶中的MBN,在分解期(360 d)内呈现出先增加后降低的变化,在180 d时三者达到最大值,其最高含量分别达到9.87、0.22和0.80 g·kg~(-1).而红椿凋落叶中的MBC在分解90 d时即达到最大值44.40 g·kg~(-1).红椿凋落叶中的MBC和MBN显著高于马尾松凋落叶.凋落叶中的微生物生物量碳和氮与日均温和凋落物的含水率显著相关,与凋落物的特性也密切相关.这说明对人工林进行抚育间伐时可将林窗控制在100~900 m~2的范围内,有利于凋落叶分解过程中微生物生物量碳和氮的增加,加快凋落叶的分解,提高人工林林地的土壤肥力.
At present, there are common ecological problems such as soil degradation and biodiversity loss in planted forests.It is one of the main ways for people to manage and manage artificial forests by thinning and artificial tending.In order to understand the effect of this mode of management on the nutrient contents of plantation ecosystem, (G_1: 100 m ~ 2, G_2: 225 m ~ 2, G_3: 400 m ~ 2, G_4: 625) in a 42-year-old masson pine plantation located in the hilly area of the upper reaches of the Yangtze River. The dynamic changes of microbial biomass carbon and nitrogen during the decomposition process of Pinus massoniana and Red Toona sinensis litter during the decomposition of mungbean and mulberry leaves showed that: Small Gap (G_1 ~ G_5) was beneficial to the increase of microbial biomass carbon (MBC) and biomass nitrogen (MBN) during litter decomposition. MBC and MBN in litter of Pinus massoniana and MBN, Which showed the first increase and then decrease in the decomposition period (360 d), and reached the maximum value at 180 d with the highest contents reaching 9.87, 0.22 and 0.80 g · kg -1, respectively. The MBC and MBN in the litter of R. soongorica were significantly higher than those of P. massoniana litter in the decomposition of 90 days. The litter of microbial biomass C and N was significantly correlated with the daily average litter moisture content and the characteristics of litterfall, which indicated that the gap can be controlled at 100 ~ 900 m ~ 2, which is in favor of the increase of microbial biomass carbon and nitrogen during litter decomposition, accelerating the decomposition of litter and improving the soil fertility of plantation woodland.