杨树、水杉林带枯落物对土壤微生物C、N的影响

杨树 (Ｐｏｐｕｌｕｓｓｐｐ .)、水杉 (Ｍｅｔａｓｅｑｕｏｉａｇｌｙｐｔｏｓｔｒｏｂｏｉｄｅｓ)是我国亚热带滨海盐土的重要造林树种 ,它们生长快且能耐轻度盐碱 ,因此常被作为这一地区复合农林业的理想树种 (钟哲科等 ,1 996 )。由于滨海地区处于陆地和海洋的交界处 ,自然环境较为恶劣 ,自然灾害频繁 ,因此复合农林业系统的研究和应用已成为保障这一地区农业持续稳定发展的重要措施。关于林木对小气候调节、改善生态环境等研究已有不少报道 ,但关于林木枯落物在复合农林业系统中对土壤微生物的作用 ,研究仍很少。植物枯落物是复合农林…

IMPACTS OF LITTER OF POPULUS AND METASEQUOIA ON SOIL MICROBIAL BIOMASS

Incubation experiment and field investigation on soil microbial biomass dynamics in agroforestry system in coastal saline soil, which impacted by litter decomposition process of Populus and Metasequoia glyptostroboides, were carried out in this study. It was showed that the litter of Populus was more favorable to soil microbial biomass increase, whereas litter of M. glyptostroboides was less favorable to soil microbial biomass increase, but the microbial biomass N content associated with litter decomposition of M. glyptostroboides was higher than that of Populus, and litter of M. glyptostroboides was easier to be accumulated in the soil. There was a positive interaction for microbial biomass increase when M. glyptostroboides leaves mixed with Populus leaves during decomposition. According to soil microbial parameters, such as ratio of microbial biomass N and total N, metabolic quotient (qCO 2) from field investigation, it was also proved that although the soil organic content under forest increased, the soil salinity content had not decreased significantly, and the qCO 2 was still high. This may suggest that the increase of organic matter through agroforesty practice did not efficiently mitigate the environmental stress for soil microbes. Therefore, in the study soil, it is still necessary to adopt other measures to improve site conditions.