【摘要】 通过人为施加蔗糖和硝酸铵对林地进行外源性C、N干扰和凋落叶分解的原位试验,结果表明,四川岷江流域上游地区的4种典型人工林地凋落叶年分解率及其大小顺序为糙皮桦(0.449 7)>连香树(0.271 0)>云杉(0.259 4)>云南松(0.236 5);对连香树、云南松林地进行轻度的C、N干扰均可以促进微生物的活动,从而加速了凋落叶的分解,而强度的N干扰无益于凋落叶分解率的进一步增加,强度的C干扰甚至对凋落叶分解有一定的抑制作用;对糙皮桦林地,不论是C干扰还是N干扰,均使凋落叶分解率有所下降,说明该林地的C、N对微生物来说都不缺乏;对云杉林地进行不同水平的C、N干扰,均能提高凋落叶的分解速率,说明该林地的C、N对微生物都表现为缺乏,但是轻度的干扰已足以补充林地C、N的不足,再多无益。更多还原

【Abstract】 Effects of C and N disturbances on the decomposition of leaf litter of forests were studied in situ through adding sugar and nitric ammonium to 4 forestlands and leaf litter decomposition experiments in the upper reach area of Mingjiang river,Sichuan province.The results showed that the annual decomposition ratios of leaf litter in the 4 artificial forests were Betula utilis(0.449 7)>Cercidiphyllum japonicum(0.271 0)>Picea asperata(0.259 4)>Pinus yunnansinsis(0.236 5).Mild disturbances of C and N on the forestlands of Cercidiphyllum japonicum and Pinus yunnansinsis have improved the activities of microorganisms in soil and accelerated the decomposition of leaf litter,but strong disturbance of N was not beneficial to further advance of the decomposition and strong disturbance of C even restrained it.For Betula utilis,both C and N disturbances have led to the decrease of litter decomposition ratio. This meant that the microorganisms in the forestland of Betula utilis were short of C and N.In addition,both C and N disturbances with different strength on the forestland of Picea asperata have accelerated the decomposition of leaf litter and mild disturbances of C and N are better than strong disturbances for acceleration.This indicated that the microorganisms in forestland of Picea asperata were short of C and N.更多还原