森林生态系统养分循环研究中若干问题的讨论

Discussion on the Problems in the Research of Nutrient Cycle in Forest Ecosystem

根据对黄土残塬沟壑区刺槐林地养分循环的研究和实践 ,对有关养分生物地球化学循环研究中遇到的若干问题进行了讨论。提出在养分循环通量的测算中 ,林木年存留量、养分随凋落物年归还量 ,及林木在整个生长过程中大气输入及雨水淋溶归还的养分测定都存在一定的误差和问题 ;养分循环过程的数学模拟假定中 ,养分吸收量的计算应考虑其受树龄的影响 ;养分利用效率指标的测算中 ,利用修正的Chapin指数 ,可克服对树木养分利用效率过高估计的偏差 。

According to the research and practice on nutrient cycle of black locust forest stands in the area of gulled loess plateau,some key problems in the research of nutrient biogeochemical cycle have been discussed.It is pointed out that in the processing of nutrient circulation flux measurement there exist some errors and problems,such as in the measurement of annual standing stock,nutrient returning amount with litter,nutrient returning amount with atmosphere input and rainfall eluviation action in the whole growth process.During the presupposition of model establishment,the influence of tree ages should be considered in the calculation of nutrient absorption amount.In the processing of nutrient efficiency using measurement,the higher estimation errors of tree nutrient utilization efficiency could be overcome with the revised Chapin index,which could really reflect the nutrient using condition in each growing stage of trees from the point of nutrient circulation utilization.