模拟大气氮沉降对柳杉人工土壤有机碳的影响

Effects of Simulated Atmospheric Nitrogen on Soil Organic Carbon in Cryptomeria fortunei Soil

指出了氮沉降引发的陆地生态系统退化和水体富营养化等生态系统"氮饱和"问题,促使一些科学家开始对氮沉降所引起生态系统退化问题开展研究。在华西雨屏区中心地带,以人工柳杉林为研究对象,研究参照NTTREX项目和北美Harvord Forest研究设计,用NH_4NO_3进行N沉降处理,共设4个水平:CK(0kg/hm^(-2)·年)、低N(50kg/hm^(-2)·年)、中N(100kg/hm^(-2)·年)和高N(150kg/hm^(-2)·年)。每月以溶液方式对林地进行喷施,研究了0~20cm土壤在施用不同氮含量的样方中土壤有机碳含量的变化。通过1年的研究发现:土壤有机碳的含量随着氮累积量的增加程先上升后下降的趋势,并且除了2016年4月份那次之外,向土壤中施加N10比N0,N5和N15增加的有机碳要明显多得多(P<0.01)。实验中还发现0~10cm的土层有机碳含量与10~20cm的土层有机碳含量相比差异显著得多(P<0.01)。

Nitrogen deposition caused by terrestrial ecosystems degradation and eutrophication of ecosystems, such as ＂nitrogen saturation＂ problem prompted some scientists began to nitrogen deposition caused by the degradation of e- cosystem research. Increasing nitrogen deposition effects on forest soil organic carbon research is very popular. In the center of Huabei rain--screen zone, the artificial Cryptomeria fortunei plantation was selected as the research object. According to NTTREX project and Harvord Forest in North America, N sedimentation was treated by NH4NO3 CK （0 kg hm^-2 · a^-l） with lowN （50 kg · hm^-2 · a^-l）, middleN （100 kg · hm^-2 · a^-l） and high Nhm^-2 · a^-1）. The forest is sprayed by solution every month. The paper studied the changes of soil organic carbon in 0 - 20 cm soil samples with different nitrogen contents. Through the study of la, it was found that the contents of soil organic carbon tended to increase and then decrease with the increase of nitrogen accumulation. In addition to that in April 2016, the increased of organic carbon on the application of N10 was significantly more than that of NO, N5 and N15（P〈0.01）. It was also found that the organic carbon content of 0--10 cm soil layer was significantly differ- ent from that of 10--20 cm soil organic carbon content （P〈0.01）.