东北典型黑土区表层土壤有机碳储量及适宜样本容量

Topsoil Organic Carbon Storage and Optimum Sample Size in Typical Black Soil Area of Northeast China

为了对典型黑土区土壤碳库有更加清晰与深刻的认识,并为其他地区土壤碳储量调查研究提供参考,利用典型黑土区2003—2004年收集的209个样点的实测数据,估算黑土区表层土壤平均有机碳密度及储量,研究碳密度的影响因素,探讨碳储量估算中的适宜样本容量。结果表明:(1)典型黑土区表层土壤有机碳平均密度为(5.75±0.33)kg/m^2,有机碳储量为(523.82±30.06)Tg。(2)表层土壤有机碳密度受气候、地貌、坡度、土壤类型和土地利用类型的影响。土壤碳密度与气温呈反比,与降水量呈正比;碳密度坡脚>坡中下部>坡上部>坡顶>宽谷平地;当坡度≥3°时,碳密度随坡度增加呈减小趋势;黑土、草甸土和黑钙土的碳密度小于暗棕壤和沼泽土;林地和草地碳密度大于农地。(3)在95%的置信度下,本研究对典型黑土区土壤有机碳储量的估算误差约为5%;要使估算误差分别为1%和10%,则所需样本容量分别为5 549和56。

In order to know soil organic carbon pool of typical black soil area clearly and deeply, and provide a reference for soil organic carbon（SOC）dynamic monitoring practice, this paper based on the measured data surveyed at 209 samples in 2003 and 2004, estimated average soil organic carbon density（SOCD） and soil organic carbon density storage（SOCS） of topsoil in typical black soil area, analyzed influence factors of SOCD, and discussed optimum sample size for SOC dynamic monitoring. The results showed as follows： （1） The average SOCD of study area is （5.75±0.33）kg/m^2 , and SOCS is （523.82±30.06）Tg; （2） There are many factors, including climate, physiognomy positions, slopes, soil types, as well as land use types, could influence SOCD. SOCD is inversely proportional to temperature and proportional to precipitation. Besides, SOCD in different physiognomy positions listed in the following order ： Slope foot 〉 lower slope 〉 upper slope〉 top slope〉wide valley and plains. In addition, when the slope is steeper than 3°, SOCD decreased gradually with the increase of slope gradient. As for soil types and land use, SOCD in black soil, meadow soil, and chernozem is lower than dark brown soil, bog soil in typical black soil area, and SOCD in forest and grassland is greater than cropland. （3） With a 95% level of confidence, the relative error of this study was about 5%, and the sample sizes needed to obtain the average SOCD of typical black soil area within errors of 1% and 10% was 5 549 and 56, respectively.