吉林省通榆县土壤有机碳储量及时空分布研究

SOIL ORGANIC CARBON STORAGES AND THEIR SPATIAL AND TEMPORAL DISTRIBUTION IN TONGYU COUNTY,JILIN PROVINCE

利用土地利用类型法,在解译通榆县1989年、2000年和2004年TM遥感影像获得土地利用数据的基础上,结合第二次土壤普查数据与1998年、2006年和2007年的实地采样测试数据,估算了3个年份土壤有机碳储量,并分析了其时空分布.人类活动导致了耕地、草地的退化以及盐碱地、沙地面积的增加,成为土壤有机碳储量变化的主要驱动因素.研究结果表明,3个年份 0～100cm的土壤有机碳储量分别为 4931.91±86.90×10^4t,4708.51±86.86×10^4t和 4874.33±88.73×10^4t,15年间减少了约57.58×10^4t; 0～20cm的有机碳储量分别为 1390.36±9.16×10^4t,1342.32±12.54×10^4t和 1378.97±13.26×10^4,约减少了11.39×10^4t.研究区土壤有机碳储量在1989年到2000年间显著减少,在2000年到2004年间有所增加.有机碳密度较高的区域集中在西北部的湿地附近,较低的地区分布在中西部.有机碳密度较高区域的面积呈整体减少趋势,有机碳密度较低区域的面积则呈增加趋势.

The soil organic carbon storages and their spatial and temporal distribution in Tongyu County, Jilin Province were based on interpreted data of 1989, 2000, and 2004 remote images in combination with the second national survey soil data and 1998, 2006,and 2007 sampling and test data. In this study, 155 topsoil samples were collected and 24 soil profiles were measured. The soil organic carbon（SOC） storages in the depths of 100cm and 20cm were calculated by the land use/cover change （LUCC）type method; the organic matter contents were measured by the potassium dichromate method. The results that the SOC storage in the depth interval of 0 - 100cm was 4931.91 ± 86.90×10^4t for 1989, 4708.51 ±86.86 ×10^4t for 2000, and 4874.33± 88.73 ×10^4t for 2004, decreased about 57.58×10^4t. And the SOC storage in the depth interval of 0 - 20cm was 1390.36±9. 16×10^4t for 1989, 1342. 32± 12.54 ×10^4 t for 2000, and 1378.97 ± 13.26 ×10^4t for 2000, reduced about 11.39 ×10^4t in the same period. The SOC storage was dramatically decreased from 1989 to 2000 and then was followed by a slight increase between 2000 and 2004. The farmland and grassland were the major SOC pool in the county. The SOC density was the highest in wetlands located at the northwest of the county, but the lowest in sandy lands and saline-alkali lands located in the middle and west of the county. A general trend was that the high SOC density area was reducing,whereas the low SOC density area was increasing. It was found that with increase of soil depth, the SOC density decreased only in wetlands,woodlands, farmlands, paddy fields, grasslands, and construction lands during the 15 years, but didn＇t change significantly in sandy lands and saline-alkali lands. The dominant driving factor of such SOC changes should be human activities