Soil Organic Carbon,Carbon Fractions and Nutrients as Affected by Land Use in Semi-Arid Region of Loess Plateau of China  

作　　者：LIU Xun,LI Feng-Min,LIU Da-Qian and SUN Guo-Jun Key Laboratory of Arid and Grassland Ecology of the Ministry of Education,School of Life Sciences,Lanzhou University,Lanzhou 730000 (China) 

出　　处：《Pedosphere》2010年第2期146-152,共7页土壤圈（英文版）

基　　金：Project supported by the National Basic Research Program (973 Program) of China (No. 2007CB106804);the International S&T Cooperation Program (ISTCP) of China (No. 2006DFA31070);the International Foundation for Sciences(No. C/3313-2)

摘　　要：Cropland (CP),native grassland (NG) and two shrub land treatments which were converted from cropland in 1985:seabuckthorn (Hippophae rhamnoides L.) (ST),and branchytamarisk (Tamarix ramosissima) (BT) were investigated to evaluate effects of land use conversion on soil organic carbon (SOC) and soil nutrients in the semi-arid region of the Loess Plateau of China.Total organic carbon (TOC),light fraction organic carbon (LFOC),heavy fraction organic carbon (HFOC),total N (TN),nitrate nitrogen (NO 3-N) and nitrite nitrogen (NO 2-N),ammonium nitrogen (NH + 4-N),total P,and available P (AP) were measured.The results showed that SOC in NG,ST and BT were 12.7%,27.7% and 34.8% higher than that of the cropland,respectively.LFOC,light fraction (LF) dry matter,ratio of TOC to TN (C/N) and the ratio of TOC to AP (C/P) were higher in the shrub land or native grassland than in the cropland.Cropland had the highest TN,the sum of NO 3-N and NO 2-N,TP and AP due to the use of chemical fertilizers.TOC significantly correlated with LFOC,HFOC and C/N.LFOC significantly correlated with dry matter of the LF and C/N.TN,the sum of NO 3-N and NO 2-N and AP were significantly negatively correlated with TOC and LFOC.Therefore,land use conversion from cropland to shrub land,or maybe grassland,contributed to SOC sequestration and improved soil nutrients stabilization.Cropland （CP）, native grassland （NG） and two shrub land treatments which were converted from cropland in 1985： seabuckthorn （Hippophae rhamnoides L.） （ST）, and branchytamarisk （Tamarix ramosissima） （BT） were investigated to evaluate effects of land use conversion on soil organic carbon （SOC） and soil nutrients in the semi-arid region of the Loess Plateau of China. Total organic carbon （TOC）, light fraction organic carbon （LFOC）, heavy fraction organic carbon （HFOC）, total N （TN）, nitrate nitrogen （NO3-N） and nitrite nitrogen （NO2^--N）, ammonium nitrogen （NH4^＋-N）, total P, and available P （AP） were measured. The results showed that SOC in NG, ST and BT were 12.7%, 27.7% and 34.8% higher than that of the cropland, respectively. LFOC, light fraction （LF） dry matter, ratio of TOC to TN （C/N） and the ratio of TOC to AP （C/P） were higher in the shrub land or native grassland than in the cropland. Cropland had the highest TN, the sum of NO3^--N and NO2^-N, TP and AP due to the use of chemical fertilizers. TOC significantly correlated with LFOC, HFOC and C/N. LFOC significantly correlated with dry matter of the LF and C/N. TN, the sum of NO3^--N and NO2^--N and AP were significantly negatively correlated with TOC and LFOC. Therefore, land use conversion from cropland to shrub land, or maybe grassland, contributed to SOC sequestration and improved soil nutrients stabilization.

关 键 词：CROPLAND heavy fraction organic carbon light fraction organic carbon native grassland shrub land 

分 类 号：S158[农业科学—土壤学]