Using a nitrogen-phosphorus ratio to identify phosphorus risk factors and their spatial heterogeneity in an intensive agricultural area
作者:Lou, HZ (Lou, Hezhen)[ 1 ] ; Yang, ST (Yang, Shengtian)[ 1 ] ; Zhao, CS (Zhao, Changsen)[ 1 ] ; Wang, ZW (Wang, Zhiwei)[ 1 ] ; Shi, LH (Shi, Liuhua)[ 2 ] ; Wu, LN (Wu, Linna)[ 1,3 ] ; Dong, GT (Dong, Guotao)[ 4 ] ; Cai, MY (Cai, Mingyong)[ 5 ] ; Hao, FH (Hao, Fanghua)[ 6 ] ; Sun, Y (Sun, Ying)[ 7 ]
卷: 149 页: 426-436 子辑: 1
出版年: FEB 2017
High phosphorus risk in intensive agricultural regions, which threatens an increasing number of water bodies within the regions, is driven by the nitrogen-phosphorus ratio (N:P ratio). The mechanism remains unclear, however. Most nutrient studies are based on local-scale field trials, which failed to identify the geographical factors that drive phosphorus accumulation at the larger scale of a watershed. To address this issue, we adopted a large-scale, remote-sensing-driven model to simulate the N:P ratio in the soil of the Sanjiang Plain, one of the most important commercial grain bases of China. A grid-random sampling method was employed to test the validity of the model. The results show that 35% of the higher N:P ratios were converted to lower ratios in old cultivated land where the concentration of soil phosphorus increased by 1-2 times over 11 years (2000-2010); however, in the new cropland cultivated from forestland, grassland and wetland, 18% of the lower N:P ratios were converted to higher ratios, with soil phosphorus concentration increased slightly. Higher N:P ratios come from greater nitrogen input into the new cropland soil, which reduces soil pH and then enhances phosphorus accumulation, thus increasing the phosphorus risk. We find that the variation in land-use types and the excessive input of anthropogenic fertilizers are the two dominant factors influencing the N:P ratio. Intensive anthropologic activities changed traditional knowledge on the relationship between the N:P ratio and phosphorus accumulation, and further necessitated large-scale research on nutrients in intensive agricultural regions. The finding can shed new light on phosphorus management and non-point source pollution control in intensive agricultural areas. (C) 2016 Elsevier B.V. All rights reserved.
通讯作者地址: Zhao, CS (通讯作者)
Beijing Normal Univ, Sch Geog, Beijing Key Lab Remote Sensing Environm & Digital, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China.
[ 1 ] Beijing Normal Univ, Sch Geog, Beijing Key Lab Remote Sensing Environm & Digital, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China
[ 2 ] Harvard TH Chan Sch Publ Hlth, Dept Environm Hlth, Landmark Ctr 404 M 401 Pk Dr, Boston, MA 02215 USA
[ 3 ] Guizhou Univ, Coll Resource & Environm Engn, Guizhou 550025, Guiyang, Peoples R China
[ 4 ] Yellow River Inst Hydraul Res, Zhengzhou 450003, Peoples R China
[ 5 ] Satellite Environm Ctr MEP, Beijing 100094, Peoples R China
[ 6 ] Sch Environm, State Key Joint Lab Environm Simulat & Pollut Con, Beijing 100875, Peoples R China
[ 7 ] Dongying Survey Bur Hydrol & Water Resources, Dongying 257000, Peoples R China