The Influence of Land Use at Different Spatial Scales on Carbon,Nitrogen,Phosphorus and Their Stoichiometry in River Water of Chaohu Lake Catchment
To better understand the influence of land use on water quality and stoichiometry,correlation and redundancy analyses were employed in this study,to quantitatively investigate the relationships between land use at different spatial scales and the concentrations of total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(COD),and the mole ratios of carbon,nitrogen and phosphorus in rivers of the Chaohu lake catchment during both high and low water periods in 2022.Results indicated that TN is the main pollutant in the rivers,with a higher N︰P ratio compared to the average of surface water at catchment and global scales.At most research scales,TN and TP exhibit a significant(P<0.05)or highly significant(P<0.01)positive correlation with the proportion of construction land,but no significant correlation with the proportion of cropland,suggesting construction land serves as an important source of TN and TP.At the sub-catchment scale,N︰P ratio exhibits a highly significant positive correlation with the construction land proportion(P<0.01),and a highly significant negative correlation with the cropland proportion(P<0.01),indicating an increase in the proportion of construction land exacerbates nitrogen-phosphorus imbalance,while an increase in cropland proportion alleviates it.Land use exhibits the highest overall explanatory power for the variation in all indicators at the sub-catchment scale.At all scales studied,the overall explanatory power of land use is higher during the water season.These findings offer a theoretical guidance for water quality management and land use planning in the Chaohu lake catchment.
Land useStoichiometryMultiple scalesChaohu lake catchmentTNTPCOD
NETL
NSTL
万方数据
