Spatial variation in soil nitrogen content along aridity gradients in the northwest desert region in China
Dryland area is substantial,and the drylands exhibit great sensitivity to global climate change.Nitro-gen,which composed of various nitrogen forms,is generally considered the second most limiting resource in des-ert ecosystems.However,it remains unclear how different levels of aridity affect the spatial distribution of soil ni-trogen.Based on data of inorganic nitrogen,organic nitrogen,and total nitrogen from 54 sampling points in the northwest desert region of China,and coupled with climate and environmental data,we explored the spatial varia-tions in nitrogen components under different levels of aridity and the driving factors.Our results indicated a distinct aridity threshold(0.87)for the spatial variations in soil nitrogen along the aridity gradient,meaning an abrupt change in response to aridity.Near the threshold,soil total nitrogen,organic nitrogen content,and the ratio of or-ganic to inorganic nitrogen exhibited rapid increases,while nitrate nitrogen content showed a rapid decrease.Be-fore and after the aridity threshold,both total nitrogen and organic nitrogen content significantly decreased with in-creasing aridity.In the 0-10 cm soil layer,soil total nitrogen and organic nitrogen content gradually increased with soil depth.The increase in aridity directly or indirectly affected the spatial variation oin nitrogen components through soil water content(SWC),electrical conductivity(EC),and pH.The study revealed the impacts of aridi-ty on soil nitrogen balance,which are beneficial for prediction on the response of soil nutrients to environmental changes in drylands,and provide crucial support for making scientifically effective environmental decisions.
NETL
NSTL
万方数据
