Soil N mineralization is a key process of nutrient cycling in ecosystems.The mechanism of the seasonal distribution of precipitation on soil N mineralization remains unclear.We conducted a precipitation manipulation experiment in a subtropical forest in the middle and lower reaches of the Yangtze River in China from 2020 to 2022,with three treatments,including control(CK),decreased precipitation in the dry season with extremely increased precipitation in the wet season(T1),and decreased precipitation in the dry season with proportionally increased precipitation in the wet season(T2).With in situ resin core method,we explored the effect of seasonal distribution of precipitation on soil N mineralization.The results showed that T1 and T2 significantly decreased dry season net nitrification rate by 57.9％and 72.5％and the net N mineralization rate by 82.5％and 89.6％,respectively,and significantly increased wet season net nitrification rate by 64.3％and 79.5％and net N mineralization rate by 64.2％and 81.1％,respectively.Proportionally increased precipitation in the wet season was more conducive to soil N mine-ralization process than extremely increased precipitation in the wet season.Results of the structural equation model showed that change in seasonal distribution of precipitation could significantly affect soil N mineralization processes in the subtropical forest by changing soil water content,ammonium nitrogen,microbial biomass nitrogen,and soil C:N.Our results had important reference for understanding soil nitrogen cycling and other ecological processes,and were conducive to more accurate assessment on the impacts of future changes in seasonal precipitation pattern on subtropical forest ecosystems.
关键词
土壤氮转化/亚热带森林/降水格局/生物地球化学循环/干湿季
Key words
soil nitrogen transformation/subtropical forest/precipitation pattern/biogeochemical cycle/dry and wet seasons
维普
万方数据