短期羊粪归还对荒漠草地土壤质量的影响OA

The return of livestock manure through grazing plays a significant role in grassland soil nutrient cycling and improvement of physical properties.However,the impact of short-term livestock manure return on soil quality in desert steppes remains understudied.This research simulated sheep manure accumulation under different grazing intensities to explore the effects of four manure accumulation levels(MN,0 kg·ha−1;ML,4000 kg·ha−1;MM,8000 kg·ha−1;MH,16000 kg·ha−1)on soil quality of a desert steppe in Yanchi,Ningxia.The results demonstrated:1)After two years of manure application,soil temperature tended to increase with increased manure accumulation level,although the average soil temperature differed significantly only in MH compared to MN,ML and MM(P<0.05).Similarly,average soil moisture content was significantly higher in MH than in ML and MM(P<0.05).2)Soil pH decreased while extracellular enzyme activity increased with increased manure accumulation.3)Manure return promoted the formation of soil macro-aggregates while reducing the proportion of micro-aggregates quantities,and the soil stability increased with increased accumulation of sheep manure.4)Compared to MN,ML,MM and MH also significantly enhanced the soil quality index(P<0.05).Correlation analysis and structural equation modelling further revealed that manure return improved soil hydrothermal conditions,and stimulated enzyme activities related to carbon and nitrogen cycling,thereby increasing nutrient inputs and macro-aggregate formation,and ultimately enhancing soil quality.In conclusion,low,medium and high levels of manure application effectively improved soil quality,providing both a theoretical foundation and practical guidance for restoring degraded grassland soils.