灌枝覆盖与羊粪添加对荒漠草原土壤养分及优势牧草生长的影响OA

Shrub branch mulching and sheep manure addition have shown potential in degraded grass-land restoration practices for improving soil moisture and nutrient availability,respectively.However,the mechanisms and effects of these two measures,whether individually or combined,on soil water and nutri-ent regulation and dominant forage growth in desert steppe remain unclear.Therefore,a two-factor split-plot experiment was conducted in the desert steppe of Yanchi,Ningxia.The main plots consisted of three levels of Caragana korshinskii branch mulch treatments:no mulch,short-branch mulch(5-10 cm),and long-branch mulch(70-130 cm).The subplots included four sheep manure addition levels of 0 kg/hm2,4 000 kg/hm2,8 000 kg/hm2,and 16 000 kg/hm2.Their effects on soil moisture,temperature,nutrients,and dominant forage growth were investigated.The results showed that:(1)Compared with no branch mulch,both short-branch mulch and long-branch mulch reduced soil temperature and increased soil water content,whereas sheep manure addition had no significant effect on soil moisture or temperature;(2)Both branch mulch and sheep manure addition significantly decreased soil pH and increased the contents of soil organic carbon,nitrogen,and phosphorus;(3)Branch mulch and sheep manure addition significantly pro-moted the growth of dominant forages.All growth indices of Agropyron mongolicum were highest under the short-branch mulch and 8 000 kg/hm2 sheep manure addition treatment,while Lespedeza potaninii per-formed best under the long-branch mulch and 8 000 kg/hm2 sheep manure addition treatment;(4)Redun-dancy analysis indicated that soil water content,temperature,and nutrients were key environmental factors influencing forage growth,with particularly pronounced effects on Agropyron mongolicum.In summary,branch mulch mainly improved soil hydrothermal conditions,whereas sheep manure addition primarily enhanced soil nutrient supply.Their combination effectively promoted the growth of dominant forages in desert steppe,providing a scientific basis for grassland ecological restoration and sustainable management.