AbstractThe objective of the study was to determine the correlation among location of sampling sites, characteristics of Leymus chinensis material and fermentation quality, to examine the effect of growth stage on nutrient composition and fermentation quality, and then to find the main factors for influencing fermentation quality and the optimum harvest stage for ensiling. L. chinensis was harvested from 27 sites in Eurasian steppe of northern China, chopped, ensiled in plastic film bags, and stored in dark for 60 days. Lactic acid bacteria (LAB), fermentation characteristics and nutrient composition were analyzed. The results showed that crude protein (CP) of L. chinensis was >80 g kg–1, and average of neutral detergent fiber and buffering capacity (BC) were 661 g kg–1 and 227 mE kg–1 respectively. The LAB number of silage was <108, the pH >4.50, and the average of lactic acid (LA) and acetic acid (AA) were 5.14 and 9.72 g kg–1 respectively; and V‐Score >80. The water‐soluble carbohydrate (WSC) of L. chinensis correlated negatively with latitude (P < 0.001) and positively with elevation (P < 0.01) of sits based on dry matter (DM) and fresh weight (FW), and CP correlated negatively with latitude (P < 0.05) based on FW. The latitude and elevation of sites correlated significantly (P < 0.05) with LA, LA/AA and ammonia nitrogen/total nitrogen (AN/TN) in L. chinensis silage, and the DM and hemicellulose of material had significant correlation with propionic acid (P < 0.05) and AN/TN (P < 0.05) of L. chinensis silage based on DM and FW. L. chinensis had lower CP (P < 0.05) and BC (P < 0.05), and higher cellulose (P < 0.05) with advancing growth stage; the silages harvested at boot stage were well fermented compared with heading and flowering stages. Those results indicated that L. chinensis is a good forage for ruminants, L. chinensis silage is well preserved, there are negative effect of latitude and positive effect of elevation on the WSC in L. chinensis, and the latitude and elevation of sites, and the DM and hemicellulose of material are main factors of affecting the fermentation quality of L. chinensis silage. The optimum harvest stage for ensiling L. chinensis is boot stage.