Study On Yield And Quality Of Perennial Legume-grass Mixture Grassland In The Hilly Region Of Sichuan

Legume-grass mixed grassland makes full use of natural resources,improving the productivity of grassland and the stability of grassland community,and prolonging soil service life.In this study,alfalfa（Medicago sativa L.）,white clover（Trrifolium repens L.）,red clover（Trifolium pratense L.）,orchardgrass（Dactylis glomerata L.）,perennial ryegrass（Lolium perenne L.）,and tall fescue（Festuca arundinacea Schreb.）were selected as materials,with different mixed types（A1:white clover+orchardgrass+tall fescue;A2:alfalfa+orchardgrass+tall fescue;B1:alfalfa+white clover+orchardgrass+tall fescue;B2:red clover+white clover+orchardgrass+tall fescue;C1:alfalfa+white clover+orchardgrass+tall fescue+perennial ryegrass;C2:red clover+white clover+orchardgrass+tall fescue+perennial ryegrass;D:alfalfa+red clover+white clover+orchardgrass+tall fescue+perennial ryegrass）and different mixed ratios（legume-grass ratio 5:5,4:6,3:7）combined to build artificial grassland.The aim was to explore the variation of forage yield,nutrition quality and community stability,and then to obtain the best mixed combination with sustainable high-yield,high-quality,which may provide guidance for the development of animal husbandry in the hilly areas of Sichuan.The results were as follows:1.Based on the average yield of the two years,A2,C1 and D had higher yields in the first harvest,which were 4487.67 kg·hm^-2,4162.41 kg·hm^-2 and 4151.32 kg·hm^-2,respectively;A2 and D were higher,which were 4252.43 kg·hm^-2 and 4016.01kg·hm^-2 in the second harvest;A2 was higher in the third cutting,which reached4598.19 kg·hm^-2.According to the total yield,A2 was significantly higher than other combinations,which was 13338.29 kg·hm^-2.Therefore,in terms of yield,the mixed combination A2 was better.2.In terms of nutritional quality,the CP yield of A2 was significantly higher than that of the other combinations in 2018,reaching 2242.73 kg·hm^-2.D,C2,A2,and C1had higher WSC yield,which was 813.03 kg·hm^-2,745.52 kg·hm^-2,736.93 kg·hm^-2and 716.16 kg·hm^-2,respectively;the NDF yield of B1 was lower,which was 4902.69kg·hm^-2;the ADF yield of A1 and B1 were lower,which was 2941.57 kg·hm^-2,3043kg·hm^-2,respectively.The relative feed value（RFV）of A2 and B1 were significantly higher than that of the other combinations,141.66 and 143.30,respectively.3.Based on the hay yield and nutritional quality,the membership function values of species combination A2 was relatively high（0.65）,followed by B1（0.56）,which had better production performance.4.The yield change between different mixed species combinations in two years had two modes:A1,no significant difference was observed in the yield change between two years,and the stability was high;for other species combinations except A1,the yield was decreasing,and the stability was weak.In terms of mixed ratio,N3（3:7）had higher stability.In 2018,legumes dominated in A2 and B1 in 2018,accounting for 75.59%and 63.96%,respectively,while other combinations were dominated by grasses..In 2019,the proportion of grasses of all combinations decreased（10-20%）,and legumes predominated.In terms of specific pasture species,alfalfa in legumes had strong competitiveness and stability;perennial ryegrass in grasses had strong competitiveness but weak adaptability to the environment.5.In terms of land equivalent ratio（LER）,the LER values of mixed species combination A1,B2,C1,and D were all greater than 1 in each harvest,and B1 and D were significantly greater than 1 except the first harvest in 2018.Each mixed combination had high interspecies compatibility The competition rate（CR）value of grasses except A1 gradually decreased,and its competitiveness gradually weakened.6.In terms of yield,quality and stability,A2（alfalfa+orchardgrass+tall fescue）and ratio N3（3:7）was more suitable to grow in the hilly areas of Sichuan.