6[3]Z.L.Tan,H.P.Chen,L.H.He,et al.Variation in the nutritional characteristics of wheat straw[J].Animal Feed Science and Technology,1995,53:337-344.
7[4]J.Lloveras,I.Ig lesias.Morphological development and forage quality changes in crimson clover (Trifolium incarnaturnal)[J].Grass and Forage Science,2001,56::395 -404.
8[13]Tilley J.M,R.A Terry.A two-stage technique for in vitro digestion of forage crop[J].J.Brit.Grassl Sol,1963,18:104-114.
9[14]Moore,J.E.Forage quality indices:development and application[M].G.C.Fahey,Jr.Fornge Quality,Evaluation,and Utilization.ASA,CSSA,SSSA,Medison,WI,1994.