3[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.
4[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.