7Leyshon A J,Camph C A. Effect of timing and intensity of first defoliation on subsequent production of 4 pasture species[J]. J. Range. Manage, 1992,45 (4) :379-384.
8Hofmann L,Kam J F. Production response of Russian wildrye (Elymus junceus Fish) to fertilizer and clipping[A]. Proc. of the ⅪⅤ Intern, Grassland Congr[C]. Kyoto: [s. n. ], 1981 : 595-598.