Regrowth, yield and nutrition of Leymus chinensis and Hordeum brevisubulatum in response to defoliation intensity and frequency

Abstract

The effects of different defoliation intensities and frequencies were studied on regrowth and herbage mass of Leymus chinensis and Hordeum brevisubulatum in northeast China for two years. Plants were defoliated to 6, 8 or 10 cm stubble height by removing about 40% of growth down to each designated defoliation height. In the first year, L. chinensis was defoliated 22, 17 or 13 times, and in the second year was defoliated 21, 15 or 15 times to reach 6, 8 or 10 cm stubble height treatments, respectively. H. brevisubulatum was defoliated 26, 21 or 15 times in the first year, and 28, 23 or 21 times in the second year to reach the 6, 8 or 10 cm stubble, respectively. L. chinensis was more productive than H. brevisubulatum, but H. brevisubulatum showed a better forage quality than L. chinensis because H. brevisubulatum showed a higher leaf to stem ratio and crude protein concentration than L. chinensis. Both species produced the highest yield, but the lowest quality when defoliated to 10 cm stubble. There were no significant differences in water soluble carbohydrate (WSC) concentrations in below-ground culm and rhizome tissues between defoliation heights, but L. chinensis had a higher WSC concentration than H.brevisubulatum.