Defoliation Management Of Leymus Chinensis (Poaceae) Affects Dry Matter Yield And Herbage Nutritive Value

Leyums chinensis Link Trin. is the main grass species in Songnen plain of China. In the northwest of China, the land was highly salted; grass species which have good tolerance to the salt could live well in the environment that provided sufficient grasses for the live stocks. Moreover, the species could improve the soil status, which were suitable species for utilizing in this area. In this research we try to compare the production and quality on the species under different defoliation treatments. We also could get some guidance from the result for grassland management.This experiment conducted in the pot and last for 2 years, it is commenced from May 2007 to Oct. 2008. This research focused on one species, which were L. chinensis, three defoliation intensities and three defoliation frequency. The three intensities defined as when the plant grew to the desirable heights, 40%(lax),60%(middle),80%(hard) of the plant had been cut off, then left the defoliation frequency were 30d,45d,60d, respectively. Three defoliation intensities and defoliation frequency combined together. Each time when we harvested we measured the plant height, tiller number, DM, Herbage Nutritive Value which we got the sample at the end of the year.According to two years data, the results showed that:1. For L. chinensis, the optimum defoliation timing to Leymus chinensis grassland should be chosen before August 11th and there were the highest growth rate, digestibility, CP concentrations and ME concentration, and the lowest fiber concentration at that time.2. The optimum defoliation frequency should be 30d twice and defoliation intensity are 40%(lax),60%(middle) of the plant had been cut off or 60d twice and defoliation intensity are 80%(hard) of the plant had been cut off in the growing season when defoliation management.