The Effect Of Different Defoliation Heights And Intensities On Production And Nutrition Of Leyums Chinensis Trin. And Hordeum Brevisubulatum Link Trin.

Leyums chinensis Link Trin. and Hordeum brevisubulatum Link Trin. are 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, these two 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 each species under different defoliation treatments and compare these two species under the same defoliation condition on production and quality. 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 2005 to Oct. 2006. This research focused on two species, which were L. chinensis and H. brevisubulatum, three defoliation intensities and three defoliation stubble heights. The three intensities defined as when the plant grew to the desirable heights, 30% (lax) , 40%(middle), 50%(hard) of the plant had been cut off, then left the stubble heights were 6cm,8cm,10cm, respectively. Three defoliation intensities and heights combined together. In all, it contained 36 treatments in each species. Each time when we harvested we measured the plant height, tiller number, DM, birth rate, mortality and WSC 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 treatment that 10cm stubble height with 50% proportion had been cut off got greater production; it was better to get good quality production by lower stubble height and hard intensity harvest.2. For H. brevisubulatum, there was a greater production on the treatment of 10cm stubble height combined with 30% being cut off. Compare with the other two stubble heights, the 10cm stubble height treatment got a significantly lower N content.3. The L. chinensis got higher production than H. brevisubulatum; the stubble height was 10cm treatment got the higher production. However, the H. brevisubulatum got better quality than L. chinensis throughout the whole grown season.