Dry Matter And Protein Yields Of Leymus Chinensis Grassland Changes Induced By Defoliation

Leymus chinensis grassland is an excellent mowing range. In this thesis, the studies onLeymus chinensis grassland herbage dry matter and protein yields changes induced bydefoliation were carried out in two consecutive years (2004,2005) to figure out reasonablecutting rules. The studies include three experiments, and all of them began on May 15th andended on September 15th. Experiment 1, seven identical Leymus chinensis grassland plotswere sequentially harvested for first cut at 20 day intervals, with second cuts on September15th;experiment 2, five identical Leymus chinensis grassland plots were defoliated withdifferent frequencies of 1, 2, 3, 4, and 7;experiment 3, interaction between defoliation andfertilization.The results indicated that, to obtain high herbage dry matter yield and high qualitywithout any improving measure, the defoliation timing to Leymus chinensis grassland shouldbe chosen between August 15th and August 25th if the grassland was defoliated once in thegrowing season;and the timing of the first silage cut should be chosen in the middle of July ifthe grassland was defoliated twice in the growing season. It was concluded from differentcutting frequencies and interaction between defoliation and fertilization that the fewer of thecutting frequencies the higher of herbage dry matter yield whether the grassland was fertilizedor not;and the herbage dry matter yield and protein yield of fertilized grassland was higherthan not if the grassland was defoliated with the same cutting frequency.Furthermore, in the practice production, it was important to carried out cuttingfrequencies fewer than four to acquire high herbage dry matter yield in fertilized grassland;and if we wanted to optimized the quality yield we would better cut four times in fertilizedgrassland. So four times defoliation would be a nice chose to fertilized Leymus chinensisgrassland.