Approach To The Tissue Turnover Of Leymus Chinensis Under Different Cutting Conditions

To explain the vegetable's adaptive mechanism when suffered disturbance such as manpower utilization and provide the theoretical base for making the valid cutting system, one experiment was conducted to investigate dynamics of leaf and plant regrowth, characteristics of vegetation, productivity, changes of WSC (water-soluble carbohydrate) and nitrogen in Leymus chinensis at different cutting times, cutting frequency and stubble heights by applying the theory of tissue turnover. The results showed that:(1) The leaf enlongation rate and appearance rate differed significantly, not for the other parameters between the two treatments with different initial cutting time. The leaf senescence rates of the first week and fourth week differed significantly, while other parameters were not different between the two frequency treatments. The enlongation rates of the first, second and fourth week after cutting in June differed significantly. The leaf enlongation rates of the first week when cutting happened in August differed significantly, however, other parameters were not different among different stubble heights. The leaf tissue turnover rate was the fastest if the cutting time is set in June and the stubble height is 8cm according to regrowth dynamics.(2) The plant regrowth rate was significantly different between the two treatments with different initial cutting time. There was significantly different in the regrowth rate of the third week after cutting between the two frequency treatments, but not for other weeks. The plant regrowth rates of the first and second week after cutting in June, the third and fourth week after cutting in August differed significantly, not for other weeks among stubble height treatments. (3) The total dry matter yield did not differ significantly between the two treatments with different initial cutting time. Nevertheless, there were significantly different among stubble height treatments. The interaction between the different initial cutting time and stubble height treatments was not remarkably different. The grass yields of regrowth were not significantly different among stubble height treatments from June to August.(4) Cutting treatments did not impact the change of accumulation WSC of the fibrous root. WSC in stem and rhizome decreased after cutting in June,however, WSC in leaf after cutting in June and in stem, leaf and rhizome after cutting in August decreased at first, then increased. WSC in leaf and stem when the stubble height was 8cm decreased at first, and followed increasing. Other treatments kept decreasing after cutting. (5) The contents of nitrogen in leaf and stem in June were higher than that in August, and nitrogen content in fibrous root was as much as that in rhizome. The contents of nitrogen in different organs of Leymus chinensis were lower than CK at early days after cutting respectively, and then increased, even exceeded CK. The content of nitrogen at lower stubble height was higher than that at higher stubble with in the belowground organs, opposite to the underground. So appropriate cutting intensity will benefit the increase of nitrogen and improve the nutrition value of herbage. Appropriate cutting could increase the tissue turnover rate and quality of forages. Based on the results of this experiment, the cutting time should be set in August and the stubble height should be 8cm if cutting once. Cutting twice annual is also feasible if the benefit in the same year is just considered, and the cutting time should be set in early June and early August.