The Effects Of Vertical Cutting Roots On Community Characteristics、photosynthetic Characteristics And Rhizome Nutrient Of Leymus Chinensis

This paper takes the moderately degraded grassland of Leymus chinensis as research objectin SuiHua, HeiLongjiang province. Researching the influence of the grassland communities’characteristics, photosynthesis and rhizome nutrient of Leymus by conducting the differentwidth and depth of cutting root treatment. Then, explicating the regular patterns of grasslandcommunities, photosynthesis, rhizome nutrient and other factors after amended thevertical cutting root. And exploring the suitable method applies to degraded grassland, as well asproviding a scientific way for melioration and restoration of degraded grassland, which canprotect the healthy development of our social economy and natural environment.After cutting root treatments of Leymus chinensis grassland, the populations and the community of Leymus chinensis have remarkable changes. Cutting root treatments has a significant impact on the height and density of Leymus chinensis, however, the results arenot consistent. The change in the order of root cutting depth is5cm>10cm>Blank>15cm,and the change of root’s widths is30cm>20cm. The results show that the vertical cutting roots can promote the growth of Leymus chinensis’ height and density, and the root depth of5cm can significantly promote the growth of the height and density of Leymus chinensis.After cutting root treatments, the abundance, diversity index and homogeneity index ofgrassland community has significantly lower than the blank, but the similarity index has notsignificantly changes. Different cutting root treatments have different effect on the communitycharacteristics of Leymus chinensis. The change in the order of root cutting depth isBlank>15cm>10cm>5cm, and it was no significant difference in the width of Leymus chinensis.Experiments show that vertical cutting roots has further improved the dominant species ofLeymus chinensis growth advantage，promoting the development of populations of Leymuschinensis at the same time. Meanwhile, the root depth of5cm and10cm has a significant impacton Leymus chinensis grassland community.The vertical cutting roots can change some physiological characteristics of Leymus chinensis,such as improving both net photosynthetic rate and water use efficiency, decreasing thetranspiration rate and so on. The net photosynthetic rate and yield of Leymus chinensis showed apositive linear correlation. The test results show that the cut roots have optimized photosyntheticcharacteristics of Leymus chinensis. It could obviously promote the yield of Leymus chinensis. 5cm deep of cutting root can significantly optimize photosynthetic characteristics of Leymus andincreasing the Leymus chinensis’ yield.After the treatment of vertical cutting roots, the rhizome nutrient change of Leymuschinensis has obvious seasonal pattern. The nutrient content of rhizome is significantly reducedin regreen stage, but the results is opposite in the late growth period. Experiments show thatcutting roots in returning green stage of Leymus chinensis has a certain extent, with theincreasing depth of the cut roots, inhibition of the more obvious. In the late growth period ofLeymus chinensis, cutting root treatment can promote the accumulation of nutrients in therhizome. The production and accumulation of nutrients showed a significant positive linearcorrelation.