Studies On The Organ-Soil-Litter Stoichiometry Of Larix Gmelinii Forest

The relationship between the content and balance of forest ecosystem elements is a hot topic in ecological research in recent years.This paper takes the herbage-Larix gmelinii primary forest and Larix gmelinii primary forest in the Greater Khingan Mountains region as the research objects,analyzes the characteristics of C,N,P contents and their stoichiometry ratios of plants,soil,litter in different ages.In order to reveal the interaction and balance among C,N,P in different forest types,and theoretical basis for scientific management of Larix gmelinii forest in this area.The results are as follows:1.With the increase of stand age,the changes of element content in different organs of Larix gmelinii are different.The content of organic C increased in leaves and branches,decreased at first and then slowly increased in roots,but did not change significantly in trunks.The order of TN and TP content is leaf > root > stem > branch and leaf > root >branch > stem.The TN content in stem and root decreased first and then increased,while the TP content in branches and stem increased.2.The contents of TOC,TN and TP in various organs of Larix gmelinii ranged from380.1 to 564.1 g/kg,0.12 to 1.79 g/kg and 0.05 to 0.73 g/kg,respectively.The fluctuation ranges of eco-stoichiometric ratios C/N,C/P and N/P are from 246.7 to 13299.5,597.5 to15484.9 and 0.61 to 37.38,respectively.The range of soil TOC,TN and TP in herbage-Larix gmelinii forest and Larix gmelinii forest is from 12.28 to 108.4g/kg,0.33 to 9.87g/kg,0.30 to 4.42g/kg,14.72 to 150.07g/kg and 0.44 to 3.34 respectively.The fluctuation ranges of ecological stoichiometry C/N,C/P and N/P are from 14.67 to 53.51,4.47 to 336.13,0.22 to 15.91 and 26.69 to 68.71,2.15 to 15.05 and 0.07 to 0.43,respectively.3.In herbage-Larix gmelinii forest,with the increase of forest age,the content of soil TOC first increased and then decreased in surface and middle soil,while the content of TP increased in all soil layers,while the content of TN increased continuously in surface and deep soil,and then decreased in middle soil.C/N and C/P increased first and then decreased in the surface and deep layers.The ratio of N/P decreased in the surface layer.The lowest value is 0.85 in the nearly mature forest.C/N and C/P in soil and litter increased at first and then decreased,and reached the highest value in middle-aged forest.The changes of soil and litter N/P showed a downward trend,first increased and then decreased.4.In Larix gmelinii forest,the contents of soil TOC,TN and TP first increased and then decreased with the increase of forest age.C/N and C/P first increased and then decreased in surface and deep soil.The value of N/P is on the rise.The content of TOC in litter showed a slow downward trend.There is no obvious change rule of TN and TP content.C/N increased at first and then decreased significantly.The trend of C/P and N/P is basically the same,showing a trend of first decreasing and then increasing,and the change is significant.5.Through the correlation analysis of C,N and P contents and their stoichiometric ratios in leaves,soil and litter of different forest types at different growth stages,it is found that there are different degrees of correlation among them.The age change is an important factor affecting the contents of C,N and P in plants and soils and their stoichiometric ratios.However,there is no significant correlation between the contents of TPC,TN and TP in plant leaves and soil,indicating that soil nutrients have little effect on the contents of tree leaves,but more on the genetic characteristics of plants themselves.