The Effects Of Vegetation Types On Soil Enzyme Activity And Soil Carbon And Nitrogen Forms In Yanhe Watersheds

Soil enzyme activity, nutrient, microorganism are an important part of soil ecologicalsystem, and an important index of soil quality and health evaluation. In this paper, weresearched soil enzyme activity and soil carbon, nitrogen under15different vegetation typesin yanhe watersheds, and discussed their distribution characteristics, and the correlation, inorder to provide basic data and theoretical basis of soil quality evaluation after vegetationrestoration. The following conclusions:(1)The influence of different vegetation types on soil enzyme activity was different. Soilinvertase (100.90mg·g-1·24h-1), β-glycosidase (0.56mg·g-1·h-1), urease(3.24mg·g-1·24h-1),alkaline phosphatase (3.32mg·g-1·10h-1) activity of Quercus liaotungensis communities washighest in forest zone. These illustrate the Quercus liaotungensis plant community to improvesoil microbial activity, and improve soil fertility; Soil proteinase activity（0.33mg·g-1·24h-1）of Platycladus orientalis was larger. In forest savanes, for Caragana intermedia, it had highersoil invertase (18.00mg·g-1·24h-1), β-glycosidase (0.088mg·g-1·h-1), alkaline phosphatase(0.31mg·g-1·10h-1); for Syzygium aromaticum, it had higher soil urease (1.18mg·g-1·24h-1), andthe lower proteinase activity (0.15mg·g-1·24h-1). The soil enzyme activity of the ElaeagnaceaeHippophae was low. In grassland-zone, Artemisia giraldii had higher β-glycosidase(0.11mg·g-1·h-1) and alkaline phosphatase (0.34mg·g-1·10h-1), lower soil proteinase enzymeactivity (0.19mg·g-1·24h-1); Lespedeza dahurica had higher soil invertase and urease enzymeactivity,soil enzyme activity of Stipa bungeana was lowest. There was significant positivecorrelation between soil enzyme activities, forest vegetation types can signifcantly improvethe soil microbial activity and improve soil quality.(2) Soil carbon components of different vegetation types were different. In forest zone,Quercus liaotungensis had higher SOC (42.67g·kg-1), EOC (11.44g·kg-1), MBC(1612.98mg·kg-1). In Forest savanes, Syzygium aromaticum had higher SOC (6.28g·kg-1),EOC (1.53g·kg-1); Syzygium aromaticum had higher MBC (688.97mg·kg-1)andDOC(384.51mg·kg-1). MBC had significant differences between Syzygium aromaticum andSyzygium aromaticum. In grassland-zone,Lespedeza dahurica had higher SOC (6.21g·kg-1), EOC(1.21g·kg-1), MBC (171.76mg·kg-1);Artemisia giraldii had higher DOC(176.36mg·kg-1),and with significant difference between with other vegetation. Significantcorrelation between soil various carbon forms, Quercus liaotungensis,Syzygium aromaticumand Syzygium aromaticum vegetation types can significantly improve the soil carbon contentand provide adequate nutrients for plants.(3) Different vegetation have different influence on soil nitrogen components. ForQuercus liaotungensis, with higher soil total nitrogen (3.10g·kg-1), NO3--N (21.13mg·kg-1),NH4+-N (17.31mg·kg-1) and MBN(351.51mg·kg-1) in forest zone. In forest savanes, Syzygiumaromaticum had higher soil TN (0.64g·kg-1), NH4+-N (1.78mg·kg-1), MBN (101.09mg·kg-1)content. Soil TN (0.42g·kg-1) and NO3--N (3.08mg·kg-1) of Elaeagnaceae Hippophae werelower. In grassland-zone, Lespedeza dahurica and Thymus mongolicus had higher TN andMBN, NO3--N and NH4+-N of artemisia vegetation is higher. The overall soil nitrogen contentof Stipa bungeana is lowest. Significant correlation between soil various nitrogen forms,Quercus liaotungensis, Syzygium aromaticum and Syzygium aromaticum,Lespedeza dahuricavegetation community has significantly positive effects on soil nitrogen accumulation.(4) Under different vegetation, soil enzyme activity and carbon, nitrogen content on thewhole showed that0~10cm soil layer was higher than10~20cm soil layer, namely with thedepth of soil layer, they showed a trend of gradual decline, and there is "table gatheredphenomenon "in a certain degree. Variance analysis showed that soil enzyme activity,carbon and nitrogen form performance in forest zone is significantly higher than the forestsavanes and grass-zones, arbor has a significantly influence on soil nutrient accumulationeffect, soil nutrient from grass to forest zone, mainly affected by vegetation communitystructure, vegetation coverage, so soil nutrient content increased gradually.(5) Soil enzyme activity had significant correlation between the four carbon, nitrogencomponents, these showed transformation of carbon and nitrogen is mutual influence, mutualinteraction, not an isolated existence in the soil ecosystem, is done under the participation ofenzyme system, and so the soil enzyme activities play an important role in the formation ofsoil fertility. The canonical correlation analysis of soil enzyme activity and carbon, nitrogencomponents showed that: the main effect factors of soil enzyme activity were soil invertase,soil urease, soil organic carbon, total nitrogen played the leading role in soil carbon andnitrogen nutrient transformation. The correlation of their transformation was caused by themain effect factors such as the invertase, urease, soil organic carbon, total nitrogen. The soilinvertase activity had most closely correlation with soil organic carbon, and can improve thecontent of soil organic carbon; soil urease had most closely correlation with nitrate nitrogenand microbial biomass nitrogen, and is associated with the transformation of carbon and nitrogen form, has promoting effect to the transformation of soil nitrogen accumulation, toimprove soil nitrogen content. Soil protease had great relevance with easy oxidation oforganic carbon and ammonium nitrogen transformation. Soil urease and proteinase hasnegative effects to the easy oxidation of organic carbon accumulation. Typical variablecumulative contribution rate of96.7%, with the interpretation of the high proportion,explained that the relationship between soil enzyme activity and carbon and nitrogencomponents was closer.