Effects Of Snow And Ice Disaster On Tai He Plantation Soil Nutrient Characteristics

At the beginning of 2008, south of China suffered a rare low-temperature freezing rain and snow disaster, disaster affected 19 provinces and cities, the loss of forest area of 19300000 Hm2, the tree of affected forest was trunks broken,tip broken, trunk splitting, root lodging at more than 50%, the direct economic losses amounting to 57.3 billion yuan.As an important natural disturbance types, the snow disaster is one of the main driving factor of the forest ecosystem structure and function.In order to reveal the influence of 08 year’s snow and ice disaster to plantation soil nutrient, This paper selected the tai he plantation which suffered serious snow disaster interference in early 2008 as the research object, selected the representative of Slash Pine *Liquidambar mingled forest, slash pine pure forest and pond pine pure forest three forest types as the research objects.In 2012, Through The type of different damage degrees and different forest’s soil pH, bulk density, organic carbon, C/N, alkali-hydrolyzable nitrogen and microbial biomass C, N, DOC content determination, and compared with data of disaster, the main results are as follows:1.soil organic carbon content decreased with soil depth, with the extent of the damage aggravated content increased, organic carbon of different damage degrees of slash pine pure forest’s years mean is:severe (14.595g/kg), moderate (12.653g/kg), mild (11.408g/kg),As the extent of the damage increase,soil organic carbon increase; Different type of forest organic carbon’s average size is pure forest slash pine (12.9149g/kg), coniferous forest (11.2184g/kg), pond pine pure forest (11.1632g/kg),seasonal dynamics appears summer and autumn higher than spring and winter.2. Different damage degree of pine forest in different soil the soil alkaline hydrolysis N, total N, total P content was decreased with the soil depth increased.seasonal dynamic changes are take on the summer and autumn is higher than spring and winter. Compared with the beginning of 2008 disaster,the fourth year after disaster(2012),Soil bulk density,pH,organic carbon content are increased, average annual value respectively increased by 2.4%,2.6%,16.18%, C/N ratio, total P were 3 times,4.1 times of 2008, only the total nitrogen decreased by 62.6%.3.In 0-15cm and 15-30cm soil layers, the dynamic changes of different damaged degree pine pure forest soil microbial biomass C, N is showed severe> moderate> mild, and soil microbial biomass C/N ratio is decreased with the aggravation of damage degree.In a word,The extent of damage of different pine pure forest microbial biomass C, N are showed summer and autumn higher than spring and winter. Each forest type microbial biomass C,N showed:the highest is slash pine*Liquidambar mingled forest, the second is slash pine pure forest,the lowest is pond pine pure forest. Compared with 2008 initial affected data analysis, we see that after snow and ice disaster, slash pine pure forest soil microbial biomass C, N were increased by 12.4%,39.8%, slash pine*Liquidambar mingled forest soil microbial biomass C, N were increased by 18.9%,32.7%, pond pine pure forest C, N were reduced by 11.5%,32.9%. And,the years mean microbial biomass C, N, C/N in 2012 were increased by 4.1%,9.6%,82.9%.4.The same soil layers of different damaged degree of pine pure forest’s content of DOC showed severe>moderate> mild, seasonal dynamics of each of the damaged degree is similar, all is higher in the summer and lower in winter.different damaged degree’s annual DOC value is severe(129.233mg/kg), moderate (114.754mg/kg), mild (94.091mg/kg). The season dynamic of Slash Pine*Liquidambar mingled forest, slash pine pure forest and pond pine pure forest are showed summer and autumn higher than spring and winter, mean value is as follows:Slash Pine*Liquidambar mingled forest (141.792mg/kg), slash pine pure forest (111.456mg/kg), pond pine pure forest (87.921mg/kg), there are significant difference.