Study On The Effects Of Different Forest Type Litters About Larix Principis-rupprechtii On The Soil Properties

Litter is the central link in the transmission of nutrients in the ecosystem.It plays a key role in maintaining material circulation and energy flow.It is an important source and return pool of soil nutrients and as an embodiment of ecosystem functions.Based on this theory,this study selected the Larix principis-rupprechtii and Betula platyphylla mixed forest,Larix principis-rupprechtii and Pinus sylvestris var.mongolica Litv.mixed forest and the pure forest of Larix principis-rupprechtii in Saihanba,Hebei Province as the research object and set standard plots.Field survey sampling(collect litter and collect soil samples)and indoor analysis(soil physical and chemical properties,enzyme activity indicators,etc.)in different months.The aim of this study is to elucidate the effects of different forest types and seasonal changes about Larix principis-rupprechtii on litter and the relationship between litter and soil fertility.Not only enriching and improving the scientific management theory of Larix principis-rupprechtii plantation forests,this research but also can provide a theoretical basis for delaying the decline of soil fertility in forest land.(1)In the same soil layer,the soil bulk density and pH are generally the lowest in the Larix principis-rupprechtii and Betula platyphylla mixed forest(6-6.5).Pure forest of Larix principis-rupprechtii has the highest bulk density and pH(6.4-6.6);The litter,soil moisture,organic matter,nitrogen,phosphorus,potassium and conductivity of forest litter were the highest in the Larix principis-rupprechtii and Betula platyphylla mixed forest.There was no significant difference in the litter,soil moisture,organic matter,nitrogen,phosphorus,potassium and conductivity between the Larix principis-rupprechtii and Pinus sylvestris var.mongolica Litv.mixed forest and the pure forest of Larix principis-rupprechtii.(2)The three litter layers(50.81t/hm2)of the Larix principis-rupprechtii and Betula platyphylla mixed forest were larger than the mixed forest of Larix principis-rupprechtii and Pinus sylvestris var.mongolica Litv.mixed forest(43.34t/hm2)and the pure forest of Larix principis-rupprechtii and pure Betula platyphylla(50.48t/hm2).The weight residual rate of litter in Larix principis-rupprechtii and Pinus sylvestris var.was the highest,which was 84.26%,and the weight residual rate of white birch litter was the smallest,which was 62.36%.There are also differences in mass residual rate during the different decomposition periods of the same litter.The order of leaf litter yield is:Larix principis-rupprechtii and Betula platyphylla mixed forest>Larix principis-rupprechtii and Pinus sylvestris var.mongolica Litv.mixed forest>pure forest of Larix principis-rupprechtii.The accounted for 16.93%-25.08%of the total amount of litter in the forest.The yield of dead branches in pure forest of Larix principis-rupprechtii is the highest,and the yield of dead branches in Larix principis-rupprechtii and Betula platyphylla mixed forest is the lowest.The yield dynamics of three types of forest litter are double peak type.(3)The seasonal dynamics of total carbon,total nitrogen,total phosphorus,total potassium and soil enzymes in the three forest types increased first and then decreased.The 50il fertility of Larix principis-rupprechtii and Betula platyphylla is better than the other two forest types.