Tree Species And Management Effect On Soil Carbon Sequestration And Fertilities Of Plantation Forests

There are many tree species of afforestation tree with Larix gmelinii, Fraxinus mandshurica, Juglans mandshurica and Betula platyphylla in Northeast area. Forest clear-cutting and follow-up of farmland is the usual land using model. How to affect soil carbon capture and fertility change is the purpose of the research about the species differences and the management measures. Soil organic carbon (SOC), soil inorganic carbon (SIC), soil total nitrogen (N), soil total phosphorus (P), soil total potassium (K), alkaline hydrolyzed nitrogen (Alkaline-N), pH value, electrical conductivity (EC) and bulk density were determined of different tree species, clear-cuts and farmlands in0-80cm soil layers. Combined with difference analysis related to soil carbon sequestration and fertility of the specific data are discussed, and find out the different tree species and management methods of Larix gmelinii soil were the change tendency. Following conclusions were got:1. Change of tree species differences effect on soil carbon sequestration and fertility.5kinds of tree species in space instead of time results show that the in different soil layers SOC storage and content in Juglans mandshurica and larch plantation were higher than other tree species. Larix gmelinii>Juglans mandshurica> Betula platyphylla> Fraxinus mandshurica>Quercus mongolica in0-80cm soil layers.The same, in0-20cm layer SIC storage and content in Fraxinus mandshurica was higher than other tree species, the change trend of deep soil layers were difference, in0-80cm soil layers SIC storage and content in Fraxinus mandshurica>Quercus mongolica>Larix gmelinii>Juglans mandshurica>Betula platyphylla. In juglans mandshurica soil N and alkaline-N were56～286%higher than other tree species in surface layer. Comprehensive in0-80cm soil layers P and available P storage Fraxinus mandshurica>Quercus mongolica>Betula platyphylla>Juglans mandshurica> Larix gmelinii.The Juglans mandshurica and Fraxinus mandshurica for nearly30years fixed sample results show that Juglans mandshurica and Fraxinus mandshurica soil organic carbon content in2008were higher than in1980compared with12%and14%. In deep soil layers (40-80cm) soil organic carbon content in1980were lower than10%in2008. Over the same period, The Juglans mandshurica and Fraxinus mandshurica soil total nitrogen content were significant decrease and the increase in soil total P obvious and little changes in soil pH.2. Difference of cut-clear, farmland and larch plantation effect on soil carbon.From the surface soil layer was analyzed, larch plantation SOC storage were30%(content46%) and147%(content66%) higher than farmland and cut-clear in the different research areas, respectively.The trend was mainly due to the forest soil were less influence sabotage and very stable in long-term. Farmland and cut-clear SOC storage were32%(content58%)and36%higher than plantation forest in20-80cm soil layers, respectively. The storage of SIC changes greatly in different samples. In different soil layers cut-clear SIC storage were33%higher than plantation forest in different samples. With the increase of soil depths, farmland SIC storage were30%lower than plantation forest, gradually. Plantation forest SIC storage were9%and32%higher than cut-clear and farmland, respectively.3. Difference of cut-clear, farmland and larch plantation effect on soil carbon fertility.Change of larch plantation and farmland soil fertility,5out of8paired samples showed higher soil N storage in surface (0-20cm)soil layer under larch plantation than that in farmland, which beget the average of the whole8samples was18%higher than that in farmland. However, in0-60cm soil layers showed soil total N storage adverse tendency and average showed13～69%higher soil total N storage in farmland than that in larch plantation. This contrary soil total N and alkaline-N pattern in the vertical soil profile made no obvious difference in soil N storage in0-80cm soil was found. Larch plantation soil C/N ration were higher than that in farmland in different soil layers, in0-80cm layers plantation forest soil C/N ratio were8%higher than that in farmland. Most of0-20cm soil layers in farmland soil K storage were1.75～26.99t.hm-2higher than in larch plantation (p<0.05) and soil P storage were0.13～4.75t.hm-2higher than in larch plantation. With the increase of soil depths, in deep layers larch plantation soil K storage higher than in farmland, in farmland soil P storage were22%higher than plantation in0-80cm soil layers and soil K storage were2%lower.From the larch plantation and clear-cut soil fertility were analyzed, Changes of total soil N and alkaline-N were consistent with SOC content and4out of5paired samples showed in different soil layers in larch plantation were higher than that in clear-cut sites, which begot0-80cm soil total N average content of in larch plantation was30%(soil content42%). Plantation forest soil C/N ration were16%higher than in clear-cut in0-40cm layers and clear-cut were15%higher than in40-80cm plantation forest. But, change of soil total N and alkaline-N storage were difference in different soil layers. Clear-cut soil alkaline-N storage were20%higher than in larch plantation0-40cm and in deep layers larch plantation were above29%higher than clear-cut. Comprehensive, in clear-cut soil alkaline-N storage were13%higher than larch plantation in0-80cm layers. With the increase of soil depths, in clear-cut soil P storage were7%higher than larch plantation in0-80cm layer and soil K storage were12%higher than that in clear-cut.4. Difference of cut-clear, farmland and larch plantation effect on soil physical propertiesDifferent soil depth of Fraxinus mandshurica soil pH value partial alkaline, other tree species soil pH value partial acidic. In0-80cm soil layers Fraxinus mandshurica>Quercus mongolica> Larix gmelinii=Juglans mandshurica>Betula platyphylla. At the same time, from the soil bulk and EC were analyzed, Quercus mongolica> Larix gmelinii>Fraxinus mandshurica>Betula platyphylla>Juglans mandshurica in0～80cm soil layers.Change of larch plantation, clear-cut and farmland effect on soil physical properties.Most of samples larch plantation soil EC and soil bulk density higher than in clear-cut and farmland.8paired sampled average results larch plantation soil EC were10%higher than in farmland. At the same time, larch plantation, clear-cut and farmland in deep soil acidification with surface (0～20cm) were obvious.