A Study On The Biomass,Carbon And Nutrient Elements Of Returning The Zenia Insignis Planting Into Forest

The average sample tree determination method is employed by this paper to analyze the relationship among the biomass,carbon and nutrient elements of returning the Zenia insignis Chun.planting into forest,so as to illustrate the effects of Zenia insignis Chun.in the aspects of biomass,productivity,effect of carbon sequestration and nutrient cycling.The results are as follows:?1?After returning planting into forest,the stand biomass of the Zenia insignis Chun.man-made forest ecological system is 45.02 t/hm² while the biomass of the arborous layer reaches 42.01 t/hm².The biomass sequence of various apparatuses for the arborous layer is:trunk>branch>root pocket>bark>large root>leaf>middle root>fine root.The biomass of the trunk is 20.13 t/hm²,which occupies 47.93%of the total biomass of the arborous layer,thus having the biggest contribution to the biomass of the entire arborous layer.The total biomass of the shrub layer,field layer and litter layer is 3.01t/hm².?2?The total productivity of returning the Zenia insignis Chun.planting into forest is 7.55t · hm^-2 · a^-1 while the productivity of the arborous layer is 6.28t · hm^-2 · a^-1.The productivity sequence of various apparatuses is:trunk>branch>leaf>root pocket>bark>large root>fine root>middle root.The net productivity of the truck is 1.83 t · hm^-2 · a^-1,which occupies 29.13%of the total productivity of the arborous layer.The productivity of the floor stratum is 1.271 · hm^-2 · a^-1.The productivity sequence of the floor stratum is:herbaceous layer t · hm^-2 · a^-1>shrub layer 0.381 · hm^-2 · a^-1.?3?The carbon contents of various apparatuses in the Zenia insignis Chun.of 11 perennials are kept within 484.65?533.39 g/kg,with an average carbon content?weighted average?of 503.75g/kg.The carbon contents sequence of various apparatuses of the arborous layer is:trunk>large root>bark>middle root>root pocket>branch>leaf>fine root.?4?The total carbon reserve in returning the Zenia insignis Chun.planting into forest is 139.67 t/hm²,with the distribution pattern as:soil layer>arborous layer>floor stratum.In floor stratum,the carbon reserve sequence of each layer is:litter layer>field layer>shrub layer.?5?Total annual net fixed carbon content of Zenia insignis Chun.arborous layer is 3.18t · hm^-2 · a^-1,with the annual net fixed carbon content of the overground part is 2.69t ·hm^-2 ·a^-1,in which the annual net fixed carbon content of the trunk is 0.98t · hm^-2 · a^-1.?6?The organic content of each soil layer in the farm land is lower than the Zenia insignis Chun.forest land.The soil nutrients in Zenia insignis Chun.forest land is higher than the farm land.?7?The gross reserves of the five nutrient elements in the arborous layer is 793.55 kg/hm²,with the sequence of the reserve of each element is:Ca>N>K>P>Mg.The reserve sequence of the five nutrient elements in the floor stratum is litter layer?52.77 kg/hm²?>field layer?49.94 kg/hm²?>shrub layer?24.33 kg/hm²?.The reserve sequence of the nutrient elements in the shrub layer is Ca>N>K>P>Mg while the reserve sequence of the nutrient elements in the field layer is Ca>N>K>Mg>P.?8?In Zenia insignis Chun.arborous layer,N has obvious positive correlation with P,K,Mg three elements.P also has obvious positive correlation with K,Ca and Mg.The K content is significantly correlated with Ca content.K content has obvious positive correlation with Mg content.Ca also has positive correlation with Mg.In the carbon and five nutrient elements of the soil layer of the Zenia insignis Chun.,the obvious positive correlations only exist between C and N as well as P and Mg.