Biomass And The Nutrients' Distribution And Accumulation Of Plantations On Loess Plateau

This paper selects Caijiachuan watershed as the research area locates in loess hilly gully region. The Robinia pseudoacacia plantation and the Pinus tabulaeformis plantation are considered to be the study objects. Based on the method of tally stem analysis and chemical analysis on sample plots, the paper analyzes the biomass of the plantation, discussing the characteristics of the accumulation and distribution of the eco-syestem of plantations,concluding the using efficiency of the plantations,the results show that:(1)The biomass of the Robinia pseudoacacia plantation is 30.449t/hm2, the distribution of the eco-syestem's biomass is: arbor storey>shrub storey>herb storey>litter storey, the distribution of the arbor storey's biomass is: trunk>tree root>branch >leaves>bark.The biomass of the Pinus tabulaeformis plantation is 58.673t/hm2, the distribution of the eco-syestem's biomass is: arbor storey>shrub storey>herb storey>litter storey, the distribution of the arbor storey's biomass is: trunk>branch>tree root> leaves>bark.(2)The order of the content of the macro-element of the Robinia pseudoacacia plantation's vegetable layer is: N>Ca>K>Mg>P, the order of the content of the micro-element is: Fe>Mn>Zn>Cu>Pb. The order of the content of the macro-element of the Pinus tabulaeformis plantation's vegetable layer is: K>N>Ca>P>Mg, the order of the content of the micro-element is: Fe>Mn>Zn>Cu>Pb.The trend of the nutrient content of the vegetanle layer is: arbor storey< shrub storey, herb storey.The content of the nutrient element of the plantations'litter layer is higher in the semi-decomposition, the content of most nutrient element of the litter layer is higher than the vegetable layer.The order of the macro-element of the Robinia pseudoacacia plantation's soil layer is Ca>K>Mg>P>N,the order of the micro-element is Fe>Mn>Zn>Pb>Cu. The order of the macro-element of the Robinia pseudoacacia plantation's soil layer is Ca>K>Mg>P>N, the order of the micro-element is Fe>Mn>Zn >Pb>Cu.(3)The changes of the content of the soil nitrogen in Robinia pseudoacacia plantation and Pinus tabulaeformis plantation are basically the same.The content of the soil nitrogen is higher in the surface and more and more lower in the Lower profile, the content of the soil nitrogen at all levels in the Pinus tabulaeformis plantation is higher than in the Robinia pseudoacacia plantation.The content of the soil total phosphorus at all levels in the Pinus tabulaeformis plantation is higher than in the Robinia pseudoacacia plantation. The content of the soil phosphorus distributed evenly in the two kinds of plantations.(4)The accumulation of the macro-element of the Robinia pseudoacacia plantation and Pinus tabulaeformis plantation is Respectively 1395.875kg.hm-2,973.164kg.hm-2,the order is:arbor storey>shrub storey>herb storey>litter storey.The accumulation of the micro-element of the Robinia pseudoacacia plantation is 11462.620g/hm2, the order is: arbor storey>shrub storey >litter storey>herb storey.The accumulation of the micro-element of the Pinus tabulaeformis plantation is 19160.917g/hm2, the order is: arbor store>herb storey >shrub storey >litter storey.(5)The trend of the accumulation ability of the macro-element in Robinia pseudoacacia plantation is N>P>Mg>Ca>K, the trend of the accumulation ability of the micro-element is Zn>Cu>Mn>Pb>Fe, The trend of the accumulation ability of the macro-element in Pinus tabulaeformis plantation is N>P>K>Ca>Mg,the trend of the accumulation ability of the micro-element is Zn>Cu>Mn>Pb>Fe.(6)The Robinia pseudoacacia produces 1t biomass needs the macro-element 48.746kg.needs the micro-element 316.110g. The Pinus tabulaeformis produces 1t biomass needs the macro-element 17.948kg.needs the micro-elemen333.257g.