| The biomass. productivity, nutrient contents, accumulation and cycling of Cinnamomum camplhora Plantation of 18 years are studied. The results show that the biomass is about 111.08t/hm2. and the distributing sequence is tree layer >litter layer>shrub layer>herb layer, whose biomasses are 91.97 t/hm2 (82.80%), 4.46 t/hm2 (4.01%), 2.23 t/hm2 (2.01%) and 12.42 t/hm2 (11.18%) respectively. The net productivity is 12.10 t/hm2?a, in which tree layer, shrub layer, herb layer is 9.55t/hm2 ?a(78.93%,) 0.25 t/hm2 ?a(2.63%), 2.33 t/hm2 ?a(18.44%) respectively. The biomass of stem. bark, branch, leaf and root is 37.7 t/hm2. 7.00 t/hm2, 22.26 t/hm2. 4.70 t/hm2 and 20.11 t/hm2 respectively in tree layer. The distributing sequence is stem>branch>root>bark>leaf. Regarding to the production structure, the biomass of trunks under 5 meters accounts to 80%. branches between 4 meters and 11 metres accounts to 86%. leaves between 8 meters and 12 meters accounts to 78%. and roots in the 40 cm-ground accounts to 84.74%.The content sequence of five macro-elements in vegetation layer is Ca>N>K>Mg>P. The content sequence of seven microelements is Mn > Fe > Zn > Cu > Ni > Cd> Pb. In the vegetable storey, the general content tendency of nutrients is trees layer N>K>Mg>P, of microelements is Mn > Fe > Zn > Cu > Ni > Cd> Pb. In different organs, the nutrient content of leaf is the highest, and stem is the lowest. In the roots, the content sequence of macro-elements is N> K>Ca>P> Mg. and the microelements is Fe > Mn > Ni >Zn > Cu > Cd> Pb. The diameter of root effects macro elements content. In bunch, the more higher, the more macro-elements. In leaf, macro-elements content, except N. is not affected by height.The content sequence of macro-elements is Ca>N>K> P > Mg in shrub layer, is N > K > Ca > P > Mg in herb layer. The content sequence of microelements is Mn > Fe > Zn > Ni > Cu > Cd> Pb in shrub layer, is Fe > Mn > Ni > Zn > Cu > Cd> Pb in herb layer. The nutrient content of up-ground is higher than under-ground.hi litter layer, the content sequence of macro-elements is N > Ca >K> P > Mg. and microelements is Fe > Mn > Ni > Zn > Cd > Cu > Pb. In the course of litter discomposing, the tendency of nutrient content is from increasing to decreasing except K. Fe and Pb. which only increasing. Perhaps because litter's lose-weight rate is higher than nutrient's discomposing rate in the beginner of discomposing, and the reverse is in the later. Another reason probably is that half-discomposing layer has strong absorbed ability. Further discussion and testify should be done.The total accumulation of macro-elements and microelements, in which the sequence is tree layer>litter layer>shrub layer>herb layer, is 1568.74kg?hm2 and 35312.37 kg?hm2 respective!} in the Cinnamomum camplhora plantation. The macro-elements distributing sequence is Ca>N>K>Mg>P. and the accumulation is 33.67%. 33.62%. 25.57%. 4.19% and 2.95% respectively. The accumulation of microelements, which are Mn. Fe, Zn. Ni. Cd and Pb. is 43.38%. 37.43%, 7.03%, 6.67%. 1.92% and 0.38% respectively. In the tree layer, the accumulation of macro-elements is 1154.17 kg?hm2. and the distributing sequence is stem>root>branch>bark>leaf. And the macro-element distributing sequence is Ca>N>K>P>Mg. The accumulation of micro-elements is 18869.76 g?hm2 in which the accumulation of stem, bark branch, leaf, and root, whose distributing sequence is root>leaf>stem>branch>bark.. accounts for 20.27%. 13.65%. 19.74%. 23.14%, 23.19% respectively. In the tree layer, the distributing accumulated microelement sequence is Mn>Fe>Zn>Cu>Ni>Cd>Pb. The capacity of Cinnamomum camplhoraaccumulating soil nutrients is different, and the total trend of the macro-elements is N>P>Ca>K>Mg. the microelement is Mn>Cu>Zn>Ni>Pb>Fe. Cinnamomum camplhora producing It dry materials needs macro-elements 12.25kg and microelements 205.16 g.The present clan structure is irrational. The using nutrient efficiency... |
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