The Study Of Ecological Stoichiometry Of Understory Plants And Soil In Continuous Planting Of Eucalyptus Plantation

Ecological stoichiometry is analyzed on C, N, P and other chemical elements of ecological interactions, ecological stoichiometry through them to study the structure and function of ecosystems, ecological stoichiometry limiting factor in plant and Discussion Learn soil quality plays a particularly important role. In this study, the first in Guangxi Dongmen Forest Farm Eucalyptus Ⅰ Ⅱand Ⅲ -generation forest for the study, as a reference to the next shrub grassland of even planting Eucalyptus Plantation plant leaves and soil C, N and P ecological stoichiometry characteristics We were studied, and discussed the relationship between diversity, understory plants and soil understory plant biomass C, N, P between. The main findings are as follows:(1) shrub and herb layers of biodiversity with increasing planting generation is reduced; understory plant biomass increases as planting generation is reduced, wherein the shrub biomass decreased with increasing planting algebra, herbaceous layer biomass with increasing planting generation increases.(2) Different Generation Plantations of understory plants C, N and P content is below the global average and the national average, The C:N and C:P higher than the global average and the national average, N:P slightly less than the national average. Shrub and herb layers of N:P range is between 9.27 ± 1.76 and 19.41 ± 10.71, which is less than 21 and the N-limiting significantly. Different planting algebra (except shrub grass), The Ⅱ generation of forest C, P, and C:N lowest, and forest of N, C:P and N:P highest in shrub layer; the second generation of forest P, C:N, and C:P highest content, C, N and N:P minimum in herb layer.(3) Replanting of eucalyptus plantation soil organic C content between 10.26 ± 2.35 and 22.39 ± 2.85 g/kg, total N content of between 0.47 ±0.15 and 1.26 ± 0.23 g/kg, soil total P content between 0.34 ± 0.05 and 0.49 ± 0.08 g/kg. The most adequate soil P content, C content stratification obvious, N content is limited by the maximum.0-20 cm soil layer C, N, C:N, C:P, N:P content increased with planting generation (except irrigation grass) increases and decreases soil P content of the law is not obvious. Different soil layer of C:N higher than the national and global average, more likely to be restricted soil N; C:P soil in 0-20 cm soil layer decreased with increasing planting algebra, were lower than C:P national and global average, more likely to soil C restricted; soil N:P in each soil were planted with the increase of algebra becomes smaller, indicating that soil N content increased with planting generation by limiting increases.(4) In the 0-20 cm soil layer of C:N different generation plantations are the lowest in summer, in the 20-40 cm soil layer are low in summer and autumn. In the case of soil P by limiting insignificant, indicating that summer soil C and N restrictive larger, wherein C by more restrictive.0-20 cm soil layer of C, N, C:N, C:P and N:P increased with planting generation increases and decreases soil P content of the law is not obvious. The C’. P and N:P is mainly controlled by soil P soil parent material impact, with little seasonal variation relationship causes.(5) Of undergrowth plant shrub layer richness index S and 0-20 cm soil layer of C:P was a significant positive correlation, and soil C, N, C:P and N:P and shrub layer different diversity It showed a positive correlation between the index; a negative correlation between the P content of 20-40 cm soil layer and shrub layer each diversity index.Understory plants and shrubs C content of 0-20 cm soil layer P content was significantly positively correlated with soil N content shrub N content was negatively correlated, indicating that changes in shrub C content of soil P content restrictions that, while shrub N content the increase will result in a reduction of soil N content; 20-40 cm soil layer shrubs and various indicators of soil correlation was not significant, indicating a greater impact on the shrub 0-20 cm soil layer. Understory herbaceous plant N content and 0-20 cm soil layer N and N:P showed a significant negative correlation with the 20-40 cm soil layer N:P was a significant negative correlation, indicating that the accumulation of herbaceous layer N content N content of each soil layer were significantly affected.