Effects of Different Mixed Ratios of Eucalyptus robusta-Castanopsis hystrx on Understory Vegetation and Soil Fertility
In order to investigate the effects of different mixed proportions of Eucalyptus robusta and Cas-tanopsis hystrx mixed forests on soil fertility and understory vegetation diversity,four different proportions of eu-calyptus and red cone mixed forests(E.robusta-C.hystrx is a potted seedling of the same year)in Shiling For-est Farm,Lianjiang city,Guangdong province were selected as the research objects.Through field investiga-tion,sampling,analysis,and comprehensive comparison,the soil physicochemical properties of E.robusta and red cone mixed forests under different mixed proportions were studied to analyze the composition of under-story vegetation and plant diversity.The results showed that the understory shrubs and herbaceous plants were the most abundant in the 5∶1 mixed forest of E.robusta,the understory shrub species were the least abundant in the 1∶1 mixed forest,and the understory herbaceous species were the least abundant in the 3∶3 mixed forest.There was a significant difference in the Patrick richness index of understory vegetation among the four types of E.robusta mixed forests(P<0.05),with the 5∶1 mixed forest being significantly higher than the 3∶3 mixed forest.The maximum soil moisture capacity of the 3∶1 mixed forest is the highest,followed by the 5∶1 mixed forest.The maximum soil moisture capacity of the 3∶1 mixed forest is significantly higher in the 0-20 cm,20-40 cm,and 40-60 cm soil layers than in the 1∶1 mixed forest,and significantly higher in the 20-60 cm soil layer than in the 3∶3 mixed forests.The maximum water holding capacity of the 5∶1 mixed forest is significantly higher in the 0-20 cm soil layer than in the 1∶1 mixed forest,and significantly higher in the 20-40 cm soil layer than in the 3∶3 mixed forests.The Simpson diversity index of understory vegetation in E.robusta mixed forest is significantly negatively correlated with total phosphorus content in 5∶1 mixed forest and 1∶1 mixed forest.The Shannon Wiener index of variation is significantly negatively correlated with total phosphorus content in a 3∶3 mixed forest,and significantly negatively correlated with total phosphorus content in a 1∶1 mixed forest.The Patrick richness index is significantly positively correlated with soil noncapillary po-rosity in a 3∶3 mixed forest,and significantly negatively correlated with total nitrogen content in a 3∶3 mixed forest.The Pielou evenness index is significantly negatively correlated with soil noncapillary porosity and soil aeration in a 3∶1 mixed forest,and significantly positively correlated with total phosphorus content in a 5∶1 mixed forest.In summary,a 5∶1 mixed ratio is more suitable for the growth of understory plants,but a 1∶1 mixed ratio is more suitable for the preservation of soil fertility.
NETL
NSTL
万方数据
