| Cupressus funebris stand is a major forest type in the hilly region of central Sichuan, also a major low-yielding and low efficiency stand. The hilly region of Sichuan basin plays an important role in the upper Yangtze river ecological barrier, in soil and water conservation and improving the ecological environment. The characteristics of Cupressus funebris low efficiency stands is forest wither away, simple structure, single species, sparse level, low degree of species diversity, serious soil erosion. Therefore, Cupressus funebris low efficiency stands transformation is crucial for the improvement of ecological benefit and the timber yield. The system’s stability and health is an important problem for stand transformation, and the degree of biodiversity plays a vital role on reform success. In order to provide theoretical basis for Cupressus funebris low efficiency stands reconstructing pattern, we explored the relationship between the aboveground and underground, organic and inorganic. Four patterns after 10 years of reformation, CZ, BZQ, BL, and BZ, are selected as research object, and CB is the contrast. The study area was located at Jingyang district, Deyang city, Sichuan province These indexes, such as soil physical and chemical properties, litter, fine root, plant diversity and soil microbial and animals on woodland were studied, and the preliminary conclusions is followed.(1)Except ammonium nitrogen and total phosphorus are not significant difference beteew reconstructing pattern and soil pattern, but other indicators likely have effect on them. Soil nutrient and moisture nearly gradually reduced with the depth of soil layer. The content of total nitrogen, total phosphorus, nitrate nitrogen, ammonium nitrogen has no significant difference in different patterns. Among different patterns, there is significant difference of total potassium content, and total potassium content of CZ (0.325 g.kg-1) is the highest, followed by CB< BZQ<BL<BZ. There is significant difference of rapidly-available potassium content between pattern, the highest is BZQ (0.059 g.kg-1), followed by BZ< CZ <BL<CB. The soil moisture content is BZ>BZQ>CZ>CB. The soil nutrient, and soil water content and the structure in the pattern of BZQ can be effectively improved compare with CB pattern, but these improvements only appeared in surface soil.(2)The fine root biomass of BZ and BZQ are significantly higher than CB and BL is the smallest, so diversity’s effect on fine root biomass was not significant. In the pattern of BZ and BZQ, fine root biomass showed a trend of rising, whereas in BL mode showed a trend of sinking, the proportion of fine roots of Cupressus funebris in the total fine root is lower than in BL, and BL pattern also has a significantly higher proportion than the other patterns.The potassium content of fine roots in CZ and the calcium content of fine roots in CB are the highest in several patterns and have significant differences between other patterns, and other fine root nutrient have no difference between different patterns; Fine root biomass and soil total P, N content of fine root and soil total N and K content of fine root and are significantly correlated with total K total N of soil, but the P content of fine roots has nothing to do with the soil nutrients.(3)The forest litter amount in different inefficient Cypress forest reconstructing patterns are BZQ> BZ> CB> BL> CZ, and the distribution is also uneven of each month. Except BZQ, other patterns have the highest forest litter amount in November up to a year, the lowest in January, and the litter biomass are general upward from January to November in all reconstructing patterns, but there is a slight decline in April of BZQ. The research of litter nutrient content in different transformation patterns of inefficient Cypress forest found that, the content of N, P, K are significantly different, and BZQ have the highest nutrient content.(4)Plant species of shrub layer and herb layer in different modes exist certain differences between its structure characteristics, but no obvious on the species distribution. Due to the unique structure of CZ, it has many unique species. In these reconstructing patterns, only BL’s biodiversity is superior to CB, so BL has higher plant diversity according to the biodiversity.(5)BZ have the largest number of soil faunal, followed by BZQ> CZ> CB> BL, and there is no significant difference (P= 0.80) between different patterns. Large soil animal predominates in all soil faunal, the proportion of BL, BZQ, BZ, CZ, CB are 42.99%,56.37%,44.34%,75.93%,44.34%. In CB, BZQ and BZ, the amount of small and medium-sized soil animal is larger than small animals, but CZ and CB are opposite. The content of N, P, K in litter had no obvious relevance with the total number of soil faunal, the number of large, small or medium-sized soil faunal, only the litter biomass have significant positive correlation with medium-sized soil faunal (P<0.01, R2=0.978). Only soil pH has significant positive correlation with large soil faunal.(6)The proportion of bacteria in soil microbial quantity is the largest, about 60%～95%; actinomycetes is 5%～40%, fungus is about 0.03%～0.24%. Soil microbial of five patterns in different soil depth distribution change significantly (P<0.01). Amount of microbes in 0～10 cm slightly more than 10 cm-20 cm. Soil microbial changes evident in the season, a general trend drop elevator, January to April fell, but relatively smooth, and April to July appeared a sharp rise, then July to November fell sharply again. Shannon diversity index and Pielou overall trend is July>November>January>April. The quantity of soil microbial is CZ>BL>BZQ>CB>BZ. The mount of bacteria was significantly positively related with the content of total P in litter and soil and the large soil faunal, but significantly negative related with the Simpson diversity (P<0.05). The number of fungi and total N in soil and fine root showed a negative correlation, but there is a positive correlation between the number of fungi and total P in soil, the content of K in fine root and plant richness. Actinomycetes is only positive related with the soil moisture content, has nothing to do with other factors. The total number of microbes is affected by the total N, P in soil, negatively correlated with total N in soil and positively correlated with total N in soil.(7)Litter biomass, the content of N in litter, the content of P in litter, plant Pilou evenness and plant richness have a significant impact on underground part, but the content of K in litter, plant Simpson and plant Shannon diversity has no obvious correlation to underground part. The litter biomass and medium-sized soil faunal were extremely significant positive correlation; the content of N in litter has a significantly positive correlation to soil total N content and the N content of fine root, but significantly negative correlate to total K in soil and K content of fine root; the content of P in litter has a significantly positive correlation to the total P content in soil, fine root biomass, K content of fine root and bacteria amount, but significantly negative correlate to N content of fine root. Plant Pilou and total N in soil were positively correlated, but with total K in soil and K content of fine root showed a negative correlation relationship; plant richness and fine root biomass, P content of fine root, K content of fine root and fungi present positive correlation, but appeared very significant negative correlation to N content of fine root. Although aboveground and underground part are connected, but from the point of this article, the relationship between the aboveground and underground is not close.Through Principal component analysis, the order of several patterns total score is CZ> BZQ> CB> BZ> BL. But through the comprehensive analysis, the advantages of litter, plant diversity and soil bacteria in BL, BZQ are relatively better than others, so BL, BZQ are reconstructing patterns for the low efficiency stands which can be used for this area. Hybrid Bamboo, meanwhile, as an exotic species, from the point of the study, CZ pattern performs poorly, so CZ pattern is not suitable as an alternative pattern of low efficiency stands Cypress transformation. Cypress was a suitable tree species for upper hilly area and made an important contribution to green of the region. Because the barren purple soil, which it grows, low environmental capacity, obvious drought and flood season and the unreasonable managing, forest productivity and ecological function are low. Numerous scholars have made a lot of research but failed to find a species can completely replace Cupressus funebris Endl. So, in the process of low efficiency stands reconstructing, it’s supposed to keep certain number of Cypress and choose the appropriate pattern to build mixed forest, besides, be careful for the whole cut to remake, especially drawing high attention to the introduction of alien species. At the same time, due to the low environmental bearing capacity of low efficiency Cypress, we should try to avoid the destruction of the human and animals and make proper enclose. |
PDF Full Text Request