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1.
Vegetation recovery is a key measure to improve ecosystems in the Loess Plateau in China. To understand the evolution of soil
microorganisms in forest plantations in the hilly areas of the Loess Plateau, the soil microbial biomass, microbial respiration
and physical and chemical properties of the soil of Robinia pseudoacacia plantations were studied. In this study, eight forest soils of different age classes were used to study the evolution of
soil microbial biomass, while a farmland and a native forest community of Platycladus orientalis L. were chosen as controls. By measuring soil microbial biomass, metabolic quotient, and physical and chemical properties,
it can be concluded that soil quality was improved steadily after planting. Soil microbial biomass of C, N and P (SMBC, SMBN
and SMBP) increased significantly after 10 to 15 years of afforestation and vegetation recovery. A relatively stable state
of soil microbial biomass was maintained in near-mature or mature plantations. There was an increase of soil microbial biomass
appearing at the end of the mature stage. After 50 years of afforestation and vegetation recovery, compared with those in
farmland, the soil microbial biomass of C, N and P increased by 213%, 201% and 83% respectively, but only accounting for 51%,
55% and 61% of the increase in P. orientalis forest. Microbial soil respiration was enhanced in the early stages, and then weakened in the later stage after restoration,
which was different from the change of soil organic carbon. The metabolic quotient (qCO2) was significantly higher in the soils of the P. orientalis forest than that in farmland at the early restoration stage and then decreased rapidly. After 25 years of afforestation and
vegetation recovery, qCO2 in soils of the R. pseudoacacia forest was lower than that in the farmland soil, and reached a minimum after 50 years, which was close to that of the P. orientalis forest. A significant relationship was found among soil microbial biomass, qCO2 and physical and chemical properties and restoration duration. Therefore, we conclude that it is possible to artificially
improve the ecological environment and soil quality in the hilly area of the Loess Plateau; a long time, even more than 100
years, is needed to reach the climax of the present natural forest.
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Translated from Acta Ecologica Sinica, 2007, 27(3): 909–917 [译自: 生态学报] 相似文献
2.
A group of scientists conducted a comprehensive investigation on ecological safety and water and soil erosion in the Northwest
Loess Plateau, Northwest China. The data gathered was analyzed in terms of achievement, existing problems, and strategy and
measures on vegetation restoration in the area. Since the policies of conversion from cropland to forest (CCF) and forbid
grazing and cutting (FGC) were carried out, vegetation quality and coverage rate increased quickly in the Loess Plateau area,
strengthening the concept of eco-environment protection. Environment harness measurements were optimized. The multiform investments
on eco-environment and urbanization development in China will benefit vegetation restoration. However, there have been some
persisting problems, such as the shortage of investment, instability of government policy, expectation of extravagant economic
benefit, larger rate of plantation, and scarce technologies supporting vegetation restoration. Many key theories and practice
problems require an urgent resolution. In the future, short-, mid-, and long-term goals for vegetation restoration should
be clear, achievement should be expanded, and the natural restoration area should be increased. The benefit for the contractor
on vegetation restoration should be ensured. Investment on vegetation building research work should be increased.
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Translated from Scientia Silvae Sinicae, 2007, 43(1): 102–106 [译自: 林业科学] 相似文献
3.
Yumei Zhou Shijie Han Junqiang Zheng Lihua Xin Haisen Zhang 《Frontiers of Forestry in China》2008,3(2):131-138
The two main components of soil respiration, i.e., root/rhizosphere and microbial respiration, respond differently to elevated
atmospheric CO2 concentrations both in mechanism and sensitivity because they have different substrates derived from plant and soil organic
matter, respectively. To model the carbon cycle and predict the carbon source/sink of forest ecosystems, we must first understand
the relative contributions of root/rhizosphere and microbial respiration to total soil respiration under elevated CO2 concentrations. Root/rhizosphere and soil microbial respiration have been shown to increase, decrease and remain unchanged
under elevated CO2 concentrations. A significantly positive relationship between root biomass and root/rhizosphere respiration has been found.
Fine roots respond more strongly to elevated CO2 concentrations than coarse roots. Evidence suggests that soil microbial respiration is highly variable and uncertain under
elevated CO2 concentrations. Microbial biomass and activity are related or unrelated to rates of microbial respiration. Because substrate
availability drives microbial metabolism in soils, it is likely that much of the variability in microbial respiration results
from differences in the response of root growth to elevated CO2 concentrations and subsequent changes in substrate production. Biotic and abiotic factors affecting soil respiration were
found to affect both root/rhizosphere and microbial respiration.
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Translated from Journal of Plant Ecology, 2007, 31(3): 386–393 [译自: 植物生态学报] 相似文献
4.
杉木纯林、混交林土壤微生物特性和土壤养分的比较研究 总被引:6,自引:0,他引:6
本文于2005年5月份,在中国科学院会同森林生态实验站选择了一块15年生的杉木纯林和两块15年生杉阔混交林作为研究对象,调查了林地土壤有机碳、全氮、全磷、硝态氮、有效磷和土壤微生物碳、氮、磷、基础呼吸以及呼吸熵,比较了纯林和混交林土壤微生物特性和土壤养分.结果表明,杉阔混交林的土壤有机碳、全氮、全磷硝态氮和有效磷含量高于杉木纯林;在混交林中,土壤微生物学特性得到改善.在0(10 cm和10(20 cm两层土壤中,杉阔混交林土壤微生物氮含量分别比杉木纯林高69%和61%.在0(10 cm土层,杉阔混交林土壤微生物碳、磷和基础呼吸分别比杉木纯林高11%、14%和4%;在10(20 cm土层,分别高6%、3%和3%.但是,杉阔混交林土壤微生物碳:氮比和呼吸熵较杉木纯林低34%和4%.另外,土壤微生物与土壤养分的相关性高于土壤呼吸、微生物碳:氮比和呼吸熵与土壤养分的相关性.由此可知,在针叶纯林中引入阔叶树后,土壤肥力得以改善,并有利于退化森林土壤的恢复. 相似文献
5.
Xiaoming Zhang Xinxiao Yu Sihong Wu Tianxing Wei Xuepei Zhang 《Frontiers of Forestry in China》2006,1(3):336-342
According to fixed-position data for 1985–2003 from nine runoff plots of Caijiachuan watershed which lies in Jixian County
of Shanxi Province in Loess area, this paper studied the relationship between vegetation and runoff and sediment production
in sloping lands in detail, which helps to provide scientific basis for vegetation re-construction and studies on environmental
transformation of water and sediment in watersheds of Loess area. Although, many study results testify that forest vegetation
has an important function in soil and water conservation and cutting runoff, the effect of vegetation on runoff and sediment
transmission is complicated, and this needs to be studied in depth. The results of the paper showed the following. Firstly,
the natural secondary forest performs better function of soil and water conservation than artificial Robinia pseudoacacia forest, and runoff and sediment produced in the former in individual rainfall were 65%–82% and 23%–92% of those produced
in the latter. At the same time, better correlative relationship between runoff and sediment production and rainfall and rainfall
intensity were testified by multiple regression, but the correlation decreased gradually with the increase of canopy density
of forest. Secondly, the difference of runoff and sediment production in several land use types was very distinct, and the
amount of runoff and sediment produced from Ostryopsis davidiana forest and natural secondary forest were the least, and runoff and sediment produced from in artificial Robinia pseudoacacia forest and Pinus tabulaeformis forest were 5-fold as much as those from O. davidiana forest. Besides, runoff and sediment produced in mixed planting of apple trees and crops were 16.14-fold and 2.96-fold than
those of O. davidiana forest, respectively, but the amount decreased obviously after high-standard soil preparation in the case of the former.
Thirdly, based on gray cognate analyses of factors affecting runoff and sediment production in sloping land, the factors of
stand canopy density and herb and litter biomass were the most significant ones, whose gray incidence degree exceeded 0.6.
Therefore, mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation re-construction
of Loess area, which will help to increase coverage and litter thickness in order to cut down the runoff and sediment dramatically
in sloping land.
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Translated from Chinese Journal of Applied Ecology, 2005, 16(9): 1,613–1,617 [译自: 应用生态学报, 2005, 16(9): 1,613–1,617] 相似文献
6.
In the semi-arid area of the Loess Plateau, Caragana korshinski, a leguminous shrub, is the dominant plant species widely used in vegetation rehabilitation programs. We collected soil samples
in 8-and 18-year-old C. korshinski plantations to assess the effects of the shrub on the physical and chemical properties of the soil as well as enzyme activities.
Soil samples were taken from two depths (0–20 and 20–40 cm) under the shrub canopy between shrubs. Results showed that shrub
rehabilitation and development enhanced accumulation of organic C and total N. Carbon and nitrogen concentrations increased
significantly with plantation age and had increased by 15.3–20.5-fold and 11.1–13.6-fold at 0–20 cm depth at the 18-year-old
plantation compared with farmland soil. It was found that C. korshinski contributed significant enrichment of C and N contents under their canopies compared with farmland. The content of water
stable aggregates in 18-year-old shrub land soil is higher than the 8-year-old shrub land, and the big aggregates (>5 mm)
increased for the most part, by 67.4% and 59.0% in different layers, respectively. The contents of aggregates of over 0.25
mm in two shrub land soils in the upper layer (0–20 cm) increased by 4.6% and 14.1% compared with farmland. It indicates that
C. korshinski afforestation can increase the content of aggregates. C. korshinski plantation can accelerate the increase of soil urea activity and invertase activity, respectively, especially in the upper
layer.
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Translated from Scientia Silvae Sinicae, 2006, 42(1): 70–74 [译自: 林业科学, 2006, 42(1): 70–74] 相似文献
7.
The soil microbial biomass and nutrient status under the native broadleaved forest and Cunninghamia lanceolata plantations at the Huitong National Research Station of Forest Ecosystem (in Hunan Province, midland of China) were examined
in this study. The results showed that after the native broadleaved forest was replaced by mono-cultured C. lanceolata or C. lanceolata, soil microbial biomass and nutrient pool decreased significantly. In the 0–10 cm soil layer, the concentrations of soil
microbial carbon and nitrogen in the broadleaved forest were 800.5 and 84.5 mg/kg, respectively. These were 1.90 and 1.03
times as much as those in the first rotation of the C. lanceolata plantation, and 2.16 and 1.27 times as much as those in the second rotation of the plantation, respectively. While in the
10–20 cm soil layer, the microbial carbon and nitrogen in the broadleaved forest were 475.4 and 63.3 mg/kg, respectively.
These were 1.86 and 1.60 times as much as those in the first rotation, and 2.11 and 1.76 times as much as those in the second
rotation, respectively. Soil nutrient pools, such as total nitrogen, total potassium, NH4
+-N, and available potassium, also declined after the C. lanceolata plantation replaced the native broadleaved forest, or Chinese fir was planted continuously. Less litter and slower decay
rate in pure Chinese fir plantation were the crucial factors leading to the decrease of soil microbial biomass and nutrient
pool in this area. Human disturbance, especially slash-burning and site preparation, was another factor leading to the decrease.
There were significant positive correlations between soil microbial carbon and nitrogen and soil nutrients. To improve soil
quality and maintain sustainable productivity, some measures, including planting mixed conifer with hardwood, preserving residues
after harvest, and adopting scientific site preparation, should be taken.
Translated from Chinese Journal of Applied Ecology, 2006, 17(12): 2,292–2,296 [译自: 应用生态学报] 相似文献
8.
Reforestation is one of the most important and efficient measures of water and soil conservation. Based on field investigations
in the Shangyang Soil Conservation and Reforestation Station in Huizhou, Guangdong Province, China, we studied the variation
in vegetation development, vegetation succession processes and soil erosion. The regional vegetation consists mainly of monsoon
evergreen broad-leaved forests (MEBF). The area was deforested and became a denuded hill area with extremely high soil erosion
in the 1960s and 1970s. Then, the area was closed in order to allow recovery of the vegetation. Under natural conditions the
vegetation development and succession processes were slow during which soil erosion and strong sunshine and evaporation slowed
down the development of the vegetation. About 25 years later, the vegetation cover was still merely 35% or so. The dominant
vegetation types were heliophilous herbage and shrubs which formed a poorly developed shrub-herbage community and erosion
remained high. In contrast, reforestation with selected tree species dramatically speeded up the vegetation succession process.
About 12 years after reforestation, vegetation cover of the Acacia auriculiformis plantations in the Shangyang Station was 90% and erosion was under control. After 23 years, understory vegetation, consisting
of indigenous species, had developed in the plantations. The planted trees and naturally developing herbage, shrubs, bamboo,
local trees and liana formed a complex vegetation community in three layers. It will take 60 years for the vegetation to succeed
from bare land to a secondary growth forest under natural conditions. Reforestation may speed up the vegetation succession
process. The time may be reduced to 20 years. Reforestation is the most effective measure of vegetation restoration and erosion
control in this area.
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Translated from Acta Ecologica Sinica, 2006, 26(8): 2558–2565 [译自: 生态学报] 相似文献
9.
The growth and water metabolism of three common shrubs on the Loess Plateau were studied under soil with different water contents.
Results showed that water consumption of those species decreased with the increase in drought stress, and water consumptions
of these shrubs were different: Forsythia suspensa was the greatest, and Syringa oblata was the lowest. The growth rate of new branches and leaf area of three species were the fastest under adequate soil water
conditions, and were the lowest under severe drought. Under the same water conditions, the growth of F. suspensa was the fastest while that of S. oblata was the slowest. The water content, proline and chlorophyll content of different species changed with the increase in soil
water stress. The leaf water content of Periploca sepium and F. suspensa was obviously higher than that of S. oblata, while the leaf proline content of F. suspensa and S. oblata was lower than that of P. sepium. The ratio leaf chlorophyll a: b of F. suspensa and S. oblata decreased with the decrease in soil water content. Although these three shrubs had different mechanisms in response to drought
stress, they all had higher drought resistance and could adapt to the drought condition on the Loess Plateau. This paper provided
some bases for choosing tree species on the Loess Plateau.
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Translated from Acta Botanica Boreali-Occidentalia Sinica, 2007, 27(1): 91–97 [译自: 西北植物学报] 相似文献
10.
In sodic soils, excessive amounts of salts have an adverse effect on soil biological activity and stability of soil organic
matter. The study analyzes the role of silvopastoral systems to improve soil organic matter and microbial activity with a
view for effective management of soil fertility. The silvopastoral systems for the present study (located at Saraswati Reserved
Forest, Kurukshetra; 29°4′ to 30°15′ N and 75°15′ to 77°16prime; E) are characterized by tree species of Acacia nilotica, Dalbergia sissoo and Prosopis juliflora along with grass species of Desmostachya bipinnata and Sporobolus marginatus. Soil microbial biomass carbon was measured using the fumigation extraction technique and nitrogen mineralization rates using
aerobic incubation method. The microbial biomass carbon in the soils of D. bipinnata and S. marginatus treatments were low. In silvopastoral systems, microbial biomass carbon increased due to increase in the carbon content in
the soil – plant system. A significant relationship was found between microbial biomass carbon and plant biomass carbon (r = 0.83) as well as the flux of carbon in net primary productivity (r = 0.92). Nitrogen mineralization rates were found greater in silvopastoral systems compared to 'grass-only' system. Soil
organic matter was linearly related to microbial biomass carbon, soil N and nitrogen mineralization rates (r = 0.95 to 0.98, p < 0.01). On the basis of improvement in soil organic matter, enlarged soil microbial biomass pool and greater soil N availability
in the tree + grass systems, agroforestry could be adopted for improving the fertility of highly sodic soil.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
11.
The estimation of the soil organic carbon content (SOC) is one of the important issues in the research of the global carbon
cycle. However, there are great differences among different scientists regarding the estimated magnitude of SOC. There are
two commonly used methods for the estimation of SOC, with each method having both advantages and disadvantages. One method
is the so called direct method, which is based on the samples of measured SOC and maps of soil or vegetation types. The other
method is the so called indirect method, which is based on the ecosystem process model of the carbon cycle. The disadvantage
of the direct method is that it mainly discloses the difference of the SOC among different soil or vegetation types. It can
hardly distinguish the difference of the SOC in the same type of soil or vegetation. The indirect method, a process-based
method, is based on the mechanics of carbon transfer in the ecosystem and can potentially improve the spatial resolution of
the SOC estimation if the input variables have a high spatial resolution. However, due to the complexity of the process-based
model, the model usually simplifies some key model parameters that have spatial heterogeneity with constants. This simplification
will produce a great deal of uncertainties in the estimation of the SOC, especially on the spatial precision. In this paper,
we combined the process-based model (CASA model) with the measured SOC, in which the remote sensing data (AVHRR NDIV) was
incorporated into the model to enhance the spatial resolution. To model the soil base respiration, the Van’t Hoff model was
used to combine with the CASA model. The results show that this method could significantly improve the spatial precision (8
km spatial resolution). The results also show that there is a relationship between soil base respiration and the SOC as the
influence of environmental factors, i.e., temperature and moisture, had been removed from soil respiration which makes the
SOC the most important factor of soil base respiration. The statistical model of soil base respiration and the SOC shows that
the determinant coefficient (R
2) is 0.78. As the method in this paper contains advantages from both direct and indirect methods, it could significantly improve
the spatial resolution and, at the same time, keep the estimation of SOC well matched with the measured SOC.
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Translated from Journal of Remote Sensing, 2007, 11(1): 127–136 [译自: 遥感学报] 相似文献
12.
Simulation of soil water dynamics in a Caragana intermedia woodland in Huangfuchuan watershed 总被引:1,自引:0,他引:1
As vegetation coverage increases, soil water content can decrease due to water uptake and evapotranspiration. At a very high
level of plant density, poor growth and even mortality can occur due to the decrease of soil water content. Hence, a better
understanding of the relationship between soil water content and the density of plants is important to design effective restoration
projects. To study these relationships, we developed a soil water dynamic simulation model of a Caragana intermedia woodland under different slope gradient and slope aspect conditions in the Huangfuchuan watershed on the basis of the previous
studies and field experiments. The model took into account the major processes that address the relationships of plants and
the environment, including soil characteristics, precipitation, infiltration, vegetation transpiration, and soil evaporation.
Daily changes in soil water content, transpiration, and evaporation of the Caragana intermedia woodland with different vegetation coverage, slope gradient, and slope aspect were simulated from 1971 to 2000. Based on
the model simulations, we determined the functional relationships among soil water content, plant coverage and slope as well
as the optimal plant density on flat slopes. We also determined the effects of slope gradient and slope aspect on soil water
content. When slope gradient was less than 10°, the optimal plant density was sensitive to slope gradient. In the slope range
from 10° to 30°, plant density was not sensitive to slope gradient. Therefore, it is important to consider planting densities
on the hillsides with slope gradients less than 10° for reconstructing vegetation.
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Translated from Acta Phytoecologica Sinica, 2005, 29(6): 910–917 [译自: 植物生态学报] 相似文献
13.
Haili Qiao Chengming Tian Youqing Luo Jianhua Sun Xiaofeng Feng 《Frontiers of Forestry in China》2008,3(3):347-351
To better understand the distribution of soil microorganisms in Populus euphratica forests in Xinjiang, northwestern China, we studied and compared the populations and numbers of bacteria, fungi and actinomycetes
in the soil at four different age stages of natural P. euphratica forests, i.e., juvenile forests, middle-aged forests, over-mature forests and degraded forests. Results showed that there
were clear differences in the amount of microorganism biomass and composition rates across the four forest stages. Dominant
and special microorganisms were present in each of the four different soil layers. The vertical distribution showed that the
microorganism biomass decreased with increasing soil depth. The population of microorganisms was the lowest at 31–40 cm of
soil depth. The microorganisms consisted of bacteria, actinomycetes, as well as fungi. Bacteria were the chief component of
microorganisms and were widely distributed, but fungi were scarce in some soil layers. Aspergillus was the dominant genus among the 11 genera of fungi isolated from the soil in different age stages of P. euphratica forests.
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Translated from Journal of Beijing Forestry University, 2007, 29(5): 127–131 [译自: 北京林业大学学报] 相似文献
14.
Hui Wang Jiangming Mo Xiankai Lu Jinghua Xue Jiong Li Yunting Fang 《Frontiers of Forestry in China》2009,4(1):21-27
2003
Wallenstein M D.McNulty S.Fernandez I J.Boggs J Schlesinger W H
Nitrogen fertilization decreases forest soil fungal and bacterial biomass in three long-term experiments [其它论文]
2006
Wang X F.Li S Y.Bai K J.Kuang T Y
Influence of doubled CO2 on plant growth and soil microbial biomass C and N
1998(12)
Xue J H.Mo J M.Li J.Li D J
The short-term response of soil microorganism number to simulated nitrogen deposition
2007(02)
Yao W H.Yu Z Y
The nutrient content of throughfall inside the artificial forests on downland
1995
Yi Z G.Yi W M.Zhou L X.Wang X M
Soil microbial biomass of the main forests in Dinghushan Biosphere Reserve
2005(05)
Zhou G Y.Yan J H
The influence of region atmospheric precipitation characteristics and its element inputs on the existence and development of Dinghushan forest ecosystems [其它论文]
-Acta Ecologica Sinica2001
15.
The dynamic change of soil water as a function of leaf area index and the soil water deficit value, prerequisites for assuring
the survival of plants, were simulated. We established a dynamic soil water model based on a theory of water balance, the
characteristics of the environment, and the physiological ecology of the plants in the Ulan Buh Desert, northwestern China.
We estimated the soil water carrying capacity of the vegetation in our study area of the desert. The results showed that the
proportion of soil evaporation in the total amount of precipitation was greater than 60% in the wandering and semifixed sands
and 44.8%in the fixed sand. When the leaf area index was less than 1.7 m2/m2, the soil water deficit was maintained at a low level, but when the leaf area index continued to increase, the soil water
deficit increased rapidly as well. In consequence, we come to the conclusion that the leaf area index of the soil water carrying
capacity of the vegetation is 1.7 m2/m2 in our study area.
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Translated from Scientia Silvae Sinicae, 2008, 44(9): 13–19 [译自: 林业科学] 相似文献
16.
Land management practices that simultaneously improve soil properties are crucial to high crop production and minimize detrimental
impact on the environment. We examined the effects of crop residues on crop performance, the fluxes of soil N2O and CO2 under wheat-maize (WM) and/or faba bean-maize (FM) rotations in Amorpha fruticosa (A) and Vetiveria zizanioides (V) intercropping systems on a loamy clay soil, in subtropical China. Crop performance, soil N2O and CO2 as well as some potential factors such as soil water content, soil carbon, soil nitrogen, microbial biomass and N mineralization
were recorded during 2006 maize crop cultivation. Soil N2O and CO2 fluxes are determined using a closed-based chamber. Maize yield was greater after faba bean than after wheat may be due to
differences in supply of N from residues. The presence of hedgerow significantly improved maize grain yields. N2O emissions from soils with maize were considerably greater after faba bean (345 g N2O–N ha−1) than after wheat (289 g N2O–N ha−1). However, the cumulated N2O emissions did not differ significantly between WM and FM. The difference in N2O emissions between WM and FM was mostly due to the amounts of crop residues. Hedgerow alley cropping tended to emit more
N2O than WM and FM, in particular A. fruticosa intercropping systems. Over the entire 118 days of measurement, the N2O fluxes represented 534 g N2O–N ha−1 (AWM) and 512 g N2O–N ha−1 (AFM) under A. fruticosa species, 403 g N2O–N ha−1 (VWM) and 423 g N2O–N ha−1 (VFM) under Vetiver grass. We observed significantly higher CO2 emission in AFM (5,335 kg CO2–C ha−1) from June to October, whereas no significant difference was observed among WM (3,480 kg CO2–C ha−1), FM (3,302 kg CO2–C ha−1), AWM (3,877 kg CO2–C ha−1), VWM (3,124 kg CO2–C ha−1) and VFM (3,309 kg CO2–C ha−1), indicating the importance of A. fruticosa along with faba bean residue on CO2 fluxes. As a result, crop residues and land conversion from agricultural to agroforestry can, in turn, influence microbial
biomass, N mineralization, soil C and N content, which can further alter the magnitude of crop growth, soil N2O and CO2 emissions in the present environmental conditions. 相似文献
17.
Yuanguang Wen Fang Chen Shirong Liu Hongwen Liang Chang’an Yuan Hongguang Zhu 《Frontiers of Forestry in China》2009,4(2):146-152
To reveal the relationship between species diversity and biomass in a eucalyptus (Eucalyptus urophylla × E. grandis) plantation located in the Dongmen State Forestry Farm of Guangxi, south China, 18 sample plots were established and the
total biomass, arbor layer biomass and undergrowth biomass of communities were subsequently harvested. The results were as
follows: 1) Species richness in eucalypt plantation had remarkable positive correlation with biomass of arbor layer, undergrowth
and community (α = 0.001), its correlation coefficients were 0.6935, 0.7028 and 0.7106 respectively. 2) Leaf area index (LAI) had remarkable
positive correlation with species richness and undergrowth biomass (α = 0.001). Its correlation coefficients were 0.7310 and 0.6856, respectively. 3) Arbor layer biomass had remarkable correlation
with soil organic matter and hydrolysable N, its correlation coefficients was 0.6416 and 0.6203 respectively. Species richness
had remarkable correlation with soil organic matter and correlation coefficient was 0.6359. Among them, the correlation was
significant at the 0.1 level. Undergrowth biomass had little correlation with nine soil nutrients and correlation coefficients
were under 0.4. To sum up, species diversity was advantageous to the promotion of the biomass of the eucalyptus plantation,
and the variation of LAI and soil nutrient in small-scales could result in the difference of species diversity and biomass
in different sample plots.
Translater from Scientia Silvae Sinicae, 2008, 44(4): 14–19 [译自: 林业科学] 相似文献
18.
G. Singh 《New Forests》2012,43(3):349-364
Natural resource conservation and rehabilitation are the best options to control land degradation and enhance biomass for
fodder and fuelwood. Rainwater harvesting structures viz. Contour trench (CT), gradonie (G), box trench (BT) and V-ditch (VD)
with a control were prepared in <10%, 10–20% and >20% slopes and Acacia catechu L. seedlings were planted in August 2005 to enhance soil water, nutrient and biomass and to rehabilitate degraded hill. Soil
pH, SOC and NH4-N decreased while EC, NO3-N and PO4-P increased in June 2009. Soil water, nutrients, plant growth and biomass were highest (P < 0.05) in <10% and lowest in 10–20% slopes. Soil waters were 13 and 52% greater in >20 and <10% than in soil at 10–20% slope.
The soil waters were 18, 16, 24 and 14% greater in CT, G, BT and VD treatments, respectively over control, which enhanced
plant height and collar diameter in December 2009 over 2005. The highest growth and biomass were in CT and VD plots, respectively.
Herbage biomass was highest (P < 0.05) in <10% slope in 2005, 10–20% slope in 2006/2008 and >20% slope in 2007/2009. Harvesting of rainwater increased herbage
biomass by 24–71%, and was highest in VD plots. Conclusively, rainwater harvesting enhanced soil water, nutrients, vegetation
covers and plant growth and biomass during restoration of degraded hills. Gradonie and CT/BT facilitated herbage and plant
growth, respectively, whereas V-ditch was effective for both. 相似文献
19.
Xiangrong Cheng Zhong Zhao Mancai Guo Dihai Wang Zhifa Yuan 《Frontiers of Forestry in China》2007,2(3):291-297
Based on a detailed investigation of vertical distributions of fine roots in Robinia pseudoacacia plantations at the Ansai Soil and Water Conservation Station, Shaanxi Province, a model was developed for the deep distribution
of fine roots of R. pseudoacacia, which reflects the growth of fine roots affected by the mixed process of infiltration water and deep soil water. The maximum
depth of the distribution h
max and the depth of the highest fine root density (FRD) h
p were determined and the maximum depth of infiltration water supplied for fine root growth h
q could also be calculated, h
q was considered as the approximate boundary between infiltration water and deep soil water in support of the growth of fine
roots. According to the model, the soil water of R. pseudoacacia woodland in the profile could be classified into three layers: the first layer from the soil surface to h
p was the active water exchange layer, very much affected by precipitation; the second was the soil water attenuation layer,
between h
p and h
q and largely affected by the vertical distribution of fine roots; the third was the relatively stable soil water layer below
h
q, below which soil water did not change much. The percentage of infiltration water supplied for the growth of fine roots reached
a level of 88.32% on the shaded slopes and 85.21% on sunny slopes. This indicated infiltration of precipitation played a crucial
role in the growth of R. pseudoacacia in the gully region of the Loess Plateau. The research of interaction between the distribution of fine roots and soil water
in the profile will help to explain the reasons for the complete drying out of soils and provide a theoretical basis for continuing
the policy of matching tree species with sites on the Loess Plateau.
Translated from Scientia Silvae Sinicae, 2006, 42(6): 40–48 [译自: 林业科学] 相似文献
20.
Jing Yin Fan He Guoyu Qiu Kangning He Jinghui Tian Weiqiang Zhang Yujiu Xiong Shaohua Zhao Jianxin Liu 《Frontiers of Forestry in China》2009,4(3):351-357
The objectives of our study were to explore the relationship of leaf area and stand density and to find a convenient way to
measure stand leaf areas. During the 2004 growing season, from May to October, we used direct and indirect methods to measure
the seasonal variation of the leaf areas of tree and shrub species. The trees were from Robinia pseudoacacia stands of four densities (3333 plants/hm2, 1666 plants/hm2, 1111 plants/hm2, and 833 plants/hm2) and Platycladus orientalis stands of three densities (3333 plants/hm2, 1666 plants/hm2, and 1111 plants/hm2). The shrub species were Caragana korshinskii, Hippophae rhamnoides, and Amorpha fruticosa. Based on our survey data, empirical formulas for calculating leaf area were obtained by correlating leaf fresh weight, diameter
of base branches, and leaf areas. Our results show the following: 1) in September, the leaf area and leaf area index (LAI)
of trees (R. pseudoacacia and P. orientalis) reached their maximum values, with LAI peak values of 10.5 and 3.2, respectively. In August, the leaf area and LAI of shrubs
(C. korshinskii, H. rhamnoides, and A. fruticosa) reached their maximum values, with LAI peak values of 1.195, 1.123, and 1.882, respectively. 2) There is a statistically
significant power relation between leaf area and leaf fresh weight for R. pseudoacacia. There are significant linear relationships between leaf area and leaf fresh weight for P. orientalis, C. korshinskii, H. rhamnoides, and A. fruticosa. Moreover, there is also a significant power relation between leaf area and diameter of base branches for C. korshinskii. There are significant linear relations between leaf area and diameter of base branches of H. rhamnoides and A. fruticosa. 3) In the hills and gully regions of the Loess Plateau, the LAIs of R. pseudoacacia stand at different densities converged after the planted stands entered their fast growth stage. Their LAI do not seem to
be affected by its initial and current density. The same is true for P. orientalis stands. However, the leaf area of individual trees is negatively and linearly related with stand density. We conclude that,
in the hills and gully regions of the Loess Plateau, the bearing capacity of R. pseudoacacia and P. orientalis stands we studied have reached their maximum limitation, owing to restricted access to soil water. Therefore, in consideration
of improving the quality of single trees, a stand density not exceeding 833 and 1111 plants/hm2 is recommended for R. pseudoacacia and P. orientalis, respectively. In consideration of improving the quality of the entire stands, the density can be reduced even a little more.
__________
Translated from Journal of Plant Ecology (Chinese Version), 2008, 32 (2): 440–447 [译自: 植物生态学报] 相似文献