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1.
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
2.
Effects of different vegetation restoration models on soil microbial biomass in eroded hilly Loess Plateau, China 总被引:2,自引:0,他引:2
Vegetation restoration is a key measure to improve the eco-environment in Loess Plateau, China. In order to find the effect
of soil microbial biomass under different vegetation restoration models in this region, six trial sites located in Zhifanggou
watershed were selected in this study. Results showed that soil microbial biomass, microbial respiration and physical and
chemical properties increased apparently. After 30 years of vegetation restoration, soil microbial biomass C, N, P (SMBC,
SMBN, SMBP) and microbial respiration, increased by 109.01%–144.22%, 34.17%–117.09%, 31.79%–79.94% and 26.78%–87.59% respectively,
as compared with the farmland. However, metabolic quotient declined dramatically by 57.45%–77.49%. Effects of different models
of vegetation restoration are different on improving the properties of soil. In general, mixed stands of Pinus tabulaeformis-Amorpha fruticosa and Robinia pseudoacacia-A. fruticosa had the most remarkable effect, followed by R. pseudoacacia and Caragana korshinkii, fallow land and P. tabulaeformis was the lowest. Restoration of mixed forest had greater effective than pure forest in eroded Hilly Loess Plateau. The significant
relationships were observed among SMBC, SMBP, microbial respiration, and physical and chemical properties of soil. It was
concluded that microbial biomass can be used as indicators of soil quality.
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Translated from Journal of Natural Resources, 2007, 22(1): 20–27 [译自: 自然资源学报] 相似文献
3.
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
4.
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
5.
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.
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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
6.
WANG Qing-kui WANG Si-long 《林业研究》2006,17(3):197-200
Conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation is a common management practice in subtropical China. In this study, we compared soil physico-chemical properties, microbial biomass in one natural secondary broad-leaved forest and two C. lanceolata plantation sites to estimate the effects of forest conversion on soil microbial biomass at the Huitong Experimental Station of Forestry Ecology, Chinese Academy of Sciences. Concentrations of soil organic carbon, total nitrogen, NH4^+-N and microbial biomass carbon and nitrogen were much lower under C. lanceolata plantations as compared to natural secondary broad-leaved forest. Soil microbial biomass C in the first and second rotation of C. lanceolata plantations was only 53%, 46% of that in natural secondary broad-leaved forest, and microbial biomass N was 97% and 79%, respectively. The contribution of microbial biomass C to soil organic C was also lower in the plantation sites. However, the contribution of microbial N to total nitrogen and NH4^+-N was greater in the C. lanceolata plantation sites. Therefore, conversion of natural secondary broad-leaved forest to C. lanceolata plantation and continuous planting of C. lanceolata led to the decline in soil microbial biomass and the degradation of forest soil in subtropical China. 相似文献
7.
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
8.
The influence of woodland soil bulk density on the growth and distribution of fine root system of main planting tree species
in the Weibei Loess Plateau was investigated by means of pot culture and field survey. Results indicated that in the woodland
of Pinus tabulaeformis, soil bulk density increased with the depth at different sites, while in the woodland of Robinia pseudoacacia, soil bulk density was higher than that in P. tabulaeformis, and there was no clear difference across the profile. Further analysis implied that there existed negative correlations
between soil bulk density and fine root length in the woodland of P. tabulaeformis. Results from pot culture indicated that although the effects of pot culture media on the fine root growth and development
of different tree species seedlings were different, all treated seedlings grew better in the soil matter with medium bulk
density and porosity and with the biggest biomass. Bulk density of pot culture media had clear effects on the growth and development
of P. tabulaeformis and R. pseudoacacia seedling roots, especially on the former, whereas it had little effect on that of Platycladus orientalis and Prunus armeniaca var. ansu, whose fine root biomass changed little in different pot culture media.
Translated from Scientia Silvae Sinicae, 2004, 40(5) (in Chinese) 相似文献
9.
Taishan Mountain has diverse habitats and abundant groups of soil animals. Five habitats,Platycladus orientalis forest,Pinus densiflora forest,Robinia pseudoacacia forest,Pinus tablaerormis forest and Grassland, were selected and the diversity of soil animals in different habitats in Mt. Taishan were investigated
and studied in 1997–1999. Totally 52 groups of soil animals were found, belonging separately to 7 Phyla, 11 Classes, 25 Orders
and 28 suborders or families. There exists remarkable difference in groups, quantity and diversity of soil animals among the
five habitats. Grassland habitat was the highest andPinus densiflora forest was the lowest in groups, quantities, Density-group index (DG) and Diversity index of comparing many communities (DIC) of soil animals. Shannon-Wiener’s diversity index (H′) for soil animals of different habitats was in order ofPlatycladus orientalis forest>Pinus densiflora forest>Pinus tablaerormis forest>Grassland>Robinia pseudoacacia forest, Pielou’s equality index (J′) wasPlatycladus orientalis forest>Pinus densiflora forest>Grassland>Pinus tablaerormis forest>Robinia pseudoacacia forest, and Simposn’s dominant index (C) was Grassland>Robinia pseudoacacia forest>Pinus tablaerormis forest>Pinus densiflora forest>Platycladus orientalis forest. The H index and J index of macro-soil animal all were larger than that of mid-small soil animal. Clustering analysis
for five soil animal communities and ordination analysis for community structure by multidimensional scaling (MDS) were made
and completely identical results were obtained. Soil animal communities of five habitats were divided into 3 groups.
Biography: Y{upuan} Xing-zhong (1963-), male, associate professor of East China Normal University, Shanghal 200062, China
Responsible editor: Chai Ruihai 相似文献
10.
11.
Weiqiang Zhang Kangning He Yunqi Wang Baitian Wang Juntao Deng Yi Zhou Xijun Zhong Zhaoqing Li 《Frontiers of Forestry in China》2007,2(2):192-197
In order to offer a scientific basis for cultivation and management of forests, effects of light radiation intensity on photosynthetic
characteristics and water use efficiency of Platycladus orientalis and Pinus tabulaeformis were studied under different soil moisture contents. By adopting artificial control methods to soil moisture, and under simulated
photosynthetic radiation (SPR), the net photosynthetic rate (P
N), transpiration rate (T
r), water use efficiency (WUE) and intercellular CO2 concentration (C
i) of Platycladus orientalis and Pinus tabulaeformis in the semi-arid region of the Loess Plateau, were studied. Results are as follows: within the photon range of 0–2,200 μmol/(m2·s), P
N, T
r and WUE were enhanced with an increase in SPR in both species. P
N and WUE of Platycladus orientalis and Pinus tabulaeformis, however, declined with continued increase in SPR. P
N, T
r, WUE and light saturation point (LSP) of Platycladus orientalis were higher than those of Pinus tabulaeformis, while light compensation point (LCP) of Platycladus orientalis was lower than that of Pinus tabulaeformis at the same soil moisture content. The efficiency of light energy utilization of Platycladus orientalis was higher than that of Pinus tabulaeformis; P
N, T
r and C
i of Platycladus orientalis and Pinus tabulaeformis were enhanced by increasing soil moisture content, whereas WUE declined. At soil moistures of 7.90%, 13.00% and 19.99%, LSP of Platycladus orientalis was 1,275, 1,450 and 1,675 μmol/(m2·s) respectively, and LCP was 42, 25 and 13 μmol/(m2·s) respectively, with corresponding maximal net CO2 photosynthetic rates (P
max) of 3.04, 4.06 and 5.53 μmol/(m2·s). At soil moistures of 7.83%, 13.04% and 20.15%, the LSP of Pinus tabulaeformis was 1,100, 1,325 and 1,500 μmol/(m2·s) respectively, and LCP was 60, 30 and 23 μmol/(m2·s), with P
max of 1.08, 3.35 and 4.36 μmol/(m2·s) respectively.
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Translated from Science of Soil and Water Conservation, 2006, 4(3): 108–113 [译自: 中国水土保持科学] 相似文献
12.
ABSTRACTSoil erosion is a major socioeconomic and environmental problem in Turkey. Almost 86% of the land in Turkey has suffered various degrees of soil erosion. The objective of this study was to determine whether differences in tree species affect soil characteristics and microbial activity in degraded soils. Results from this study showed that organic C (Corg) was highest in the black locust soil at 0–20 cm depth and lowest in the bare land. Microbial biomass C (Cmic) increased in the order black locust > Scotch pine > bare land at two soil depths. One-way ANOVA demonstrated that afforested soils contain significantly higher microbial biomass C than those in the bare land soils. Microbial quotient (Cmic/Corg) of soils are positively influenced by afforestation as the bare land soils exhibited lower microbial quotient than the associated Scotch pine and black locust soils. Microbial communities in black locust soils were energetically more efficient—had a lower metabolic quotient (qCO2)—with a higher Cmic/Corg compared to those in Scotch pine soils. However, the microbial quotient in our study was still below range and cannot reach equilibrium again 15 yr after afforestation. Restoration of degraded lands could be a long-term process from microbial activity in the observed regions. 相似文献
13.
Soil properties under an exotic plantation (Pinus caribaea) and an indigenous plantation (Podocarpus imbricatus) were compared with adjacent secondary forests and abandoned land in the tropical forest areas of Jianfengling National Nature
Reserve in Hainan province, southern China. The surface soil (0–0.2 m) under Pi. caribaea has higher bulk density, lower soil organic carbon, total N, total K, available N, microbial biomass carbon, and smaller
soil microbial communities (as indicated by soil Biolog profiles) than under Po. imbricatus. Both land use types showed negative cumulative soil deterioration index (DI) compared to secondary forests. However, compared
to abandoned land (DI = –262), the soil quality of Po. imbricatus showed improvement (DI = –194) while that of Pi. caribaea showed deterioration (DI = –358). These results demonstrated that these exotic pine plantations can significantly and negatively
influence soil properties. By contrast, our results showed that adoption of indigenous species in plantations, or natural
regeneration, can improve soil quality. 相似文献
14.
《Forest Ecology and Management》2005,217(1):117-125
Microbial biomass, organic carbon, total nitrogen, and microbial quotient (MBC/Corg) in soil were determined during the secondary forest succession in north Ziwulin region in the middle of Loess Plateau, China. The results showed that with secondary forest succession organic carbon (Corg), total nitrogen (TN), microbial biomass carbon (MBC) and N (MBN) in soil increased quickly, and tended to be the highest contents under SF17 (17-year secondary forest), after that they decreased and gradually remained at quite a constant level, suggesting that accumulations of organic C, total N, MBC and MBN in soil occurred mainly at the early succession stages (before SF17). Soil microbial biomass was markedly correlated with the organic carbon and total nitrogen content of soil (p < 0.01), Furthermore, microbial quotient showed significant correlation not only with MBC and organic C, but also with succession duration during the secondary forest succession. Therefore, the results suggested that changes in microbial biomass in soil were relative not only to the quantity, but also to the quality of soil organic matter during secondary forest succession, and that changes in aboveground plant species during succession were critical to improve degradation soil physical, chemical and microbial properties in north Ziwulin of Loess Plateau, China. 相似文献
15.
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
16.
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
17.
In this paper, based on a long-term monitoring of water cycle in the water and soil conservation forest stands of Pinus tabulaeformis and Robinia pseudoacacia, the soil moisture deficit is calculated. Following the principles of runoff-collecting forestry and applying the forest
structure investigation results, the authors developed a formula to calculate appropriate density for forests on the basis
of different diameters at breast height (DBH). Using this method to manage forests, the natural water requirement of forests
can be met and soil drought can be avoided. In addition, with long-term monitoring of soil moisture in stands, the authors
also give an appropriate managing density specifically for the water and soil conservation forests of P. tabulaeformis and R. pseudoacacia in the loess area which is according to soil moisture content, or with the lowest soil moisture content and invalid moisture
frequency as the indexes.
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Translated from Science of Water and Soil Conservation, 2007, 5(2): 55–59 [译自: 中国水土保持科学] 相似文献
18.
From 2002 to 2003, based on the investigation of sample plots and stem analysis of remained plantation communities in the areas of returning farmland to forest in the 1980s in Datong County, Qinghai Province, this paper studies tree productivity and moisture potential productivity of six types of plantations on the land of returning farmland to forest, such as green poplar (Populus cathayana Rehd.) and shrub mixed forest, Asia white birch (Betula platyphylla) and China spruce (Picea asperata) mixed forest, Dahurian larch (Larix gmelinii) pure forest, China spruce pure forest and Asia white birch pure forest and so on. The results show that: in sub-humid region of Loess Plateau, 3 000 trees per hm2 is a proper standard of planting density. Under current condition, the productivity index of green poplar and shrub mixed forest, Asia white birch pure forest, China spruce pure forest, and Asia white birch and China spruce mixed forest with the density of 2 100–3 333 trees per hm2 can serve as potential productivity standard of actual biomass of arbor established forest. In sub-humid area, Thornthwaite Model is adopted to estimate plant climate potential productivity, which is about 8 462 kg8226;hm–28226;a–1. The actual potential water productive efficiency of Purplecone spruce (Picea purpurea) and Asia white birch pure established forest are 17.22 and 22.14 kg8226;mm–18226;hm–28226;a–1 respectively, and that of green poplar and shrub mixed established forest, and Asia white birch and China spruce mixed established forest are 21.14 and 19.09 kg8226;mm–18226;hm–28226;a–1 respectively. The potential productivity of green poplar and shrub mixed forest, Asia white birch and China spruce mixed forest, China spruce pure forest and Asia white birch pure forest which have grown into forest with the density of 3 000 trees per hm2 have attained or been close to that of local climax community, which is local maximum tree productivity at present. These types of forestation models are the developing direction of the returning farmland to forest project. 相似文献
19.
To enrich resource of species, 105 arbor species (25 genera, 15 families) were introduced to the hilly and gully areas on
Loess Plateau. By acclimation and selection, more than 90 tree species (12 genera, 8 families) were identified as fine species,
including trees suitable for sloping fields such as Pinus sylvestri var mongolica, Pinus tabulaeformis, Platycladus orientalis, and Robinia pseudoacacia, trees suitable for gully bottoms such as Populus davidiana, Populus diversifolia, and Salix cheilophila and non-timber trees such as Prunus armeniaca, Ziziphus jujuba and Prunus persica. For those fine trees, habitat conditions and regularity of requirement of water and fertilizers were studied and then habitat
ranges were given. From research results, it could be seen that Robinia pseudoacacia consumed more water, but it could improve the content of organic matters in soil; by contrast, Pinus tabulaeformis and Platycladus orientalis consumed less water and were suitable for dry sloping fields; species of apricot were suitable for sunny or semi-shady sloping
fields with good conditions of water and fertilizer; species of pear were suitable for both shady sloping fields and sunny
sloping fields; species of Chinese date were suitable for sunny sloping fields.
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Translated from Scientia Silvae Sinica, 2005, 41(5) [译自: 林业科学, 2005, 41(5)] 相似文献
20.
Soil and microbial respiration in a loblolly pine plantation in response to seven years of irrigation and fertilization 总被引:2,自引:0,他引:2
Lisa Samuelson Reji Mathew Tom Stokes Yucheng Feng Doug Aubrey Mark Coleman 《Forest Ecology and Management》2009,258(11):2431-2438
Because soil CO2 efflux or soil respiration (RS) is the major component of forest carbon fluxes, the effects of forest management on RS and microbial biomass carbon (C), microbial respiration (RH), microbial activity and fine root biomass were studied over two years in a loblolly pine (Pinus taeda L.) plantation located near Aiken, SC. Stands were six-years-old at the beginning of the study and were subjected to irrigation (no irrigation versus irrigation) and fertilization (no fertilization versus fertilization) treatments since planting. Soil respiration ranged from 2 to 6 μmol m−2 s−1 and was strongly and linearly related to soil temperature. Soil moisture and C inputs to the soil (coarse woody debris and litter mass) which may influence RH were significantly but only weakly related to RS. No interaction effects between irrigation and fertilization were observed for RS and microbial variables. Irrigation increased RS, fine root mass and microbial biomass C. In contrast, fertilization increased RH, microbial biomass C and microbial activity but reduced fine root biomass and had no influence on RS. Predicted annual soil C efflux ranged from 8.8 to 10.7 Mg C ha−1 year−1 and was lower than net primary productivity (NPP) in all stands except the non-fertilized treatment. The influence of forest management on RS was small or insignificant relative to biomass accumulation suggesting that NPP controls the transition between a carbon source and sink in rapidly growing pine systems. 相似文献