Table of Content

20 August 2008, Volume 19 Issue 08

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Articles

Effects of elevated temperature on soil organic carbon and soil respiration under subalpine coniferous forest in western Sichuan Province, China.

PAN Xin-li^1，2; LIN Bo¹;LIU Qing¹

2008, 19(08):  1637-1643 . 

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To investigate the effects of elevated temperature on the soil organic carbon content, soil respiration rate, and soil enzyme activities in subalpine Picea asperata plantations in western Sichuan Province of China, a simulation study was conducted in situ with opentop chambers from November 2005 to July 2007. The results showed that under elevated temperature, the mean air temperature and soil temperature were 0.42 ℃ and 0.25 ℃ higher than the control, respectively. In the first and the second year, the increased temperature had somewhat decreasing effects on the soil organic carbon and the C/N ratio at the soil depths of 0-10 cm and 10-20 cm. In the first year the soil organic carbon and the C/N ratio in 0-10 cm soil layer decreased by 8.69%, and 8.52%, respectively; but in the second year, the decrements were lesser. Soil respiration rate was significantly enhanced in the first year of warming, but had no significant difference with the control in the second year. In the first year of warming, the activities of soil invertase, polyphenol oxidase, catalase, protease, and urease increased, and the invertase and polyphenol oxidase activities in 0-10 cm soil layer were significantly higher than the control. In the second year of warming, the activities of invertase, protease and urease still had an increase, but those of catalase and polyphenol oxidase had a downtrend, compared with the control.

Characteristics of carbon stock in artificial forest ecosystem in Sichuan Province of China.

HUANG Cong-de;ZHANG Jian;YANG Wan-qin;ZHANG Guo-qing

2008, 19(08):  1644-1650 . 

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By using forest inventory data in combination with plot measurement, the characteristics of carbon density, stock, and partitioning in artificial forest ecosystem in Sichuan Province of China were studied. The results showed that the carbon density in this forest ecosystem was averagely 161.16 Mg C·hm^-2, being ranked in the order of soil layer (141.64 Mg C·hm^-2)＞tree layer (17.95 Mg C·hm^-2)＞litter layer (1.06 Mg C·hm^-2)＞shrub layer (0.52 Mg C·hm^-2), and the total carbon stock was 573.57 Tg C, with 63.88 Tg C, 1.836 Tg C, 3.764 Tg C, and 504.09 Tg C, accounting for 11.14%, 0.32%, 0.66%, and 87.88% of the total in tree layer, shrub layer, litter layer, and soil layer, respectively. The carbon density and stock in different artificial forest ecosystems varied from 75.50 Mg C·hm^-2 to 251.74 Mg C·hm^-2 and from 1.21 Tg C to 99.44 Tg C, with the highest and lowest values observed in soil layer and shrub layer, respectively. Comparing with other regions in China, Sichuan Province had a lower carbon density in the tree layer of artificial forest ecosystem, due to the higher proportion of young and middle age forest stands, which implied that a proper management of artificial forest could increase the carbon sequestration in forest ecosystem of Sichuan. To monitor the carbon stock in artificial forest ecosystem at ecosystem level could be helpful to the improvement of the precision of forest carbon sequestration evaluation.

Characteristics of standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding.

LI Ji-mei¹;XU Hai-liang¹;ZHANG Zhan-jiang²;YE Mao³;WANG Zeng-ru¹;LI Yuan¹

2008, 19(08):  1651-1657 . 

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An investigation was made on the standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding. The results showed that the standing vegetation in nonflooded and flooded sites was composed of 14 species in 13 genera of 8 families, and 26 species in 21 genera of 10 families, respectively, and some shallowrooted and hygrophilous species were recorded in flooded sites. The indices per unit area plant species number, vegetative coverage, plant density, and species diversity of the vegetation were all higher in flooded than in nonflooded sites. The species number of the soil seed bank in flooded sites was 19, with 5 species more than that in nonflooded sites, and the seed bank density in flooded sites was 2.94 times higher than that in nonflooded sites. The proportion of annual herbaceous species seeds in flooded sites increased by 23.07% while that of shrub species seeds decreased by 2099%, compared with those in non-flooded sites, and the proportion of perennial herbaceous species seeds had less difference between these two sites. River-flooding increased the diversity of soil seed bank. In flooded and non-flooded sites, the co-occurrence species in seed bank and in standing vegetation were 18 and 9, with the similarity coefficients of species composition between soil seed bank and standing vegetation being 0.842 and 0.667, respectively.

Interactive effects of light intensity and nitrogen supply on Fraxinus mandshurica seedlings growth, biomass, and nitrogen allocation.

HUO Chang-fu^1,2;WANG Zheng-quan¹;SUN Hai-long¹;FAN Zhi-qiang¹;ZHAO Xiao-min¹

2008, 19(08):  1658-1664 . 

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With sand culture in greenhouse, the responses of Fraxinus mandshurica seedlings growth, biomass, and N allocation to 2 levels of light intensity and 4 levels of N supply were studied. The results showed that under low light intensity, the seedlings shoot/root ratio (S/R) and net N uptake rate (NNUR) increased significantly (P<0.01), but their relative growth rate (RGR) and net assimilation rate (NAR) had a significant decrease (P<0.01). The biomass of root, stem, leaf, and total plant under low light was decreased by 36.8% (P<0.01), 1.7%, 12.7% (P<0.05), and 24.3% (P<0.01), respectively, and the N allocation to leaf increased but that to root was in adverse. At the two light levels, N supply had an obvious promotion effect on the seedlings growth, and the S/R and the N allocation to leaf were increased obviously with increasing N supply. Significant interactive effects of light and N supply were observed on the seedlings diameter, S/R, RGR, and biomass allocation.

Effects of different calcium salts on freezing resistance of satsuma mandarin.

LI Xin-guo^1,2;ZENG Bin¹;YANG Xiao-hong¹;HE Li-gang¹;WANG Hui-liang¹;SUN Zhong-hai^1,3

2008, 19(08):  1665-1669 . 

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The study on the effects of foliar spraying 20 mmol·L^-1 of CaCl₂, Ca(NO₃)₂ and CaAc₂ on the freezing resistance of satsuma mandarin (Citrus unshiu Marc. cv. Guoqing No.1) showed that after treated with these Ca salts, the leaves of test plant had a lower half lethal temperature (LT₅₀) than the control (sprayed with distilled water). The LT₅₀ after treated with CaCl₂ was 0.54 ℃ lower, whereas that after treated with CaAc₂ and Ca(NO₃)₂ was 1.34 ℃ and 1.35 ℃ lower, respectively, implying that the latter two Ca salts were more effective in enhancing the freezing resistance of satsuma mandarin. Moreover, foliar spraying Ca salts increased the superoxidase (SOD) and peroxidase (POD) activities and the contents of soluble proteins, soluble sugars and praline in leaves, and decreased the leaf MDA content.

Geographic distribution characteristics of the national key protected wild plants in China.

ZHANG Yin-bo^1,2;MA Ke-ping¹

2008, 19(08):  1670-1675 . 

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Rare and endangered wild plants, being an important component of biological diversity, have become one of the hot issues for conservation biology, and the study of their geographic distribution is of significance to the theories of biodiversity conservation and the mechanisms of their endangerment. In this study, the floristic elements and geographic distribution characteristics of national key protected wild plants in China were analyzed at national scale, based on the information from published literatures and the specimen records mainly from the Chinese Virtual Herbarium. The results indicated that there are 2 177 species of protected plants, belonging to 130 families and 484 genera. The flora is characteristic of extremely diversified, old and endemic, and obviously rich in tropical and temperate elements. The geographic distribution of the protected plants is uneven, and concentrates in the southwestern regions and Taiwan of China. Yunnan, Sichuan, Guangxi, Tibet, Guizhou and Taiwan are the hotspots of protected plant diversity. The protected plants have a pretty wide vertical distribution range, but mainly distribute in lower and middle mountains with an elevation from 800 m to 1 600 m. The spatial pattern of the protected plants is unimodalalong elevation gradient. This study would provide sound basis for the identification of the priority areas of biodiversity conservation, and the establishment of conservation strategies.

Nutrient contents in Kingdonia uniflora ramet and their relations to heterogeneous environment on Taibai Mountains.

LI Yu-hua;LIU Xiao;YUE-Ming

2008, 19(08):  1676-1681 . 

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Taking the guerrilla type clonal plant Kingdonia uniflora at different altitudes in Taibai Mountain National Forest Park of Shaanxi Province, China as test material, the C, N, P, K and Mg contents in different vegetative organs of its ramet were measured. The results showed that ramet age, altitude, and their interaction had no significant effects on the total C content in ramet leaf, rhizome, and root (P>0.05), but different effects on the total N, total P, K and Mg contents in these vegetative organs, suggesting that ramet could regulate the allocation of nutritive elements in its vegetative organs through physiological metabolism. At high altitude (3 000-3 100 m), ramet age had significant effects on the K content in all vegetative organs and the N content in rhizome and root (P<0.05). All the test nutrient contents were significantly correlated with each other at all altitudes, except at middle altitude (2 800-2 900 m) where the ramet K content had no significant correlations with its N, P, and Mg contents. It was suggested that physiological plasticity contributed more to the performances of clonal plants at high altitude than at low altitude. Powerful physiological plasticity could help K. uniflora to effectively utilize heterogeneous resources, realize population expansion, and open up new habitat at high altitude. It was likely that the physiological plasticity of K. uniflora responding to heterogeneous habitats was formed in its long-term evolvement.

Effects of compensation capacity and palatability on the dominance of plant species in grazing community.

PAN Sheng-wang^1,2;WANG Hai-yang^2,3;DU Guo-zhen³;LEI Shu-qing²;WEI Shi-qiang¹

2008, 19(08):  1682-1687 . 

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With simulated mowing experiment and field survey, the compensation capacity and dominance shift of nine alpine plant species in grazing community were studied. The results showed that for most test species, there existed definite correlations between their compensation capacity and palatability. The species with better palatability, i.e.,Astragalus polycladus, Medicago rythenica, Kobresia humilis, and Polygonum viviparvum, had higher compensation capacity, with their compensation index being 1.013, 0.907, 0.849, and 0.802, respectively, followed by Elymus nutans, with its compensation index being 0.668, while the species with poorer palatability, i.e., Taraxacum tibetanum, Swertis bimaculata, and Ajania tenuifolia had lower compensation capacity, with their compensation index being 0.649, 0.587, and 0.553, respectively. Festuca sinensis was more palatable but had the lowest compensation index (0.473). The nine species had three types of dominance shift, i.e., decreasing, increasing, and neutral. F. sinensiswas of decreasing type， E. nutans, A. polycladus and P. viviparvum were of neutral, and the other five species were of increasing type. The compensation capacity and palatability of plant species in grazing community could explain their dominance shift to a certain extent.

Effects of nutrient deficiency on principal components of ginseng root exudates.

LI Yong;HUANG Xiao-fang;DING Wan-long

2008, 19(08):  1688-1693 . 

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By the method of solution culture, the effects of N， P， and K deficiency on the principol components in root exudates of ginseng at its early growth stage were studied. The results showed that in treatments N and K deficiency and control, no significant difference was observed in the principal components of ginseng root exudates, and 28, 29, and 27 principal chromatographic peaks were detected by GC-MS, respectively; while in treatment P deficiency, only 22 principal chromatographic peaks were detected. Furthermore compounds in the root exudates from treatments N, P, and K deficiency and control were identified, respectively. Compared with control, treatments N and K deficiency had more kinds of organic acids and phenolic acids in root exudates, while treatment P deficiency was in adverse, which suggested that at early growth stages, ginseng had more requirement to N and K than P, and N and K deficiency would accelerate the exudation of organic acids and phenolic acids by roots.

Ecological distribution and antimicrobial effects of soil actinomycetes in artificial vegetation systems in Shazhuyu of Qinghai, China.

YANG Bin^1,2;XUE Quan-hong¹;CHEN Zhan-quan³;GUO Zhi-ying¹;ZHANG Xiao-lu²;ZHOU Yong-qiang²;XU Ying-jun²; SUN De-fu⁴

2008, 19(08):  1694-1701 . 

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In order to probe into the effects of artificial vegetation rehabilitation on soil actinomycetes, dilution plate and agar block methods were used to investigate the ecological distribution and antimicrobial effects of actinomycetes in sandy soil in Shazhuyu area of Qinghai after artificial vegetation restoration. The results showed that with the vegetation rehabilitation and the improvement of vegetation coverage on alpine sandy dry land, the quantity of soil actinomycetes increased significantly, being 145.4% higher in the grassland transferred from farmland than in sandy land. The quantity of soil Micromonospora in grassland transferred from farmland was about six times as much as that in sandy land. The average selection rate of antimicrobial actinomycetes was increased greatly, with the antimicrobial actinomycetes in the soil of grassland transferred from farmland, the antibacterial actinomycetes in the soil of natural grassland, and the pathogenic fungus resistant actinomycetes in the soil of forestland being approximately 2, 3.2 and 1.5 times as much as those in the soil of sandy land, respectively. Vegetation coverage and soil nutrients had great influences on the quantities of actinomycetes and antimicrobial actinomycetes. The contents of soil organic matter and alkali-hydrolyzable nitrogen and the yield of fresh grasses had significant correlations with the quantities of actinomycetes (P<0.01), and the content of soil organic matter and the yield of fresh grasses significantly correlated with the strain numbers of antimicrobial actinomycetes (P<0.01). Furthermore, vegetation coverage and the contents of soil total nitrogen, total phosphorous, total potassium, total salt, and available potassium had significant correlations with the total quantities of actinomycetes, Streptomycetes, and Micromonospora (P<0.05).

Effects of silicon on exchange characteristics of H₂O and CO₂ in ginger leaves.

ZHANG Guo-qin; XU Kun;WANG Xing-cui;ZHANG Xiao-yan;DONG Can-xing

2008, 19(08):  1702-1707 . 

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With solution culture, this paper studied the effects of silicon (Si) on the plant growth, Si content, photosynthetic rate, and transpiration rate of ginger (Zingiber officinale Rosc.) cultivar, Laiwu big ginger. The results indicated that the biomass per plant and the leaf Si content were increased dramatically with increasing Si level in culture solution. In treatments T₁ (1.0 mmol Si·L^-1), T₂ (1.5 mmol Si·L^-1), and T₃ (2.0 mmol Si·L^-1), the leaf Si content was increased by 604.4%, 834.8%, and 1130.4%, and the biomass per plant was increased by 9.4%, 19.4%, and 22.8%, respectively, compared with the control. With increasing Si level, the leaf Mg²⁺ATPase and Ca²⁺ATPase activities, photosynthetic rate (P_n), and water use efficiency (WUE) increased, while the transpiration rate (T_r) decreased. At 11:00 o’clock, the P_n in treatments T₁, T₂, and T₃ increased by 11.2%, 21.8%, and 28.2%, WUE increased by 23.1%, 55.9% and 54.8%, whileT_r decreased by 6.3%, 17.1% and 19.2%, respectively, compared with the control. Si also improved the leaf light saturation point (LSP), carboxylation efficiency (CE), and carotenoid content significantly, but had less effect on chlorophyll content. In our study, the suitable Si concentration for ginger was 1.5-2.0 mmol·L^-1.

Effects of nutrient and light on seedlings morphological plasticity of four Saussurea species with different ecological breadth.

WU Gao-lin;CHEN-Min;DU Guo-zhen

2008, 19(08):  1708-1713 . 

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Taking four Saussurea species with different ecological breadth in the eastern QinghaiTibetan Plateau as test materials, their seedlings relative growth rate (RGR), root mass to shoot mass ratio (R/S), and specific leaf area (SLA) were determined under different nutrient and light treatments. The results showed that nutrient and light had significant effects on the seedlings RGR, R/S and SLA of the four Saussurea species, and there existed a certain interactive effect between nutrient and light. The plasticity of these morphological characteristics and their response patterns to the variation of nutrient and light conditions varied with species. Significant interactive effects (P<0.001) between light, nutrient, and species were observed on the R/S and SLA of Saussurea. For the four Saussureaspecies, the mean phenotypic plasticity index of their seedlings was positively correlated with their ecological distribution, being the highest (0.71) for S. japonica, the best widespread species in the four species. The morphological plasticity of Saussurea species was positively related to their distribution ecological breadth.

Effects of simulated nitrogen deposition on biomass of wetland plant and soil active carbon pool.

DOU Jing-xin^1,2;LIU Jing-shuang¹;WANG Yang¹;ZHAO Guang-ying¹

2008, 19(08):  1714-1720 . 

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A simulation study was made on the responses of biomass of Deyeuxia angustifolia and soil active carbon pool in Sanjiang Plain of Northeast China to simulated nitrogen deposition. Two water conditions (W₁: nonflooded, W₂: flooded) and four N treatments (equivalent to 0, 1, 3, 5 g N·m^-2·a^-1 nitrogen deposition rate) were installed. The results showed that under effects of nitrogen deposition, the total biomass, aboveground biomass, and root biomass of D. angustifolia were higher than the control, and the increment of root biomass was the highest. Both the carbon content and its allocation proportion in D. angustifolia root increased significantly, while the carbon content in aboveground part decreased dramatically (P<0.05). Nitrogen deposition also had significant effects on soil active carbon pools, and the contents of various fractions in the carbon pool were the highest in treatment 5 g N·m^-2·a^-1. The responses of various fractions in soil active carbon pool to nitrogen deposition followed the sequence of carbohydrate carbon＞labile carbon＞dissolved organic carbon＞microbial biomass carbon, and the interaction between nitrogen deposition and flooded water condition facilitated the release of soil active carbon. Regression analysis indicated that there were significant correlations between soil active carbon pools and plant indices of D. angustifolia. Nitrogen deposition could enhance the biomass of D. angustifoliat and soil active carbon content.

Effects of longterm fertilization on soil organic nitrogen components in paddy soil derived from red earth.

ZONG Hai-ying¹;WANG Kai-rong¹;lXIE Xiao-li²

2008, 19(08):  1721-1726 . 

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A 16-year long-term fertilization experiment was conducted on paddy soil derived from red earth to investigate the effects of different fertilization patterns on the concentrations of soil organic nitrogen (N) components. When chemical fertilizers were applied only, the soil nitrogen content was slightly infuenced. Organic fertilization, especially its combination with chemical fertilization, could significantly increase the contents of soil mineralizable N and organic nitrogen by 55.2% and 38.8%, respectively. In addition, organic fertilization could significantly improve the components of acid hydrolysable N, and lead to the increase of ammonium N (AN), amino sugar N (ASN), and hydrolysable unidentified N (HUN) by 36.5%, 68.4%, and 73.9%, respectively. When the organic fertilization was combined with chemical fertilization, soil amino acid N content was increased by 71.1%, while HUN content was decreased by 34.5%. In all fertilization treatments, the cumulative amount of soil mineralized N increased with increasing incubation time. The content of soil mineralized N under organic fertilization and its combination with chemical fertilization was higher than that under chemical fertilization.

Effects of latitude on grain’s protein components of winter wheat cultivars.

ZHANG Xue-lin;WANG Zhi-qiang;GUO Tian-cai;WANG Chen-yang;ZHU Yun-ji

2008, 19(08):  1727-1732 . 

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Six representative winter wheat cultivars were planted at five locations with the latitude varied from 32°N to 36°N in Henan Province to study the effects of latitude on their grain’s protein components. The results showed that with increasing latitude, the contents of albumin and gliadin decreased, while glutenin content, glutenin/gliadin ratio, sum of protein components, and grain yield increased. The grain’s albumin content of test cultivars at Xinyang, gliadin content at Zhumadian and Xuchang, and glutenin content and glutenin/gliadin ratio at Wuzhi and Tangyin were higher than those at other locations. The average air temperature, total sunlight hours, and precipitation in May had close relations with the grain’s protein components of test winter wheat cultivars at different locations. In order to improve wheat grain quality, suitable cultivars should be chosen to match the local ecological conditions, and, management practices for improving photosynthesis and extending grain-filling period should be performed in May.

Effects of sowing date and planting density on the grain’s protein component and quality of strong and medium gluten winter wheat cultivars.

YAN Cui-ping¹;ZHANG Yong=qing²;ZHANG Ding=yi¹;DANG Jian=you¹

2008, 19(08):  1733-1740 . 

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In a field experiment with splitsplit plot design, the effects of sowing date and planting density on the grain’s protein component and quality of strong gluten wheat cultivar Linyou 145 and medium gluten wheat cultivar Linyou 2018 were studied. The results showed that proper sowing date brought the highest protein content and yield in wheat grain. With sowing date postponed, the grain’s gliadin and glutenin contents of Linyou 145 increased obviously, while those of Linyou 2018 changed little. The grain quality of Linyou 145 was more affected by sowing date, compared with that of Linyou 2018. When sowing at proper date, the grain’s protein and glutenin contents had significant correlations with its wet gluten content, sedimentation value, dough stability time, softness, and evaluation value; while when the sowing date postponed, there existed a positive correlation between the contents of gliadin and wet gluten. The change of the proportions of different protein components in wheat grain induced by the variation of sowing date could be the main reason of the improvement in wheat grain quality. Within the test range (2.25 million -3.75 million plants·hm^-2) of planting density, the grain’s protein content was less affected, but the grain quality of Linyou 145 was affected to a certain extent. Low planting density (2.25 million plants·hm^-2) brought the best grain quality of Linyou 2018.

Dynamic changes of soil microbial populations and enzyme activities in super-high yielding summer maize farmland soil.

HOU Peng¹;WANG Yong-jun¹;WANG Kong-jun¹;YANG Jin-sheng²; LI Deng-hai²; DONG Shu-ting¹;LIU Jing-guo²

2008, 19(08):  1741-1746 . 

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To reveal the characteristics of the dynamic changes of soil microbial populations and enzyme activities in superhigh yielding (>15 000 kg·hm^-2) summer maize farmland soil, a comparative study was conducted in the experimental fields in National Maize Engineering Research Center (Shandong). On the fields with an annual yield of >15 000 kg·hm^-2 in continuous three years, a plot with the yield of 20 322 kg·hm^-2 (HF) was chosen to make comparison with the conventional farmland (CF) whose maize yield was 8920.1 kg·hm^-2. The numbers of bacteria, fungi, and actinomycetes as well as the activities of urease and invertase in 0-20 cm soil layer were determined. The results showed that in the growth period of maize, the numbers of bacteria, fungi, and actinomycetes in the two farmland soils increased first and declined then. At the later growth stages of maize, the numbers of soil microbes, especially those of bacteria and actinomycetes, were lower in HF than those in CF. At harvest stage, the ratio of the number of soil bacteria to fungi (B/F) in HF was 2.03 times higher than that at sowing stage, and 3.02 times higher than that in CF. The B/F in CF had less difference at harvest and sowing stages. The soil urease activity in HF was significantly lower than that in CF at jointing stage, and the invertase activity in HF decreased rapidly after blooming stage, being significantly lower than that in CF.

Root morphology and nodule traits of two soybean varieties on alfisol and mollisol.

JIN Jian^1,2;WANG Guang-hua¹;LIU Xiao-bing¹;XU Yan-xia¹;LIU Jun-jie¹;MI Liang1;WANG Cheng¹;Stephen James Herbert³

2008, 19(08):  1747-1753 . 

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A pot experiment was conducted with two soybean varieties (Di2003-1 and Hefeng25) and two main soil types (alfisol and mollisol) in Heilongjiang Province to study the interactive effects of variety and soil type on the root morphology and nodule traits of soybean plants. Root samples were collected at the fifth trifoliolate stage, bloombeginning stage, podbeginning stage, full pod stage, seedbeginning stage, full seed stage, and full maturity stage for the analysis of root dry mass, root length, root surface area, average root diameter, nodule number, nodule fresh mass, and mass per nodule. The results showed that soil type had significant effects on the root morphology and nodule traits of test varieties. In alfisol, the root dry mass, root length, and root surface area of test varieties were greater at the fifth trifoliolate stage and bloom-beginning stages while smaller after seedbeginning stage, compared with those in mollisol, and the average root diameter after seedbeginning stage was higher in alfisol than that in mollisol. Soil type did not affect rootshoot ratio. The nodule number after seedbeginning stage was much smaller in alfisol than in mollisol, while the nodule fresh mass and the mass per nodule were in adverse. The root traits in the two soil types varied with soybean variety. Compared with that of Hefeng25, the response of root traits of Di2003-1 to soil type was more sensitive. The interactive effects of variety and soil type on the root morphology and nodule traits of soybean plants were more significant at full seed stage.

Relative expression of SOD and CAT mRNA and activities of SOD and CAT in grafted cucumber leaves under NaCl stress.

GAO Jun-jie;ZHANG Lin;QIN Ai-guo;YU Xian-chang

2008, 19(08):  1754-1758 . 

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Taking grafted and ownroot cucumber (Junlv No.3) plants as test materials, the changes of their leaf Cu/Zn-SOD, Mn-SOD and CAT mRNA relative expression, leaf SOD, Cu/Zn-SOD, Mn-SOD and CAT activities, leaf MDA content, and leaf electrolytic leakage under NaCl stress were studied. The results showed that under NaCl stress, grafted cucumber had a higher relative expression of its leaf Cu/Zn-SOD, Mn-SOD and CAT mRNA, and higher activities of its leaf SOD, Cu/Zn-SOD, Mn-SOD and CAT, compared with ownroot cucumber, which suggested that the higher relative expression of Cu/Zn-SOD, Mn-SOD and CAT mRNA in grafted cucumber leaves resulted in the higher activities of their SOD, Cu/Zn-SOD, Mn-SOD and CAT. With the NaCl stress prolonged, the relative expression of Cu/Zn-SOD, Mn-SOD and CAT mRNA in both grafted and own-root cucumber leaves had an increasing rend, but the changing trend of Cu/Zn-SOD, MnSOD and CAT activities were not the same as that of mRNA, indicating that the activities of SOD and CAT were also regulated by other factors. The leaf MDA content and electrolytic leakage of grafted cucumber were lower than those of ownroot cucumber, suggesting that grafted cucumber had a higher scavenging metabolism, which could decrease oxidative damage and increase its salt-tolerance.

Pinus koraiensis seed consumption by rodents and birds.

YAO Xiao-lin^1,2;PIAO Zheng-ji³;LI Bu-hang^1,2;ZHANG Jian^1,2; WANG Xu-gao¹; YE Ji^1,2;HAO Zhan-qing¹

2008, 19(08):  1759-1763 . 

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An investigation from 2006 to 2007 was made on the Pinus koraiensis seed consumption by rodents and birds in the broadleaved P. koraiensis mixed forest and birch forest at the same altitude in Changbai Mountains. The results showed that in broadleaved P. koraiensis mixed forest, rodents consumed more pinecone seeds than birds; while in birch forest, birds did more than rodents. In the two forests, the total number of pinecone seeds consumed by rodents was significantly higher than that consumed by birds (P<0.01). In addition, rodents consumed more embedded seeds in broad-leaved P. koraiensis mixed forest than in birch forest, and the consumption amount in the two forests decreased with increasing embedded depth.

Change patterns of protective enzyme activities in pre-diapause, diapause, and post-diapause larvae of Sitodiplosis mosellana Gehin.

CHENG Wei-ning¹;WANG Hong-liang²;LI Yi-ping¹;LI Jian-jun¹;LI Xiu-lian¹;WU Jun-xiang¹

2008, 19(08):  1764-1768 . 

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The activities of protective enzymes peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) in prediapause, diapause, and postdiapause larvae of Sitodiplosis mosellana Gehin were determined by using protective enzyme testing kits. The results indicated that the activities of the three protective enzymes showed a decreasing trend from prediapause to early diapause larvae. In one-year cycle, the SOD and CAT activities of diapause larvae had the same responses to environmental temperature, i.e., increased at lower temperature but decreased at higher temperature, while POD activity was related to both environmental temperature and the development situation of the larvae. A similar seasonal variation trend was observed in the three protective enzymes of both no-cocooned and cocooned larvae in one-year cycle. The three protective enzyme activities of no-cocooned larvae were higher than those of cocooned larvae at the same diapause stage. No significant difference of the three protective enzyme activities was found between 1st and 2nd year diapause larvae. The activities of the three protective enzymes increased gradually with the development of post-diapause larvae.

Animal community structure in greenhouse soils with different planting years in Shouguang City.

DONG Bo¹;ZHANG Ren-zhi¹;JING Shi-jie²;XIE Yong¹;YAO Hua¹

2008, 19(08):  1769-1774 . 

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By the methods of handsorting, Tullgren’s and Baermann’s, the animal community structure in greenhouse soils with different planting years in Shouguang City of Shandong Province was investigated from March 2006 to April 2007. A total of 20966 soil animals belonging to 3 phylums and 12 classes were obtained. Collembola, Nematoda, Acariformes and Oribatida were the dominant groups, accounting for 82.3% of the total individuals. The soil animals had an obvious vertical distribution pattern, with most of them assembled in surface soil and occupying 75.4% and 14.6% of the total at the depths of 0-5 cm and 5-10 cm, respectively. The animals’ amount in greenhouse soils was the highest from March to May and from October to December, and the lowest in August; while that in open field soils was the highest from July to September, and the lowest in January. The animal community in greenhouse soils in this region had a high diversity, but the density of dominant groups increased obviously with increasing planting years, resulting in a decrease of diversity index.

Modeling of forest landscape change in Xiaoxinganling Mountains under different planting proportions of coniferous and broadleaved species.

ZHOU Yu-fei^1,2; HE Hong-shi^1,3; BU Ren-cang¹;JIN Long-ru^1,2; LI Xiu-zhen¹

2008, 19(08):  1775-1778 . 

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With spatially explicit landscape model (LANDIS), the dynamic change of forest landscape in Youhao Forest Bureau in Xiaoxinganling Mountains from 2001-2201 under 5 planting proportions of coniferous and broadleaved species, i.e., 100% broadleaved species, 70% broadleaved and 30% coniferous species, 50% broadleaved and 50% coniferous species, 30% broadleaved and 70% coniferous species, and 100% coniferous species, was studied, taking the forest under natural regeneration after harvesting as the control. The results showed that afforestation effectively promoted the recovery of forest resources, but single planting of coniferous species would lead to the area percent of broadleaved species lower than the control. When broadleaved species were planted only, the area percent of coniferous species was lower than the control. The area percent and aggregation index of Pinus koraiensis and Larix gmelini increased with increasing planting proportion of coniferous species, and those of Quercus mongolica increased with increasing planting proportion of broadleaved species. Afforestation decreased the area percent of Betula phatyphylla, but had no significant effects on its aggregation index. Different afforestation strategies not only altered the species area percent, but also affected the species spatial pattern.

Spatiotemporal variation of eco-environmental frangibility based on remote sensing and catastrophe theory: A case study of Kenli County in Yellow River Delta, China.

WANG Rui-yan¹;ZHAO Geng-xing¹;JIANG Shu-qian¹;WANG Ai-ling¹;WANG Jing²

2008, 19(08):  1782-1788 . 

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Based on remote sensing and the nonlinear theories of entropy and catastrophe, the spatiotemporal variation of ecoenvironmental frangibility in Kenli County of Yellow River Delta was analyzed through the installation of sampling plots. The methods of analyzing and estimating ecoenvironmental frangibility were also established. The results indicated that in 1987-2005, the environment of Kenli County tended to deteriorating, and two catastrophes of environmental frangibility occurred, one in 1997, and the other in 2004. The former catastrophe was mainly caused by storm tide and the water shortage from Yellow River, with the main appearance characteristics being habitat change and dominant species substitution, while the latter one was mainly from the water shortage from Yellow River, increase of evaporation-precipitation ratio, a great deal construction of reservoir, and increases of traffic road and population density, with the main appearances of the changes in vegetation type and coverage ratio. The analysis on the spatial variations of the environmental frangibility along the directions of different distances to the Yellow River and to the ocean testified the spatial gradual change pattern of the frangibility. This research was a new attempt, and provided an effective way for the quantitative easurement of environmental frangibility.

Optimization of ecological footprint model based on environmental pollution accounts: A case study in Pearl River Delta urban agglomeration.

BAI Yu¹;ZENG Hui^1,2; WEI Jian-bing¹;ZHANG Wen-juan¹;ZHAO Hong-wei¹

2008, 19(08):  1789-1796 . 

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To solve the problem of ignoring the calculation of environment pollution in traditional ecological footprint model accounts, this paper put forward an optimized ecological footprint (EF) model, taking the pollution footprint into account. In the meantime, the environmental capacity’s calculation was also added into the system of ecological capacity, and further used to do ecological assessment of Pearl River Delta urban agglomeration in 2005. The results showed a perfect inosculation between the ecological footprint and the development characteristics and spatial pattern, and illustrated that the optimized EF model could make a better orientation for the environmental pollution in the system, and also, could roundly explain the environmental effects of human activity. The optimization of ecological footprint model had better integrality and objectivity than traditional models.

Microclimate and comfortable degree of Shanghai urban open spaces in summer.

CAO Dan^1,2;ZHOU Li-chen^1,2; MAO Yi-wei^1,2; LI Yin^1,2; LIU Yi-ning^1,2;WANG Tian-hou^1,2

2008, 19(08):  1797-1802 . 

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Based on the observation data of air temperature, relative humidity, wind speed, and solar radiation from May to August 2006, the regulation effects of five types of open spaces (square, fountain, grassplot, corridor, and woodland) in Shanghai urban districts on the microclimate were analyzed, and discomfort index (DI) was introduced to evaluate the effects of these five types of open spaces on human body’s comfortable degree. The results showed that there existed definite differences in the air temperature and relative humidity among the open spaces, with the mean temperature decreased in the order of square＞grassplot＞fountain＞corridor＞woodland, and the mean relative humidity decreased in the order of woodland＞corridor＞fountain＞grassplot＞square. The area of the square, the wind speed and direction near the fountain, the grass species on the grassplot, the width and tree coverage of the corridor, and the tree coverage and canopy height of the woodland had significant correlations with the microclimate parameters of corresponding open spaces. Comparing with other three types of open spaces, woodland and corridor had better regulation effects on the microclimate via shading, decreasing air temperature, and increasing relative humidity.

Impact of urbanization on vegetation phenology in major cities in Yangtze River Delta region.

HAN Gui-feng¹;XU Jian-hua²;YUAN Xing-zhong³

2008, 19(08):  1803-1809 . 

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Based on the time seriesNDVI images from 1998 to 2005 and by the method of moving average, the vegetation phenology in urban areas and buffer zones of Shanghai, Hangzhou, Nanjing, Changzhou, Wuxi and Suzhou in Yangtze River Delta region were calculated. The difference of average phenology in urban areas and buffer zones was analyzed, and the relationship between this difference and the distance away from urban edge was studied. The results showed that in 1998-2005, the urbanization of the cities made the vegetations in their urban area had an earlier start of growing season (SOS), later end of growing season (EOS), longer growing season length (GSL), and smaller NDVI_amp (difference of maximal and minimal NDVI in a year). These changes were more obvious in buffer zones if they were closer to urban area. In general, urbanization made the SOS within 4 kilometers away from the urban edge started obviously earlier, and the EOS, GSL and NDVI_amp within 10 kilometers away from the urban edge changed obviously. The differences of GSL between urban and buffer zones had a significant logarithmic relationship with the distance away from the urban edge, so did the NDVI_amp.

Comparison of accumulated temperature above 10 ℃ before and after the year 1978 in China.

BAI Qin-feng¹;HUO Zhi-guo¹;LI Shi-kui¹;DU Hai-jiang²;HE Nan¹; JIANG Yan¹

2008, 19(08):  1810-1816 . 

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By using the observation data from 620 meteorological stations in China, the annual accumulated temperature above 10 ℃, its starting date, ending date, and duration days from 1951 to 1978 and from 1979 to 2005 were calculated and compared. The results showed that in most areas of China, especially in Northeastern, North, and South China, the accumulated temperature above 10 ℃ from 1979 to 2005 was higher than that from 1951 to1978. The starting date of accumulated temperature above 10 ℃ in northern areas of Yangtze River was 0-5 days earlier from 1979 to 2005 than from 1951 to 1979, while that in southern areas of Yangtze River was 0-5 days later from 1979 to 2005 than from 1951 to 1979. The ending date of accumulated temperature above 10 ℃ in most areas of China was delayed 0-5 days, except that in near coastal areas of South China and some regions of Southwest China, which was delayed more than 5 days. The duration days of accumulated temperature above 10 ℃ were generally increased by 0-5 days or 5-10 days in most areas of China, but the increase amplitude was different and could not be linked together in different areas. To accurately know the changing trend of accumulated temperature above 10 ℃ could provide an important basis for the adjustment of agricultural production structure and the assessment of agricultural potential productivity.

Biogas yield and its relations with the duration and temperature of mixed anaerobic fermentation of livestock dungs and wheat straw.

ZHANG Cui-li^1,3; LI Yi-bing^2,3; BU Dong-sheng⁴;YANG Gai-he^2,3

2008, 19(08):  1817-1822 . 

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To approach the relationships between the biogas yield of mixed anaerobic fermentation of livestock dungs and crop straw and the fermentation duration and temperature is the key of selecting fermentation materials for rural household biogas, determining optimal fermentation temperature, and improving the reuse efficiency of agricultural residues. In this paper, a batch of experiments under the condition of 8% mass fraction of total solid were conducted in a selfmanufactured anaerobic fermentation reactor, with pig dung, cattle dung, and wheat straw as fermentation materials, and the substrate of constant temperature fermentation pool as inoculation substance. The biogas yield, fermentation duration, and optimal temperature were determined. It was shown that the cumulative biogas yield of mixed anaerobic fermentation of pig dung and wheat straw was 2.4 times higher than that of the fermentation of pig dung alone, but no significant difference was observed between the cumulative biogas yields of the mixed fermentation of cattle dung and wheat straw and the fermentation of cattle dung alone. The optimal fermentation temperature for the mixed anaerobic fermentation was above 30 ℃, and the fermentation duration was about 60 days. The fermentation duration was not always shortened by increasing temperature, and it would be not feasible to only use temperature to determine the duration of anaerobic fermentation.

Application of solidification technology in ecological protection of rural riverbank.

FU Rong-bing¹;CHEN Xiao-hua¹;LUO Qi-shi¹;ZHANG Shu-jiu²; LI Xiao-ping¹; GENG Chun-nü¹

2008, 19(08):  1823-1828 . 

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A selfdeveloped binder was used for the solidification of construction refuse piles and whole soil matrix, and a technology of this solidification combining with grassplanting was adopted to ecologically protect the rural riverbanks at Tianshan Village of Shanghai. This technology and other ecological engineering techniques were also employed to reconstruct the ecological environment of a sewage pond at the Village. The results showed that the solidified piles had an anticompression strength of up to 73 MPa, with good hydraulic permeability, fast hardening rate, and low drying shrinkage, which met the requirements for ecological safety. The solidified stakes could be used at a low temperature of above -18 ℃ with addition of certain antifreezing agents. The riverbank underpinned with the solidified stakes had higher anticompressive strength, higher ability of antisoil erosion, and better hydraulic permeability; and its soil had the similar moisture content to bare riverbank soil, with no detrimental effects on the root growth of planted grass. After soil solidification, the shearing strength of the riverbank increased by 50 times, and its soil loss was only 5% of the bare riverbank. In the first 10 days after adopting this technology, parts of Cynodon dactylon roots on the surface of solidified soil matrix began to extend into soil; after one month, 60% of the roots penetrated into deeper soil layer; and 11 months later, the grass roots completely grew in-depth in the soil. The combination of our solidification technique with vegetation reconstruction satisfied the requirements of both stabilizing riverbank and improving riparian habitat.

Soil N₂O flux and its affecting factors under different vegetations in central Guizhou Province.

LIU Fang^1,2; LIU Cong-qiang¹;WANG Shi-lu¹;Lv Ying-chun^1,2

2008, 19(08):  1829-1834 . 

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By using close chamber-GC method, the N₂O fluxes in defarming grassland, bush land,Pinus massoniana forestland, and broadleaved forestland in central Guizhou were measured in situ in 2006 and 2007 to investigate the seasonal change patterns of soil N₂O flux under different vegetations in karst region of southwest China. The results indicated that in a whole year round, the soils in all test sites played the source of atmospheric N₂O, only acting as a N₂O sink in exceptional months. The soil type and the vegetation had obvious effets on the N₂O flux from soil. Yellow soil had a smaller N₂O flux than calcareous soil, except for broadleaved forestland. The N₂O fluxes from defarming grassland and bush land were higher in spring and lower in autumn and winter, and varied within the range of -20.7-103.09 μg N·m^-2·h^-1 and -33.0-67.3 μg N·m^-2·h^-1, respectively; while those from P. massoniana forestland and broadleaved forestland were the highest in spring but had no definite change patterns in other seasons, and varied within the range of -5.3-35.0 μg N·m^-2·h^-1 and -14.4-152.8 μg N·m^-2·h^-1, respectively. The correlation analysis showed that there existed a negative correlation between soil moisture content and N₂O flux, suggesting that soil moisture was the main factor driving the seasonal change of N₂O flux. Temperature indirectly affected the soil N₂O flux through affecting soil moisture.

Effects of Miscanthus floridulus on microbial biomass and basal respiration in heavy metals polluted soils.

WANG Jiang¹; ZHANG Chong-bang¹;CHANG Jie²;KE Shi-xing¹;ZHANG Lei¹

2008, 19(08):  1835-1840 . 

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Three habitats of Miscanthus floridulusin Zhejiang Province, i.e., Pb/Zn mine tailings in Huangyan area (W), Pb/Zn mine tailings in Sanmen area (Y), and heavy metals contaminated agricultural field near smelters (N), were chosen as sampling sites, and the microbial basal respiration, microbial biomass carbon and nitrogen, physical and chemical properties, and heavy metals contents in bulk and rhizosphere soils were determined. The results indicated that the microbial basal respiration and microbial biomass nitrogen were significantly higher in rhizosphere soil than in bulk soil (P<0.05), while microbial biomass carbon, except that in site N, had no significant difference between bulk soil and rhizosphere soil (P>0.05). The organic carbon, total nitrogen (except in site Y), and cation exchangeable capacity (except in site N) were lower in rhizosphere soil than in bulk soil, and the total and DTPAextractable Pb, Zn, Cu and Cd were generally lower in rhizosphere soil than in bulk soil. Redundancy discriminant analysis (RDA) showed that the microbial parameters in bulk and rhizosphere soils had definite positive correlations with soil physical and chemical properties, and negative correlations with soil heavy metals contents. Principal components analysis (PCA) and regression analysis also showed that the overall changes in microbial parameters were positively correlated with soil physical and chemical properties (bulk soil:R²=0.653; rizhosphere soil: R²=0.690), and negatively correlated with soil heavy metal contents (bulk soil: R²=0.610; rizhosphere: R²=0.662).

Effects of cadmium and mercury combined pollution on soil urease and acid phosphatase activities.

YU Shou-na;LIAO Min;HUANG Chang-yong

2008, 19(08):  1841-1847 . 

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With incubation test, the effects of cadmium (Cd) and mercury (Hg) combined pollution on the urease and acid phosphatase activities in marine sediment silty loam soil (S₁) and yellowish red soil (S₂) were studied. The results indicated that during the whole incubation period, Cd and Hg, whether singly or combined together, had significant inhibitory effects on the urease and phosphatase activities in the two test soils, and the effects increased with their increasing concentration (except for Cd ≤1 mg·kg^-1). Compared with that under Cd or Hg pollution, the net change rates of soil urease and acid phosphatase activities under the same level Cd and Hg combined pollution were higher than 0, suggesting the synergistic effects of these two heavy metals on the inhibition of soil urease and acid phosphatase activities. In all treatments, the activities of urease and acid phosphatase were higher in S₂ than in S₁, possibly due to the higher contents of organic matter and clay particle in S₂.

Heavy metal pollution ecology of macro-fungi: research advances and expectation.

ZHOU Qi-xing^1,2;AN Xin-long²;WEI Shu-he¹

2008, 19(08):  1848-1853 . 

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Macro-fungi are the main component of biosphere and one of the ecological resources, and play very important roles in matter cycling and in maintaining ecological balances. This paper summarized and reviewed the research advances in the eco-toxicological effects of heavy metals on macrofungi, the bioaccumulation function of macro-fungi on heavy metals, the ecological adaptation mechanisms of macro-fungi to heavy metal pollution, the role of macro fungi as a bio-indicator of heavy metal pollution, and the potential of macro-fungi in the ecological remediation of contaminated environment. To strengthen the researches on the heavy metal pollution ecology of macrofungi would be of practical significance in the reasonable utilization of macro-fungi resources and in the ecological remediation of contaminated environment.

Differences of physiological responses of cucumber seedlings to NaCl and NaHCO₃ stress.

ZHANG Li-ping¹;WANG Xiu-feng^1,2; SHI Qing-hua^1,2; GAO Qing-hai¹; LIU Ze-zhou¹

2008, 19(08):  1854-1859 . 

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By a solution culture experiment, cucumber seedlings were treated with different concentration (0, 25, 50 and 75 mmol·L^-1) NaCl and NaHCO₃, and their physiological responses were studied. The results showed that with increasing NaCl and NaHCO₃ stress, the shoot and root growth, the leaf chlorophyll content and relative water content of the seedlings decreased dramatically, and the decrements were greater under NaHCO₃ than under NaCl stress. The shoot Na⁺ content increased significantly with increasing NaCl and NaHCO₃ stress, while shoot K⁺ content was in adverse. At the same concentration of Na⁺ in culture solution, the addition of NaHCO₃ induced a greater decrement of shoot K⁺ content, and thus, a lower shoot K⁺/Na⁺ ratio. Under NaHCO₃ stress, the leaf electrolyte leakage rate and the leaf MDA, proline, and soluble sugar contents increased much greater, compared with those under NaCl stress. Under NaCl and NaHCO₃ stress, the leaf superoxide dismutase (SOD), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) activities were induced significantly, while the leaf peroxidase (POD) activity was inhibited obviously.

Estimation of vegetation coverage based on an improved sub-pixel model.

YANG Xiao-qiong;ZHU Wen-quan;PAN Yao-zhong;SONG Guo-bao

2008, 19(08):  1860-1864 . 

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Vegetation coverage is an important parameter in terrestrial ecological process, meteorological, and climatic models. By eliminating the errors from the precision of image classification and the noises of remote sensing images, and by using the actual data from fieldwork, this paper determined the maximum and minimum values of normalized difference vegetation index (NDVI), improved the sub-pixel model, and verified this model by calculating the vegetation coverage of Beijing. The results showed that the estimation value of the improved model was very close to the measurements, especially for the herbaceous plants whose vegetation types were the same but the densities were different. However, the estimation error of arborous vegetation coverage was relatively large, probably due to the effects of remote sensing image resolution, vegetation fragmentation, and mixed pixel model.