Table of Content

18 February 2014, Volume 25 Issue 2

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Spatial autocorrelation of genetic structure of Prunus padus population in broadleaved Korean pine forest of Changbai Mountains.

NIU Xiao-min1,2, SHI Shuai1,2, WANG Zheng-feng3, YE Wan-hui3, HAO Zhan-qing1

2014, 25(2):  305-310. 

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All 396 Prunus padus individuals of the population with DBH (diameter at breast height) ≥1 cm were sampled in a 25 hm² broadleaved Korean pine forest plot of Changbai Mountains and divided into three DBH classes: 1-3 cm, 3-10 cm, and >10 cm. They were then genotyped using microsatellite loci. The spatial autocorrelation of their genetic structure was analyzed at different distance classes and life stages. The results showed that positive autocorrelation mainly occurred at scales less than 70 m, while negative autocorrelation occurred at scales larger than 110 m. The spatial genetic structure (SGS) at different life stages was similar due to limited pollen/seed dispersal and asexual reproduction. No significant self-thinning occurred in the studied population.

Spatial heterogeneity of natural regeneration in a spruce-fir mixed broadleaf-conifer forest in Changbai Mountains.

LI Yan-li, YANG Hua, KANG Xin-gang, WANG Yan, YUE Gang, SHEN Lin

2014, 25(2):  311-317. 

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Based on fieldwork on a plot of 60 m× 60 m in the Changbai Mountain area of Northeast China in August 2012, the spatial distribution pattern and heterogeneity of natural regeneration in the spruce-fir mixed broadleaf-conifer forest were analyzed using semi-variograms, fractal dimensions and Kriging interpolation methods. The results showed that Abies nephrolepis and Acer mono were the most common regeneration species, accounting for 87.4% of the total. The regeneration seedlings and saplings presented an aggregate distribution pattern with the biggest radius of 9.93 m. Distinct spatial autocorrelation existed among regeneration seedlings and saplings, with 88.7% of variation coming from structure factors (biological and ecological properties and  environmental heterogeneity) and 11.3% from random factors. The spatial distribution of the regeneration seedlings and saplings presented anisotropy, with the smallest fractal dimension and strongest spatial heterogeneity from north to south, and the highest fractal dimension and weakest spatial heterogeneity from northeast to southwest. The spatial heterogeneity of heights of seedlings and saplings was greater than that of root collar diameters. The distance of spatial autocorrelation for tree root collar diameters was 29.97 m, and that for heights was 31.86 m. Random factors and structure factors were found to contribute equally to the spatial heterogeneity.

Effects of tree species diversity on fine-root biomass and morphological characteristics in subtropical Castanopsis carlesii forests.

WANG Wei-wei1,2, HUANG Jin-xue1,2, CHEN Feng3, XIONG De-cheng1,2, LU Zheng-li1,2, HUANG Chao-chao1,2, YANG Zhi-jie1,2, CHEN Guang-shui1,2

2014, 25(2):  318-324. 

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Fine roots in the Castanopsis carlesii plantation forest (MZ), the secondary forest of C. carlesii through natural regeneration with anthropogenic promotion (AR), and the secondary forest of C. carlesii through natural regeneration (NR) in Sanming City, Fujian Province, were estimated by soil core method to determine the influence of tree species diversity on biomass, vertical distribution and morphological characteristics of fine roots. The results showed that fine root biomass  for the 0-80 cm soil layer in the MZ, AR and NR  were (182.46±10.81), (242.73±17.85) and (353.11±16.46) g·m^-2, respectively, showing an increased tendency with increasing tree species diversity. In the three forests, fine root biomass was significantly influenced by soil depth, and fine roots at the 0-10 cm soil layer accounted for more than 35% of the total fine root biomass. However, the interaction of stand type and soil depth on fineroot distribution was not significant, indicating no influence of tree species diversity on spatial niche segregation in fine roots. Root surface area density and root length density were the highest in NR and lowest in the MZ. Specific root length was in the order of AR>MZ>NR, while specific root surface area was in the order of NR>MZ>AR. There was no significant interaction of stand type and soil depth on specific root length and specific root surface area. Fine root morphological plasticity at the stand level had no significant response to tree species diversity.

Root exudates and soil microbes in three Picea asperata plantations with different stand ages.

LI Jiao1,2, JIANG Xian-min3, YIN Hua-jun1, YIN Chun-ying1, WEI Yu-hang1，2, LIU Qing1

2014, 25(2):  325-332. 

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This study investigated the dynamics of in situ root exudates and soil microbial composition among three Picea asperata plantations with different stand ages (9, 13 and 31 a) in Miyaluo, west Sichuan, China. The results showed that the secretion rates of root exudation per fine biomass, length, surface area and tip were significantly different among the three plantations with different stand ages. The secretion rate of root exudation was the highest in the 9-year-old plantation stand. The root activity of P. asperata was the weakest in the 13-year-old plantation stand. Besides, soil microbial biomass C (MBC) and N (MBN) between rhizosphere and non-rhizosphere soils were significantly different among the three plantation stands. MBC and MBN contents of rhizosphere soil gradually increased with stand ages, while those of non-rhizosphere soil were the largest in the 13-year-old plantation stand. The phospholipid fatty acids (PLFAs) of bacteria, fungi, actinomycetes and their summation in rhizosphere soil presented a trend of high-low-high with stand ages. The opposite pattern was found in the PLFAs of bacteria, fungi, the summation of PLFA, and the ratio of fungi number to bacteria in non-rhizosphere soil. It is suggested that root exudates might have a positive rhizosphere effect on soil microbial biomass C, N and PLFAs of functional groups.

Storage and allocation of carbon and nitrogen in Robinia pseudoacacia plantation at different ages in the loess hilly region, China.

AI Ze-min1, CHEN Yun-ming2,3, CAO Yang2,3

2014, 25(2):  333-341. 

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The 9-, 17-, 30- and 37-year-old Robinia pseudoacacia plantations in the loess hilly region were investigated to study the dynamics and allocation patterns of carbon and nitrogen storage. The results showed that the ranges of carbon and nitrogen contents were 435.9-493.4 g·kg^-1 and 6.8-21.0 g·kg^-1 in the arbor layer, 396.3-459.2 g·kg^-1 and 14.2-23.5 g·kg^-1 in the herb and litter layer, and 2.7-10.7 g·kg^-1 and 0.2-0.7 g·kg^-1 in the soil layer, respectively. The branch was the major carbon and nitrogen pool in the arbor layer, accounting for 46.9%-63.3% and 39.3%-57.8%, respectively. The maximum storage values were 30.1 and 1.8 Mg·hm^-2 for carbon and nitrogen, respectively, in the 0-20 cm soil layer in the 37-year-old R. pseudoacacia plantation. The total carbon and nitrogen storage in the R. pseudoacacia plantation ecosystem increased with increasing forest age, and the maximum values were 127.9 Mg·hm^-2 and 6512.8 kg·hm^-2 for carbon and nitrogen storage, respectively, in the 37-year-old R. pseudoacacia plantation. Soil layer was the major carbon and nitrogen pool of R. pseudoacacia plantation ecosystem, accounting for 63.3%-83.3% and 80.3%-91.4%, respectively.

Soil respiration characteristics in the clearcutting site of Quercus aliena var. acuteserrata forest in Xiaolong Mountain in Qinling Mountains.

KANG Yong-xiang1, XIA Guo-wei1,2, LIU Jian-jun1, ZHOU Wei1, CHEN Guang-ping2

2014, 25(2):  342-350. 

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By using Li-6400 portable photosynthesis system with soil chamber, the soil respiration rates (R_s) of Quercus aliena var. acuteserrata forest land (control site) and their clear-cutting site were measured in Xiaolong Mountain of Qinling Mountains from May 2011 to April 2012 to understand the diurnal and monthly dynamics of soil respiration rate and the influences from soil temperature, soil moisture, soil physical and chemical properties. The results showed that both diurnal and monthly dynamics of soil respiration rate presented a single-peak curve, similar to the variation of soil temperature at the clear-cutting and control sites. During the study period, the maximum monthly mean values of soil respiration rate at the clearcutting and control sites occurred in July (4.63 and 4.01 μmol·m^-2·s^-1, respectively) and the minimum values presented in February (0.10 and 0.30 μmol·m^-2·s^-1, respectively). Soil respiration rate in 4-6 months after clear-cutting was higher than at the control site, and became lower afterwards. 89.6%-90.8% of soil respiration rate variation was interpreted by the multiple regression models of soil temperature, soil moisture and their interaction at the clear-cutting site, and 94.7%-95.5% at the control site. The Q₁₀ values computed by exponential equations were 3.47-4.22 and 3.54-3.96 at the clear-cutting and control sites, respectively. The C fluxes at the clear-cutting and control sites were 344.8 and 512.9 g·m^-2 annually, and 24.2 and 40.9 g·m^-2 in winter, respectively.

Soil quality assessment of Robinia psedudoacia plantations with various ages in the GrainforGreen Program in hilly area of North China.

ZHAO Na1, MENG Ping1,2, ZHANG Jin-song1,2, LU Sen1,2, CHENG Zhi-qing1

2014, 25(2):  351-358. 

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Four land use types of cropland, abandoned cropland, 10-year-old and 43-year-old Robinia psedudoacia plantations in the GrainforGreen Program in hilly area of North China were studied to investigate the effects of returning cropland to forestland on soil quality by using integrated soil quality index. The results showed that the nutrients of topsoil increased significantly with increasing tree age, and soil properties in 0-5 cm soil layer improved. Compared with the cropland, soil physical and chemical properties of the two R. psedudoacia plantations improved, and the soil microbial biomass C and N increased significantly. The integrated soil quality index decreased in order of 43-year-old R. psedudoacia plantation (0.542)>10-year-old R. psedudoacia plantation (0.536)> the abandoned cropland (0.499)> the cropland (0.498), suggesting the soil quality was improved during the conversion from cropland to forestland.

Effects of grazing disturbance on soil active organic carbon in mountain forest-arid valley ecotone in the upper reaches of Minjiang River.

LIU Shan-shan, ZHANG Xing-hua, GONG Yuan-bo, LI Yuan, WANG Yan, YIN Yan-jie, MA Jin-song, GUO Ting

2014, 25(2):  359-366. 

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Effects of grazing disturbance on the soil carbon contents and active components in the four vegetations, i.e., artificial Robinia pseudoacacia plantation, artificial poplar plantation, Berberis aggregate shrubland and grassland, were studied in the mountain forestarid valley ecotone in the upper Minjiang River. Soil organic carbon and active component contents in 0-10 cm soil layer were greater than in 10-20 cm soil layer at each level of grazing disturbance. With increasing the grazing intensity, the total organic carbon (TOC), light fraction organic carbon (LFOC), particulate organic carbon (POC) and easily oxidized carbon (LOC) contents in 0-10 cm soil layer decreased gradually in the artificial R. pseudoacacia plantation. The LFOC content decreased, the POC content increased, and the TOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the artificial poplar plantation. The POC content decreased, and the TOC, LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the B. aggregate shrubland. The POC and TOC contents decreased, and the LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the grassland. The decreasing ranges of LOC, LFOC and POC contents were 0.1-7.9 times more than that of TOC content. There were significant positive relationships between TOC and LOC, LFOC and POC, suggesting that the active organic carbon components could reflect the change of soil total carbon content.

Spatial distribution of aboveground biomass of shrubs in Tianlaochi catchment of the Qilian Mountains.

LIANG Bei1, DI Li1, ZHAO Chuan-yan2, PENG Shou-zhang2, PENG Huan-hua3, WANG Chao3

2014, 25(2):  367-373. 

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This study estimated the spatial distribution of the aboveground biomass of shrubs in the Tianlaochi catchment of Qilian Mountains based on the field survey and remote sensing data. A relationship model of the aboveground biomass and its feasibly measured factors (i.e., canopy perimeter and plant height) was built. The land use was classified by objectoriented technique with the high resolution image (GeoEye-1) of the study area, and the distribution of shrub coverage was extracted. Then the total aboveground biomass of shrubs in the study area was estimated by the relationship model with the distribution of shrub coverage. The results showed that the aboveground biomass of shrubs in the study area was 1.8×10³ t and the aboveground biomass per unit area was 1598.45 kg·m^-2. The distribution of shrubs mainly was at altitudes of 3000-3700 m, and the aboveground biomass of shrubs on the sunny slope (1.15×10³ t) was higher than that on the shady slope (0.65×10³ t).

Impact of the Beijing and Tianjin Sand Source Control Project on the grassland soil organic carbon storage: A case study of Xilingol League, Inner Mongolia, China.

ZHANG Liang-xia1,2, FAN Jiang-wen1, ZHANG Wen-yan1, TANG Feng-pei3

2014, 25(2):  374-380. 

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Understanding the impacts of ecoconstruction project on grassland soil carbon storage is crucial to assess the effectiveness of the project and its role in carbon cycling of the grassland ecosystems. Using IPCC carbon budget inventory method, this paper analyzed the influence of Beijing and Tianjin Sand Source Control Project (BTSSCP) on the grassland soil carbon storage between 2000 and 2006 in Xilingol League, Inner Mongolia, and evaluated the time needed to reach the maximal soil carbon density for three management practices (i.e., sown pasture, aerial sowing pasture, and grazing exclosure). Results showed that the BTSSCP significantly increased soil carbon storage, with a carbon sequestration of 59.26×10⁴ t C from 2000 to 2006. The rate and effectiveness of soil carbon sequestration varied significantly with management practices, with the highest rate in sown pasture (0.25 t C·hm^-2·a^-1) while a greater benefit of soil carbon sequestration in the grazing exclosure (63 million yuan). Compared with other grassland vegetations, lowland meadow and temperate meadow steppe both had higher carbon sequestration rates of 0.14 t C·hm^-2·a^-1. Long time would be needed to reach the maximum soil carbon density in grassland under the three practices, yet shorter for sown pasture with average of 57.75 years.

Impact of wind-water alternate erosion on the characteristics of sediment particles.

TUO Deng-feng1,2, XU Ming-xiang1,2, MA Xin-xin1,2, ZHENG Shi-qing2

2014, 25(2):  381-386. 

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Wind and water are the two dominant erosion agents that caused soil and water losses in the windwater alternate erosion region on the Loess Plateau. It is meaningful to study the impact of windwater alternate erosion on the characteristics of soil particles for understanding the response of soil quality and environment to erosion. Through wind tunnel combined rainfall simulation, this paper studied the characteristics of the erosive sediment particles under the effect of wind-water alternate erosion. The results showed that the particles of 0-1 cm soil were coarsened by wind erosion at the wind speeds of 11 and 14 m·s^-1 compared with no wind erosion. Soil fine particles (<0.01 mm) decreased by 9.8%-10.8%, and coarse particles (>0.05 mm) increased by 16.8%-20.8%. The physical property of surface soil was changed by the wind erosion, which, in turn, caused an increase in finer particles content in the sediment. Compared with no wind erosion, fine particles (<0.01 mm) in sediment under the waterwind alternate erosion increased by 2.7%-18.9%, and coarse particles (>0.05 mm) decreased by 3.7%-9.3%. However, the changing trend of erosive sediment particles after the wind erosion at wind speeds of 11 and 14 m·s^-1  was different along with the rainfall intensity and duration. The erosive sediment particles at the rainfall intensities of 60, 80, 100 mm·h^-1 changed to greater extents than  at the 150 mm·h^-1 rainfall intensity with longer than 15 min runoff flowing.

CO₂ release characteristics from Stipa baicalensis meadow steppe in the Hulunbeir region, Inner Mogolia, China.

ZHANG Pan-di1,2, WANG Xu1,2, CHEN Bao-rui1,2, XIN Xiao-ping1,2

2014, 25(2):  387-393. 

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Based on the measurement of soil CO₂ evolution with the Li8150 from June 2009 to June 2010, the characteristics of soil CO₂ flux from the Stipa baicalensis meadow steppe in the Hulunbeir, Inner Mongolia were analyzed. The daily dynamics of soil respiration rate in this study area presented a peak curve in growing season, the daily maximum value appeared in 13:00-15:00 p.m., while the minimum value appeared in 5:00-6:00 a.m. The soil respiration had obviously seasonal dynamics, similar with the dynamics of soil temperature and soil water content. The relationships of soil respiration with soil temperature and soil water content could be better expressed with linear or exponentialpower equation. Using the Van’t Hoff exponential equation to fit soil respiration and soil temperature, the results showed that they all had good exponential regression relationships in growing season  and in non-growing season. Q₁₀ was slightly different at different depths, varying from 1.68 to 2.14 in growing season and from 3.03 to 3.60 in non-growing season. The effect of soil temperature on soil respiration was more sensitive in non-growing season than in growing season. There was  significant a correlation between soil respiration and soil water content at the depth of 10 cm. The annual soil CO₂ fluxes were 488.47 g C·a^-1 and 507.20 g C·a^-1 in 2009 and 2010, respectively. The contribution of soil respiration in growing season to the annual soil CO₂ flux was about 90%.

Responses of net soil nitrogen mineralization rate in moss-covered soil to hydrothermic factors in Shapotou regions, northern China.

HU Rui, WANG Xin-ping, PAN Yan-xia, ZHANG Ya-feng, ZHANG Ke, ZHANG Hao

2014, 25(2):  394-400. 

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Undisturbed soil cores were incubated in laboratory at different temperatures (-10, 5, 15, 25, 35 and 40 ℃) and moistures (29%, 58%, 85% and 170% of field water content, FWC) to analyze the effect of moss crusts, which were sampled from the natural vegetation area of Shapotou, on soil nitrogen transformation and their responses to hydrothermic factors. Results showed that immobilization was the dominant form of nitrogen transformation at the lower temperatures (<15 ℃), and when the temperature surpassed 25 ℃, the nitrogen transformation rate significantly increased. The nitrogen transformation rate in the moss-covered soil was more sensitive to temperature variation than in the bare soil, and the highest temperature sensitivity was at 85%FWC. It indicated that the existence and succession of moss crusts facilitated nitrogen transformation. In addition, the nitrogen transformation rates of two microhabitats increased initially and then declined with the increasing moisture, and the maximum nitrogen transformation rate was observed at 85% FWC. Significant interactive effects were found between temperature and moisture in the moss-covered soil. While, the greater enhancement in nitrogen transformation rate appeared at higher temperatures (25-40 ℃) and moderate moisture levels (58%FWC and 85%FWC). It was concluded that the existence and succession of moss crusts would increase the ability of soil nitrogen supply, promote nitrogen cycling and even contribute to the restoration of soil ecosystem.

Spatial and temporal dynamics of the weed community in the Zoysia matrella lawn.

LIU Jia-qi, LI You-han, ZENG Ying, XIE Xin-ming

2014, 25(2):  401-407. 

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The heterogeneity of species composition is one of the main attributes in weed community dynamics. Based on species frequency and power law, this paper studied the variations of weed community species composition and spatial heterogeneity in a Zoysia matrella lawn in Guangzhou at different time. The results showed that there were 43 weed species belonging to 19 families in the Z. matrella lawn from 2007 to 2009, in which Gramineae, Compositae, Cyperaceae and Rubiaceae had a comparative advantage. Perennial weeds accounted for the largest proportion of weeds and increased gradually in the three years. Weed communities distributed in higher heterogeneity than in a random model. Dominant weeds varied with season and displayed regularity in the order of ‘dicotyledonmonocotyledondicotyledon weeds’ and ‘perennialannualperennial weeds’. The spatial heterogeneity of weed community in Z. matrella lawn was higher in summer than in winter. The diversity and evenness of weed community were higher in summer and autumn than in winter and spring. The number of weed species with high heterogeneity in summer was higher than in the other seasons. The spatial heterogeneity and diversity of weed community had no significant change in the three years, while the evenness of weed community had the tendency to decline gradually

Effects of water table manipulation on leaf photosynthesis, morphology and growth of Phragmites australis and Imperata cylindrica in the reclaimed tidal wetland at Dongtan of Chongming Island, China.

ZHONG Qi-cheng, WANG Jiang-tao, Zhou Jian-hong, OU Qiang, WANG Kai-yun

2014, 25(2):  408-418. 

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During the growing season of 2011, the leaf photosynthesis, morphological and growth traits of Phragmites australis and Imperata cylindrica were investigated along a gradient of water table (low, medium and high) in the reclaimed tidal wetland at the Dongtan of Chongming Island in the Yangtze Estuary of China. A series of soil factors, i.e., soil temperature, moisture, salinity and inorganic nitrogen content, were also measured. During the peak growing season, leaf photosynthetic capacity of P. australis in the wetland with high water table was significantly lower than those in the wetland with low and medium water tables, and no difference was observed in leaf photosynthetic capacity of I. cylindrica at the three water tables. During the entire growing season, at the shoot level, the morphological and growth traits of P. australis got the optimum in the wetland with medium water table, but most of the morphological and growth traits of I. cylindrica had no significant differences at the three water tables. At the population level, the shoot density, leaf area index and aboveground biomass per unit area were the highest in the wetland with high water table for P. australis, but all of the three traits were the highest in the wetland with low water table for I. cylindrica. At the early growing season, the rhizome biomass of P. australis in the 0-20 cm soil layer had no difference at the three water tables, and the rhizome biomass of I. cylindrica in the 0-20 cm soil layer in the wetland with high water table was significantly lower than those in the wetland with low and medium water table. As a native hygrophyte before the reclamation, the variations of performances of P. australis at the three water tables were probably attributed to the differences in the soil factors as well as the intensity of competition from I. cylindrica. To appropriately manipulate water table in the reclaimed tidal wetland may restrict the growth and propagation of the mesophyte I. cylindrica, and facilitate the restoration of P. australisdominated marsh plant community.

Effects of exogenous AsA and GSH on the growth of Dianthus chinensis seedlings exposed to Cd.

DING Ji-jun1,2, LIU Shi-liang1, PAN Yuan-zhi1, LI Li3

2014, 25(2):  419-426. 

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A pot experiment was carried out under greenhouse condition to investigate the effects of different concentrations (0, 20, 40, 60, 80 and 100 mg·L^-1) of exogenous AsA, GSH on Dianthus chinensis seedlings which were stressed by 50 mg·kg^-1 Cd in the soil. The results indicated that 50 mg·kg^-1 of Cd significantly inhibited the growth of D. chinensis seedlings. An appropriate concentration of exogenous AsA significantly improved the biomass, plant height, tiller number, GAT and APX activities, and AsA and GSH contents. However, with the increase of exogenous AsA concentration, the ameliorating effect decreased and prooxidant effect occurred. Exogenous GSH could replenish the nonenzymatic antioxidants of D. chinensis seedlings, but the changes of antioxidant enzyme activities were relatively slight. The main mechanisms of GSH to alleviate Cd toxicity might be promoting root PCs synthesis, thereby reducing the Cd concentration in the seedlings. Both 35-45 mg·L^-1 exogenous AsA and 55-65 mg·L^-1 exogenous GSH could alleviate the Cd toxicity on D. chinensis seedlings, and the former was superior to the latter.

Lead adsorption by the root cell wall of tea plant.

XU Jie1, BAO Ji-qing1, YU Ming-ge2，3, CHEN Ying-xu2

2014, 25(2):  427-432. 

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A research was done to study the Pb adsorption by the root cell wall of tea plant extracted from Longjing 43. It was indicated that the amount of Pb adsorbed by the root cell wall increased with augment of the initial pH of the solution under acidic condition, dramatically as the pH ranged from 2.0 to 4.5. The amount of Pb increased with the Pb concentration in the solution at pH 4.5, which could be well fitted by the Freundlich adsorption model. The adsorbed Pb reached 9.7 mg·g^-1  under equilibrium condition, 90% of which was adsorbed in 320 minutes, while 50% was desorbed in 60 minutes based on the desorption dynamic curve. The kinetics of both adsorption and desorption could be well described by a second-order rate equation. The amount of absorbed Pb by the root cell wall varied after modified treatments, reducing by 51.1% after esterifing, 41.3% with pectinase, and 10.8% via aminomethylation, suggesting that carboxyl, galacturonic acid, pectin and amino, to some extent, all took part in the Pb adsorption by the root cell wall.

Effects of combined applications of pig farm slurry and chemical fertilizer on medium and microelement contents and quality of wheat.

GAO Wei, TAO Xiao-ting, WANG Yuan-ling, QUAN Xiao-yan, XU Xing, LU Jian-fei, ZHUANG Heng-yang

2014, 25(2):  433-440. 

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Taking Yangmai 18, widely cultivated in south of Huaihe River, as experimental material, this study investigated the effects of application of 0, 30, 60, 90 and 120 m³·hm^-2 pig farm slurry (PS) at the wintering stage combined with the application of 0, 30, 60, 90 kg·hm^-2urea at the heading stage on medium and microelement contents and quality of wheat. The results showed that the Ca, Mg and Fe contents of plant firstly decreased then increased with the extension of the growth period, but the Cu, Zn and Mn contents decreased continuously through the growth period. Ca, Mg, Cu and Zn reached the highest value at every growth stage except the jointing stage when applying 120 m³·hm^-2 PS with 90 kg·hm^-2 urea. Fe and Mn reached the highest value at every growth stage when applying 120 m³·hm^-2 PS with 90 kg·hm^-2 urea. The contents of Ca, Mg, Cu, Zn, Fe and Mn all increased with increasing PS application across the growth period. Regarding the quality of wheat, applying 90 m³·hm^-2 PS with 60 kg·hm^-2 urea was the best fertilization pattern. Combined applications of anaerobically treated PS with N fertilizer could increase medium and microelement contents and quality of wheat. Generally, it was recommended to apply 60-120 m³·hm^-2 PS at the wintering stage and 90 kg·hm^-2 urea at the heading stage under field conditions.

Effects of row spacing on canopy structure and grain-filling characteristics of high-yield summer maize.

WEI Shan-shan, WANG Xiang-yu, DONG Shu-ting

2014, 25(2):  441-450. 

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Using two summer maize (Zea mays L.) varieties Zhengdan 958 and Xianyu 335, a field experiment was conducted to study the regulatory effects of row-spacing (equidistant row and narrow-wide row) and plant-spot spacing arrangement (1 plant per spot, 2 plants per spot, 3 plants per spot) on grain yield components, canopy structure and photosynthetic characteristics after anthesis under plant population density 7.5×10⁴ plants·hm^-2. Moreover, the characters of grain-filling were simulated by Richards’model. The results suggested that yield, dry matter accumulated, crop growth rate, grainfilling rate, canopy photosynthesis capacity were higher under widenarrow row than under equidistant row, and were higher for 2 plants per spot than for 1 or 3 plants per spot. The highest maize yields (13.12 and 13.72 t·hm^-2 for Zhengdan 958 and Xianyu 335, respectively) were observed under widenarrow row with 2 plants per spot. Under this pattern, internal illumination condition of the canopy, net photosynthetic rate and leaf area index were improved, and the contradiction between the plant individual and group was alleviated. Meanwhile, grainfilling capacity was promoted and accumulated amount of dry matter was elevated ultimately. It was concluded that widenarrow pattern with 2 plants per spot is an effective cultivation pattern to increase mai
ze yield  in HuangHuaiHai Plain.

Response of maize emergence rate and yield to soil water stress in period of seeding emergence and its meteorological assessment in central area of Jilin Province.

MA Shu-qing1, WANG Qi2, ZHANG Tie-lin3, YU Hai3, XU Li-ping3, JI Ling-ling1

2014, 25(2):  451-457. 

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In spring of 2010-2011, an experiment with treatments on soil water stress and sowing by stages of spring maize (Zea mays) was conducted in the central Jilin Province. The responses of maize emergence rate and yield to soil water stress were analyzed, and the assessment models of the emergence rate and reduction of yield caused by drought were established based on meteorological conditions. The results showed that during the study period, the relationship between maize emergence rate or per unit yield, and the soil moisture in 0-20 cm layer or soil available water content presented a significant quadratic function. The emergence rate and yield increased with the higher surface soil moisture, while decreased obviously under the drought condition. The emergence rate and yield were higher in the conditions of soil moisture in the range of 22%-24% or soil available water content in 50-65 mm, while the emergence rate and yield decreased obviously with the soil moisture less than 19% or available water content less than 35 mm. The soil moisture decreased 1% each, along with the emergence rate decreased by about 6%, and the yield decreased by about 7%. The soil available water content decreased by 10 mm, along with the emergence rate and yield decreased by about 13% and 14%, respectively. The indicators and models in this article could be applied to assessment and prediction of maize emergence rate and the reduction of yield caused by drought.

 

Effects of plastic film mulching and rain harvesting modes on chlorophyll fluorescence characteristics, yield and water use efficiency of dryland maize.

LI Shang-zhong1, FAN Ting-lu2, WANG Yong1, ZHAO Gang1, WANG Lei1, TANG Xiao-ming1, DANG Yi1, ZHAO Hui3

2014, 25(2):  458-466. 

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The differences on chlorophyll fluorescence parameters, yield and water use efficiency of dryland maize were compared among full plastic film mulching on double ridges and planting in catchment furrows (FFDRF), half plastic film mulching on double ridges and planting in catchment furrows (HFDRF), plastic film mulching on ridge and planting in filmside (FS), and flat planting with no plastic film mulching (NM) under field conditions in dry highland of Loess Plateau in 2007-2012.The results showed that fluorescence yield (F_o), the maximum fluorescence yield (F_m), lightadapted fluorescence yield when PSⅡ reaction centers were totally open (F), lightadapted fluorescence yield when PSⅡ reaction centers closed (F_m′), the maximal photochemical efficiency of PSⅡ(F_v/F_m), the actual photochemical efficiency of PSⅡ in the light (Φ_PSⅡ), the relative electron transport rate (ETR), photochemical quenching (q_P) and nonphotochemical quenching (q_N) in maize leaves of FFDRF were higher than that of control (NM), and the value of 1-q_P was lower than that of control, at 13:00,  chlorophyll fluorescence parameters values of FFDRF was significantly higher than control, which were increased by 5.3%, 568%, 10.7%, 36.3%, 23.6%, 56.7%, 64.4%, 45.5%, 23.6% and -55.6%, respectively, compared with the control. Yield and water use efficiency of FFDRF were the highest in every year no matter dry year, normal year, humid year and hail disaster year. Average yield and water use efficiency of FFDRF were 12650 kg·hm^-2 and 40.4 kg·mm^-1·hm^-2 during 2007-2012, increased by 57.8% and 61.6% compared with the control, respectively, and also significantly higher compared with HFDRF and PS. Therefore, it was concluded that FFDRF had significantly increased the efficiency of light energy conversion and improved the production capacity of dryland maize.

Temporal and spatial variations of soil NO₃^--N in Orychophragmus violaceus/spring maize rotation system in North China.

XIONG Jing1,2, WANG Gai-lan2, CAO Wei-dong1,3, BAI Jin-shun1, ZENG Nao-hua1, YANG Lu4, GAO Song-juan4, SHIMIZU Katsuyoshi5

2014, 25(2):  467-473. 

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The February orchid (Orychophragmus violaceus)spring maize rotation system is established to resolve the problems caused by the expansion of fallow fields in North China. Based on a sitespecific experiment, temporal and spatial variations of soil NO₃^--N were investigated during the period from February orchid incorporation to maize harvest. The results showed that the nitrate content in soil profiles not only showed a temporal characteristic, i.e., increasing at the beginning of the maize season and decreasing then after, but also showed a spatial characteristic, i.e., the gradual occurrence of the peak of nitrate content from shallower to deeper layer with the growth season of maize. Meanwhile, incorporation of February orchid could affect temporal and spatial variations of soil NO₃^--N. February orchid planting reduced the soil NO₃^--N accumulation in the profile of 0-180 cm. After incorporation of February orchid, similar characteristics were observed at the seedling and bell stages of maize, i.e., the soil NO₃^--N mainly stayed in the profile of 0-20 cm, and NO₃^--N concentrations in the treatments with February orchid were higher in 0-100 cm layer and lower in 100-180 cm layer than those of the treatments without February orchid. After tasseling stage, opposite phenomena were found, and the soil NO₃^--N content was all relative low. Overall, incorporation of February orchid could increase the storage capacity of soil NO₃^--N in the profile of 0-180 cm.

Effects of reduced N application rate on yield and nutrient uptake and utilization in maize-soybean relay strip intercropping system.

YONG Tai-wen1,2, LIU Xiao-ming1,2, LIU Wen-yu1,2, SU Ben-ying1,2, SONG Chun2,3, YANG Feng1,2, WANG Xiao-chun1,2, YANG Wen-yu1,2

2014, 25(2):  474-482. 

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A field experiment with three N application rates (0, 180, 240 N kg·hm^-2, representing zero, reduced and conventional N application, respectively) and three planting patterns (maize monoculture, soybean monoculture and maizesoybean relay strip intercropping) was conducted to reveal the effects of cropping patterns and N application rates on yield, nutrient uptake and nitrogen use efficiency of maize and soybean. The results showed that the grain yield, N, P and K uptake and harvest index of the intercropped maize reduced slightly compared with the monoculture maize, however these indices of the intercropped soybean increased significantly compared with the monoculture. With the increase in nitrogen fertilizer application, the excellence of relay strip intercropping was weakened in the maize-soybean intercropping system. The grain yield, economic coefficient, N, P and K uptake, harvest index, N agronomy efficiency and N uptake efficiency of maize and soybean increased significantly at the reduced nitrogen rate (180 N kg·hm^-2), but the rate of soil N contribution declined, compared with the conventional rate of N application by local farmers (240 N kg·hm^-2). In the reduced nitrogen rate treatment, total soil N and P contents of the maize strip reduced, whereas the total soil N, P and K contents of soybean strip and the total K content of maize strip increased compared with the zero N application treatment. With the reduced N application, the annual total grain yield, N, P and K uptake of above-ground biomass in the maizesoybean relay strip intercropping system were higher than in the monoculture, and the land equivalent ratio (LER) was 2.28. N uptake efficiency of maize in the relay strip intercropping system was 20.2% higher than in the maize monoculture, and the index of soybean was 30.5% lower than in the monoculture. The rate of soil N contribution in the relay strip intercropping system was 20.0% and 8.8% lower than in the maize and soybean monoculture, respectively. The reduced N application in the maizesoybean relay strip intercropping system was helpful to promote annual grain yield and improve N utilization efficiency.

Effects of light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut seedling leaves.

YAN Meng-meng, WANG Ming-lun, WANG Hong-bo, WANG Yue-fu, ZHAO Chang-xing

2014, 25(2):  483-487. 

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This study explored the effects of different light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut (Qinhua 6) seedling leaves. The results showed that, compared with natural light, blue light (445-470 nm) could significantly improve the specific leaf area (SLA), chlorophyll a/b value and carotenoid content of peanut seedlings. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate were higher, the intercellular CO₂ content was lower, and the photosynthetic efficiency was improved significantly under blue light. Red light (610-660 nm) could improve the chlorophyll content significantly, and reduce SLA, chlorophyll a/b value and carotenoid content, with a lower photosynthetic efficiency than natural light. Green light (515-520 nm) and yellow light (590-595 nm) were not conducive to photosynthetic pigment accumulation of leaves, and significantly inhibited leaf photosynthesis of peanut seedlings.

Response of yield, quality and nitrogen use efficiency to nitrogen fertilizer from mechanical transplanting super japonica rice.

WEI Hai-yan, WANG Ya-jiang, MENG Tian-yao, GE Meng-jie, ZHANG Hong-cheng, DAI Qi-gen, HUO Zhong-yang, XU Ke

2014, 25(2):  488-496. 

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Five super japonica rice cultivars were grown by mechanical transplanting in field and seven N treatments with total N application rate of 0, 150, 187.5, 225, 262.5, 300 and 337.5 kg·hm^-2 respectively were adopted to study the effects of N rate on rice yield, quality and N use efficiency. The differences between N requirement for obtaining the highest yield and for achieving the best economic benefit were compared.  With the increase of N fertilizer rate, the yields of five super japonica rice cultivars increased firstly and then descended, achieving the highest yield at the N level of 300 kg·hm^-2 ranging from 10.33-10.60 kg·hm^-2. Yield increase mainly attributed to the large number of spikelet, for the total spikelet number of each rice cultivar reached the maximum value at the 300 kg·hm^-2 N level. With the increase of N application, the rates of brown rice, milled rice, head milled rice and the protein content of the five super japonica rice cultivars were all increased, and the rates of brown rice, milled rice, head milled rice and the protein content were higher at 337.5 kg·hm^-2 N level than at 0 kg·hm^-2 N level by 3.3%-4.2%, 2.9%-6.0%, 4.4%-33.7% and 23.8%-44.3%, respectively. While the amylose content, gel consistency and taste value of the five rice cultivars were all decreased, and the amylose content, gel consistency and taste value were lower at 337.5 kg·hm^-2 N level than at 0 kg·hm^-2 N level by 12.4%-38.9%, 10.3%-28.5% and 20.3%-29.7%, respectively. The chalkiness increased firstly and then decreased while the change of chalky rate varied with the cultivars. With the increase of N application, the N use efficiency, agronomic N use efficiency and physiological N use efficiency decreased while the N uptake of grain increased significantly. If the cost of N fertilizer was taken into account, the N fertilizer amount to obtain the optimal economic benefits would be 275.68 kg·hm^-2 with the corresponding yield of 9.97 t·hm^-2. Therefore, in the existing super rice production, classified management of N fertilizer would be required to meet differentiated demands of high yield, good quality, high efficiency, low N fertilizer input and so on.

Impact of long-term continuous cropping on the Fusarium population in soybean rhizosphere.

WEI Wei1,2, XU Yan-li1, ZHU Lin3, ZHANG Si-jia1,2, LI S4

2014, 25(2):  497-504. 

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The impact of long-term continuous cropping on the Fusarium population abundance and diversity, pathogenicity and phylogeny in soybean field were analyzed by using isolation, morphological identification, pathogenicity test, sequencing analysis and molecular marker with restricted fragment length polymorphisms (RFLP). The soybean field was located at the Hailun Experimental Station of Agricultural Ecology of Chinese Academy of Sciences in Northeast China and had been under a longterm rotation experiment designed to two treatments, i.e., longterm continuous cropping (LCC) of soybean for 20 years and shortterm continuous cropping (SCC) for 3 years. In SCC field, the population density  of Fusarium spp. was 6.0×10⁴ CFU·g^-1, in which F. oxysporum, F. graminearum and F. verticillioides possessing high pathogenicity and F. solani possessing moderate pathogenicity were the dominant species. In LCC field, the population density of Fusarium population and the dominance index of dominant species were significantly lower than that in SCC. The population density of F. oxysporum, F. graminearum and F. solani were only 36%, 32% and 22% of that in SCC, and F. verticillioide with highest pathogenicity was absent. The diversity and evenness index of Fusarium population were significantly higher than that in SCC. F. tricinctum, F. lateritium and F. avenaceum, just isolated from LCC, possessing a distant genetic relationship with Fusarium isolates possessing high pathogenicity based on internal transcribed spacer (ITS) and translation elongation factor 1alpha (EF-1α) gene, were nonpathogenicity for soybean. Thus, it seemed that LCC of soybean could cause the inhibition of soil Fusarium population size, alteration of Fusarium community composition and genetic diversity, and even the decline of pathogenicity for soybean root rot disease of Fusarium population.

Effects of different fertilization regimes on abundance and community structure of the nirKtype denitrifying bacteria in greenhouse vegetable soils.

ZENG Xi-bai1, WANG Ya-nan1, WANG Yu-zhong2, BAI Ling-yu1, LI Lian-fang1, DUAN Ran1, SU Shi-ming1, WU Cui-xia1

2014, 25(2):  505-514. 

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The community structure and abundance of nirKtype denitrifying bacteria in different soil layers (0-20 cm and 20-40 cm) under various fertilization regimes in Wuwei, Gansu Province were investigated by the combination of terminal restriction fragment length polymorphism (T-RFLP) and realtime quantitative PCR. Results showed that the nirKtype denitrifying bacteria community structure was significantly affected by fertilization regimes, especially for 70, 156 and 190 bp T-RFs that represented the dominant populations in greenhouse soil. Fertilization regimes significantly influenced the abundance of nirK gene in the 0-20 cm soil layer with the highest abundance of nirK gene copy number (2.16×107 copies·g^-1 soil) detected in the manure treatment (M), which was 2.04 and 2.02 times of that in the control (CK) and chemical fertilizer (NPK) treatments, respectively. Both the dominant population and abundance of nirKtype denitrifying bacteria in the greenhouse soil were significantly different between the 0-20 cm and 20-40 cm soil layers, and the nirKtype denitrifying bacteria community structure and abundance in the greenhouse soil were obviously different from that in the field. Soil pH, soil organic matter content and nitrateN content had the greatest influence on the bacterial community composition. Phylogenetic
analysis indicated that there were not only anaerobic nirKtype denitrifying bacteria in greenhouse soil, but also aerobic denitrifying bacteria, such as Rhizobium, Ochrobactrum, Agrobacterium.

Spatial-temporal pattern and obstacle factors of cultivated land ecological security in major grain producing areas of Northeast China: A case study in Jilin Province.

ZHAO Hong-bo1,2, MA Yan-ji1

2014, 25(2):  515-524. 

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According to the cultivated land ecological security in major grain production areas of Northeast China, this paper selected 48 counties of Jilin Province as the research object. Based on the PSR-EES conceptual framework model, an evaluation index system of cultivated land ecological security was built. By using the improved TOPSIS, Markov chains, GIS spatial analysis and obstacle degree models, the spatial-temporal pattern of cultivated land ecological security and the obstacle factors were analyzed from 1995 to 2011 in Jilin Province. The results indicated that, the composite index of cultivated land ecological security appeared in a rising trend in Jilin Province from 1995 to 2011, and the cultivated land ecological security level changed from being sensitive to being general. There was a pattern of ‘Club Convergence’ in cultivated land ecological security level in each county and the spatial discrepancy tended to become larger. The ‘Polarization’ trend of cultivated land ecological security level was obvious. The distributions of sensitive level and critical security level with ribbon patterns tended to be dispersed, the general security level and relative security levels concentrated, and the distributions of security level scattered. The unstable trend of cultivated land ecological security level was more and more obvious. The main obstacle factors that affected the cultivated land ecological security level in Jilin Province were rural net income per capita, economic density, the proportion of environmental protection investment in GDP, degree of machinery cultivation and the comprehensive utilization rate of industrial solid wastes.

Ecological compensation standard in Dongting Lake region of returning cropland to lake based on emergy analysis.

MAO De-hua1, HU Guang-wei1, LIU Hui-jie1, LI Zheng-zui2, LI Zhi-long1, TAN Zi-fang1

2014, 25(2):  525-532. 

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The annual emergy and currency value of the main ecological service value of returning cropland to lake in Dongting Lake region from 1999 to 2010 was calculated based on emergy analysis. The calculation method of ecological compensation standard was established by calculating annual total emergy of ecological service function increment since the starting year of returning cropland to lake, and the annual ecological compensation standard and compensation area were analyzed from 1999 to 2010. The results indicated that ecological compensation standard from 1999 to 2010 was 40.31-86.48 yuan·m^-2 with the mean of 57.33 yuan·m^-2. The ecological compensation standard presented an increase trend year by year due to the effect of ecorecovery of returning cropland to lake. The ecological compensation standard in the research area presented a swift and steady growth trend after 2005 mainly due to the intensive economy development of Hunan Province, suggesting the value of natural ecological resources would increase along with the development of society and economy. Appling the emergy analysis to research  the ecological compensation standard could reveal the dynamics of annual ecological compensation standard, solve the abutment problem of matter flow, energy flow and economic flow, and overcome the subjective and arbitrary of environment economic methods. The empirical research of ecological compensation standard in Dongting Lake region showed that the emergy analysis was feasible and advanced.

Comparison of GIMMS and MODIS normalized vegetation index composite data for Qinghai-Tibet Plateau.

DU Jia-qiang1,2,3, SHU Jian-min1,2,3, WANG Yue-hui1,4, LI Ying-chang1,4, ZHANG Lin-bo1,2,3, GUO Yang1,2,3

2014, 25(2):  533-544. 

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Consistent NDVI time series are basic and prerequisite in long-term monitoring of land surface properties. Advanced very high resolution radiometer (AVHRR) measurements provide the longest records of continuous global satellite measurements sensitive to live green vegetation, and moderate resolution imaging spectroradiometer (MODIS) is more recent typical with high spatial and temporal resolution. Understanding the relationship between the AVHRRderived NDVI and MODIS NDVI is critical to continued longterm monitoring of ecological resources. NDVI time series acquired by the global inventory modeling and mapping studies (GIMMS) and Terra MODIS were compared over the same time periods from 2000 to 2006 at four scales of Qinghai-Tibet Plateau (whole region, sub-region, biome and pixel) to assess the level of agreement in terms of absolute values and dynamic change by independently assessing the performance of GIMMS and MODIS NDVI and using 495 Landsat samples of 20 km ×20 km covering major land cover type. High correlations existed between the two datasets at the four scales, indicating their mostly equal capability of capturing seasonal and monthly phenological variations (mostly at 0.001 significance level). Similarities of the two datasets differed significantly among different vegetation types. The relative low correlation coefficients and large difference of NDVI value between the two datasets were found among dense vegetation types including broadleaf forest and needleleaf forest, yet the correlations were strong and the deviations were small in more homogeneous vegetation types, such as meadow, steppe and crop. 82% of study area was characterized by strong consistency between GIMMS and MODIS NDVI at pixel scale. In the Landsat NDVI vs. GIMMS and MODIS NDVI comparison of absolute values, the MODIS NDVI performed slightly better than GIMMS NDVI, whereas in the comparison of temporal change values, the GIMMS data set performed best. Similar with comparison results of GIMMS and MODIS NDVI, the consistency across the three datasets was clearly different among various vegetation types. In dynamic changes, differences between Landsat and MODIS NDVI were smaller than Landsat NDVI vs. GIMMS NDVI for forest, but Landsat and GIMMS NDVI agreed better for grass and crop. The results suggested that spatial patterns and dynamic trends of GIMMS NDVI were found to be in overall acceptable agreement with MODIS NDVI. It might be feasible to successfully integrate historical GIMMS and more recent MODIS NDVI to provide continuity of NDVI products. The accuracy of merging AVHRR historical data recorded with more modern MODIS NDVI data strongly depends on vegetation type, season and phenological period, and spatial scale. The integration of the two datasets for needleleaf forest, broadleaf forest, and for all vegetation types in the phenological transition periods in spring and autumn should be treated with caution.

Evaluating the performance of the UCLA method for spatially downscaling soil moisture products using three Ts/VI indices.

LING Zi-wei1, HE Long-bin1, ZENG Hui1,2

2014, 25(2):  545-552. 

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Soil moisture products derived from microwave remote sensing data are commonly used in the studies of large-scale water resources or climate change. However, the spatial resolutions of these products are usually too coarse to be used in regional  or watershedscale studies. Therefore, it is necessary to spatially downscale the coarseresolution soil moisture products for use in regional or watershedscale studies. The UCLA method is one of the methods for spatially downscaling soil moisture products. In this method, the spatial indices (Ts/VI indices) calculated from land surface temperature and vegetation index are used as auxiliary variables for spatial downscaling. In this paper, we compared the performance of the UCLA method for spatially downscaling the coarseresolution AMSR-E soil moisture products, using three Ts/VI indices as auxiliary variables, i.e., the soil wetness index (SW), temperature vegetation dryness index (TVDI), and vegetation temperature condition index (VTCI). These auxiliary variables were calculated from the products of MODIS land surface temperature (MYD11A1) and MODIS vegetation index (MYD13A2). The downscaled results using the three Ts/VI indices were all reasonable. However, the downscaled results using TVDI and VTCI were better than using SW. Therefore, we concluded that TVDI and VTCI are more suitable than SW to be used as the auxiliary variable when applying the UCLA method for downscaling soil moisture products. Finally, we discussed the error sources of applying the UCLA method, such as measurement errors of coarse resolution soil products, calculation errors from spatial indices, and errors from the UCLA method itself, and we also discussed the potential improvements of future research.

Vulnerability assessment on the coastal wetlands in the Yangtze Estuary under sea-level rise.

CUI Li-fang, WANG Ning, GE Zhen-ming, ZHANG Li-quan

2014, 25(2):  553-561. 

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To study the response of coastal wetlands to climate change, assess the impacts of climate change on the coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisite for securing coastal ecosystems. In this paper, the possible impacts of sea level rise caused by climate change on the coastal wetlands in the Yangtze Estuary were analyzed by the SourcePathwayReceptorConsequence (SPRC) model and IPCC definition on the vulnerability. An indicator system for vulnerability assessment was established, in which sealevel rise rate, subsidence rate, habitat elevation, inundation threshold of habitat and sedimentation rate were selected as the key indicators. A quantitatively spatial assessment method based on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability index for the assessment of coastal wetlands in the Yangtze Estuary under the scenarios of sea-level rise. The vulnerability assessments on the coastal wetlands in the Yangtze Estuary in 2030 and 2050 were performed under two sealevel rise scenarios (the present sealevel rise trend over recent 30 years and IPCC A₁F₁ scenario). The results showed that with the projection in 2030 under the present trend of sea-level rise (0.26 cm·a^-1), 6.6% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.8% and 0.2% of the coastal wetlands were in low and moderate vulnerabilities, respectively. With the projection in 2030 under the A₁F₁ scenario (0.59 cm·a^-1), 9.0% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.5%, 1.0% and 0.3% of the coastal wetlands were in the low, moderate and high vulnerabilities, respectively.

Genetic structure of the geographical populations of Athetis lepigone in Shandong Province, China.

WANG Jing1, YU Yi1, TAO Yun-li2, LI Li-li1, CHU Dong2

2014, 25(2):  562-568. 

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Athetis lepigone (M-schler) is a new insect pest of summer corn in HuangHuaiHai Region of China. To understand the spread and damage of this insect pest in Shandong Province, we analyzed the genetic structure of the A. lepigone populations collected from 12 counties and one morphologically alike species from Weihai using mitochondrial cytochrome oxidase I (mtCOI, 608 bp) gene. The results showed that there were 24 mtCOI haplotypes generated from 130 sequences of A. lepigone and 2 haplotypes from 7 sequences of morphologically alike species of A. lepigone. The haplotype network and phylogenetic tree showed that the populations in the study formed two distinct groups, i.e., the population of Weihai (WH) and the other populations. The two groups were significantly differentiated and the genetic distance between them was 0.044-0.054. Molecular variance (AMOVA) analysis showed that a high proportion of the total genetic variance was attributed to variations among groups,  indicating that there was no obvious population expansion among A. lepigone populations   in this province. The study provided the scientific basis for the forecasting and prevention of the insect pest.

Community structure characteristics of phytoplankton and related affecting factors in Heng-shan Reservoir, Zhejiang, China.

YANG Liang-jie1, YU Peng-fei1, ZHU Jun-quan1, XU Zhen1, LU Guang-han2, JIN Chun-hua1

2014, 25(2):  569-576. 

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In order to reveal the community structure characteristics  of phytoplankton and the relationships with environmental factors in Hengshan Reservoir, the phytoplankton species composition, abundance, biomass and 12 environmental factors at 4 sampling sites were analyzed from March 2011 to February 2012. A total of 246 phytoplankton species were identified, which belong to 78 genera and 7 phyla. The dominant species were Melosira varians, M. granulate, Cyclotella meneghiniana, Asterianella formosa, Synedra acus, Achnanthes exigua, Ankistrodesmus falcatus, Oscillatoria lacustris, Cryptomonas erosa, Chroomonas acuta, Phormidium tenue and Microcystis aeruginosa, etc. Seasonal variations of species were obvious. The annual abundance and biomass of the phytoplankton were 0.51×10⁵-14.22×10⁵ ind·L^-1 and 0.07-1.27 mg·L^-1, respectively. The values of the Margelef index, Pielou index and Shannon index of the phytoplankton community were 1.10-3.33, 0.26-0.81 and 0.51-2.38, respectively. The phytoplankton community structure was of Bacillariophyta-Cryptophyta type in spring and winter, of Chlorophyta-Cyanophyta type in summer, and of Bacillariophyta type in autumn. Canonical correlation analysis (CCA) showed that temperature, transparency, chemical oxygen demand and pH had the closest relationships with the phytoplankton community structure in the reservoir. Water quality evaluation showed that Hengshan Reservoir was in α secondary pollution with a mesotrophic level.

Effects of surgically implanted dummy ultrasonic transmitters on grass carp Ctenopharyngodon idella.

LUO Hong-wei, DUAN Xin-bin, WANG Sheng, TIAN Hui-wu, LIU Shao-ping, CHEN Da-qing

2014, 25(2):  577-583. 

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In order to study the effects of surgically implanted dummy ultrasonic transmitters on grass carp Ctenopharyngodon idella, two experiments were conducted from October 2010 to December 2010 and November 2010 to October 2011. The results showed that surgical implantation of dummy ultrasonic transmitters had a significant negative influence on the growth of grass carp within 30 days following the surgery. However, the negative influence after 30 days faded away. One and two fish died during the 60-day and 360-day experiments, equivalent to the mortalities of 4.2% and 6.7%, respectively. All fish incisions were completely healed in 30 days after surgery, and all sutures were lost in 360 days after surgery. Two and one fish expelled the transmitters through the unclosed wound during the 60 days and 360 days, and the discharges were 8.7% and 3.3%, respectively. All the remaining transmitters were encapsulated in fibrous capsules and adhered to body wall, intestinal tract or viscera multiply. The result suggested that surgical implantation of ultrasonic transmitters could be applied to the ultrasonic telemetry research on grass carp. Nevertheless, the grass carp should be given for at least 30 days with the purpose of incision healing and growth recovery from the surgical procedure.

Joint effects of apoptosis induced by microcystins and bacterial lipopolysaccharides on grass carp (Ctenopharyngodon idellus) lymphocytes.

FANG Wen-di, ZHANG Hang-jun, WU Yu-huan

2014, 25(2):  584-590. 

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In this study, grass carp (Ctenopharyngodon idellus) lymphocytes were used as the vitro test object to demonstrate the joint effects of microcystins (MC-LR) and bacterial lipopolysaccharides (LPS) on fish immune system. The results showed that MC-LR and LPS in the single and combined exposure groups could both induce grass carp lymphocytes apoptosis with typical ladderlike DNA electrophoresis characteristics. However, comparing the apoptosis rate of the combined and single exposure groups, it was suggested that bacterial LPS could cooperate with MC-LR causing a higher rate of fish lymphocytes apoptosis （2.1 and 3.3fold of that for the single exposure group Ⅰ (MC-LR) and Ⅱ (LPS), respectively）, and there existed a significant dose-response relationship.  The MC-LR cooperating with bacterial LPS decreased the activity of glutathione Stransferase (GST), increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), resulted in DNA damage and cell arrest in G0 phase, which inhibited cell proliferation and accelerated apoptosis. It was proved that MC-LR exacerbated fish immunotoxicity by collaborating with LPS, which had a serious adverse effect on aquaculture industry.

Basic features and monitoring methodologies of atmospheric nitrogen deposition.

SONG Huan-huan, JIANG Chun-ming, YU Wan-tai

2014, 25(2):  599-610. 

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Atmospheric nitrogen (N) deposition, including dry and wet deposition, is an important inorganic and organic N source for ecosystems, and also a key link of the N biogeochemical cycle. Recently, considerable active nitrogen has been emitted into the atmosphere due to enhanced human activities. High N emission leads to high deposition which has caused a series of environment risks, and more attentions have been focused on this issue. This article gave an overview of the basic content about the present N deposition research, such as the component, process, spatial and temporal variation, as well as ecological effect. Then the sampling methods of wet and dry deposition in the field, analysis methods in laboratory and primary techniques of N source identification were summarized. The N deposition research trend in the future was emphasized.

Research progress on urban carbon fluxes based on eddy covariance technique.

LIU Min, FU Yu-ling, YANG Fang

2014, 25(2):  611-619. 

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Land use change and fossil fuel consumption due to urbanization have made significant effect on global carbon cycle and climate change. Accurate estimating and understanding of the carbon budget and its characteristics are the premises for studying carbon cycle and its driving mechanisms in urban system. Based on the theory of eddy covariance (EC) technique, the characteristics atmospheric boundary layer and carbon cycle in urban area, this study systematically reviewed the principles of CO₂ flux monitoring in urban system with EC technique, and then summarized the problems faced in urban CO₂ flux monitoring and the method for data processing and further assessment. The main research processes on urban carbon fluxes with EC technique were also illustrated. The results showed that the urban surface was mostly acting as net carbon source. The CO₂ exchange between urban surface and atmosphere showed obvious diurnal, weekly and seasonal variation resulted from the vehicle exhaust, domestic heating and vegetation respiration. However, there still exist great uncertainties in urban flux measurement and its explanation due to high spatial heterogeneity and complex distributions of carbon source/sink in urban environments. In the end, we suggested that further researches on EC technique and data assessment in complex urban area should be strengthened. It was also requisite to develop models of urban carbon cycle on the basis of the system principle, to investigate the influencing mechanism and variability of urban cycle at regional scale with spatial analysis technique.

Application of genetic diversity in the researches on rodents.

LIU Zhu1,2, YANG Chun-wen2, XU Yan-chun1, JIN Zhi-min2, MA Jian-zhang1

2014, 25(2):  620-624. 

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Genetic diversity is the base of the species diversity and ecosystem diversity, and also the foundation for biological evolution and species differentiation. Furthermore, genetic diversity is important evidence for evaluation of biological resources of nature. The genetic diversity data from a wide variety of rodents have many complex applications. We summarized the application of rodent prevention, the origin and differentiation including evolutionary history of rodents, the potential adaptation of rodents, the dynamics of population and regulatory mechanisms, and the conservation biology of rodents. Researches in the future should focus on the systematic study on the relationships between population dynamics and genetic diversity, and long-term monitoring of genetic diversity of rodents.