Table of Content

18 February 2015, Volume 26 Issue 2

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Influence of fire disturbance on aboveground deadwood debris carbon storage in Huzhong forest region of Great Xing’an Mountains, Northeast China.

YANG Da1,2, HE Hong-shi1, WU Zhi-wei1, LIANG Yu1, HUANG Chao1, LUO Xu1, XIAO Jiang-tao1, ZHANG Qing-long1

2015, 26(2):  331-339. 

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Based on the field inventory data, the aboveground deadwood debris carbon storage under different fire severities was analyzed in Huzhong forest region of Great Xing’an Mountains. The results showed that the fire severity had a significant effect on aboveground deadwood debris carbon storage. The deadwood debris carbon storage was in the order of highseverity > low-severity > unburned in Larix gmelinii stands, and mixed coniferbroadleaf stands (L. gmelinii and Betula platyphylla), and in the order of high severity > unburned > low-severity in B. platyphylla stands. Fire disturbance significantly changed the component percentage of the deadwood debris carbon storage. The component percentage of snags increased and litter decreased with the increasing fire severity. Logs and stumps did not change significantly with the increasing fire severity. The spatial variation of deadwood debris carbon storage in forests burned with lowseverity fire was higher than that in unburned forests. The spatial variation of deadwood debris carbon storage with highseverity fires was lowest. This spatial variation needed to be accounted when calculating forest deadwood debris carbon storage.

Effects of crop tree release on stand growth and stand structure of Cunninghamia lanceolata plantation.

WU Jian-qiang1,2, WANG Yi-xiang1,2, YANG Yi1,2, ZHU Ting-ting1,2, ZHU Xu-dan1,2

2015, 26(2):  340-348. 

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Crop trees were selected in a 26-year-old evenaged Cunninghamia lanceolata plantation in  Lin’an, and compared in plots that were released and unreleased to examine growth and structure responses for 3 years after thinning. Crop tree release significantly increased the mean increments of diameter and volume of individual tree by 1.30 and 1.25 times relative to trees in control stands, respectively. The increments of diameter and volume of crop trees were significantly higher than those of general trees in thinning plots, crop trees and general trees in control plots, which suggested that the responses from different tree types to crop tree release treatment were different. Crop tree release increased the average distances of crop trees to the nearest neighboring trees, reducing competition among crop trees by about 68.2%. 3year stand volume increment for thinning stands had no significant difference with that of control stands although the number of trees was only 81.5% of the control. Crop trees in thinned plots with diameters over than 14 cm reached 18.0% over 3 years, compared with 12.0% for trees without thinning, suggesting that crop tree release benefited the larger individual trees. The pattern of tree locations in thinning plots tended to be random, complying with the rule that tree distribution pattern changes with growth. Crop tree release in C. lanceolata plantation not only promoted the stand growth, but also optimized the stand structure, benefiting crop trees sustained rapid growth and larger diameter trees production.

Effect of timber moisture content and terrain conditions on the decay degree of Korean pine live standing trees.

SUN Tian-yong1, WANG Li-hai2, HOU Jie-jian1, GE Xiao-wen1

2015, 26(2):  349-355. 

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Vast loss of timber resources can be reduced by preventing and controlling the decay of standing trees in forest management. Therefore,  research concerning the effect of site conditions on decay of standing trees is particularly important for decay prevention and cure. A relevant study was carried out in Xiaoxing’anling Mountains on October, 2013, and thirty decayed and ten normal mature or postmature Korean pine (Pinus koraiensis) live standing trees were selected as sample trees, respectively. Two increment core samples were selected from the basal trunk of each sample tree to measure the mass loss ratio of rotted increment core samples. Meanwhile, moisture content of the soil near sample trees’ roots and the gradient, exposure, slope position and elevation of the site where sample trees located were tested or measured. Analysis was made upon the relationship between factors such as sapwood and heartwood moisture contents and the decay of sample trees by correlation analysis and analysis of variance. The results indicated that moisture content of the sapwood negatively correlated with the decay degree of Korean pine live standing trees at a very significant level, so did the heartwood moisture content. Soil moisture content had a positive correlation with the decay degree at a highly significant level. Significant differences  in the moisture contents of sapwood, heartwood and soils were observed between decayed and normal sample trees. Slope position was the only factor that had a significant effect on the decay degree among all the three slope factors. The decay degree of live standing trees on the middle part of slopes was significantly higher than that on the upper part of slope, mainly due to the significantly higher soil moisture content on the middle part of slope. Elevation of the site where sample trees located had no significant correlation with the decay degree of Korean pine.

Biomass allometric equations of nine common tree species in an evergreen broadleaved forest of subtropical China.

ZUO Shu-di1, REN Yin1, WENG Xian2, DING Hong-feng2, LUO Yun-jian1

2015, 26(2):  356-362. 

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Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the speciesspecific and generalized BAEs using biomass measurement for 9 common broadleaved trees (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in speciesspecific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total tree than a combined variable (D₂H) of D and H (tree height), but D₂H was better than D in estimating stem biomass. R² (coefficient of determination) values of BAEs for 6 species decreased when adding H as the second independent variable into Donly BAEs, where R² value for S. sinensis decreased by 5.6%. Compared with generalized D and D₂Hbased BAEs, standard errors of estimate (SEE) of BAEs for 8 tree species decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by tree species and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in tree species and model types.

C, N and P stoichiometric characteristics of different root orders for three dominant tree species in subalpine forests of western Sichuan, China.

TANG Shi-shan1, YANG Wan-qin1, XIONG Li1, YIN Rui1, WANG Hai-peng2, ZHANG Yan1, XU Zhen-feng1

2015, 26(2):  363-369. 

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Fine root order was classified according to Pregitzer’s method. This study measured carbon (C), nitrogen (N) and phosphorus (P) concentrations of the 1-5 root orders (diameter<2 mm) in three dominant subalpine tree species (Betula albosinensis, Abies faxoniana and Picea asperata) of western Sichuan. Their stoichiometric ratios of different root orders were also calculated. The results showed that C concentration, C/N and C/P increased, but N and P concentrations decreased from the first to fifth order of fine root for all tree species. No significant changes in N/P among root orders were detected in each species. There were significant differences in C, N, P concentrations and their stoichiometric ratios among the tree species. The speciesassociated differences were dependent on root order. There were significant correlations between C, N, P concentrations and their stoichiometric ratios in the three tree species.

Variations of CO₂ concentration and δ¹³C and influencing factors of Quercus variabilis plantation in low hilly area of North China.

SUN Shou-jia1,2, MENG Ping1,2, ZHANG Jin-song1,2, ZHENG Ning1,2, HE Chun-xia1,2， LI Yan-quan1，2

2015, 26(2):  370-378. 

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The offaxis integrated cavity output spectroscopy technique was used to measure air CO₂ concentration and stable carbon isotope ratio (δ¹³C) above (11 m) and at the bottom (6 m) of canopy of a Quercus variabilis plantation in a low hilly area of North China. The variations of CO₂ concentration and δ¹³C value in Q. variabilis plantation canopy and the influencing factors were analyzed at hourly timescale. The results showed that diurnal variation in the CO₂ concentration had a trend, while there was no obvious similar tendency in the diurnal change of δ¹³C value. Daytime atmosphere stability frequency during the experiment time was 70.2%. With the combined effects of photosynthesis and turbulent in the canopy, CO₂ concentration at the bottom of canopy was 1.70 μmol·mol^-1 higher than that above the canopy, while the δ¹³C value was 0.81‰ lower than that above the canopy. Atmosphere stability frequency was 76.2% at night. The CO₂ from leaf was not easy to move because of weak turbulent. Thus, CO₂ concentration at the bottom of canopy was 1.24 μmol·mol^-1 higher than that above canopy, while the δ¹³C value was 0.58‰ lower than that above canopy. The difference of CO₂ concentration between above and at the bottom of the canopy was strongly correlated with their δ¹³C difference both in daytime and at nighttime. Stepwise regression analysis indicated that solar radiation and relative humidity in daytime were the main environmental factors causing CO₂ concentration and δ¹³C difference between above and at the bottom of the canopy, whereas at nighttime temperature was a key environmental factor influencing δ¹³C value. The above environmental factors strongly influenced CO₂ concentration and δ¹³C value in air above and at the bottom of Q. variabilis plantation canopy by increasing or decreasing photosynthesis and respiration.

Effects of water levels and the additions of different nitrogen forms on soil net nitrogen transformation rate and N₂O emission in  subtropical forest soils.

MA Fen1,2, MA Hong-liang1,2, QIU Hong1,2, YANG Hong-yu1,2

2015, 26(2):  379-387. 

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An incubation experiment was conducted to investigate the effects of the additions of different nitrogen forms on nitrogen transformation in red soils of subtropical forest under soil moisture conditions with 40%, 70% and 110% of water holding capacity (WHC). The results showed that soil net mineralization and ammonification rates were maximum at 70% WHC and minimum at 40% WHC. Compared with the control, the addition of NO₃^--N decreased the soil net mineralization and ammonification rates by 56.1% and 43.0% under 70% WHC condition, and decreased by 68.2% and 19.0% under 110% WHC, respectively. However, the proportion of ammonification to mineralization increased at 70% and 110% WHC, which suggested that nitrate addition inhibited the nitrification. With addition of NO₃^--N at 110% WHC, the net nitrification rate was lowest while N₂O emission was highest with the concomitant decrease of nitrate content, indicating that N₂O emission was largely derived from denitrification. However, at 40% WHC and 70% WHC, the maximum N₂O flux was found at the early stage of incubation. Even with addition of NH₄⁺-N and NO₃^--N, N₂O flux did not change much at the latter stage of incubation, indicating that autotrophic nitrification was dominant for N₂O production at the early stage of incubation. Under 40% WHC condition, soluble organic carbon increased more and it increased largely with NH₄⁺-N addition, which meant NH₄⁺-N addition could enhance the mineralization of soil organic matter. Under 40% and 110% WHC conditions, the addition of NH₄⁺-N increased significantly the soil soluble organic nitrogen (SON) by 73.6% and 176.6% compared with the control, respectively. A significant increase of 78.7% for SON was only found at 40% WHC under addition of NO₃^--N  compared with the control. These results showed that high soil moisture condition and addition of NH₄⁺-N were of benefit to SON formation.

Plant community patterns of piosphere in the Mu Us Sandland of China.

YU Hong1,2, WU Bo3, HE Ji3, JIA Zi-yi3, YAN Feng3

2015, 26(2):  388-394. 

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Piosphere is ubiquitous in drylands. Plant communities of ten paddocks were investigated along transects starting from watering points in the Mu Us Sandland. By using the method of regression and indirect gradient ordination, the richness of plant community and plant functional types were analyzed. The results showed that with the increase of distance from the watering points, the traits of the plant communities varied significantly. The coverage of the community, shrubs and grasses gradually increased and the coverage of forbs decreased with the distance increasing from the watering points. The patterns of the community richness and coverage suggested the grazing gradient surrounding the watering points. The piosphere is a breakthrough point to reveal the degradation pattern of rangeland and its driving forces in northern China.

Characteristics of seed rain on abandoned slopes in the hilly-gullied Loess Plateau, Northwest China.

YU Wei-jie1, CHEN Yu2,3, JIAO Ju-ying1,4, WANG Dong-li2, WANG Zhi-jie4, WEI Yan-hong4, KOU Meng4, Yin Qiu-long5

2015, 26(2):  395-403. 

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The objective of this study was to analyze the dynamic characteristics of seed rain on abandoned slopes in the hilly-gullied Loess Plateau region and identify the relationship between seed rain and standing vegetation. Three abandoned slopes were chosen as sampling sites in Zhifanggou watershed. Thirty traps were installed at each site to collect seed rain from October 2010 to April 2013. Standing vegetation was surveyed to identify dominant species in August 2011 and 2012, respectively. Thirtyseven species belonging to seventeen families were identified in the seed rain, and the dominant species, i.e., Lespedeza davurica, Astragalus scaberrimus, Setaria viridis, Cleistogenes squarrosa, Stipa bungeana, Bothriochloa ischcemum, Artemisia scoparia, A. gmelinii, and Heteropappus altaicus, took up to 95.8% of the total seed rain. Three species in seed rain were not found in the standing vegetation. The Sorensen similarity index between seed rain and standing vegetation was 0.77. Seed rain densities were 3737 and 6449 seeds·m^-2 in May 2011-April 2012 and May 2012-April 2013, respectively, and alternate bearing existed. During the study period, seed rain from different positions varied from 3853 to 37923 seeds·m^-2 and belonged to 7-15 species. The results indicated the space limitation of seed dispersal. Seed rain densities were in the middle of the pack compared with similar ecosystems in other studies. High temporal and spatial heterogeneity of seed rain was observed because of rainfall, micro-topography and so on.

Bud population dynamics of Phragmites australis in heterogeneous habitats of Northeast grassland, China.

JIAO De-zhi1,2, YAO Lu1, HUANG Zhao-yue1, YANG Yun-fei2

2015, 26(2):  404-410. 

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To adapt ecological environment, typical clonal plants can occur continuously by means of buds. The changes in the bud bank and bud flow in the heterogeneous habitats become the foundation for deep understanding the characteristics of vegetative propagation. By sampling soil from the unit area, a comparative analysis was performed for rhizome bud population dynamics of Phragmites australis community in both meadow soil and salinealkali soil habitats in meadow grassland of Northeast China. The oneage class rhizome buds formed in the current year were used as input, with the other age classes rhizome buds as output, counting the dormancy buds and death buds. The results showed that the storage, input, output, dormancy, death and the input rates of P. australis rhizome bud populations in meadow soil habitat were significantly higher than that in salinealkali habitat. There was no significant difference in output rate between the two habitats. The dormant rate in salinealkali habitat was significantly greater than that in meadow soil habitat. The death rates remained at relatively low levels in both, less than 2%. With the going of growing season, the input buds and input rate of bud bank increased in the two habitats, while the output buds remained relatively stable. The output rate increased first and decreased later, the dormancy buds and dormant rate decreased. Bud bank and bud flow were positively related to soil moisture, soil organic matter and soil available nitrogen content. However, they were negatively related to soil pH value and soil available phosphorus content. Bud bank and bud flow had a similar seasonal variation. Constantly for both habitats, P. australis populations generated new rhizome buds supplied to the bud bank and kept a stable output to maintain their vegetative propagation.

Speciesassociated differences in foliageroot coupling soilreinforcement and antierosion.

LIU Fu-quan1, LIU Jing1, NAO Min2, YAO Xi-jun1, ZHENG Yong-gang1, LI You-fang1, SU Yu1, WANG Chen-jia1

2015, 26(2):  411-418. 

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This paper took four kinds of common soil and water conservation plants of the study area, Caragana microphylla, Salix psammophila, Artemisia sphaerocephala and Hippophae rhamnides at ages of 4 as the research object. Thirteen indicators, i.e., single shrub to reduce wind velocity ration, shelterbelt reducing wind velocity ration, community reducing wind velocity ration, taproot tensile strength, representative root constitutive properties, representative root elasticity modulus, lateral root branch tensile strength, accumulative surface area, rootsoil interface sheer strength, interface friction coefficient,   accumulative root length, rootsoil composite cohesive, rootsoil composite equivalent friction angle, reflecting the characteristics of windbreak and roots, were chose to evaluate the differences of foliageroot coupling soilreinforcement and antierosion among four kinds of plants by analytic hierarchy process (AHP) under the condition of spring gale and summer rainstorm, respectively. The results showed the antierosion index of foliageroot coupling was in the sequence of S. psammophila (0.841) > C. microphylla (0.454) > A. sphaerocephala (-0.466) > H. rhamnides (-0.829) in spring gale, and C. microphylla (0.841) > S. psammophila (0.474) > A. sphaerocephala (-0.470) > H. rhamnides (-0.844) in summer rainstorm. S. psammophila could be regarded as one of the most important windbreak and antierosion species, while C. microphylla could be the most valuable soil and water conservation plant for the study area.

Negative air ions generated by plants upon pulsed electric field stimulation applied to soil.

WU Ren-ye1, DENG Chuan-yuan2, YANG Zhi-jian3, WENG Hai-yong4, ZHU Tie-jun-rong3, ZHENG Jin-gui3

2015, 26(2):  419-424. 

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This paper investigated the capacity of plants (Schlumbergera truncata, Aloe vera var. chinensis, Chlorophytum comosum, Schlumbergera bridgesii, Gymnocalycium mihanovichii var. friedrichii, Aspidistra elatior, Cymbidium kanran, Echinocactus grusonii, Agave americana var. marginata, Asparagus setaceus) to generate negative air ions (NAI) under pulsed electric field stimulation. The results showed that single plant generated low amounts of NAI in natural condition. The capacity of C. comosum and G. mihanovichii var. friedrichii generated most NAI among the above ten species, with a daily average of 43 ion·cm^-3. The least one was A. americana var. marginata with the value of 19 ion·cm^-3. When proper pulsed electric field stimulation was applied to soil, the  NAI of ten plant species were greatly improved. The effect of pulsed electric field u³(average voltage over the pulse period was 2.0×10⁴ V, pulse frequency was 1 Hz, and pulse duration was 50 ms) was the greatest. The mean NAI concentration of C. kanran was the highest  1454967
ion·cm^-3, which was 48498.9 times as much as that in natural condition. The lowest one was S. truncata with the value of 34567 ion·cm^-3, which was 843.1 times as much as that in natural condition. The capacity of the same plants to generate negative air ion varied extremely under different intensity pulsed electric fields.

Relationships between H₂O₂ metabolism and Ca²⁺ transport in dormancybreaking process of nectarine floral buds.

TAN Yue1,2, GAO Dong-sheng2, LI Ling2, WEI Hai-rong1, WANG Jia-wei1, LIU Qing-zhong1

2015, 26(2):  425-429. 

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In order to explore regulatory function of H₂O₂ in bud dormancy release, main effects of three dormancybreaking treatments (high temperature, hydrogen cyanamide and TDZ) on H₂O₂ metabolism were determined, and impacts of H₂O₂ on Ca²⁺ transport were tested using noninvasive microtest technique. The results showed that both high temperature and hydrogen cyanamide induced H2O2 accumulation and CAT inhibition were efficient in breaking dormancy during deep dormancy period. However, TDZ showed little impacts on H₂O₂ metabolism and was much less effective in breaking dormancy. Dormant floral primordium was absorbing state to exogenous Ca²⁺ due to active calcium channels. The Ca²⁺ transport could be changed by exogenous H₂O₂. H₂O₂ of low concentration reduced the absorption rate of Ca²⁺, and  at high concentration, it changed the Ca²⁺ transport direction from absorption to release. The results indicated that H₂O₂ signals were related with Ca²⁺ signals in dormant buds. Ca²⁺ signal regulated by H₂O₂ accumulation might be important in the dormancybreaking signal transduction process induced by high temperature and hydrogen cyanamide.

Effects of wheat-straw returning into paddy soil on dissolved organic carbon contents and rice grain yield.

XU Ke, LIU Meng, CHEN Jing-du, GU Hai-yan, DAI Qi-gen, MA Ke-qiang, JIANG Feng, HE Li

2015, 26(2):  430-436. 

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A tank experiment using conventional rice cultivar Nanjing 44 as experimental material was conducted at the Experimental Farm of Yangzhou University to investigate the dynamics of wheat straw decomposition rate and the amount of carbon release in clay and sandy soils, as well as its effects on the content of dissolved organic carbon (DOC) and rice yield. The two rates of wheat straw returning were 0 and 6000 kg·hm^-2, and three N application levels were 0, 225, 300 kg·hm^-2. The results showed that, the rate of wheat straw decomposition and the amount of carbon release in clay and sandy soils were highest during the initial 30 days after wheat straw returning, and then slowed down after, which could be promoted by a higher level of nitrogen application. The rate of wheat straw decomposition and the amount of carbon release in clay soil were higher than that in sandy soil. The DOC content in soil increased gradually with wheat straw returning into paddy soil and at the twentyfifth day, and then decreased gradually to a stable value. The DOC content at the soil depth of 15 cm was significantly increased by wheat straw returning, but not at the soil depth of 30 cm and 45 cm. It was concluded that wheat straw returning increased the DOC content in the soil depth of 0-15 cm mainly. N application decreased the DOC content and there was no difference between the two N application levels. Straw returning decreased the number of tillers in the early growth period, resulted in significantly reduced panicles per unit area, but increased spikelets per panicle, filled-grain percentages, 1000-grain mass, and then enhanced grain yield.

Effects of phosphorus fertilization on yield of winter wheat and utilization of soil nitrogen.

XING Dan1, LI Shu-wen1,2, XIA Bo1,2, WEN Hong-da1,2

2015, 26(2):  437-442. 

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In order to evaluate the threshold of phosphorus (P) application rate and improve the utilization efficiency of fertilizers in Baoding region of Hebei Province, a field experiment was conducted to examine the impacts of P fertilization on wheat yield, soil NO₃^--N and nitrogen use efficiency. Results showed that, compared with the CK (P₀), all treatments with P application (P₁, 120 kg·hm^-2; P₂, 240 kg·hm^-2 and P₃, 480 kg·hm^-2) increased the plant height, flag leaf areas and total leaf areas per plant of winter wheat, which was conducive to the accumulation of photosynthetic products. In addition, P application increased the spike number, kernels per spike and yield of winter wheat but slightly decreased the grain mass per 1000 seeds. Of the Pfertilized treatments, P₂ had the highest wheat yield of 6102 kg·hm^-2, which was similar to P₁ but significantly greater than those of P₀ and P₃. Furthermore, P fertilization reduced the NO^₃--N content in top soil layer although the total accumulation of NO₃^- was still rather high. The N grain production efficiencies (GPE_N) and N uptake efficiencies (UE_N) of P₁ and P₂ were similar but greater than the other treatments. The use efficiency (UR_P), agronomic efficiency (AE_P) and partial productivity of P fertilizer (PFP_P) in P₁ were significantly greater than P₂ and P₃. In conclusion, the P application rate of 120 kg·hm^-2(P₁) in this study could be an appropriate threshold in Baoding, Hebei, from the aspects of wheat yield, nitrogen and phosphate use efficiencies and accumulation of soil NO₃^-.

Real-time irrigation forecast of cotton mulched with plastic film under drip irrigation based on meteorological date.

SHEN Xiao-jun1,2, SUN Jing-sheng1,2, LI Ming-si3, ZHANG Ji-yang1,2, WANG Jing-lei1,2, LI Dong-wei1

2015, 26(2):  443-449. 

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It is important to improve the realtime irrigation forecasting precision by predicting realtime water consumption of cotton mulched with plastic film under drip irrigation based on meteorological data and cotton growth status. The model parameters  for calculating ET₀ based on Hargreaves formula were determined using historical meteorological data from 1953 to 2008 in Shihezi reclamation area. According to the field experimental data of growing season in 2009-2010, the model of computing crop coefficient K_c was established based on accumulated temperature. On the basis of crop water requirement (ET₀) and K_c, a realtime irrigation forecast model was finally constructed, and it was verified by the field experimental data in 2011. The results showed that the forecast model had high forecasting precision, and the average absolute values of relative error between the predicted value and measured value were about 3.7%, 2.4% and 1.6% during seedling, squaring and blossomboll forming stages, respectively. The forecast model could be used to modify the predicted values in time according to the realtime meteorological data and to guide the water management in local filmmulched cotton field under drip irrigation.

Effects of water stress and nitrogen fertilization on peanut root morphological development and leaf physiological activities.

DING Hong1, ZHANG Zhi-meng1, DAI Liang-xiang1, CI Dun-wei1, QIN Fei-fei1, SONG Wen-wu1, LIU Meng-juan1,2, FU Xiao1,2

2015, 26(2):  450-456. 

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Taking ‘Huayu 22’ peanut as test material, effect of soil water content and nitrogen fertilization on the leaf physiological activities and root morphological characteristics of peanut plants were analyzed. Two levels of soil water condition were: (1) wellwatered condition and (2) moderate water stress, and three levels of nitrogen were: (1) none nitrogen (N₀), (2) moderate nitrogen (N₁, 90 kg·hm^-2) and (3) high nitrogen (N₂, 180 kg·hm^-2). The results showed that N₁ significantly increased the peanut yield under two water conditions, but showed no significant effect on harvest index compared with N₀. Under water stress condition, N₁ had no significant effects on total root biomass and total root length, but the total root surface area was remarkably increased. The nitrogen fertilization significantly increased the root length and root surface area in 20-40 cm soil layer, and N₂ significantly increased the root biomass and root surface area in the soil layer below 40 cm. The application of nitrogen remarkably increased CAT and POD activities in leaf, while MDA content was decreased with the increase of nitrogen level. Under wellwatered condition, the root biomass, root length and root surface area in the soil layer below 40 cm and total root surface area were significantly reduced by nitrogen application, however, only N₁ could increase leaf protective enzyme activities. Correlation analysis showed that the root length in 20-40 cm soil layer and SOD, CAT, POD activities in leaf were highly significantly related with peanut yield.

Inhibition of decomposing leaf litter of Cinnamomum camphora on growth of Capsicum annuum and the alleviation effect of nitrogen application.

CHEN Hong, HU Ting-xing, WANG Qian, HU Hong-ling, JIANG Xue, ZHOU Guang-liang, CHEN Gang

2015, 26(2):  457-465. 

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Effects of decomposing leaf litter of Cinnamomum camphora on growth, physiological and phenological traits of Capsicum annuum, and modification of these effects by nitrogen application were investigated using a pot experiment. C. camphora leaf litter was applied at rate of 0, 25, 50 100 g per pot, resulting into four treatments, i.e., CK (the control), L₂₅, L₅₀ and L₁₀₀. Nitrogen application was firstly performed on the 39th d of decomposition (3.0 g urea was added to each pot six times). Leaf area, plant height, basal diameter and biomass production of C. annuum were all inhibited sharply by exposure to the leaf litter, and the inhibition effect increased with the increasing leaf litter in terms of both the intensity and the stability. Treated with L₂₅, budding number   reduced by 88.7% averagely during 55th-75th d, and the rate of fructification plant decreased by 40% on the 96th d of decomposition, while neither buds nor fruits were observed when exposed to L₅₀ and L₁₀₀ at that time. Pigment contents and net photosynthetic rate (P_n) were impacted due to leaf litter addition, and malonaldehyde (MDA) was only markedly promoted by L₁₀₀. Inhibition on growth and development of C. annuum caused by leaf litter decomposition could be alleviated by nitrogen application. Leaf area treated with leaf litter recovered to the control level on the 52nd d after nitrogen application, and similar results appeared on the 83rd d after nitrogen application for other growth traits. Budding and fructification status were also visibly improved.

Effects of fertilization on the P accumulation and leaching in vegetable greenhouse soil.

ZHAO Ya-jie1,2, ZHAO Mu-qiu1,3, LU Cai-yan1, SHI Yi1, CHEN Xin1

2015, 26(2):  466-472. 

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A packed soil column experiment was conducted to investigate the effect of different fertilization practices on phosphorus (P) accumulation and leaching potential in a vegetable greenhouse soil with different fertility levels. The results showed that the leaching loss of total P in the leachates elevated with the increment of leaching time while the accumulative leaching loss of total P was relatively low, indicating P was mainly accumulated in the soil instead of in the leachate. At the end of the leaching experiment, soil fertility and fertilization treatment affected the content of total phosphorus and OlsenP significantly. Compared with the lowlevelfertility soil, the contents of total P and OlsenP increased by 14.3% and 12.2% in the mediumlevelfertility soil, 33.3% and 37.7% in the highlevelfertility soil. Total P in the combined application of poultry manure and chemical fertilizer (M+NPK)  was elevated by 5.7% and 4.3%, compared with the NPK and M treatment. Compared  with NPK treatment, OlsenP in M and M+NPK treatments augmented by 13.0% and 3.1%, respectively. Soil total P and OlsenP mainly accumulated in the 0-10 cm and 10-20 cm soil layers, and much less in the 20-40 cm soil layer.

Comparison of growth and field microclimate characteristics of broomcorn millet under different fertilization conditions.

ZHANG Pan-pan1,2, ZHOU Yu1, SONG Hui3, QIAO Zhi-jun4, WANG Hai-gang4, ZHENG Dian-feng2, FENG Bai-li1

2015, 26(2):  473-480. 

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A field experiment with two broomcorn millet varieties Longmi 8 (strong droughtresistant variety) and Jinmi 4 (droughtsensitive variety) was conducted to compare their differences in growth, field microclimate and photosynthetic capacity from anthesis to maturity under different fertility conditions. The results showed that, fertilization decreased canopy temperature, air temperature, soil temperature, illumination, but improved the relative humidity among broomcorn millet plants compared with the nonfertilization treatment. With an increase of the fertilizer level, the plant height, SPAD, LAI, net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO₂ concentration in broomcorn millet showed an increasing trend, which of the high fertilization treatment were 9.2%, 15.1%, 56.6%, 17.8%, 24.6%, 14.2%, 29.7% higher than those of nonfertilization treatment, respectively. Compared with Jinmi 4, Longmi 8 showed a cold wet characteristic, with lower canopy temperature, air temperature, soil temperature, illumination, and higher plant height, LAI, SPAD and relative humidity during grain filling. Moreover, each photosynthetic index of Longmi 8 slowly decreased and extended the period of leaf photosynthetic function so as to accumulate more photosynthetic products.

 

 

Effects of continuous application of bio-organic fertilizer on banana production and cultural microflora of bulk soil in orchard with serious disease incidence.

ZHONG Shu-tang1, SHEN Zong-zhuan1, SUN Yi-fei1, LYU Na-na1, RUAN Yun-ze2, LI Rong1, SHEN Qi-rong1

2015, 26(2):  481-489. 

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A field experiment was conducted for two years to investigate the effects of different fertilization applications on the suppression of banana fusarium wilt disease, crop yield, fruit quality and culturable microflora in a banana orchard which has been monocultured with banana for 12 years and suffered serious banana fusarium wilt disease. The fertilizers included chemical fertilizer (CF), cow manure compost (CM), pig manure compost (PM) and bio-organic fertilizer (BIO). The banana soil microflora was invested using platecounting method and culture-dependent polymerase chain reaction denaturing gradient gel electrophoresis method (CD PCR-DGGE). Results showed that, compared with  the other treatments, 2-year consecutive application of BIO significantly reduced the banana fusarium wilt disease incidence, and improved the banana mass per tree, crop yield, total soluble sugar content and the ratio of total soluble sugar to titratable acidity of fruits (sugar/acid ratio). Moreover, the analysis of culturable microflora showed that BIO application significantly increased the soil microbial biomass, soil culturable bacteria, bacillus and actinomycetes, and the ratio of bacteria to fungi (B/F), while decreased the Fusarium oxysporum. Based on the CD PCR-DGGE results, the BIO application significantly altered the soil culturable bacterial structure and showed highest richness and diversity after 2 years of BIO application. The phylogenetic analysis of the selected bands showed that BIO application enriched the soil with the species of Paenibacillus sp., Burkholderia sp., uncultured Verrucomicrobia sp. and Bacillus aryabhattai, and depressed the species of Ralstonia sp., Chryseobacterium gleum, Fluviicola taffensis, Enterobacter sp. and Bacillus megaterium. These results confirmed that the continuous application of BIO effectively controlled the fusarium wilt disease, improved the crop yield and fruit quality, and modulated the soil culturable microflora under field condition.

Effects of different cropping patterns on soil enzyme activities and soil microbial community diversity in oasis farmland.

2015, 26(2):  490-496. 

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Effects of long-term cropping patterns on the activities of peroxidase, invertase, arylsulfatase, dehydrogenase and protease were investigated in this paper. Four long-term cropping patterns included (1) 10 years continuous cropping of corn, (2) 8 years continuous cropping of wheat followed by 10 years continuous cropping of cotton, (3) 15 years continuous cropping of cotton, and (4) 6 years continuous cropping of cotton followed by 6 years of wheat/sunflower rotation. The responses of soil bacteria, fungi, ammonia oxidizing bacteria (AOB), and the ammonia oxidizing archaea (AOA) to different copping patterns were analyzed. The results showed that cropping patterns significantly affected the activities of soil peroxidase, arylsulfatase, dehydrogenase and protease, while had no significant effect on soil invertase activity. The cropping patterns significantly influenced the diversity index of AOA, but had no significant influence on that of soil bacteria, fungi and AOB. The community structures of soil fungi and AOB were more sensitive to cropping patterns than soil bacteria and AOA. In conclusion, long-term continuous cropping of cotton decreased the activities of soil enzymes activities and soil microbial diversity in oasis farmland, while crop rotation could alleviate the negative influence.

Applicability of daytime downward longwave radiation parameterized models in Changbai Mountains, Northeast China.

LI Wei-bin1,2, WU Jia-bing1, WANG An-zhi1, GUAN De-xin1, JIN Chang-jie1

2015, 26(2):  497-504. 

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A total of eight clearsky and eight cloudysky parameterized models for estimating daytime downward longwave radiation were evaluated by using the meteorological data measured in the Changbai Mountains region, Northeast China. The results indicated that the Satterlund model performed better in estimating clearsky downward longwave radiation, and the bias (BIAS) and root mean square error (RMSE) were -23.34 and 28.55 W·m^-2, respectively. Although the coefficients were not significantly changed, the performance of Satterlund model was significantly improved after the locally calibrated, and the BIAS and RMSE decreased to -6.33 and 18.08 W·m^-2, respectively. Jacobs model was found to be best for modeling cloudysky downward longwave radiation and the BIAS and RMSE were 0.38 and 29.29 W·m^-2, respectively. Sensitivity analysis showed that the vapor pressure  was the most sensitive variable to the atmospheric emissivity and the temperature was not sensitive to it. The predicted results of the optimal model (clear and cloudysky) were consistent with the measured data, while the performance of these models was
affected by a sudden change of cloudy cover.

Simulation of Stipa purpurea distribution pattern on Tibetan Plateau based on MaxEnt model and GIS

HU Zhong-jun1,2，3, ZHANG Yi-li1，2, Yu Hai-bin1

2015, 26(2):  505-511. 

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The impact of climate change on species distribution is a hot issue in biogeography research. This study utilized the constructive species Stipa purpurea as the research object, which was widely distributed in alpine meadow of the Tibetan Plateau, investigated its distribution in the Tibetan Plateau through the field survey and herbarium search, and used MaxEnt model to simulate its historical, current and future distribution trends to analyze its distribution pattern in each historical period and explore the cause of species distribution changes. Research results showed that diversity of Stipa species in alpine grassland of the Tibetan Plateau was high, its main distribution area was the hinterland of the Tibetan Plateau and areas along the Himalaya, and its distribution was strongly affected by precipitation of warmest quarter, precipitation of wettest quarter and annual precipitation. According to the distribution pattern of S. purpurea in the Last Glacial Maximum, and geographical and geological features of the Tibetan Plateau, this paper proposed that: North Tibet core area of South Qiangtang and Ali region of west Himalaya mountainous area were the core area of the potential distribution for S. purpurea, since these regions could provide more suitable habitats for S. purpurea than other regions and be the refugia where the current S. purpurea was migrated and differentiated from. The presence of refugia may contribute to the understanding of related issues of the alpine plants’ origin and differentiation in the Tibetan Plateau.

Spatio-temporal variation of drought condition during 1961 to 2012 based on composite index of meteorological drought in Altay region, China.

WU Yan-feng1, BAKE Batur1, LI Wei1, WEI Xiao-qin1, WOZATIHAN Jiayinaguli1, RASULOV Hamid2

2015, 26(2):  512-520. 

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Based on the daily meteorological data of seven stations in Altay region, China, this study investigated the temporal (seasonal, inter-annual and decadal) and spatial variations of drought by using composite index of meteorological drought, as well as trend analysis, M-K abrupt analysis, wavelet analysis and interpolation tools in ArcGIS. The results indicated that the composite index of meteorological drought could reflect the drought condition in Altay region well. Although the frequency and the covered area of both interannual and seasonal droughts presented decreasing trends in the recent 52 a, the drought was still serious when considering the annual drought. The frequencies of interannual and spring droughts had no abrupt changes, whereas the frequencies of inter-summer, autumn and winter droughts had abrupt changes during the past 52 a. A significant periodic trend was also observed for the frequencies of inter-annual and seasonal droughts. The distribution of frequency and covered area suggested that the conditions of drought were heavily serious in Qinghe County, moderately serious in Altay City, Fuyun County, Buerjin County and Fuhai County, and slightly serious in Habahe County and Jimunai County.

Scale invariance analysis of the ten-day sunshine duration in Henan Province, China.

WANG Ji-jun1, PAN Pan1, HU Cai-hong2, LI Feng-xiu1

2015, 26(2):  521-526. 

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Using the  ten-day sunshine duration data of 107 meteorological stations in Henan Province from 1961 to 2012, spatialtemporal variation characteristics of  ten-day sunshine duration were analyzed, and the scale invariance analysis of  tenday sunshine duration was studied by using the method of detrended fluctuation analysis. The results showed that the means of  tenday sunshine duration and its standardized error among stations were 57.90 and 9.18 h, respectively, and their probability distributions were not subject to normal distribution. The cumulative abnormal of sunshine duration had a distinct linear increasing trend, however, its square deviation among the stations was of phase characteristics. The scale index of  ten-day sunshine of each station was above 0.5, indicated that time series of scale index was of permanence. Variation of scale index among stations was small, which obeyed the normal distribution.

Sediment transport characteristics at different erosion stages for non-hardened roads of the Shenfu Coalfield, west China.

GUO Ming-ming1, WANG Wen-long1,2, LI Jian-ming1, HUANG Peng-fei3, ZHU Bao-cai1,4, WANG Zhen5, LUO Ting6

2015, 26(2):  527-534. 

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Non-hardened roads formed in the production of the Shenfu Coalfield have a unique condition of underlying surface. The road surface is composed of a regolith layer with a certain thickness resulted from longterm rolling and thus, is characterized by weakened antiscourabilty and antierodibility. In contrast, soil layer below the regolith has a higher bulk density and antierodibility. The processes of soil erosion on the nonhardened roads exhibit some differences under rainfall condition. The process of sediment transport and the relationship between sediment transport rate and erosion factors at different erosion stages were studied on nonhardened roads with slope degrees ranging from 3° to 12° (3°, 6°, 9°, 12°) by a field experiment under artificial rainfall. Results showed that the first peak of sediment transport on the regolith surface was observed at the sheet erosion stage. Sheet erosion occurred only at 3° slope degree, with an average variation coefficient of 0.07 for sediment transport rate. Rills in every testing began to develop at slope degrees of 6° to 12° about 15 min after runoff initiation. At the sheet erosion stage, the process of sediment transport fluctuated considerably at rainfall intensities of ＞1.5 mm·min^-1, but the differences in its variation were little at the three slope degrees, with average variation coefficients of 0.20, 0.19 and 0.16, respectively. Rainfall intensity had a more significant impact on sediment transport rate than slope degree. The process of sediment transport at the rill erosion stage fluctuated, but the fluctuation was obviously smaller than that at the sheet erosion stage, with average variation coefficients of 0.05, 0.09 and 0.10 at the three slope degrees. Many wide and shallow rills evolved at the rill erosion stage. The sediment transport rate could be well predicted by a power function of rainfall intensity and slope degree at the sheet and rill erosion stages. The stable sediment transport rate for all the tests was linearly related to runoff rate and sediment concentration.

Influence factors of deposition induced by melt water erosion in Naqu region, China. 

FENG Jun-yuan1,2, CAI Qiang-guo1, LI Zhao-xia2, SUN Li-ying2

2015, 26(2):  535-540. 

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Melt water erosion is one of the important soil erosion forms caused by the melt water from glacier and snow in high altitude cold areas of China. This paper  investigated the influencing factors of deposition caused by melt water erosion in Naqu region. Alluvial fan ratio was presented as an index to characterize the degree of the deposition induced by melt water erosion. Minimum polygon was determined based on spatial overlay technology of Geographic Information System (GIS). The regression equation between the deposition index and the influencing factors was established through the stepwise regression analysis based on minimum polygon. Key influencing factors were identified according to the stepwise regression equation. The results showed that large amounts of alluvial fan were observed in Naqu region; extensive alluvial fans were centered at gentle slope areas in the central part of Naqu region with great spatial differences; alluvial fans were mainly distributed at valley exits, most of which were at large scale with vast differences in area and thickness. Wind speed, normalized difference vegetation index (NDVI), K value of soil erodibility, annual temperature range and the steep slope area ratio were identified as the key influencing factors on the deposition induced by melt water erosion in the studied area. Index of deposition was positively correlated with the wind speed and NDVI, and showed negative relationships with the K value of soil erodibility, the annual temperature range and steep slope area ratio.

Remote sensing analysis of ecological change caused by construction of the new island city: Pingtan Comprehensive Experimental Zone, Fujian Province.

WEN Xiao-le1, LIN Zheng-feng2, TANG Fei1

2015, 26(2):  541-547. 

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Pingtan Island was officially established as the ‘Pingtan Comprehensive Experimental Zone of Fujian’ in 2010, and it led to a surge of construction in the island city. Based on the Landsat-5 images for 2007 and the latest Landsat-8 images for 2013, this paper studied the ecological status, the temporal trends of the ecological changes and the reasons for those changes in Pingtan Comprehensive Experimental Zone at its early stage of construction, by using the remote sensing of ecological index (RSEI). The results showed that as an ecologically fragile area, Pingtan Island had a moderate level of overall ecological status. In the early construction period (from 2007 to 2013), the ecological status of the island showed a downward trend, with a 14% drop of RSEI from 0.511 in 2007 down to 0.450 in 2013, and approximately 36.5% of the area of the island faced the degradation of ecological status, which mainly occurred in the central and southwestern parts of the island. The reason for the degradation was mainly due to the largescale construction which further damaged the scarce vegetation on the island. Therefore, in order to curb the downward trend of the ecological quality of Pingtan Comprehensive Experimental Zone, some effective ecological protection measures must be developed and implemented during the construction.


 

Geostatistical analysis on distribution dynamics of  Myzus persicae(Sulzer) in fluecured tobacco field.

XIA Peng-liang1,2, LIU Ying-hong2, FAN Jun1, TAN Jun1

2015, 26(2):  548-554. 

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Myzus persicae belonging to Aphididae, Hemiptera, is an important migratory pest in tobacco field. As nymph and adult, it sucks the juice, breeds the mildew stains disease, spreads tobacco virus diseases and causes huge losses to the yield and quality. The distribution pattern and dynamics of winged and wingless aphids in the field were investigated from the transplanting of tobacco to the harvesting stage of midplace tobacco leaves in Enshi, Hubei. The semivariable function characteristics were analyzed by geostatistical method, and the field migration pattern were simulated. The results showed that the population dynamics of winged aphids in Enshi were of bimodal curve, with two peaks at 3 weeks after transplanting and 2 weeks after multitopping of tobacco leaves, and there were fivestep process such as random, aggregation, random, aggregation and random. The population dynamics of wingless peach aphids were of singlepeak curve, getting its peak before multitopping, and had random, aggregation, random threestep process. Human factors and the hosts had considerable effects on the population density. Spatial distribution simulationinterpolationfigure could clearly reflect the dynamics of tobacco aphids. Combined with the Pearson correlation analysis, we found that the population density was low and highly concentrated as winged type in the immigration period, which was the key period for the management of peach aphids.

Structure dynamics of insect communities in typical artificial and primeval forests during restoring stages in Xiaoxing’an Mountain, Northeast China.

LIU Zhe-qiang1, MA Ling1, JIAO Yue1, ZHANG Jing2, CAO Chuan-wang1, GU Wei1, MAN Zi-yuan1, ZHANG Man-yin3

2015, 26(2):  555-562. 

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In order to study the insect community structure of typical artificial and primeval forests during different restoring stages in Xiaoxing’an Mountains, we had systematically investigated the insect communities of four typical forests in Liangshui Natural Reserve. A total of 11712 specimens of 293 species were collected, which belonged to 81 families of 10 orders, with Hymenoptera, Diptera, and Coleoptera being the dominant groups. The community stability analysis on insect communities showed that the insect communities of Dahurian larch plantation and original broadleaved Korean pine forest were more stable than other forest types. The principal components analysis indicated that predatory and neutral insects played important roles in the community stability which increased with the increasing predatory insect species and quantities. Polar ordination analysis showed that there was little difference between the environmental factors of Korean pine plantation and the original Korean pine forest.

 

Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain, Northeast China.

SONG Li-hong1,2, YAN Xiu-min1,2, WANG Ke-hong1,2, ZHU Xiao-yan1,2, WANG Xue-feng1, WU Dong-hui1

2015, 26(2):  563-569. 

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In the present study, an in situ control experiment was carried out to explore the response of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels （6 g N·m^-2）, while decreased it at higher levels (>12 g N·m^-2).  At genus level, nitrogen addition significantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis.  At species level, nitrogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands.

Distribution characteristics of soil nematodes in reclaimed  land of copperminetailings in different plant associations.

ZHU Yong-heng1,2, LI Ke-zhong1, ZHANG Heng1, HAN Fei1, ZHOU Ju-hua1, GAO Ting-ting1

2015, 26(2):  570-578. 

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A survey was carried out to investigate soil nematode communities in the plant associations of gramineae (Arthraxon lanceolatus, AL; Imperata cylindrica, IC) and leguminosae (Glycine soja, GS) in  reclaimed land of copperminetailings and in the plant associations of gramineae (Digitaria chrysoblephara, DC-CK) of peripheral control in Fenghuang Mountain, Tongling City. A total of 1277 nematodes were extracted and sorted into 51 genera. The average individual density of the nematodes was 590 individuals·100 g^-1 dry soil. In order to analyze the distribution characteristics of soil nematode communities in reclaimed land of copperminetailings, Shannon community diversity index and soil food web structure indices were applied in the research. The results showed that the total number of nematode genus and the Shannon community diversity index of soil nematode in the three plant associations of AL, IC and GS were less than that in the plant associations of DC-CK. Compared with the ecological indices of soil nematode communities among the different plant associations in reclaimed land of copperminetailings and peripheral natural habitat, we found that the structure of soil food web in the plant associations of GS was more mature, with bacterial decomposition being dominant in the soil organic matter decomposition, and that the soil ecosystem in the plant associations of GS was not stable with low interference. This indicated that the soil food web in the plant associations of leguminosae had a greater development potential to improve the ecological stability of the reclaimed land of copperminetailings. On the other hand, the structure of soil food web in the plant associations of AL and IC were relatively stable in a structured state with fungal decomposition being dominant in the decomposition of soil organic matter. This indicated that the soil food web in the plant associations of gramineae was at a  poor development level.

Population change of farmland rodent and the influences of climate and  cultivation factors in Fengxian District of Shanghai, China.

FEI Lei1, WANG Zu-guo2, YAO Yao3, XU Xiang-ming1, GU Pin-qiang1

2015, 26(2):  579-587. 

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We analyzed the changes of rodent population from 1988 to 2013 in Fengxian District, Shanghai, and discussed the relevance of rodent population dynamics and climate, and ecological factors. Results showed that the average rat density was 1.3% from 1988 to 2013, and the dominant species was Apodemus agrarius. There was little change of density between years. The average composition ratio was 97.5%. The peak of rodent density appeared from February to May, highest in March. Average density and peak decreased obviously year after year. Numbers of adult rodents of 1st group were positively correlated, while that of adult rodents of 2nd group and elderly group negatively correlated with years. Rat age presented a shortened trend annually. Rodent density and temperature factors were negatively correlated except in January. Extreme warmth in February had a lagged, positive effect on the rat density. Precipitation factors had no significant correlation with the density of rodents. Relative humidity was positively correlated with the density, mostly. Planting structure adjustment and reduction of planting acreage were significantly correlated with the reduction of rodent density. Increased deratization rate was also correlated with the reduction.

Effect of stock abundance and environmental factors on the recruitment success of small yellow croaker in the East China Sea.

LIU Zun-lei1,2, YUAN Xing-wei1,2, YANG Lin-lin1,2, YAN Li-ping1,2, ZHANG Hui1,2, CHENG Jia-hua1,2

2015, 26(2):  588-600. 

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Multiple hypotheses are available to explain recruitment rate. Model selection methods can be used to identify the best model that supports a particular hypothesis. However, using a single model for estimating recruitment success is often inadequate for overexploited population because of high model uncertainty. In this study, stockrecruitment data of small yellow croaker in the East China Sea collected from fishery dependent and independent surveys between 1992 and 2012 were used to examine densitydependent effects on recruitment success. Model selection methods based on frequentist (AIC, maximum adjusted R² and P_values) and Bayesian (Bayesian model averaging, BMA) methods were applied to identify the relationship between recruitment and environment conditions. Interannual variability of the East China Sea environment was indicated by sea surface temperature (SST), meridional wind stress (MWS), zonal wind stress (ZWS), sea surface pressure (SPP) and runoff of Changjiang River (RCR). Mean absolute error, mean squared predictive error and continuous ranked probability score were calculated to evaluate the predictive performance of recruitment success. The results showed that models structures were not consistent based on three kinds of model selection methods, predictive variables of models were spawning abundance and MWS by AIC, spawning abundance by P_values, spawning abundance, MWS and RCR by maximum adjusted R². The recruitment success decreased linearly with stock abundance (P<0.01), suggesting overcompensation effect in the recruitment success might be due to cannibalism or food competition. Meridional wind intensity showed marginally significant and positive effects on the recruitment success (P=0.06), while runoff of Changjiang River showed a marginally negative effect (P=0.07). Based on mean absolute error and continuous ranked probability score, predictive error associated with models obtained from BMA was the smallest amongst different approaches, while that from models selected based on the P_value of the independent variables was the highest. However, mean squared predictive error from models selected based on the maximum adjusted R² was highest. We found that BMA method could improve the prediction of recruitment success, derive more accurate prediction interval and quantitatively evaluate model uncertainty.

Spatial-temporal distribution of bigeye tuna Thunnus obesus in the tropical Atlantic Ocean based on Argo data.

YANG Sheng-long1,2, JIN Shao-fei3, HUA Cheng-jun1, DAI Yang1

2015, 26(2):  601-608. 

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In order to analyze the correlation between spatial-temporal distribution of the bigeye tuna (Thunnus obesus) and subsurface factors, the study explored the isothermal distribution of subsurface temperatures in the bigeye tuna fishing grounds in the tropical Atlantic Ocean, and built up the spatial overlay chart of the isothermal lines of 9, 12, 13 and 15 ℃ and monthly CPUE (catch per unit effort) from bigeye tuna longlines. The results showed that the bigeye tuna mainly distributed in the water layer (150-450 m) below the lower boundary depth of thermocline. At the isothermal line of 12 ℃, the bigeye tuna mainly lived in the water layer of 190-260 m, while few individuals were found at water depth more than 400 m. As to the 13 ℃ isothermal line, high CPUE often appeared at water depth less than 250 m, mainly between 150-230 m, while no CPUE appeared at water depth more than 300 m. The optimum range of subsurface factors calculated by frequency analysis and empirical cumulative distribution function (ECDF) exhibited that the optimum depth range of 12 ℃ isothermal depth was 190-260 m and the 13 ℃ isothermal depth was 160-240 m, while the optimum depth difference range of 12 ℃ isothermal depth was -10 to 100 m and the 13 ℃ isothermal depth was -40 to 60 m. The study explored the optimum range of subsurface factors (water temperature and depth) that drive horizontal and vertical distribution of bigeye tuna. The preliminary result would help to discover the central fishing ground, instruct fishing depth, and provide theoretical and practical references for the longline production and resource management of bigeye tuna in the Atlantic Ocean.

Macrobenthic community structure of intertidal zone of Rushan Bay in spring.

JI Ying-lu1, ZHAO Ning1, WANG Zhen-zhong2, JI Xiang-xing3, YANG Chuan-ping1, YU Zi-shan1

2015, 26(2):  609-615. 

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Quantitative study on macrobenthos was carried out in 8 transects along intertidal zone of Rushan Bay in May, 2011. In total, 116 macrobenthic species were identified, among which 58 were polychaetes, 15 were mollusks, 27 were crustaceans, 3 were echinoderms and 13 were other groups. The average abundance and biomass of macrobenthos were 872.6 ind·m^-2 and 9.37 g·m^-2, respectively. By IRI index, Mediomastus sp., Helice sheni, Nemertinea and Neanthes sp. were ranked as the top 4 dominant species in the study area. Average Margalef’s species richness diversity (d), Shannon diversity (H) and Pielou’s evenness index (J) of macrobenthos were 2.119, 2.384 and 0.608, respectively, indicating slight pollution in the study area. Based on 30% similarity level, 8 transects could be grouped into 3 different communities. Compared with other intertidal zones in similar latitude,  macrobenthos of Rushan Bay intertidal zone were characterized by higher species number, smaller body size and higher abundance. Besides the macrobenthic community structure and diversities, more exhaustive studies were needed to reveal the possible influence of shellfish culture on intertidal macrobenthic community.

Assemblage composition and distribution of meiofauna in the southern Yellow Sea cold water mass during summer and autumn.

XU Man, LIU Xiao-shou, LIU Qing-he, HUANG De-ming, YUAN Zi-hao, ZHANG Zhi-nan

2015, 26(2):  616-624. 

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In order to study the impact of the Yellow Sea cold water mass (YSCWM) on meiofauna, the composition, abundance, biomass of meiofauna and their relationships with environmental variables were analyzed through the samples from 8 stations investigated by R/V ‘Dongfanghong Ⅱ’in June and November, 2013. The results showed that the average abundances of meiofauna were 900.8 and 758.4 ind·10 cm^-2, and biomasses were 886.9 and 615.7 μg·10 cm^-2 in June and November, 2013, respectively. Results of ANOVA showed that no significant differences of meiofaunal abundance and biomass were detected among the 8 stations in the two study cruises. A total of 17 meiofaunal groups were identified. The most dominant taxonomic group was freeliving marine nematodes, with relative dominance of 88.5% in June and 94.0% in November. The following groups were also important, including benthic copepods, polychaetes, kinorhynchs and ostracods. Analysis of meiofaunal vertical distribution indicated that 92.5% and 95.4% of meiofauna distributed in the top 5 cm of the sediment in the two study cruises, while 59.1% of nematodes and 78.2% of copepods were found in the top 2 cm of the sediment. Correlation analysis among meiofaunal abundance and biomass, nematode and copepod abundance and environmental variables showed that meiofaunal abundance and biomass had significant negative correlations with bottom water temperature (BWT) and sediment siltclay percentage. Copepod abundance also had significant negative correlations with BWT and siltclay percentage while it had significant positive correlation with sediment median diameter. The results of BIOENV indicated that BWT, bottom water salinity, sediment water content, sediment chlorophyll a and phaeophorbide contents were the most important factors to influence meiofaunal assemblages.

Distribution, dissemination and removal of antibiotic resistant genes (ARGs) in the aquatic environment.

WEN Han-qing, SHI Jun, XUN Hao, DENG Hui-ping

2015, 26(2):  625-635. 

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In recent years, the intensive use of antibiotics induces the development of antibiotic resistant genes (ARGs), which is an increasingly critical problem affecting human health, and the potential toxic effects of the ARGs have drawn great attention all over the world. This review gave an overview of the occurrence, potential sources, fate and ecological risks of ARGs in the environment. What’s more, the removal of ARGs by different treatment processes such as sludge digestion, constructed wetland, disinfection and advanced treatments were assessed, and the improving directions of different treatment processes were also pointed out. Additionally, the highlights  in need for further research  were proposed based on the current pollution status.

 

Impacts of urban cooling effect based on landscape scale: A review.

YU Zhao-wu1, 2, GUO Qing-hai1, SUN Ran-hao3

2015, 26(2):  636-642. 

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The urban cooling island (UCI) effect is put forward in comparison with the urban heat island effect, and emphasizes on landscape planning for optimization of function and way of urban thermal environment. In this paper, we summarized current research of the UCI effects of waters, green space, and urban park from the perspective of patch area, landscape index, threshold value, landscape pattern and correlation analyses. Great controversy was found on which of the two factors patch area and shape index has a more significant impact, the quantification of UCI threshold is particularly lacking, and attention was paid too much on the UCI effect of landscape composition but little on that of landscape configuration. More attention should be paid on shape, width and location for water landscape, and on the type of green space, green area, configuration and management for green space landscape. The altitude of urban park and human activities could also influence UCI effect. In the future, the threshold determination should dominate the research of UCI effect, the reasons of controversy should be further explored, the study of time sequence should be strengthened, the UCI effects from landscape pattern and landscape configuration should be identified, and more attention should be paid to spatial scale and resolution for the precision and accuracy of the UCI results. Also, synthesizing the multidisciplinary research should be taken into consideration.