Table of Content

18 March 2015, Volume 26 Issue 3

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Storage and allocation of carbon and nitrogen in Pinus tabuliformis plantations on the south slope of the East Qinling Mountains, China.

LIU Bing-yan1, CHEN Yun-ming2,3, CAO Yang2,3, WU Xu1

2015, 26(3):  643-652. 

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The objective of this study was to study carbon and nitrogen storages and distributions in Pinus tabuliformis plantations along an age chronosequence of 8-, 25-, 35-, 42- and 61-year-old on the south slope of the East Qinling Mountains, China. Results showed that the carbon content and nitrogen contents ranged from 441.40 to 526.21 g·kg^-1 and from 3.13 to 3.99 g·kg^-1 in arbor layer, from 426.06 to 447.25 g·kg^-1 and from 10.62 to 12.45 g·kg^-1 in shrub layer, from 301.37 to 401.52 g·kg^-1and from 10.35 to 13.33 g·kg^-1 in herb layer, from 382.83 to 424.71 g·kg^-1, and from 8.69 to 11.90 g·kg^-1 in litter layer, and from 1.51 to 18.17 g·kg^-1 and from 0.29 to 1.45 g·kg^-1 in soil layer (0-100 cm), respectively. The largest carbon and nitrogen storages in arbor layer were trunks and branches, which made up 48.5% to 62.7% and 39.2% to 48.4% of the total storage, respectively. Carbon and nitrogen storages of P. tabuliformis plantations were obviously agedependent. Carbon storage at first increased with stand age before the stand was ripe. It was the highest (146.06 t·hm^-2) when the stand was 35 year-old, after which the carbon storage decreased. The nitrogen storage reached the peak value of 10.99 t·hm^-2 at 25 yearold. The average carbon and nitrogen storages were 45.33 t·hm^-2 and 568.55 kg·hm^-2 in the plant layer and, 73.12 and 8.57 t·hm^-2 in soil layer, respectively. Moreover, carbon and nitrogen were accumulated at higher levels in the surface soil layer. In addition, the storages of carbon and nitrogen were mainly distributed in soil layer and arbor layer in this region. The average carbon storage in different components followed an order as soil layer (64.1%) > arbor layer (30.0%) > shrubherb and litter layers (5.9%), while the nitrogen storage followed as: soil layer (93.2%) > arbor layer (5.3%) > shrubherb and litter layers (1.5%).

Characteristics of ‘salt island’ and ‘fertile island’ for Tamarix chinensis and soil carbon, nitrogen and phosphorus ecological stoichiometry in saline-alkali land.

ZHANG Li-hua, CHEN Xiao-bing

2015, 26(3):  653-658. 

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To clarify the nutrient characteristics of ‘salt island’ and ‘fertile island’ effects in salinealkali soil, the native Tamarix chinensis of the Yellow River Delta (YRD) was selected to measure its soil pH, electrical conductivity (EC), organic carbon (SOC), total nitrogen (N), total phosphorus (P) and their stoichiometry characteristics at different soil depths. The results showed that soil pH and EC increased with the increasing soil depth. Soil EC and P in the 0-20 cm layer decreased and increased from canopied area to interspace, respectively. SOC, N, N/P and C/P in the 20-40 cm soil layer decreased, and C/N increased from the shrub center to interspace. SOC and N contents between island and interspace both decreased but P content decreased firstly and then increased with the increasing soil depth. Soil pH correlated positively with EC. In addition, pH and EC correlated negatively with C, N, P contents and their ecological stoichiometry.

Leaf and soil stoichiometry of four herbs in the Gurbantunggut Desert,China.

TAO Ye1,2, ZHANG Yuan-ming2

2015, 26(3):  659-665. 

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The leaf and soil stoichiometric characteristics and their relationships of two ephemeral plants (Hypecoum erectum and Euphorbia turczaninowii) and two ephemeroid plants (Ferula meyeri and Astragalus flexus) were analyzed in extreme desert environment. There was no significant difference among each soil factor in different sampling plots of each species. Soil nitrogen (N) content (0.18-0.22 mg·g^-1) was far lower than soil phosphorus (P) content (1.58-1.62 mg·g^-1), and the N/P only ranged 0.12-0.15, indicating a serious lack of soil N. N, P and N/P all represented significant difference among the four species, in which A. flexus had the highest values with 57.36 mg·g^-1, 2.46 mg·g^-1 and 23.43, followed by H. erectum with 34.05 mg·g^-1, 1.98 mg·g^-1 and 17.56, the values for E. turczaninowii were 27.07 mg·g^-1, 1.87 mg·g^-1 and 14.51, and the values for F. meyeri were 28.63 mg·g^-1, 2.20 mg·g^-1 and 13.10, respectively. N and P contents showed significant correlation of each species, while most soil factors did not show significant correlation with leaf stoichiometric values.

Effects of understory removal on soil greenhouse gas emissions in Carya cathayensis stands.

LIU Juan1,2, CHEN Xue-shuang1,2, WU Jia-sen1,2, JIANG Pei-kun1,2, ZHOU Guo-mo1,2, LI Yong-fu1,2

2015, 26(3):  666-674. 

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CO₂, N₂O and CH₄ are important greenhouse gases, and soils in forest ecosystems are their important sources. Carya cathayensis is a unique tree species with seeds used for highgrade dry fruit and oil production. Understory vegetation management plays an important role in soil greenhouse gases emission of Carya cathayensis stands. A oneyear in situ experiment was conducted to study the effects of understory removal on soil CO₂, N₂O and CH₄ emissions in C. cathayensis plantation by closed static chamber technique and gas chromatography method. Soil CO₂ flux had a similar seasonal trend in the understory removal and preservation treatments, which was high in summer and autumn, and low in winter and spring. N₂O emission occurred mainly in summer, while CH₄ emission showed no seasonal trend. Understory removal significantly decreased soil CO₂ emission, increased N₂O emission and CH₄ uptake, but had no significant effect on soil water soluble organic carbon and microbial biomass carbon. The global warming potential  of soil greenhouse gases emitted in the understory removal treatment was 15.12 t CO₂e·hm^-2·a^-1, which was significantly lower than that in understory preservation treatment (17.04 t CO₂e·hm^-2·a^-1).

Adaptability of mangrove Kandelia obovata seedlings to salinitywaterlogging.

YOU Hui-ming1,2

2015, 26(3):  675-680. 

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A laboratory test on the effects of 12 salinitywaterlogging stresses on the growth of Kandelia obovata seedlings was conducted. Nine growth indexes including seedling height, stem height, basal diameter, node number, leaf number, root biomass, stem biomass, leaf biomass and total biomass were measured. The results showed that salinity and salinitywaterlogging stresses had significant effects on the growth of K. obovata seedlings, while waterlogging stress had no significant effects on the seedling height, stem height, basal diameter, node number and leaf number, but had significant effects on root biomass, stem biomass, leaf biomass and total biomass. The growth and biomass of K. obovata seedlings decreased with increasing the salinity and waterlogging time. The principal components analysis showed that K. obovata seedlings would grow best under the 7‰ salinity+2 h waterlogging stress, while the 21‰+8 h combination was a critical stress.

Spatial-temporal characteristics of land surface temperature in Tianshan Mountains area based on MODIS data.

GUAN Yan-long1,2, WANG Rang-hui1,2, LI Cheng1, YAO Jian1, ZHANG Meng1, ZHAO Jian-ping1

2015, 26(3):  681-688. 

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Based on the MODIS/MOD11A2 data from 2001 to 2013, this paper researched the characteristics of land surface temperature (LST) of Tianshan Mountains area. The results indicated that the average of LST in the study area was 1.73 ℃, and LST was much higher in the east than in the west. The interannual variation range of LST in the northwest was significantly large than in other regions, with the largest above 0.55 ℃ in some areas. The LST tended to slowly increase with time, and the increase rate was  0.147 ℃·a^-1. It showed a significant seasonal difference, and the fluctuation of winter was significantly larger than in other seasons with the coefficient of variation reaching 12.7%. The LST difference of day time was greater than that at night, and that in summer was greater than in other seasons. The LST differed with land use types, and the fitted results were inconsistent between the LST and NDVI. With the increase of NDVI of woodland and grassland, the LST decreased dramatically. The LST of construction land and cropland under the influence of human activities had higher sensitivity with NDVI than other land types.

Growth response of Abies fargesii to climate in Shennongjia Mount of Hubei Province, Southeastern China.

HOU Xin-yuan1, SHI Jiang-feng1,2, LI Ling-ling1, LU Hua-yu1,2

2015, 26(3):  689-696. 

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A wellreplicated Abies fargesii treering width chronology in the Shennongjia Mount was developed to investigate its radial growth response to climate variables (e.g., monthly mean temperature and total precipitation) and other growing season indicators (e.g., cumulative temperature, continuous days, initial and final dates). Correlation analyses showed that the treering width was positively correlated to the mean temperatures of February, April and September, and negatively correlated to the total precipitation of September, prior September and prior December.  The analyses between the chronology and other growing season parameters showed that tree growth responded positively to the cumulative temperature and continuous days of the growing season. The correlation was the highest when the growing season was defined as the days above the temperature threshold of 9.0 ℃. Defined this way, the growing season typically started in lateMay and ended in midSeptember, lasting about 120 days. Correlation analyses were also conducted between the treering growth and the initial and final dates of the growing season. Results showed that correlation was the highest for initial dates defined at 9.0 ℃ (with the coefficient of -0.25 and pvalue close to 0.05), and for final dates defined at 9.3 ℃ (with the coefficient of 0.33 and pvalue less than 0.05). All these results indicated that the sensitive temperature threshold for photosynthesis of A. fargesii was around 9.0 ℃. The year 1978 marked an abrupt shift of climate in southeast China. We compared A. fargesii growth between pre1978 and post1978 periods. Results showed that as temperature rose, the growing season was lengthened with both earlier initial dates and later final dates. Longer growing season increased the A. fargesii growth in the Shennongjia Mount, southeastern China.

Comparative observation of diffuse radiation in Qianyanzhou during the spring of 2012.

HAN Jia-yin1,2, LI Sheng-gong1, ZHANG Lei-ming1, WEN Xue-fa1, LI Qing-kang1, WANG Hui-min1

2015, 26(3):  697-703. 

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Global radiation and diffuse radiation were measured from March  to June of 2012 in  Qianyanzhou Experimental Station of Red Soil and Hilly Land, Chinese Academy of Sciences by using three types of pyranometers, including CMP11 attached with a shadow ring, SPN1 and RSR3, which were placed in parallel. The observations showed that both global radiation and diffuse radiation measured by these pyranometers had a good linear correlation. The global radiation measured by SPN1 and RSR3 was respectively 3.0% and 20.5% lower than that measured by the CMP11. The diffuse radiation measured by SPN1 and RSR3 was respectively 5.5% and 7.9% lower of than that measured by the CMP11. Under the sunny, cloudy and overcast conditions, the daily variations of diffuse radiation measured by the three pyranometers were similar, and hence, the diffuse radiation values at a specific solar elevation angle measured by the different pyranometers were also similar. There was difference in daily accumulative diffuse radiation measured by the different pyranometers. Monthly diffuse fractions of March, April and May were 0.56, 0.59 and 0.70, respectively. In the subtropical area of southern China, the diffuse radiation accounted for a relatively large proportion of the global solar radiation and varied considerably over time. It is necessary to conduct longterm continuous measurements to capture the variability of diffuse radiation over different underlying surfaces.

Error structure and additivity of individual tree biomass model for four natural conifer species in Northeast China.

DONG Li-hu1, LI Feng-ri1, SONG Yu-wen2

2015, 26(3):  704-714. 

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Based on the biomass data of 276 sampling trees of Pinus koraiensis, Abies nephrolepis, Picea koraiensis and Larix gmelinii, the monoelement and dualelement additive system of biomass equations for the four conifer species was developed. The model error structure (additive vs. multiplicative) of the allometric equation was evaluated using the likelihood analysis, while nonlinear seemly unrelated regression  was used to estimate the parameters in the additive system of biomass equations. The results indicated that the assumption of multiplicative error structure was strongly supported for the biomass equations of total and tree components for the four conifer species. Thus, the additive system of logtransformed biomass equations was developed. The adjusted coefficient of determination (R_a²) of the additive system of biomass equations for the four conifer species was 0.85-0.99, the mean relative error  was between -7.7% and 5.5%, and the mean absolute relative
error  was less than 30.5%. Adding total tree height in the additive systems of biomass equations could significantly improve model fitting performance and predicting precision, and the biomass equations of total, aboveground and stem were better than biomass equations of root, branch, foliage and crown. The precision of each biomass equation in the additive system varied from 77.0% to 99.7% with a mean value of 92.3% that would be suitable for predicting the biomass of the four natural conifer species.

Responses of soil microbial carbon metabolism  to the leaf litter composition in Liaohe River Nature Reserve of northern Hebei Province, China.

LI Tian-yu, KANG Feng-feng, HAN Hai-rong, GAO Jing, SONG Xiao-shuai, YU Shu, ZHAO Jin-long, YU Xiao-wen

2015, 26(3):  715-722. 

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Using litter bag method, we studied the effects of single and mixed litters from Betula platyphlla, Populus davidiana and Quercus mongolica on soil microbial biomass carbon (MBC), microbial respiration (MR) and microbial metabolic quotient (qCO₂) in 0-5, 5-10 and 10-20 cm soil layers. The results showed that the average contents of MBC in 0-20 cm soil layer were 124.84, 325.29, 349.79 and 319.02 mg·kg^-1 in the leaf litter removal treatment, Betula platyphlla treatment, Populus davidiana treatment and Quercus mongolica treatment, and the corresponding average rates of MR were 0.66, 1.12, 1.16 and 1.10 μg·g^-1·h^-1, respectively. Meanwhile, in 0-20 cm soil layer, the average contents of MBC in the treatments with single leaf litter, mixed litter of two plant species and mixed litter of three plant species were 331.37, 418.52 and 529.34 mg·kg^-1, and the corresponding average rates of MR were 1.13, 1.30 and 1.46 μg·g^-1·h^-1, respectively. In contrast to the MBC and MR, qCO₂ in soil showed a reverse pattern. Our study suggested that characteristics of microbial carbolic metabolism were influenced by litter quality. Namely, the treatment with high litter quality had higher MBC, MR and utilization efficiency of soil carbon, compared with the treatment with low litter quality. Moreover, mixture of different species of leaf litter improved soil microbial activities, increased utilization efficiency on soil carbon and promoted diversity of microbial metabolic pathways, which could then contribute to maintaining and enhancing soil quality of forestland.

Litter decomposition and soil faunal diversity of two understory plant debris in the alpine timberline ecotone of western Sichuan in a snow cover season.

HE Run-lian, CHEN Ya-mei, DENG Chang-chun, YAN Wan-qin, ZHANG Jian, LIU Yang

2015, 26(3):  723-731. 

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In order to understand the relationship between litter decomposition and soil fauna diversity during snow cover season, litterbags with plant debris of Actinothuidium hookeri, Cystopteris montana, two representative understory plants in the alpine timberline ecotone, and their mixed litter were incubated in the dark coniferous forest, timberline and alpine meadow, respectively. After a snow cover season, the mass loss and soil fauna in litterbags were investigated. After decomposition with a snow cover season, alpine meadow showed the highest mass loss of plant debris in comparison with coniferous forest and timberline, and the mass loss of A. hookeri was more significant. The mixture of two plants debris accelerated the mass loss, especially in the timberline. A total of 968 soil invertebrates, which belonged to 5 classes, 10 orders and 35 families, were captured in litterbags. Acarina and Collembola were the dominant groups in plant debris. The numbers of individuals and groups of soil faunal communities in litter of timberline were higher than those of alpine meadow and dark coniferous forest. Canonical correspondence analysis (CCA) indicated that the groups of soil animals were related closely with the average temperature, and endemic species such as Isoptera and Geophilomorpha were observed only in coniferous forest, while Hemiptera and Psocoptera only in the alpine meadow. The diversity of soil faunal community was more affected by plant debris varieties in the timberline than in the coniferous forest and alpine meadow. Multiple regression analysis indicated that the average temperature and snow depth explained 30.8% of the variation of litter mass loss rate, soil animals explained 8.3%, and altogether explained 34.1%. Snow was one of the most critical factors impacting the decomposition of A. hookeri and C. montana debris in the alpine timberline ecotone.

Correlation between chemical constituents and ecological factors of Astragalus membranaceus var. mongholicus.

YANG Qing-zhen1,2, WANG Zeng-hui1, FU Juan1, LIU De-wang3, HUANG Lin-fang1

2015, 26(3):  732-738. 

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Principal component analysis (PCA) and correlation analysis (CA) were applied to analyze the correlation of the main chemical components in Astragalus membranaceus var. mongholicus and ecological factors. The results showed that the contents of astragaloside, campanulin, ononin, kaempferol and astragalus polysaccharides (APS) of A. membranaceus var. mongholicus produced in Shanxi were significantly higher than in Inner Mongolia and Gansu. The main climatic factors for affecting the contents of chemical ingredients in A. membranaceus var. mongholicus were annual average relative humidity, sunshine hours and average July temperature. Calcium was the main factor in the soil affecting the chemical ingredient contents, and calcium was negatively correlated with the contents of calycosin glycosides, kaempferol, ononin, quercetin and APS in A. membranaceus var. mongholicus within a certain range.

Effects of nitrogen and water addition on soil bacterial diversity and community structure in temperate grasslands in northern China.

YANG Shan1,2, LI Xiao-bing2, WANG Ru-zhen2, CAI Jiang-ping2, XU Zhu-wen2, ZHANG Yu-ge1, LI Hui2, JIANG Yong2

2015, 26(3):  739-746. 

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In this study, we measured the responses of soil bacterial diversity and community structure to nitrogen (N) and water addition in the typical temperate grassland in northern China. Results showed that N addition significantly reduced microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) under regular precipitation treatment. Similar declined trends of MBC and MBN caused by N addition were also found under increased precipitation condition. Nevertheless, water addition alleviated the inhibition by N addition. N addition exerted no significant effects on bacterial α-diversity indices, including richness, Shannon diversity and evenness index under regular precipitation condition. Precipitation increment tended to increase bacterial α-diversity, and the diversity indices of each N gradient under regular precipitation were much lower than that of the corresponding N addition rate under increased precipitation. Correlation analysis showed that soil moisture, nitrate (NO₃^--N) and ammonium (NH₄⁺-N) were significantly negatively correlated with bacterial evenness index, and MBC and MBN had a significant positive correlation with bacterial richness and evenness. Nonmetric multidimensional scaling (NMDS) ordination illustrated that the bacterial communities were significantly separated by N addition rates, under both water ambient and water addition treatments. Redundancy analysis (RDA) revealed that soil MBC, MBN, pH and NH₄⁺-N were the key environmental factors for shaping bacterial communities.

Effects of compound fertilizer of (NH₂)₂ CO and KH₂PO₄ on the chestnut photosynthesis characteristics, growth and fruiting.

TIAN Shou-le, SUN Xiao-li, SHEN Guang-ning, XU Lin

2015, 26(3):  747-754. 

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Compound fertilizer can improve the fertilizer use efficiency and tree nutrition status to ensure balanced fertilization. Taking 7 year-old chestnut trees as test material, with (NH₂)₂CO and KH₂PO₄ being mixed at the different ratios, the effects of different compound fertilizers on the photosynthesis characteristics as well as the growth and fruiting of chestnut were studied quantitatively by trunk injection method. Results showed that compound fertilizer of (NH₂)₂CO and KH₂PO₄ induced positive synergistic effects to enhance photosynthetic capacity, yield and quality of chestnut obviously. The content of chlorophyll was decreased by (NH₂)₂CO and increased by KH₂PO₄, but increased obviously by the compound fertilizer. The contents of N, P, K of leaf and branch rose under the four compounded fertilization treatments, among which 0.3%(NH₂)₂CO+0.3%KH₂ PO₄ was the best. All fertilizer treatments could advance the photosynthetic parameters, while the compound fertilizer performed better. 0.3%(NH₂)₂CO+0.3%KH₂PO₄ treatment significantly increased the photosynthetic rate, the maximum net photosynthesis, apparent quantum yield, carboxylation efficiency, instantaneous water use efficiency and nitrogen use efficiency. Compound fertilizer could promote the growth of branch in diameter and length synchronously, and increase the number of mixed buds, while (NH₂)₂CO only promoted the growth of branch in length, and did little in the number of mixed buds. The compound fertilizer did better in advancing nuts yield and quality than single fertilization of N or P. The nuts yield, mass and total sugar were increased by 68.2%, 25.5% and 14.9% respectively under 0.3%(NH₂)₂CO+0.3%KH₂PO₄ treatment compared with the control.

Effect of fertilization depth on ¹⁵Nurea absorption, utilization and loss in dwarf apple trees.

DING Ning1, CHEN Qian2, XU Hai-gang1, JI Meng-meng1, JIANG Han1, JIANG Yuan-mao1

2015, 26(3):  755-760. 

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Five-year-old ‘Fuji’3/M26/M. hupehensis Rehd. seedlings were treated by ¹⁵N tracer to study the effects of fertilization depth (0, 20 and 40 cm) on ¹⁵Nurea absorption, distribution, utilization and loss in soil. The results showed that the plant leaf area, chlorophyll content and total N of apple leaves in 20 cm treatment were obviously higher than 0 cm and 40 cm treatments. The ¹⁵N derived from fertilizer (Ndff) in different organs of apple plant under different depths were significantly different, and the Ndff was the highest in roots at the fullbloom stage, and then in perennial branches. During the shoot rapidgrowing and flower bud differentiation stage, the Ndff of new organs higher than that of the storage organs, and the Ndff of different organs were high level at fruit rapidexpanding stage, and the Ndff of fruit was the highest. The distribution ratio of ¹⁵N at fruit maturity stage was significantly different under fertilization depths, and that of the vegetative and reproductive organs of 20 cm treatment were obviously higher than 0 cm and 40 cm treatments, but that of the storage organs of 20 cm treatment was lower than 0 cm and 40 cm treatments. At fruit maturity stage, ¹⁵N utilization rate of apple plant of 20 cm treatment was 24.0%, which was obviously higher than 0 cm (14.1%) and 40 cm (7.6%) treatments, and ¹⁵N loss rate was 54.0%, which was obviously lower than 0 cm (67.8%) and 40 cm (63.5%) treatments. With the increase of fertilization depths, the N residue in soil increased sharply.

Monitoring of seasonal variation of vegetation cover and evaluation of biologicalcontrol factor in orchards of China.

YU Yue1, ZHANG Wen-bo1， WANG Guo-yan2

2015, 26(3):  761-768. 

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Biological-control factor (B) can quantitatively reflect the effect of vegetation on soil erosion. Vertical photography method was used to monitor the seasonal changes of orchard coverage in 18 small watersheds, covering all five water erosion zones in China. The canopy coverage and ground green coverage were then calculated, and the B values were estimated. The result indicated that the orchard canopy coverage varied with season and distributed with a bell shape. The trend of ground green coverage and total
coverage changed with season and was affected by the land management. For the orchard where the land surface was not treated and the weeds could grow freely, the distribution of the green coverage season change for all five soil erosion zones had a bell shape. The total coverage in the Northwest Loess Plateau area changed with season with a bell shape  as well. The total coverage in the other four areas did not vary with the season and almost kept constant. For the orchard where land surface was cleaned up from time to time, the green coverage and total coverage in all five water erosion areas irregularly varied with season. The average B value of orchards in Northeast black soil area was the minimum with a value of 0.0006, while that in the Northwest Loess Plateau area was the maximum (0.1212). The average orchard B values in the Northern rocky earthy area, the Southern red soil area and the Southwest rocky earthy area were not significantly different and were 0.0548, 0.0627 and 0.0639, respectively.

Spatial distribution of soil moisture and salinity and their influence factors in the farmland of Manas River catchment, Northwest China. 

SHEN Hao1,2, Jilili ABUDUWAILI1

2015, 26(3):  769-776. 

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Applying methods of statistics and geostatistics, Manas River catchment was selected as the research area to study the spatial distribution of soil moisture and salinity in the soil profile as well as their influence factors. The coupling relationship between soil moisture and salinity presented in the spatial distribution was explored as well. The result showed that the soil moisture was overall at a low level (varying from 14.2% to 20.9%), while the salinity was relatively high (about 6.00-9.15 g·kg^-1). The soil profile distribution of water and salt contents both showed a trend of bottom accumulation. The variation of soil water moisture was moderate, while that of salt content was strong. Soil salinity and moisture of all layers showed strong spatial autocorrelation, which were mainly affected by structural factors. The horizontal distribution patterns of water and salt contents were irregular, and were constrained by factors like terrain and landforms, etc. Disturbed by human activities, the coupling relation of soil moisture and salinity became much more complex, but their spatial distribution variation was synchronized to some extent.

 

Land use pattern change in Ejin Delta of Northwest China during 1930-2010.

NIAN Yan-yun1,2, WANG Xiao-li3, CHEN Lu1

2015, 26(3):  777-785. 

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The land use and landscape pattern in the lower reaches of the arid inland river basin is meaningful to water resource allocation. Based on the land use data in 1930, 1961, 1990, 2000, 2010, the purpose of this study was to quantitatively analyze the change of landscape pattern in the Ejin Delta in the lower reaches of the Heihe River Basin, a typical inland river basin in Northwest China. The results showed that the desert area accounted for 73.4% of the total research area in 2010, and the grassland 20.8%. During the past 80 years, the grassland, farmland and construction land increased. The transformation of land use types were characterized by switching to farmland and construction land. The fragmentation and diversity of the landscape increased, while the dominance of the landscape decreased. The landscape pattern obviously lied on the water resource and had regional diversity. Land use changes tended to make the landscape welldistributed, diverse and fragmentized. At last, the driving factors and ecological environment effects of land use change were discussed. In a word, to ensure harmonious development between human and ecohydrology, suggestions such as planning ecological resettlement, limiting farmland area, developing precision agriculture and increasing the proportion of ecological water use should be put forward.

Variation characteristics of agricultural heat resource and its effect on agriculture in Shanxi Province, China.

QIAN Jin-xia, ZHANG Jian-xin, LI Na, HAN Pu

2015, 26(3):  786-792. 

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Based on the data of the daily mean air temperature and the minimum soil surface temperature of 70 meteorological stations in Shanxi Province from 1970 to 2012, the heat indices of agricultural resources including accumulated temperatures above 0 ℃ and 10 ℃, the average temperature in July and the annual frostfree duration were calculated. Their variation trends and mutation were analyzed by using linear regression and accumulated anomaly methods. The effect of agricultural heat resource on crop producing area was analyzed. The results showed that the accumulated temperatures for above 0 ℃ and 10 ℃ had increased significantly at a rate of about 64.8 and 57.9 ℃·d·（10 a）^-1, respectively (P<0.001). The average temperature in July and the annual frostfree duration had significantly increased at a rate of about 0.3 ℃·（10 a）^-1 and 5.9 d·（10 a）^-1, respectively. The increasing ranges of heat resource indices had different spatial distribution patterns in Shanxi Province. The accumulated temperatures were greater in the west than that in the east. The average temperature in July was greater in middle and north than that in the south. The annual frostfree duration was greater in the middle than that in the south and north. The accumulated temperatures above 0 ℃ and 10 ℃ showed a clear mutation in 1996, so were the average temperature in July in 1993 and the annual frostfree duration in 1997. Compared to the time before mutation, the accumulated temperatures above 0 ℃ and 10 ℃ increased by 219.4 ℃·d and 196.7 ℃·d, respectively, the average temperature in July by 0.8 ℃ and the annual frostfree duration by 15 d. As a result, hot crop cultivable area and warm crop cultivable area were expanded northward, while the mild crop cultivable area, cool crop cultivable area, cold crop cultivable area and alpine plants area were shrunk. The maximum expansion was of the warm crop cultivable area (by 175.7%). The maximum shrinkage was of the cold area (by 87.9 %). The cultivable area of cotton was expanded by 1.7×10⁶ hm² (53.5%), and that of potato was shrunk by 8.9×10⁶ hm² (30.5%).

China’s rice field greenhouse gas emission under climate change based on DNDC model simulation.

TIAN Zhan1,2, NIU Yi-long1,2, SUN Lai-xiang3, LI Chang-sheng4, LIU Chun-jiang4, FAN Dong-li1

2015, 26(3):  793-799. 

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In contrast to a large body of literature assessing the impact of agriculture greenhouse gas (GHG) emissions on climate change, there is a lack of research examining the impact of climate change on agricultural GHG emissions. This study employed the DNDC v9.5, a stateofart biogeochemical model, to simulate greenhouse gas emissions in China’s ricegrowing fields during 1971-2010. The results showed that owing to temperature rising (on average 0.49 ℃ higher in the second 20 years than in the first 20 year) and precipitation increase (11 mm more in the second 20 years than in the first 20 years) during the rice growing season, CH₄ and N₂O emissions in paddy field increased by 0.25 kg C·hm^-2 and 0.25 kg N·hm^-2, respectively. The rising temperature accelerated CH₄ emission and N₂O emission increased with precipitation. These results indicated that climate change exerted impact on the mechanism of GHG emissions in paddy field.

Simulated responses of winter wheat yield and soil moisture to different conservation tillage practices in Weibei Highlands, Northwest China.

ZHANG Yu-jiao1, LI Jun1, GUO Zheng2, YUE Zhi-fang2

2015, 26(3):  800-808. 

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Based on the verified precision results by simulation, the WinEPIC (EPIC, environmental/policy integrated climate model) was employed to quantitatively simulate effects of three conservation tillage practices adopted during the period of summer fallow, i.e. subsoiling, notillage and conventional tillage, on wheat yield and soil moisture in Weibei Highlands during 1980-2009. The results showed that during the study period, the yield and annual water consumption of winter wheat under the different tillage practices tended to decrease with fluctuation in the growing period. The yield and water use efficiency of winter wheat under subsoiling were the highest, averaging 3.33
t·hm^-2 and 8.50 kg·hm^-2·mm^-1 over the thirty years, respectively, and that of no tillage was the lowest. The annual water consumption of winter wheat was slightly higher under subsoiling than under no tillage and conventional tillage. In 0-3 m soil layer, the available soil water content tended to decline in a strongly and seasonally fluctuating manner. No tillage performed best in soil moisture conservation, with the average available soil water content being 89.5 mm, and that of conventional tillage was the lowest. The soil water moisture fluctuated with the seasonal rainfalls in 0-1 m soil layer and kept stable in 1-3 m with no great difference among the tillage practices. Under longterm continuous cropping, subsoiling showed the best effects on the yield of winter wheat and the most comprehensive effect on soil moisture, and  was the best practice of conservation tillage for wheat lands on Weibei Highlands.

Selenium uptake and transport of rice under different Se-enriched natural soils.

JIANG Chao-qiang, SHEN Jia, ZU Chao-long

2015, 26(3):  809-816. 

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In this study, a pot experiment was conducted with “Wandao 205” as test materials to investigate Se uptake and translocation in rice  under different Se concentrations (0.5, 1.0, and 1.5 mg·kg^-1). Results showed that there was no significant change in rice yield when Se concentration in soil was lower than 1.5 mg·kg^-1. Significant linear correlations existed between Se concentration in soil and different rice plant tissues. Se concentration in rice plant followed the order of root > straw > grain. Se concentration in different rice grain fractions followed the order of bran > polished rice > hull. The root absorption index of Se was more than 1.86, suggest that the rice could absorpt Se from soil effectively. However, the transport and accumulation of Se in seeds from Seenriched soil was relatively constant. The Se transport index in seeds was between 0.53 and 0.59. Soil Se concentration within the range of 0.5 to 1.0 mg·kg^-1 could produce Seenriched rice, which might be enough for human requirement of 60-80 μg·d^-1 Se. However, polished rice at highSe treatment (1.5 mg·kg^-1) exceeded the maximum standard limit of Se (0.3 mg·kg^-1) for cereals in China. These results suggested that we could produce Seenriched rice under soil Se concentration in the range of 0.5 to 1.0 mg·kg^-1 without spraying Se fertilizer, thus reducing the cost and avoiding soil and water pollution caused by exogenous Se.

Effects of reduced nitrogen application and soybean intercropping on nitrogen balance of sugarcane field.

LIU Yu1,2,3, ZHANG Ying1,2,3, YANG Wen-ting1,2,3, LI Zhi-xian1,2,3, GUAN Ao-mei1,2,3, WANG Jian-wu1,2,3

2015, 26(3):  817-825. 

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A four-year (2010-2013) field experiment was carried out to explore the effects of three planting patterns (sugarcane, soybean monoculture and sugarcane-soybean 1:2 intercropping) with two nitrogen input levels (300 and 525 kg·hm^-2) on soybean nitrogen fixation, sugarcane and soybean nitrogen accumulation, and ammonia volatilization and nitrogen leaching in sugarcane field. The results showed that the soybean nitrogen fixation efficiency (NFE) of sugarcane-soybean intercropping was lower than that of soybean monoculture. There was no significant difference in NFE among the treatments with the two nitrogen application rates. The nitrogen application rate and intercropping did not remarkably affect nitrogen accumulation of sugarcane and soybean. The ammonia volatilization of the reduced nitrogen input treatment was significantly lower than that of the conventional nitrogen input treatment. Furthermore, there was no significant difference in nitrogen leaching at different nitrogen input levels and among different planting patterns. The sugarcane field nitrogen balance analysis indicated that the nitrogen application rate dominated the nitrogen budget of sugarcane field. During the four-year experiment, all treatments leaved a nitrogen surplus (from 73.10 to 400.03 kg·hm^-2), except a nitrogen deficit of 66.22 kg·hm^-2 in 2011 in the treatment of sugarcane monoculture with the reduced nitrogen application. The excessive nitrogen surplus might increase the risk of nitrogen pollution in the field. In conclusion, sugarcane-soybean intercropping with reduced nitrogen application is feasible to practice in consideration of enriching the soil fertility, reducing nitrogen pollution and saving production cost in sugarcane field.

Effect of different organic fertilizers on bioavailability of soil Cd and Zn.

XIE Yun-he1,2,3, JI Xiong-hui1,2,3, WU Jia-mei1,2,3, HUANG Juan2,3, GUAN Di1,3, ZHU Jian1,2,3

2015, 26(3):  826-832. 

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The active effect of soil Cd and Zn and their interaction was studied in typical paddy field in south China by monitoring the contents of Cd and Zn in soil and rice in rice fields applied with pig manure, chicken manure or rice straw for 4 years continuously. The results showed that applying  pig manure, chicken manure or rice straw had no significant impact on the soil total Cd content, soil available Cd content and soil Cd activity, but tended to increase the soil total Cd content and increased the soil total Zn content, soil available Zn content and Zn activity significantly. Applications of pig manure, chicken manure and rice straw all reduced the Cd content of brown rice, in order of pig manure > chicken manure > rice straw. The Cd contents of brown rice, stem and leaf in the treatment applied with pig manure were lower than in the control by 37.5%, 44.0% and 36.4%, respectively; the Cd contents of brown rice, stem and leaf in the treatment applied with chicken manure were lower than in the control by 22.5%, 33.8%, and 22.7%, respectively; the Cd content of brown rice in the treatment applied with rice straw was lower than in the control by 7.5% but its contents in stem and leaf increased by 8.2% and 22.7% , respectively. The reduction in the brown rice Cd content was mainly due to the reduction of Cd enrichment from soil to brown rice after application of pig or chicken manure, but mainly due to the reduction of Cd transportation from stem to brown rice after straw application. Applications of pig manure, chicken manure and rice straw increased Zn contents in rice stem by 53.4%, 53.4% and 13.9%, respectively, but all had no significant effect on brown rice and leaf’s Zn contents. Zn and Cd had the significant antagonistic effects in the soil and rice stem. The increase of Zn content in soil and rice stem inhibited the adsorption and accumulation of Cd in the brown rice, stem and leaf significantly, and with the increase of the proportion of Zn/Cd, the competitive absorption between Cd and Zn by rice was the main control factor  affecting the Cd absorption by rice than their competitive adsorption by soil.

Effects of different long-term fertilization on the activities of enzymes related to carbon, nitrogen, and phosphorus cycles in a red soil.

FAN Miao-zhen1, YIN Chang2, FAN Fen-liang2, SONG A-lin2, WANG Bo-ren2, LI Dong-chu2, LIANG Yong-chao2

2015, 26(3):  833-838. 

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Using a microplate fluorimetric assay method, five fertilization treatments, i.e. nofertilizer control (CK), sole application of nitrogen (N), balanced application of nitrogen, phosphorus, and potassium fertilizer (NPK), application of pig manure (M), and combination of pig manure with balanced chemical fertilizer (MNPK) were selected to investigate the effects of different long-term fertilization regimes on the activity of five enzymes (β-1,4-glucosidase, βG; cellobiohydrolase, CBH; β-1,4-xylosidase, βX; β-1,4-Nacetylglucosaminidase, NAG; acid phosphatase, AP) in a red soil sampled from Qiyang, Hunnan Province. The results showed that compared with CK treatment, N treatment had no impact on βG, βX, CBH, and NAG activities but reduced AP activity, while NPK, M and MNPK treatments increased the activities of all the five enzymes. Correlation analysis indicated that all the five enzyme activities were positively correlated with the content of nitrate (r=0.465-0.733), the content of available phosphorus (r=0.612-0.947), soil respiration (r=0.781-0.949) and crop yield (r=0.735-0.960), while βG, CBH and AP were positively correlated with pH (r=0.707-0.809), only AP was significantly correlated with dissolvable organic carbon (r=-0.480). These results suggested that the activities of the measured enzymes could be used as indicators of red soil fertility under different fertilization regimes, but the five enzymes tested provided limited information on the degree of acidification induced by application of mineral nitrogen.

Impact of temperature increment before the over-wintering period on growth and development and grain yield of winter wheat.

LI Xiang-dong, ZHANG De-qi, WANG Han-fang, SHAO Yun-hui, FANG Bao-ting, LYU Feng-rong, YUE Jun-qin, MA Fu-ju

2015, 26(3):  839-846. 

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The effect of temperature increment before the over-wintering period on winter wheat development and grain yield was evaluated in an artificial climate chamber (TPG 1260, Australia) from 2010 to 2011. Winter wheat cultivar ‘Zhengmai 7698’ was used in this study. Three temperature increment treatments were involved in this study, i.e., temperature increment last 40, 50 and 60 days, respectively, before the over-wintering period. Control was not treated by temperature increment. The results showed that temperature increment before the over-wintering period had no significant effect on earlier phase spike differentiation. But an apparent effect on later phase spike differentiation was observed. High temperature effect on spike differentiation disappeared when the difference of effective accumulated temperature between the temperature increment treatment and the control was lower than 25 ℃. However, the foliar age at the jointing stage was enhanced more than 0.8, heading and physiological ripening were advanced 1 day each, when the effective accumulated temperature before the over-wintering period increased 60 ℃. Higher effective accumulated temperature before the over-wintering period accelerated winter wheat growth and development, which resulted in a short spike differentiation period. Winter wheat was easy to suffer freeze damage, which lead to floret abortion and spikelet death in spring under this situation. Meanwhile, higher effective accumulated temperature before the over-wintering period also reduced photosynthetic capacity of flag leaf, shortened the grain filling period, and led to wheat grain yield reduction.

Effects of exogenous 24-epibrassinolide on leaf morphology and photosynthetic characteristics of tomato seedlings under low light stress.

LI Ning, GUO Shi-rong, SHU Sheng, SUN Jin

2015, 26(3):  847-852. 

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This study investigated the effects of exogenous 24-epibrassinolide (EBR) on the leaf morphology and photosynthetic characteristics of tomato seedlings (cv. Jiersi) cultured hydroponically under low light stress. The results showed that low light stress induced adaptive changes in the leaf morphology of tomato seedling. Low light stress significantly increased the leaf area, specific leaf area, angle between stem and leaf, vertical angle and cable bent, but significantly decreased the dry mass of leaf. Low light stress also significantly decreased the maximum net photosynthetic rate, apparent quantum yield, dark respiration rate, carboxylation efficiency and Rubisco large subunit content. The light compensation point and carbon dioxide compensation point were dramatically enhanced under low light stress. However, foliar spraying EBR significantly increased the leaf area, leaf dry mass, angle between stem and leaf, vertical angle by 14.1%, 57.1%, 12.3% and 7.7% under low light stress, respectively. EBR significantly decreased the specific leaf area and cable bent by 30.5% and 10.6% in low light stressed plants. In addition, EBR significantly enhanced the apparent quantum yield, dark respiration rate and carboxylation efficiency by 20.4%, 17.9% and 9.3%, respectively, but significantly reduced the light compensation point and carbon dioxide compensation point by 21.9% and 4.3% under low light stress. Moreover, EBR also significantly increased the Rubisco large subunit content in low light stressed leaves. These results suggested that application of exogenous EBR could effectively alleviate the inhibition of photosynthesis induced by low light stress via improving the apparent quantum yield, dark respiration rate, carboxylation efficiency and Rubisco content, and maintaining the stability of leaf morphology, thus low light tolerance of tomato seedlings.

Effects of brief exposure to high temperature on Neoseiulus californicus.

YUAN Xiu-ping, WANG Xiao-dong, WANG Jia-wu, ZHAO Yi-ying

2015, 26(3):  853-858. 

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To determine the influence of high temperature shock on the survival characteristics and population development of N. californicus, the hatching rate, survival rate and developmental duration were investigated after the eggs, larvae and adults of N. californicus were exposed to high temperatures (35, 38, 42, 45 ℃) for 1-8 h. The results showed that with higher temperature and longer time, the survival rate of eggs and larvae would be lower, and their developmental duration declined firstly and then increased. The hatching rate of eggs treated at 42 ℃ for 8 h was significantly lower than that at 35 ℃ for 8 h. The developmental duration of egg (4.1 d) was shortest when treated at 38 ℃ for 8 h. The egg couldn’t hatch when treated at 45 ℃ for 2 h. The survival rate of larvae which was treated at 45 ℃ for 4 h was significantly lower than that at 35 ℃ for 4 h, and the larvae wouldn’t survive when treated at 45 ℃ for 8 h. The spawning period and total eggs of female adults increased firstly and then decreased. The egglaying amount of a female N. californicus was 38.9, 36.7 and 14.5 at 35, 38 and 45 ℃, respectively. High temperature exposure had significant effects on the egg hatching rate, survival rate and development duration of N. californicus, but had little effect on the preoviposition and survival rate of the adults.

Identification of chemicals in root exudates of potato and their effects on Rhizoctonia solani.

ZHANG Wen-ming1,2, QIU Hui-zhen1,2, ZHANG Chun-hong1,2, HAI Long1,2

2015, 26(3):  859-866. 

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This study was conducted to identify chemicals in root exudates and their effect on Rhizoctonia solani in potato cropping systems. Root exudates were collected from the fields with 5 years of continuous potato cropping in comparison with rotational cropping of potato and other crops, using inhouse made root boxes at the seedling and squaring stages. Chemicals in the root exudates were identified using the GC-MS method. The results showed that glucide concentration was the highest in the root exudates, followed by organic acids. Compared with the rotational cropping, the continuous cropping significantly decreased the glucide content and increased the content of organic acids in the root exudates. The contents of almitic acid in root exudates under continuous cropping was 0.94% at seedling stage and 1.4% at squaring stage, the dibutyl phthalate was 0.15%, whereas under rotational cropping, those values were decreased to 0.15%, 0.2%, and being negligible, respectively. The root exudates promoted the growth of R. solani, especially under continuous potato cropping. The simulation test showed that the palmitic acid and dibutyl phthalate in root exudates could promote the growth of R. solani.

Temporal characteristics of ecological risk assessment indicators in coal-mining city with the application of LVQ method.

PENG Jian, TAO Jing-xian, LIU Yan-xu

2015, 26(3):  867-874. 

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Because the ability of selected indicators in assessing ecological risk at different temporal scales is not the same, it is necessary to clear the definite comparability of such indicators at temporal scale to explore a new method for dynamic assessing the ecological risk. In this case, five mining cities in Liaoning Province were selected as the study area, with the application of learning vector quantization (LVQ) neural network, the significance of the indicators for the ecological risk assessment was quantitatively analyzed to clarify their characteristics at temporal scale. The expression with twodimension (long-term and shortterm) of temporal scale was put forward as a new method to assess the ecological risk for mining cities. The results showed that the amount of industrial SO₂ removed per output value, the amount of industrial dust removed per output value, coverage rate of urban green space, precipitation, coordination degree among subsystems, percentage of mining practitioners, and current year investment on pollution abatement projects were effective at long-term temporal scale, while the other indicators acted at shortterm temporal scale. With the combination of long-term and shortterm temporal scales, the dynamic assessment of ecological risk for mining cities could be expressed on twodimension of temporal scale. It was found that Fuxin City got the highest ecological risk in current status, with the risk increasing most in Fushun City at the shortterm temporal scale as well as in Chaoyang City at the long-term temporal scale. The method adopted in this study might act as a significant guidance in dynamic controlling and integrative management of ecological risk for mining cities.

Ecology-economy harmonious development based on the ecological services value change in Yanqi Basin, Northwest China.

Zulpiya MAMAT1,2, Umut HALIK1,3, Rouzi AJI4, Ilyas NURMEMET1, Mirigul ANWAR1, Maierdang KEYIMU1

2015, 26(3):  875-883. 

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In this paper, we used land use/cover ecosystem service value estimation model and ecological economic coordination degree model to analyze the changes of the ecosystem service value by the land use/cover changes during 1985, 1990, 1996, 2000, 2005 and 2011 in Yanqi Basin, Xinjiang. Then we evaluated the ecology-economy harmony and the regional differences. The results showed that during 1985-2011, there was an increasing trend in the areas of waters, wetland, sand, cultivated land and construction land in Yanqi Basin. In contrast, that of the saline-alkali land, grassland and woodland areas exhibited a decreasing trend. The ecosystem service value in Yanqi Basin during this period presented an increasing trend, among which the waters and cultivated land contributed most to the total value of ecosystem services, while the grassland and the woodland had obviously declined contribution to the total value of ecosystem services. The research showed that the development of ecological economy in the study area was at a low conflict and low coordination level. So, taking reasonable and effective use of the regional waters and soil resources is the key element to maintain the ecosystem service function and sustainable and harmonious development of economy in Yanqi Basin.

Spectral reflectance characteristics and modeling of typical Takyr Solonetzs water content.

ZHANG Jun-hua1, JIA Ke-li2

2015, 26(3):  884-890. 

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Based on the analysis of the spectral reflectance of the typical Takyr Solonetzs soil in Ningxia, the relationship of soil water content and spectral reflectance was determined, and a quantitative model for the prediction of soil water content was constructed. The results showed that soil spectral reflectance decreased with the increasing soil water content when it was below the water holding capacity but increased with the increasing soil water content when it  was  higher than the water holding capacity. Soil water content presented significantly negative correlation with original reflectance (r), smooth reflectance (R), logarithm of reflectance (lgR), and positive correlation with the reciprocal of R and logarithm of reciprocal ［lg(1/R］. The correlation coefficient of soil water content and R in the whole wavelength was 0.0013, 0.0397 higher than r and lgR, respectively. Average correlation coefficient of soil water content with 1/R and ［lg(1/R)］ at the wavelength of 950-1000 nm was 0.2350 higher than that of 400-950 nm. The relationships of soil water content with the first derivate differential (R′), the first derivate differential of logarithm (lgR)′ and the first derivate differential of logarithm of reciprocal \[lg(1/R)\]′ were unstable. Base on the coefficients of r, lg(1/R), R′ and (lgR)′, different regression models were established to predict soil water content, and the coefficients of determination were 0.7610, 0.8184, 0.8524 and 0.8255, respectively. The determination coefficient for power function model of R′ reached 0.9447, while the fitting degree between the predicted value based on this model and onsite measured value was 0.8279. The model of R′ had the highest fitted accuracy, while that of r had the lowest one. The results could provide a scientific basis for soil water content prediction and field irrigation in the Takyr Solonetzs region.

Application of simulated annealing method and neural network on optimizing soil sampling schemes based on road distribution.

HAN Zong-wei1, HUANG Wei1, LUO Yun1, ZHANG Chun-di1, QI Da-cheng2

2015, 26(3):  891-900. 

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Taking the soil organic matter in eastern Zhongxiang County, Hubei Province, as a research object, thirteen sample sets from different regions were arranged surrounding the road network, the spatial configuration of which was optimized by the simulated annealing approach. The topographic factors of these thirteen sample sets, including slope, plane curvature, profile curvature, topographic wetness index, stream power index and sediment transport index, were extracted by the terrain analysis. Based on the results of optimization, a multiple linear regression model with topographic factors as independent variables was built. At the same time, a multilayer perception model on the basis of neural network approach was implemented. The comparison between these two models was carried out then. The results revealed that the proposed approach was practicable in optimizing soil sampling scheme. The optimal configuration was capable of gaining soil-landscape knowledge exactly, and the accuracy of optimal configuration was better than that of original samples. This study designed a sampling configuration to study the soil attribute distribution by referring to the spatial layout of road network, historical samples, and digital elevation data, which provided an effective means as well as a theoretical basis for determining the sampling configuration and displaying spatial distribution of soil organic matter with low cost and high efficiency.

Effect of climate change on the fisheries community pattern in the overwintering ground of open waters of northern East China Sea.

LIU Zun-lei1,2, YUAN Xing-wei1,2, YANG Lin-lin1,2, YAN Li-ping1,2, TIAN Yong-jun3, CHENG Jia-hua1,2

2015, 26(3):  901-911. 

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Data sets of 26 fisheries target species from the fisherydependent and fisheryindependent surveys in the overwintering ground of open waters of northern East China Sea (OWNECS), combined sea surface temperature (SST), were used to examine the links between diversity index, pattern of common variability and climate changes based on the principal component analysis (PCA) and generalized additive model (GAM). The results showed that the shift from a cold regime to a warm regime was detected in SST during the 1970s-2011 with step changes around 1982/1983. SST increased during the cold regime and the warm regime before 1998 (warming trend period, 1972-1998), and decreased during the warm regime after 1998 (cooling trend period, 1999-2011). Shannon diversity index was largely dependent on the filefish, which contributed up to 50% of the total production as a single species, with low diversity in the waters of the OW-NECS, during the late 1980s and early 1990s. Excluding the filefish, the diversity index linearly increased  and decreased  during 1972-1998 and 1999-2011, respectively. The variation pattern generally corresponds with the trend in water temperature, strongly suggesting the effect of the SST on the diversity. The first two components (PC1 and PC2) of PCA for target species, which accounted for 32.43% of the total variance, showed evident decadal variation patterns with a step change during 1992-1999 and interannual variability with shortperiod fluctuation, respectively. It seems that PC1 was associated with large scale climatic change, while PC2 was related to interannual oceanographic variability such as ENSO events. Linear fitting results showed winEOF1 had significant effect on PC1, and GAM analysis for PC1 showed that winter EOF1 (winEOF1) and summer EOF2 (sumEOF2) can explain 88.9% of the total variance. Nonlinear effect was also found between PC2 and winEOF1, indicating that the fish community structure, which had predominantly decadal/interannual variation patterns, was influenced by interannual variations in oceanographic conditions.

Vertical distribution of main species captured by tuna longline fishery in the southeast Pacific Ocean.

ZHANG Yan-bo1, DAI Xiao-jie1,2, ZHU Jiang-feng1,2, GAO Chun-xia1,2, WU Feng1,2, ZHENG Xiao-chun1

2015, 26(3):  912-918. 

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Information of vertical distribution of longlinehook species is important for the development of effective measures to mitigate bycatch, and very helpful for better understanding of the oceanic ecosystem structure and implementation of ecosystembased fisheries management. Based on depth data of longline hook and capture hook position of pelagic species, collected by on board scientific observer in the southeast Pacific Ocean from September 2013 to January 2014, shoaling rate of longline hook and vertical distribution of 14 pelagic species were analyzed. The results showed that the relative shoaling rate range of longline hook was 8.9%-17.1%, and the average relative shoaling rate was 13.5%. The depth ranges of 14 capture species were different. The species with the deepest depth was Opah (Lampris guttatus), and the species with the shallowest depth was skipjack (Katsuwonus pelamis). Except for yellowfin tuna (Thunnus albacares) and striped marlin (Tetrapturus audax), the mean depth and depth distributions of bycatch species were significantly different from that of the targeted albacore tuna (Thunnus alalunga).


 

Advances in studies of absorption and utilization of amino acids by plants: A review.

CAO Xiao-chuang1,2, WU Liang-huan2,3, MA Qing-xu2,3, JIN Qian-yu1

2015, 26(3):  919-929. 

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Plant can directly take up the intact amino acids, thus bypass the microbial mineralization of organic nitrogen. As an excellent carbon and nitrogen source, there exists competition for amino acid absorption between plant roots and soil microorganisms. And the total flux of amino acids in soil may be enormous due to the extensive sources and short halflife. Studies on amino acid nitrogen nutritional contribution for plant by the technique of nitrogen isotopic tracer, has become a research topic in recent years, which will help us better understand the principle of soil fertility. This paper summarized the recent researches on amino acid morphological characteristics in soil and its metabolic mechanism and nitrogen nutritional contribution for plant in different ecosystems, and discussed the present status and development trend of the amino acid circulation mechanism in the plantsoilmicroorganism ecosystem and its bioavailability for plant. Finally, the topics of environmental regulating mechanism of amino acid bioavailability, amino acid carbonnitrogen metabolism, and how to improve the field organic nitrogen management were all the core issues to be resolved.

Impacts of climate change on food production in Gansu: A review. 

YANG Feng-ke1,2, HE Bao-lin1,2, GAO Shi-ming3

2015, 26(3):  930-938. 

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The climate of Gansu turned to be overall warmingdrying and partly warmingwetting since 1986. In contrast to that of 1960, the average annual temperature had raised by 1.1℃ with the average annual precipitation decreased by 28 mm correspondingly, which made the arid region expanded southward by 50 km in 2010. Climate warming increased the growth period effective accumulated temperature of main food grain crops and lengthened the crop growth period. It changed crop maturity, crop disposition, cropping system and generally increased the cultivatable area and planting altitude above the sea level of major crops and expanded northward the multiple cropping system, which further resulted in expansion of autumn grain crop sown area, shrink of summer grain crop sown area, and replacement of strong winter early maturing varieties by weak winter middle late maturing varieties. It benefited the crop yield by increasing the use efficiency of photothermal resources. Warmingwetting climate increased the climate productivity of oasis crop while warmingdrying weather decreased the climate productivity of rainfed crops, which were mostly determined by the precipitation regimes and water conditions. Any advanced technique that can increase precipitation use ratio and water use efficiency as well as improve and promote soil quality and fertility should be regarded as an effective countermeasure to increase food grain production under climate change in Gsansu. So, selecting and breeding new crop varieties with the characteristics of strong resistance, weak winter, middlelate mature and high water use efficiency, establishing new planting structure and cropping system that suitable to the precipitation and temperature features of changed climate, are the development direction of food grain production in Gansu to cope with the climate change.

Effects of tillage methods on soil physicochemical properties and biological characteristics in farmland: A review.

LI Yu-jie, WANG Hui, ZHAO Jian-ning, HUANGFU Chao-he, YANG Dian-lin

2015, 26(3):  939-948. 

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Tillage methods affect soil heat, water, nutrients and soil biology in different ways. Reasonable soil management system can not only improve physical and chemical properties of the soil, but also change the ecological process of farmland soil. Conservation tillage can improve the quality of the soil to different degrees. For example, no-tillage system can effectively improve soil enzyme activity. No tillage and subsoiling tillage can provide abundant resources for soil microbe’s growth and reproduction. No tillage, minimum tillage and other conservation tillage methods exert little disturbance to soil animals, and in turn affect the quantity and diversity of the soil animals as well as their population structure. Effects of different tillage methods on soil physical and chemical properties as well as biological characteristics were reviewed in this article, with the soil physical and chemical indices, enzyme activities, soil microbe diversity and soil animals under different tillage patterns analyzed. The possibility of soil quality restoration with appropriate tillage methods and the future research direction were pointed out.

Research progress on the application of IPAT model and its variants.

WANG Yong-gang1,2,WANG Xu1,2,SUN Chang-hong1,2, LU Xiao-yan3

2015, 26(3):  949-957. 

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IPAT model and its variants could describe the quantitative relationships between human driving force and the environmental pressure, benefit fundamental understanding of the dynamics of coupled human and natural systems, and are regarded as effective tools in solving the environmental problems caused by the social and economic development. In this paper, the fundamental concepts of IPAT model and its variants were discussed including definitions, historical developments and the hot issues in their applications. The future research trends were put forward aiming to further expand the use of IPAT models in the sustainable development of environment and social decisionmaking.

Research progress on molecular ecology of Sciurus vulgaris.

LIU Zhu1,2, TIAN Xin-min1, CHEN Huan1, GUO Hui-yan1,2, JIN Jian-li1, ZHANG Xiao-jun1

2015, 26(3):  958-964. 

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Today, the main threats for Sciurus vulgaris are illegal hunting, deforestation, and subsequent population fragmentation, combined with interspecific competition from S. carolinensis in some regions of Europe, which has led to a sharp reduction in the number of population. S. vulgaris has been listed as Near Threatened IUCN Red List and included in key protected wild animals in Jilin Province, China. The molecular ecology of S. vulgaris is developing rapidly with the rapid development of molecular biology methods. In particular, the research of mtDNA fragments and the application squirrel study microsatellite loci has further promoted the molecular ecology of S. vulgaris. In this study, the molecular phylogeny, the genetic diversity and the molecular phylogeography involving the molecular ecology of S. vulgaris were reviewed. Four areas for the future development in molecular ecology of S. vulgaris were proposed: 1) to further explore the molecular phylogeny relationship between S. vulgaris and S. lis; 2) the comparative analysis of the genetic diversity of S. vulgaris for continuous populations, isolated populations and metapopulation; 3) the analysis of molecular phylogeography of S. vulgaris based on other markers of nuclear; 4) to explore whether there existed the quaternary glacial refuge in Asia.