Table of Content

18 December 2017, Volume 28 Issue 12

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Contents

Niche analysis of dominant species of forest community in Xiaowutai Mountain, China

BAI Xiao-hang, ZHANG Jin-tun

2017, 28(12):  3815-3826.  doi:10.13287/j.1001-9332.201712.002

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This paper analyzed the niche breadth and niche overlap of dominant species of forest community in Xiaowutai Mountain, and fitted the response patterns of dominant species to the environment gradients by generalized additive models. The results showed that a total of 392 species of vascular plants, belonging to 222 genera, 75 families were recorded in 148 quadrats. A total of 36 dominant species were selected from the tree layer, shrub layer and herb layer by importance va-lues. Betula albosinensis, Betula platyphylla, Larix principis-rupprechtii, Pinus tabuliformis at the tree layer, Spiraea pubescens, Abelia biflora, Rosa bella, Corylus mandshurica at the shrub layer, Carex breviculmis, Deyeuxia arundinacea, Sanguisorba officinalis, Carex siderosticta at the herb la-yer had higher niche breadth, and these species had greater competitiveness and stronger environmental adaptability. In the same layer, niche overlap index was high indicating that species had similar habitats, and there was competitive relationship between them. Although Acer momo and Quercus wutaishanica had high niche overlap, their competition was not strong in the condition of rich resources. There was niche overlap between B. platyphylla and a variety of mixed tree species including A. momo, Q. wutaishanica, Sorbus alnifolia, and limited resources leaded to strong competition in these communities. The adaptability of each species to environmental factors was diffe-rent. The response of most dominant species to altitude showed a single peak curve, and they distri-buted within a certain altitude range. The response of some dominant species to altitude was linearly increased or decreased, and concentrated at high altitudes or low altitudes. The response of dominant species to slope position was similar to altitude. The dominant species showed a linear change along the slope, showed significantly positive correlation with soil temperature, and showed the cha-racteristics of shade-requiring or sunny-requiring. The response of B. albosinensis, A. biflora, H. bretschneideri, C. breviculmis, C. dahurica to litter layer thickness and soil thickness showed linearly increased. The response of L. principis-rupprechtii, B. albosinensis, P. fruticosa, D. arundinacea to soil moisture showed linearly increased, while linearly decreased to soil electrical conductivity. Most dominant species to soil pH and environmental disturbance showed a single peak curve, and the others showed linearly decreased.

Fine root production and turnover of Pinus massoniana and their influencing factors in the Three Gorges Reservoir Area, China

WANG Na, SHEN Ya-fei, CHENG Rui-mei, XIAO Wen-fa, YANG Shao, GUO Yan

2017, 28(12):  3827-3832.  doi:10.13287/j.1001-9332.201712.010

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In this study, the annual production and turnover rate of fine root of Pinus massoniana in Three Gorges Reservoir Area were calculated using sequential soil core,litterbag and compartment flux model methods, and the relationship between fine root production, turnover rate and factors was analyzed. The results showed that the annual mean biomass of <0.5, 0.5-1 and 1-2 mm fine root was 0.29, 0.59 and 0.76 t·hm^-2, annual production was 0.13, 0.49, 0.37 t·hm^-2, and annual turnover rate was 1.49, 1.01, 0.40 a^-1, respectively. The effects of factors on production and turnover of fine roots with different diameters were different. Soil temperature and soil Ca content had significant effects on production and turnover of <0.5 mm fine roots, and soil temperature explained the variation of production and turnover by 32.8% and 25.0%, and soil Ca content explained by 65.6% and 73.1%, respectively. There was a positive relationship between fine root biomass and fine root production, and the biomass of fine root explained 41.0%, 41.1% and 54.5% of variation in fine root production for <0.5, 0.5-1 and 1-2 mm fine roots, respectively. P and K contents of fine roots correlated significantly with <0.5 mm fine root production, and explained 32.2% and 39.2% of the variation of <0.5 mm fine root production, respectively. The fine root with diameter <0.5 mm was most closely associated with soil factors, and soil temperature and soil Ca content were the main factors affecting fine root biomass.

Physiological responses of Salix rehderiana and Populus cathayana grafted seedlings to nitrogen deficiency

HAN Qing-quan, SONG Hai-feng, TANG Duo-teng, ZHANG Sheng

2017, 28(12):  3833-3840.  doi:10.13287/j.1001-9332.201712.004

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Morphological and physiological responses of Salix plants are different from Populus to nitrogen (N) deficiency. In this study, grafting technology was used in S. rehderiana and P. cathayana to investigate the graft compatibility of Salix and Populus, and whether grafting could improve the resistance to N deficiency in Salicaceae plants. The survival rate, growth, biomass accumulation and allocation, gas exchange parameters and non-structural carbohydrates (NSCs) were measured to evaluate the resistance to N deficiency among different grafting combinations. The results showed that the graft compatibility between S. rehderiana and P. cathayana was quite high. The survival rate was 74% and 96% in S/P (S. rehderiana was used as scions and P. cathayana as rootstocks) and P/S (P. cathayana was used as scions and S. rehderiana as rootstocks) combinations, respectively. N deficiency reduced the survival rate in all grafting combinations, which were 53.3% and 86.7% in S/P and P/S, respectively. The survival rate of S/P was lower than that of the other grafting combinations. Under control and N-deficient conditions, the height, basal diameter, biomass and net photosynthetic rate (P_n) of P/P and P/S combinations were higher than those of S/S and S/P combinations. N deficiency significantly reduced growth rate, biomass accumulation and P_n in all grafting combinations. The rate between root biomass and aboveground biomass of S. rehderiana rootstock combinations (S/S and P/S) was significantly higher than those of P. catha-yana rootstock combinations (P/P and S/P) under both control and N-deficient conditions. It indicated that more photosynthates might be allocated to belowground in S. rehderiana, while to aboveground in P. cathayana. The NSCs in roots of all grafting combinations were more sensitive to N deficiency than in stems and leaves. Except for the S/P combination, the starch, fructose, sucrose and total soluble sugar concentrations were significantly increased in roots in P/P, S/S and P/S combinations. Additionally, under N-deficient condition, the NSCs contents were significantly higher in P/P and P/S combinations than in S/S and S/P combinations.

Carbon density distribution characteristics and influencing factors in aerially seeded Pinus massoniana plantations

PAN Ping, HAN Tian-yi, OUYANG Xun-zhi, LIU Yuan-qiu, ZANG Hao, NING Jin-kui, YANG Yang

2017, 28(12):  3841-3847.  doi:10.13287/j.1001-9332.201712.001

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The distribution characteristics of carbon density under aerially seeded Pinus massoniana plantations in Ganzhou City of Jiangxi Province were studied. Total 15 factors, including site, stand, understory vegetation, litter and so on were selected to establish a relationship model between stand carbon density and influencing factors, and the main influencing factors were also screened. The results showed that the average carbon density was 98.29 t·hm^-2 at stand level with soil layer (49.58 t·hm^-2) > tree layer (45.25 t·hm^-2) > understory vegetation layer (2.23 t·hm^-2) > litter layer (1.23 t·hm^-2). Significantly positive correlations were found among the tree, litter and soil layers, but not among the other layers. The main factors were tree density, avera-ge diameter at breast height (DBH), soil thickness, slope position, stand age and canopy density to affect carbon density in aerially seeded P. massoniana plantations. The partial correlation coefficients of the six main factors ranged from 0.331 to 0.434 with significance by t test. The multiple correlation coefficient of quantitative model I reached 0.796 with significance by F test (F=9.28). For stand density, the best tree density and canopy density were 1500-2100 plants·hm^-2 and 0.4-0.7, respectively. The moderate density was helpful to improve ecosystem carbon sequestration. The carbon density increased with increasing stand age, DBH and soil thickness, and was higher in lower than middle and upper slope positions.

Impact of short-term grazing disturbance on nitrogen accumulation of biological soil crusts in the hilly Loess Plateau region, China

WANG Shan-shan, ZHAO Yun-ge, SHI Ya-fang, GAO Li-qian, YANG Qiao-yun

2017, 28(12):  3848-3854.  doi:10.13287/j.1001-9332.201712.021

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The variations of total nitrogen, available nitrogen and microbial biomass nitrogen caused by simulated grazing disturbance were investigated in the sixth and twelfth months by using field survey combined with laboratory analysis in order to reveal the sensitivity of nitrogen content in biocrustal soils to disturbance in the hilly Loess Plateau region. The results showed that nitrogen contents in biocrustal soil were sensitive to disturbance. Total nitrogen and available nitrogen in the biocrustal layers were decreased by 0.17-0.39 g·kg^-1 and 1.78-5.65 mg·kg^-1 during the first half-year compared to the undisturbed treatment, and they were found respectively decreased by 0.13-0.40 g·kg^-1 and 11.45-32.68 mg·kg^-1 one year later since disturbance. The content of microbial biomass nitrogen in the biocrustal layer was reduced by 69.99-330.97 mg·kg^-1, whereas the content was increased by 25.51-352.17 mg·kg^-1 in soil of 0-2 cm layer. The induction of nitrogen accumulation depended on the intensity of disturbance. Slight variation was observed in the nitrogen accumulation in biocrustal layer under 20% and 30% disturbance, while significant reduction was found in the 40% and 50% disturbance. Significant reduction was detected only in nitrogen accumulation in the biocrustal layers, whereas no significant influence was found in the top 5 cm soil layer.

Soil propagule bank of ectomycorrhizal fungi in natural forest of Pinus bungeana

ZHAO Nan-xing, HAN Qi-sheng, HUANG Jian

2017, 28(12):  3855-3861.  doi:10.13287/j.1001-9332.201712.006

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To conserve and restore the forest of Pinu bungeana, we investigated the soil propagule bank of ectomycorrhizal (ECM) fungi in a severely disturbed natural forest of P. bungeana in Shaanxi Province, China. We used a seedling-bioassay method to bait the ECM fungal propagules in the soils collected from the forest site. ECM was identified by combining morph typing with ITS-PCR-sequencing. We obtained 73 unique sequences from the ECM associated with P. bungeana seedlings, and assigned them into 12 ECM fungal OTUs at the threshold of 97% based on the sequence similarity. Rarefaction curve displayed almost all ECM fungi in the propagule bank were detected. The most frequent OTU (80%) showed poor similarity (75%) with existing sequences in the online database, which suggested it might be a new species. Cenococcum geophilum, Tomentella sp., Tuber sp. were common species in the propagule bank. Although C. geophilum and Tomentella sp. were frequently detected in other soil propagule banks of pine forest, the most frequent OTU was not assigned to known genus or family, which indicated the host-specif of ECM propagule banks associa-ted with P. bungeana. This result confirmed the importance of the special ECM propagule banks associated with P. bungeana for natural forest restoration.

Effects of increased O₃ concentration on growth, subcellular structure and reactive oxygen metabolism of turf-type Festuca arundinace

PING Qin, XU Sheng, CHEN Wei, HE Xing-yuan, HUANG Yan-qing, WU Xian

2017, 28(12):  3862-3870.  doi:10.13287/j.1001-9332.201712.009

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Taking ambient environmental O₃(40 nmol·mol^-1) as control, the study was conducted to assess the impact of elevated O₃(80 and 160 nmol·mol^-1) on the growth, subcellular structure and reactive oxygen metabolism of turf-type Festuca arundinace in open top-chambers (OTCs). The results showed that under 14-day fumigation, the height and leaf width of F. arundinace decreased significantly, and the total biomass decreased by 43.7%, and some fully expanded leaves yellowed under 80 nmol·mol^-1 O₃. Some visible injury symptoms, brown spots and necrosis appeared in the leaves, the total biomass decreased by 46.2%, and plasma membrane became loose from the cell wall and convoluted, chloroplast and mitochondria were damaged under 160 nmol·mol^-1 O₃. The rate of superoxide anion (O₂^-·) production, hydrogen peroxide (H₂O₂) content, malonaldehyde (MDA) content and the activities of antioxidant enzymes were higher under the increasing O₃ concentrations (80 and 160 nmol·mol^-1) compared with control. Total phenolics and the antioxidant capacity increased at first and then decreased with the rise of O₃ concentration. It indicated that O₃ has already affected F. arundinace growth and antioxidative metabolism before visible injury symptom appeared. F. arundinace had an adaptive response to elevated O₃, but it could not protect itself from excessive O₃ or long-term O₃ exposure.

Characteristics of soil microorganisms and soil nutrients in different sand-fixation shrub plantations in Kubuqi Desert, China

ZHANG Li-xin, DUAN Yu-xi, WANG Bo, WANG Wei-feng, LI Xiao-jing, LIU Jin-jie

2017, 28(12):  3871-3880.  doi:10.13287/j.1001-9332.201712.003

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Three types of sand-fixation shrub plantations, including Artemisia ordosica + Hedysarum fruticosum, Caragana korshinskii and Salix psammophila, were selected in the eastern area of Kubuqi Desert to study the changes in soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), quantities of soil microorganisms, contents of soil nutrients and the relations among these variables under the different plantation types and shifting sandy land. The restoration effects of each plantation type on soil quality were assessed by synthetic index method. The results showed that the contents of soil organic matter, total nitrogen and phosphorus, and available nitrogen and phosphorus under different plantations were all significantly greater than those under shifting sandy land, and the order of increase was A. ordosica + H. fruticosum ＞ C. korshinskii ＞ S. psammophila. The soil nutrient contents decreased with the increase of soil depth under all plantation types. The quantities of soil microorganisms and the contents of soil MBC and MBN under the plantations were higher at different degrees than those under shifting sandy land. MBC, MBN and the relative numbers of bacteria under A. ordosica+H. fruticosum plantation were higher than those under C. korshinskii plantation and S. psammophila plantation. The relative numbers of fungi and actinobacteria decreased in the order of C. korshinskii ＞ S. psammophila ＞ A. ordosica + H. fruticosum. The relative number of bacteria, MBC and MBN under the plantations were mainly affected by the contents of soil organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus, as well as C/N, and the relative numbers of actinobacteria and fungi were primarily affected by the contents of soil total phosphorus, available nitrogen and available phosphorus. Soil quality was ranked in the order of A. ordosica + H. fruticosum ＞ C. korshinskii ＞ S. psammophila ＞ shifting sandy land. These results demonstrated that different sand-fixation shrub plantations could improve the quality of the desert soil and the A. ordosica + H. fruticosum plantation was the best for soil restoration and quality improvement in the desert.

Characteristics of soil microbes and enzyme activities in different degraded alpine meadows

YIN Ya-li, WANG Yu-qin, BAO Gen-sheng, WANG Hong-sheng, LI Shi-xiong, SONG Mei-ling, SHAO Bao-lian, WEN Yu-cun

2017, 28(12):  3881-3890.  doi:10.13287/j.1001-9332.201712.040

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Soil microbial biomass C and N, microbial diversities and enzyme activity in 0-10 cm and 10-20 cm soil layers of different degraded grasslands (non-degradation, ND; light degradation, LD; moderate degradation, MD; sever degradation, SD; and black soil beach, ED) were measured by Biolog and other methods. The results showed that: 1) There were significant diffe-rences between 0-10 cm and 10-20 cm soil layers in soil microbial biomass, diversities and inver-tase activities in all grasslands. 2) The ratio of soil microbial biomass C to N decreased significantly with the grassland degradation. In the 0-10 cm soil layer, microbial biomass C and N in ND and LD were significantly higher than that in MD, SD and ED. Among the latter three kinds of grasslands, there was no difference for microbial biomass C, but microbial biomass N was lower in MD than in the other grasslands. The average color change rate (AWCD) and McIntosh Index (U) also decreased with grassland degradation, but only the reduction from ND to MD was significant. There were no differences among all grasslands for Shannon index (H) and Simpson Index (D). The urease activity was highest in MD and SD, and the activity of phosphatase and invertase was lowest in ED. In the 10-20 cm soil layer, microbial biomass C in ND and LD were significantly higher than that in the other grasslands. Microbial biomass N in LD and ED were significantly higher than that in the other grasslands. Carbon metabolism index in MD was significantly lower than that in LD and SD. AWCD and U index in ND and LD were significantly higher than that in ED. H index and D index showed no difference among different grasslands. The urease activity in ND and MD was significantly higher than that in the other grasslands. The phosphatase activity was highest in MD, and the invertase activity was lowest in MD. 3) The belowground biomass was significantly positively correlated with microbial biomass, carbon metabolic index and phosphatase activity, and the urease activity was negatively correlated with microbial biomass N, H index and D index.

Relation between species distribution of plant community and soil factors under grazing in alpine meadow

NIU Yu-jie, YANG Si-wei, WANG Gui-zhen, LIU Li, DU Guo-zhen, HUA Li-min

2017, 28(12):  3891-3898.  doi:10.13287/j.1001-9332.201712.005

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The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

Prediction and spatial distribution of recruitment trees of natural secondary forest based on geographically weighted Poisson model

ZHANG Ling-yu, LIU Zhao-gang

2017, 28(12):  3899-3907.  doi:10.13287/j.1001-9332.201712.008

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Based on the data collected from 108 permanent plots of the forest resources survey in Maoershan Experimental Forest Farm during 2004-2016, this study investigated the spatial distribution of recruitment trees in natural secondary forest by global Poisson regression and geographically weighted Poisson regression (GWPR) with four bandwidths of 2.5, 5, 10 and 15 km. The simulation effects of the 5 regressions and the factors influencing the recruitment trees in stands were analyzed, a description was given to the spatial autocorrelation of the regression residuals on global and local levels using Moran’s I. The results showed that the spatial distribution of the number of natural secondary forest recruitment was significantly influenced by stands and topographic factors, especially average DBH. The GWPR model with small scale (2.5 km) had high accuracy of model fitting, a large range of model parameter estimates was generated, and the localized spatial distribution effect of the model parameters was obtained. The GWPR model at small scale (2.5 and 5 km) had produced a small range of model residuals, and the stability of the model was improved. The global spatial auto-correlation of the GWPR model residual at the small scale (2.5 km) was the lowe-st, and the local spatial auto-correlation was significantly reduced, in which an ideal spatial distribution pattern of small clusters with different observations was formed. The local model at small scale (2.5 km) was much better than the global model in the simulation effect on the spatial distribution of recruitment tree number.

Seed morphology and effects of sheep rumen digestion on seed germination of 28 Gramineae plants.

WANG Shu-lin, PENG Feng, LU Wei-hua, CHEN Yi-shi, JING Peng-cheng

2017, 28(12):  3908-3916.  doi:10.13287/j.1001-9332.201712.007

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An experiment was undertaken to compare the morphological characteristics of seeds of 28 Gramineae plants which widely distributed in north Xinjiang and to study their digestion in the rumen of sheep. After determining their morphological characteristics including seed length, width, height, seed shape index, 100-seed mass, and seed germination percentage, seeds were put into nylon bags and then placed in the rumen of sheep through a fistula. The bags were removed at different times to determine the morphological characteristics and seed germination rates. The results showed that 23 plant seeds were all elliptic or flat types except for Melica scabrosa, Agrostis ma-tsumurae, Poa bulbosa, Phleum pratense and Triticum aestivum. 100-seed mass of T. aestivum (3.25 g) and Avena sativa (1.69 g) were >1 g, and the 100-seed mass of the other seeds ranged from 0.01-1 g, indicating they were all medium or small type seeds. The color of seed coat was deepened, seed structure was destructed, and the lengths of seed appendages, i.e., awn, lemma and glume were decreased with increasing digestion time. Seed length, width, height, 100-seed mass were decreased with increasing digestion time, but the changes were not significant compared with the non-digested seeds. The seed germination percentages were extremely decreased after sheep rumen digestion. After 6 h of sheep rumen digestion, the germination rates of the seeds of R. kamoji and A. sativa were decreased to 0, and part of the seeds of other 26 plants still had some vigor.

Effects of tillage practices on root spatial distribution and yield of spring wheat and pea in the dry land farming areas of central Gansu, China

ZHANG Ming-jun, LI Ling-ling, XIE Jun-hong, PENG Zheng-kai, REN Jin-hu

2017, 28(12):  3917-3925.  doi:10.13287/j.1001-9332.201712.028

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A field experiment was conducted to explore the mechanism of cultivation measures in affecting crop yield by investigating root distribution in spring wheat-pea rotation based on a long-term conservation tillage practices in a farming region of Gansu. The results showed that with the develo-pment of growth period, the total root length, root surface area of spring wheat and pea showed a consistent trend of increase after initial decrease and reached the maximum at flowering stage. Higher root distribution was found in the 0-10 cm soil layer at seedling and 10-30 cm soil layer at flowering and maturity stages in spring wheat, while in the field pea, higher root distribution was found in the 0-10 cm soil layer at seedling and maturity, and in the 10-30 cm soil layer at flowering stages. No tillage with straw mulching and plastic mulching increased the root length and root surface area. Compared with conventional tillage in spring wheat and field pea, root length increased by 35.9% to 92.6%, and root surface area increased by 43.2% to 162.4%, respectively. No tillage with straw mulching and plastic mulching optimized spring wheat and pea root system distribution, compared with conventional tillage, increased spring wheat and field pea root length and root surface area ratio at 0-10 cm depths at the seedling stage, the root distribution at deeper depths increased significantly at flowering and maturity stages, and no tillage with straw mulching increased root length and root surface area ratio by 3.3% and 9.7% respectively, in 30-80 cm soil layer at the flowering stage. The total root length, root surface area and yield had significantly positive correlation for spring wheat in each growth period, and the total root length and pea yield also had significant positive correlation. No tillage with straw mulching and plastic mulching boosted yield of spring wheat and pea by 23.4%-38.7% compared with the conventional tillage, and the water use efficiency was increased by 13.7%-28.5%. It was concluded that no-till farming and straw mulching (plastic) could increase crop root length and root surface area, optimize the spatial distribution of roots in the soil, enhance crop root layer absorption ability, so as to improve crop yield and water utilization.

Stability of a winter wheat population with high yield and high resource use efficiency

MA Xin, DAI Xing-long, WANG Xiao-jing, DONG Shu-xin, WANG Yue-chao, XU Hai-cheng, ZHU Yuan-gang, HE Ming-rong

2017, 28(12):  3926-3934.  doi:10.13287/j.1001-9332.201712.025

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Using the winter wheat cultivar Tainong 18 as the experimental material, we analyzed yield stability from 2012 to 2016 under three different treatments: T₁(following typical local field management practices), T₂(high-yield: high nitrogen and water were supplied to foster high grain yield), and T₃(high-yield, high-efficiency: optimized field management including increasing plant density, reducing nitrogen input and delaying of the sowing date). Yield related phenotypic traits, including the number of ears on the main stem and tillers, leaf area index (LAI), photosynthetically active radiation (PAR) interception, dry matter accumulation and distribution, as well as grain yield, were analyzed over four seasons to determine their relationships with annual radiation, accumulated temperature and precipitation. We then determined grain yield stability for each of the three treatments. The amount and distribution of radiation, accumulated temperature, and precipitation varied greatly within each season. The ears on the main stem represented 38.9%, 58.7%, and 66.9% of the total ears, respectively, for wheat grown in the T₁, T₂ and T₃ treatments, indicating that T₁ ears originated mainly from the tillers, T₂ ears from both the main stem and the tillers, and T₃ ears from the main stem. The T₂ and T₁ treatments produced the highest and lowest amount of dry matter and grain yield, respectively. Although having relatively lower dry matter accumulation at maturity compared with T₂, T₃ led to higher grain yield due to high LAI, high PAR interception and utilization, high net canopy photosynthetic rate from booting (especially from 14 days after anthesis) to maturity and a higher harvest index. Among the three treatments, T₃ resulted in the lowest annual range, standard deviation, and coefficient of variation for LAI, PAR interception, and dry matter accumulation. Thus, grain yield was most stable in wheat grown in the T₃ treatment mainly due to stability in biological production during all four seasons.

Effects of different irrigation treatments during heading and flowering stage on cold resis-tance, yield and physiological characteristics of late rice

CAO Na, CHEN Xiao-rong, HE Hao-hua, ZHU Chang-lan,CAI Shuo, XU Tao, XIE Heng-wang, LIU Fang-ping

2017, 28(12):  3935-3944.  doi:10.13287/j.1001-9332.201712.030

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Taking super hybrid rice variety ‘Wufengyou T025’ as test material, the effects of different irrigation methods and water layer depth on physiological characteristics and yield in double-season late rice under low temperature conditions during heading and flowering stage were investigated. Three treatments were set, i.e., draining during day and containing 4-5 cm water layer during night (H₁), draining during day and containing 8-10 cm water layer during night (H₂), and containing 8-10 cm water layer day and night (H₃), with the 0-1 cm water layer day and night was as the control (CK). The results showed that rice leaf temperature, soil layer temperature and canopy temperature under the different irrigation treatments were higher than that of CK, and the warming effect of treatment H₂ was the best during the low temperature period. Leaf chlorophyll content, net photosynthetic rate, transpiration rate, leaf stomatal conductance and intercellular CO₂ concentration of rice plants decreased gradually under the low temperature, while the smallest reduction occurred in H₂. The increase ranges of malondialdehyde and proline content in H₂ were lower, while its soluble protein content was the highest compared with other irrigation treatments. The increase ranges for the activities of superoxide dismutase and peroxidase in H₂ were lower, while its decrease range for the activity of catalase was the lowest. Irrigation for heat preservation could increase the yield, and H₂ performed best. Yield of H₂ at the second sowing date in 2014 and 2015 encountering low temperature increased by 12.9% and 13.5% respectively compared to CK. The yield components including the effective panicle numbers per plant, panicle length, seed setting rate and 1000-grain mass were improved in all irrigation treatments compared to CK. Draining during day and containing 8-10 cm water layer during night (H₂) was the most effective agronomic measure to enhance the tolerance to low temperature during heading and flowering stage for double-season hybrid late rice.

Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton

SI Zhuan-yun, GAO Yang, SHEN Xiao-jun, LIU Hao, GONG Xue-wen, DUAN Ai-wang

2017, 28(12):  3945-3954.  doi:10.13287/j.1001-9332.201712.022

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A field experiment was carried out to study the effects of nitrogen and irrigation water application on growth, yield, and water and nitrogen use efficiency of summer cotton, and to develop the optimal water and nitrogen management model for suitable yield and less nitrogen loss in summer cotton field in the Huang-Huai region. Two experimental factors were arranged in a split plot design. The main plots were used for arranging nitrogen factor which consisted of five nitrogen fertilizer le-vels(0, 60, 120, 180, 240 kg·hm^-2, referred as N₀, N₁, N₂, N₃, N₄), and the subplots for irrigation factor which consisted of three irrigation quota levels (30, 22.5, 15 mm, referred as I₁, I₂, I₃). There were 15 treatments with three replications. Water was applied with drip irrigation system. Experimental results showed that both irrigation and nitrogen fertilization promoted cotton growth and yield obviously, but nitrogen fertilizer showed more important effects than irrigation and was the main factor of regulating growth and yield of summer cotton in the experimental region. With the increase of nitrogen fertilization rate and irrigation amount, the dry mater accumulation of reproductive organs, the above-ground biomass at the flowering-bolling stage and seed cotton yield increased gradually, reached peak values at nitrogen fertilization rate of 180 kg·hm^-2 and decreased slowly with the nitrogen fertilization rate further increased. The maximum yield of 4016 kg·hm^-2 was observed in the treatment of N₃I₁. Increasing nitrogen fertilizer amount would improve significantly total N absorption of shoots and N content of stem and leaf, but decrease nitrogen partial factor productivity. The maximum irrigation-water use efficiency of 5.40 kg·m^-3 and field water use efficiency of 1.24 kg·m^-3 were found in the treatments of N₃I₃ and N₃I₁, respectively. With increasing nitrogen fertilization amount, soil NO₃^--N content increased and the main soil NO₃^--N accumulation layer moved downward. By comprehensively considering above-ground biomass, seed cotton yield, water and nitrogen uptake and utilization, and soil NO₃^--N accumulation in the soil profile, the treatment N₃I₁ could be recommended as the optimal water and nitrogen application pattern for summer cotton production in the experimental region.

Effects of different mulching and drip irrigation patterns on photosynthetic characteristics of maize leaves in the Hetao Irrigation District, Inner Mongolia, China

HU Min-jie, JIANG Liang-chao, LI Shou-zhong, ZHOU Li-feng, TONG Chuan

2017, 28(12):  3955-3964.  doi:10.13287/j.1001-9332.201712.024

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Photosynthesis controls crop growth and yield, and differences in planting methods and soil moisture can significantly affect the photosynthetic characteristics of crops. Grain filling stage and milking stage are two important stages of maize from flowering to maturity, which are essential for maize grain formation and dry matter accumulation. The effects of different mulching and drip irrigation patterns on the photosynthetic characteristics and maize yield at grain filling and milking stages were investigated in a field experiment in the Hetao Irrigation District, Inner Mongolia. Maize leaf photosynthesis during the grain filling stage was not significantly different under the different treatments. During the milking stage, photosynthetic and transpiration rates under both partial (B₂) and full (Q₂) film mulching with drip irrigation level 2 (350 mm) were significantly higher than those in both the partial (B₁) and full (Q₁) film mulching with drip irrigation level 1 (200 mm). Photosynthetic and transpiration rates, water use efficiency and stomatal conductance under the B₁ and Q₁ treatments were significantly higher in the grain filling stage than in the milking stage. Diurnal variations in photosynthetic and transpiration rates, stomatal conductance and water use efficiency of maize leaves during the grain filling and milking stages were synchronous and showed an upside-down “U” pattern, but the intercellular CO₂ concentration showed the opposite pattern. Stepwise regression analysis showed that photosynthetically active radiation, air temperature and relative humidity were the main environmental factors influencing photosynthetic characteristics of maize leaves under the different mulching and drip irrigation treatments. In addition, maize yield was significantly higher under the B₂ and the Q₂ treatments than under the B₁ and Q₁(increase of 29.3% and 50.9%, respectively), but no significant differences were found between the B₁ and Q₁ treatments, indicating that drip irrigation level affects the yield of maize and its photosynthetic capacity more than mulching mode in arid regions.

Characteristics of ground-dwelling soil macro-arthropod communities in a biodiversity monitoring plot of black soil cropland, northeastern China

LIU Jie, GAO Mie-xiang, WU Dong-hui

2017, 28(12):  3965-3975.  doi:10.13287/j.1001-9332.201712.037

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Agro-ecosystem is an important component of terrestrial ecosystems and it is one of the key areas of global ecological and environmental studies. A 16 hm² permanent plot in black soil cropland was built to study the community structure of soil biodiversity in typical black soil region in Northeast China. Pitfall trap was used to investigate the ground-dwelling soil macro-arthropods from August to October 2015 in accordance with the three crop growth stages: whirling stage, silking stage, and milk stage. A total of 5284 ground-dwelling soil macro-arthropods belonging to 47 species were captured sorted into 3 classes, 12 orders, 32 families. 3 dominant groups and 11 common groups were found. Phytophages and Omnivores were dominant groups. The individuals and species numbers of ground-dwelling soil macro-arthropods had significant changes with the vegetative growth period. The maximum values of the Shannon index, Margalef index, Pielou index of soil macro-arthropods all appeared in September, but the maximum dominant index appeared in August. From the variation coefficient (CV) and spatial interpolation of different species, it could be seen that there was heterogeneity in the horizontal direction of the ground-dwelling soil macro-arthropod communities. Regarding the relationships between the ground-dwelling soil macro-arthropod communities and soil environmental factors including soil pH, soil organic matter, total nitrogen and soil water content, the bivariate correlation analysis showed there was no significant correlation between them. Results of canonical correspondence analysis (CCA) further indicated that the dominant and common groups were adaptable to environmental factors and widely distributed in the study area. The results showed that the species richness of ground-dwelling soil macro-arthropods was very high in cropland, and the dynamic of soil arthropod’s composition and spatial distribution pattern in diffe-rent crop growth stages were significantly changed. It was indicated that biodiversity plot monitoring of black soil cropland had become important means to solve the formation and maintenance mechanism of soil fauna community through large-scale and long-term investigation.

Tasseled cap triangle (TCT)-leaf area index (LAI)model of rice fields based on PROSAIL model and its application

LI Ya-ni, LU Lei, LIU Yong

2017, 28(12):  3976-3984.  doi:10.13287/j.1001-9332.201712.016

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The tasseled cap triangle (TCT)-leaf area index (LAI) isoline is a model that reflects the distribution of LAI isoline in the spectral space constituted by reflectance of red and near-infrared (NIR) bands, and the LAI retrieval model developed on the basis of this is more accurate than the commonly used statistical relationship models. This study used ground-based measurements of the rice field, validated the applicability of PROSAIL model in simulating canopy reflectance of rice field, and calibrated the input parameters of the model. The ranges of values of PROSAIL input parameters for simulating rice canopy reflectance were determined. Based on this, the TCT-LAI isoline model of rice field was established, and a look-up table (LUT) required in remote sensing retrieval of LAI was developed. Then, the LUT was used for Landsat 8 and WorldView 3 data to retrieve LAI of rice field, respectively. The results showed that the LAI retrieved using the LUT developed from TCT-LAI isoline model had a good linear relationship with the measured LAI R²=0.76, RMSE=0.47. Compared with the LAI retrieved from Landsat 8, LAI values retrieved from WorldView 3 va-ried with wider range, and data distribution was more scattered. Resampling the Landsat 8 and WorldView 3 reflectance data to 1 km to retrieve LAI, the result of MODIS LAI product was significantly underestimated compared to that of retrieved LAI.

Effects of N application on wheat powdery mildew occurrence, nitrogen accumulation and allocation in intercropping system

ZHU Jin-hui, DONG Yan, XIAO Jing-xiu, ZHENG Yi, TANG Li

2017, 28(12):  3985-3993.  doi:10.13287/j.1001-9332.201712.029

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The main objective of this field experiment was to study the effects of wheat and faba bean intercropping on occurrence of wheat powdery mildew, nitrogen content, accumulation and allocation of wheat plant at 4 nitrogen levels of N₀(0 kg·hm^-2), N₁(112.5 kg·hm^-2), N₂(225 kg·hm^-2), N₃(337.5 kg·hm^-2), and to explore the relationship between N content, accumulation, allocation and the occurrence of wheat powdery mildew. The results showed that both monocropped and intercropped wheat yields increased with nitrogen application, with the highest yields of monocropped and intercropped wheat being 4146 kg·hm^-2 and 4679 kg·hm^-2 at N₂ le-vel, respectively. The occurrence and development of wheat powdery mildew become more severe with the increase of N application and area under disease progression curve (AUDPC) were averagely increased by 39.6%-55.6%(calculated with disease incidence, DI) and 92.5%-217.0% (calculated with disease severity index, DSI) with N₁, N₂ and N₃ treatments. The disease severity index was more affected by nitrogen regulation than by disease incidence. The nitrogen content and accumulation of wheat plant were significantly increased by 8.4%-51.6% and 19.7%-133.7% with nitrogen application, but there was no significant effect on N allocation ratio. Compared with monocropped wheat, yield of intercropped wheat was averagely increased by 12%, whereas, the AUDPC(DI) and AUDPC(DSI) of intercropped wheat were averagely decreased by 11.5% and 30.7%, respectively. The control effect of the disease severity index by intercropping was better than disease incidence. The nitrogen content, accumulation and nitrogen allocation ratio in intercropped wheat leaves were significantly decreased by 6.6%-12.5%, 1.4%-6.9% and 9.0%-15.5% respectively at the peak infection stage of powdery mildew. Overall findings showed that the maximum rate of nitrogen application for wheat should not exceed 225 kg·hm^-2 when taking into account both disease control and yield effect.

Prediction model of meteorological grade of wheat stripe rust in winter-reproductive area, Sichuan Basin, China

GUO Xiang, WANG Ming-tian, ZHANG Guo-zhi

2017, 28(12):  3994-4000.  doi:10.13287/j.1001-9332.201712.018

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The winter reproductive areas of Puccinia striiformis var. striiformis in Sichuan Basin are often the places mostly affected by wheat stripe rust. With data on the meteorological condition and stripe rust situation at typical stations in the winter reproductive area in Sichuan Basin from 1999 to 2016, this paper classified the meteorological conditions inducing wheat stripe rust into 5 grades, based on the incidence area ratio of the disease. The meteorological factors which were biologically related to wheat stripe rust were determined through multiple analytical methods, and a meteorological grade model for forecasting wheat stripe rust was created. The result showed that wheat stripe rust in Sichuan Basin was significantly correlated with many meteorological factors, such as the ave-rage (maximum and minimum) temperature, precipitation and its anomaly percentage, relative humidity and its anomaly percentage, average wind speed and sunshine duration. Among these, the average temperature and the anomaly percentage of relative humidity were the determining factors. According to a historical retrospective test, the accuracy of the forecast based on the model was 64% for samples in the county-level test, and 89% for samples in the municipal-level test. In a meteorological grade forecast of wheat stripe rust in the winter reproductive areas in Sichuan Basin in 2017, the prediction was accurate for 62.8% of the samples, with 27.9% error by one grade and only 9.3% error by two or more grades. As a result, the model could deliver satisfactory forecast results, and predicate future wheat stripe rust from a meteorological point of view.

Evaluating the performance of species distribution models Biomod2 and MaxEnt using the giant panda distribution data

LUO Mei, WANG Hao, LYU Zhi

2017, 28(12):  4001-4006.  doi:10.13287/j.1001-9332.201712.011

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Species distribution models (SDMs) are widely used by researchers and conservationists. Results of prediction from different models vary significantly, which makes users feel difficult in selecting models. In this study, we evaluated the performance of two commonly used SDMs, the Biomod2 and Maximum Entropy (MaxEnt), with real presence/absence data of giant panda, and used three indicators, i.e., area under the ROC curve (AUC), true skill statistics (TSS), and Cohen’s Kappa, to evaluate the accuracy of the two model predictions. The results showed that both models could produce accurate predictions with adequate occurrence inputs and simulation repeats. Comparedto MaxEnt, Biomod2 made more accurate prediction, especially when occurrence inputs were few. However, Biomod2 was more difficult to be applied, required longer running time, and had less data processing capability. To choose the right models, users should refer to the error requirements of their objectives. MaxEnt should be considered if the error requirement was clear and both models could achieve, otherwise, we recommend the use of Biomod2 as much as possible.

Assessment of ecosystem in giant panda distribution area based on entropy method and coefficient of variation

YAN Zhi-gang, LI Jun-qing

2017, 28(12):  4007-4016.  doi:10.13287/j.1001-9332.201712.039

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The areas of the habitat and bamboo forest, and the size of the giant panda wild population have greatly increased, while habitat fragmentation and local population isolation have also intensified in recent years. Accurate evaluation of ecosystem status of the panda in the giant panda distribution area is important for giant panda conservation. The ecosystems of the distribution area and six mountain ranges were subdivided into habitat and population subsystems based on the hie-rarchical system theory. Using the panda distribution area as the study area and the three national surveys as the time node, the evolution laws of ecosystems were studied using the entropy method, coefficient of variation, and correlation analysis. We found that with continuous improvement, some differences existed in the evolution and present situation of the ecosystems of six mountain ranges could be divided into three groups. Ecosystems classified into the same group showed many commonalities, and difference between the groups was considerable. Problems of habitat fragmentation and local population isolation became more serious, resulting in ecosystem degradation. Individuali-zed ecological protection measures should be formulated and implemented in accordance with the conditions in each mountain system to achieve the best results.

Effect of soil phenolic acids on soil microbe of coal-mining depressed land after afforestation restoration by different tree species

JI Li, YANG Li-xue

2017, 28(12):  4017-4024.  doi:10.13287/j.1001-9332.201712.019

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Phenolic acids are one of the most important factors that influence microbial community structure. Investigating the dynamic changes of phenolic acids and their relationship with the microbial community structure in plantation soils with different tree species could contribute to better understanding and revealing the mechanisms of microbial community changes under afforestation restoration in coal-mining subsidence areas. In this study, plantations of three conifer and one deciduous species (Pinus koraiensis, Larix gmelinii, Pinus sylvestris var. mongolica, and Populus ussuriensis) were established on abandoned coal-mining subsidence areas in Baoshan District, Shuangyashan City. The contents of soil phenols, 11 types of phenolic acids, and microbial communities in all plots were determined. The results showed that the contents of soil complex phenol in plantations were significantly higher than that of abandoned land overall. Specifically, soils in larch and poplar plantations had higher contents of complex phenol, while soils in larch and Korean pine plantations had greater contents of total phenol. Moreover, soil in the P. koraiensis plantation had a higher content of water-soluble phenol compared with abandoned lands. The determination of 11 phenolic acids indicated that the contents of ferulic acid, abietic acid, β-sitosterol, oleanolic acid, shikimic acid, linoleic acid, and stearic acid were higher in plantation soils. Although soil phenol contents were not related with soil microbial biomass, the individual phenolic acids showed a significant relationship with soil microbes. Ferulic acid, abietic acid, and β-sitosterol showed significant promoting effects on soil microbial biomass, and they showed positive correlations with fungi and fungi/bacteria ratio. These three phenolic acids had higher contents in the poplar plantation, suggesting that poplar affo-restation had a beneficial effect on soil quality in coal-mining subsidence areas.

Effects of land use changes on soil water conservation in Hainan Island, China

WEN Zhi, ZHAO He, LIU Lei, OUYANG Zhi-yun, ZHENG Hua, MI Hong-xu, LI Yan-min

2017, 28(12):  4025-4033.  doi:10.13287/j.1001-9332.201712.017

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In tropical areas, a large number of natural forests have been transformed into other plantations, which affected the water conservation function of terrestrial ecosystems. In order to clari-fy the effects of land use changes on soil water conservation function, we selected four typical land use types in the central mountainous region of Hainan Island, i.e., natural forests with stand age greater than 100 years (VF), secondary forests with stand age of 10 years (SF), areca plantations with stand age of 12 years (AF) and rubber plantations with stand age of 35 years (RF). The effects of land use change on soil water holding capacity and water conservation (presented by soil water index, SWI) were assessed. The results showed that, compared with VF, the soil water holding capacity index of other land types decreased in the top soil layer (0-10 cm). AF had the lowest soil water holding capacity in all soil layers. Soil water content and maximum water holding capacity were significantly related to canopy density, soil organic matter and soil bulk density, which indicated that canopy density, soil organic matter and compactness were important factors influencing soil water holding capacity. Compared to VF, soil water conservation of SF, AF and RF were reduced by 27.7%, 54.3% and 11.5%, respectively. The change of soil water conservation was inconsistent in different soil layers. Vegetation canopy density, soil organic matter and soil bulk density explained 83.3% of the variance of soil water conservation. It was suggested that land use conversion had significantly altered soil water holding capacity and water conservation function. RF could keep the soil water better than AF in the research area. Increasing soil organic matter and reducing soil compaction would be helpful to improve soil water holding capacity and water conservation function in land management.

Coupling effects of periodic rewatering after drought stress and nitrogen fertilizer on growth and water and nitrogen productivity of Coffea arabica

HAO Kun, LIU Xiao-gang, ZHANG Yan, HAN Zhi-hui, YU Ning,YANG Qi-liang, LIU Yan-wei

2017, 28(12):  4034-4042.  doi:10.13287/j.1001-9332.201712.027

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The effects of periodic rewatering after drought stress and nitrogen fertilizer on growth, yield, photosynthetic characteristics of leaves and water and nitrogen productivity of Coffea arabica (Katim P7963) were studied under different nitrogen application levels in 2.5 consecutive years. Irrigation (periodic rewatering after drought stress) and nitrogen were designed as two factors, with four modes of irrigation, namely, full irrigation (I_F-F: 100%ET₀+100%ET₀, ET₀ was reference crop evapotranspiration), rewatering after light drought stress (I_L-F: 80%ET₀+100%ET₀), rewatering after moderate drought stress (I_M-F: 60%ET₀+100%ET₀) and rewatering after severe drought stress (I_S-F: 40%ET₀+100%ET₀), and three levels of nitrogen, namely, high nitrogen (N_H: 750 kg N·hm^-2 each time), middle nitrogen (N_M: 500 kg N·hm^-2 each time), low nitrogen (N_L: 250 kg N·hm^-2 each time), and nitrogen was equally applied for 4 times. The results showed that irrigation and nitrogen had significant effect on plant height, stem diameter, yield and water and nitrogen productivity of C. arabica, and plant height and stem diameter showed S-curve with the day ordinal number, and leaf photosynthesis decreased significantly under drought stress but most photosynthesis index recovered somewhat after rewatering. Compared with I_F-F, I_L-F increased dry bean yield by 6.9%, while I_M-F and I_S-F decreased dry bean yield by 15.2% and 38.5%, respectively; I_L-F and I_M-F increased water use efficiency by 18.8% and 6.0%, respectively, while I_S-F decreased water use efficiency by 12.1%; I_L-F increased nitrogen partial productivity by 6.1%, while I_M-F and I_S-F decreased nitrogen partial productivity by 14.0% and 36.0%, respectively. Compared with N_H, N_M increased dry bean yield and water use efficiency by 20.9% and 19.3%, while N_L decreased dry bean yield and water use efficiency by 42.4% and 41.9%, respectively; N_M and N_L increased nitrogen partial productivity by 81.4% and 72.9%, respectively. Compared with I_F-FN_H, I_L-FN_M increased dry bean yield, water use efficiency and nitrogen partial productivity by 37.6%, 52.9% and 106.4%, respectively. Regression analysis showed that the yield of dry bean was the maximum (2362 kg·hm^-2) when the irrigation amount was 318 mm and the nitrogen application amount was 583 kg·hm^-2; the water use efficiency was the maximum (0.78 kg·m^-3) when the irrigationamount was 295 mm and the nitrogen application amount was 584 kg·hm^-2, that’s to say when yield of dry bean and water use efficiency reach the maximum value at the same time, the combination was the closest to I_L-FN_M. Therefore, the best combination of water and nitrogen model for C. arabica was I_L-FN_M.

Spatial-temporal dynamics of rainstorm in East China based on spatial-temporal data mining technology

LOU Ning

2017, 28(12):  4043-4050.  doi:10.13287/j.1001-9332.201712.012

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Based on TRMM 3B42 precipitation data, 5 time series at annual scale were constructed. Then the spatial and temporal dynamics of rainstorm in East China region from 2003 to 2015 were evaluated in the support of data mining and GIS spatial analysis technology. The results showed that, the spatial distributions of annual precipitation and annual rainstorm precipitation were similar during 2003-2015. Annual precipitation exhibited a slight increase trend while annual rainstorm ratio showed significant fluctuation. The imbalanced distribution of rainstorm in latitudinal direction was more obvious than that of longitudinal direction. Annual rainstorm frequency changed smoothly with significant spatial difference. Rainstorm showed a tendency of moving to north in the past 13 years. The changing trends of the five variables showed significant spatial differences, and most pixels showed non-significant increasing (or decreasing) trends.

A process of aquatic ecological function regionalization: The dual tree framework and conceptual model

GUO Shu-hai, WU Bo

2017, 28(12):  4051-4056.  doi:10.13287/j.1001-9332.201712.015

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Aquatic ecological regionalization and aquatic ecological function regionalization are the basis of water environmental management of a river basin and rational utilization of an aquatic ecosystem, and have been studied in China for more than ten years. Regarding the common problems in this field, the relationship between aquatic ecological regionalization and aquatic ecological function regionalization was discussed in this study by systematic analysis of the aquatic ecological zoning and the types of aquatic ecological function. Based on the dual tree structure, we put forward the RFCH process and the diamond conceptual model. Taking Liaohe River basin as an example and referring to the results of existing regionalization studies, we classified the aquatic ecological function regions based on three-class aquatic ecological regionalization. This study provided a process framework for aquatic ecological function regionalization of a river basin.

Process of land use transition and its impact on regional ecological quality in the Middle Reaches of Heihe River, China

WANG Fu-hong, ZHAO Rui-feng, ZHANG Li-hua, LI Hong-wei

2017, 28(12):  4057-4066.  doi:10.13287/j.1001-9332.201712.020

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Land use transition is one of the main drivers of regional ecosystem change in arid area, which directly affects human well-being. Based on the satellite images of 1987, 2001 and 2016, the change detection assessment model and ecological response model were used to analyze the process of land use transition and response of ecological quality during 1987-2016 in the ecologically fragile middle reaches of the Heihe River. The results showed that the land use change was significant during 1987-2016 and the total change increased significantly, as well as the continuous increase of the cultivated land and construction land. There was a strong tendency of transform from grassland to cultivated land, while the tendency of transforming unused land to other land classes was not strong under a random process of gain or loss. During 1987-2016, the ecological quality of the study area displayed a decreasing trend as a whole and the ecological land decreased by 2.8%. The land use transition with the greatest impact on the ecological environment degradation was the transition of the grassland to the cultivated land and unused land. Therefore, in order to promote the sustainable use of regional land resources and to improve the regional ecological quality, it is necessary to allocate the proportion of production land and ecological land according to the regional water resources.

Dynamics of natural capital in Shenyang based on improved three-dimensional ecological footprint

LIU Hai-yan, CHENG Quan-guo, WEI Jian-bing, HUANG Xiao

2017, 28(12):  4067-4074.  doi:10.13287/j.1001-9332.201712.014

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Natural capital trends of Shenyang from 1995 to 2014 were analyzed using improved three-dimensional ecological footprint model. The results showed that, from 1995 to 2014, the ecological carrying capacity per capita of Shenyang fluctuated within a narrow range generally; the per capital ecological footprint, ecological deficit, footprint size and the footprint depth per capita increased along a wave-like curve. The changing rates of footprint size and depth tended to stabilize gradually. The way of natural capital utilization of cultivated land changed from capital flow in 2004 to capital stock, the capital stock replaced capital flow and became a source to meet the need of na-tural resources in the regional cultivated land, the use ratios of stock-flows increased gradually. The capital flow had been used by woodland and the occupancy rates of capital flows remained unchanged. The capital stock had been used by grassland and water, and the use ratios of stock-flows increased gradually. The development of Shenyang was in an unsustainable state. Coordinating the relationship between natural capital stock consumption and the utilization of stock-flows was one of the key ways to realize the sustainable development of Shenyang. Developing new resource, rationally planning the land and improving land utilization should be to reduce the consumption of natural capi-tal, at the same time, the protection of ecological environment should be to achieve sustainable development.

Effect of influent C/N on nitrogen removal performance in tidal flow constructed wetland via CANON process

HUANG Meng-lu, LI Zhan-peng, WANG Zhen

2017, 28(12):  4075-4082.  doi:10.13287/j.1001-9332.201712.038

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This study was conducted to explore nitrogen transformation and associated microbial characteristics in a tidal flow constructed wetland (TFCW) with the complete autotrophic nitrogen removal over nitrite (CANON) process under influent COD/TN (C/N) constraints. The influent C/N increased from 0.0 to 10.0 via the addition of glucose in the influent as a source of organics. The results showed that influent C/N significantly affected nitrogen transformation rates in the TFCW throughout the experiment. As the influent C/N increased from 0.0 to 6.0, the absolute abundance of functional genes involved in denitrification could be enriched as a consequence of the addition of organics in influent, and then the simultaneous nitrification, anammox, and denitrification (SNAD) processes occurred in the TFCW, resulting in the enhancement of nitrogen removal in the system. However, as the influent C/N was more than 6.0, the activity of aerobic ammonia-oxidizing bacteria was inhibited and its quantity reduced, leading to the deterioration in nitrogen removal of the system. When the influent C/N was 6.0, the SNAD process was enhanced most effectively in the system owing to the development of multiple and complete nitrogen removal pathways in the TFCW. The TFCW respectively had the best TN removal efficiency and removal loading rate [(93.3±2.3)% and (149.30±8.00) mg·L^-1·d^-1], indicating that the results had been than the maximal TN removal efficiency in a CANON process under ideal conditions.

Dynamics of habitat suitability for waterfowls from 1990 to 2015 in the ecological function zone of Sanjiang Plain, Northeast China

MAN Wei-dong, LIU Ming-yue, WANG Zong-ming, MAO De-hua, TIAN Yan-lin, JIA Ming-ming, LI Xiang, REN Chun-ying

2017, 28(12):  4083-4091.  doi:10.13287/j.1001-9332.201712.036

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As a wetland of international importance, the ecological function zone of the Sanjiang Plain (EFZSP) plays an important role in maintaining waterfowl habitat. With the increasing disturbance of human beings, land use and climate changes, habitat suitability for waterfowls (HSW) has drawn greater attention of ecologists. In this study, Landsat TM/ETM+/OLI and HJ-1B images in 1990, 2000, 2010 and 2015 were used to obtain land cover classification by object-based image analysis, and the entropy and analytic hierarchy process methods were adopted to determine the factors and their weights, the factors selected in this study included water condition (lake and river density), disturbance factor (residence and road density), shelter condition (land cover type and slope), and food abundance (NDVI). Finally, the evaluation results of habitat suitability of year 1990, 2000, 2010, and 2015 were achieved based on the habitat suitability index (HSI) system, and the spatio-temporal dynamics and driving forces causing the changes were analyzed. The results showed that the excellent level of HSW mainly distributed in abundant water areas, especially along the riparian zone of the Heilongjiang River, Naoli River, Ussuri River, Muling River and Xingkai Lake. Its area decreased by 3.2% from 1990 to 2015 because of wetland reclamation. The good level of HSW concentrated in Raohe County over the past 25 years, the condition of Hulin County and Fuyuan County were improved to a good level from 2010 to 2015 due to the substantial increase of paddy field areas. The fair level of HSW distributed dispersedly, and the areas first increased from 1990 to 2000 and then decreased during 2000-2010 and 2010-2015 periods. The areas of poor le-vel increased by 6.7% from 1990 to 2000 and decreased by 3.1% from 2000 to 2015. The change of HSW level in this study area was dominated by land cover change, and both of the increasing population and economy and the drying and worming climate resulted in the decline of the HSW level, whereas the establishment of nature reserves is crucial to protect habitat for waterfowls.

Identification of key factors of marine industrial ecologization

QIN Man, DU Yuan-wei

2017, 28(12):  4092-4100.  doi:10.13287/j.1001-9332.201712.034

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It is extremely important to identify key factors of marine industrial ecologization and discriminate the factors that influence degrees and causal relationships for the transformation of marine industrial ecologization nowadays. Based on the conceptual model of marine industrial ecologization, this research built an evaluation system for influencing factors in regional marine industrial ecologization, which included the marine industrial structure ecologization, marine industrial organization ecologization, marine production mode ecologization and marine technological innovations ecologization. The DEMATEL method was applied to analyze the relationships between various influencing factors and drew a network diagram. The results showed that the marine production mode ecologization and marine technological innovation ecologization were in the core position of the evaluation system. They not only revealed the causes of the whole ecological evaluation dimension, but affected the marine industrial organization ecologization and marine industrial structure ecologization. Finally, on the basis of specific indicators in each dimension, some countermeasures and suggestions were put forward to improve the transformation of marine industrial ecologization.

Effects of cascading hydropower dams operation on the structure and distribution pattern of benthic macroinvertebrate assemblages in Manwan Reservoir, Southwest China

LI Jin-peng, DONG Shi-kui, PENG Ming-chun, WU Xuan, ZHOU Fang, YU Yin

2017, 28(12):  4101-4108.  doi:10.13287/j.1001-9332.201712.033

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Benthic macroinvertebrate assemblages are one of the biological groups in aquatic ecosystem most sensitive to the habitat change and degradation, and can be a biological indicator for the aquatic ecosystem change and succession in cascading hydropower dam reservoir. The middle and lower reaches of the Lancang River are key spot for international biodiversity conservation and ecological studies on the effects of cascading hydropower dam exploitation. In this study, the reservoir of Manwan hydropower dam, the first dam in Lancang-Mekong river main stream, was selected as the study site. The benthic macroinvertebrate assemblages were sampled in 2011 and 2016 respectively. Meanwhile, the survey data before impounding (natural river, 1996) and early stage of single dam (1997) were collected to conduct the overall analysis for structure, distribution pattern and evolution of benthic macroinvertebrate assemblages. The results showed that the dominant biological group was gradually changed from the Oligochaeta and Insecta to the Mollusca. Along the longitudinal gradient, the density and biomass of the benthic macroinvertebrate assemblages were remarkably increased in reservoir, especially in the lacustrine zone. As for the functional feeding group, the predator and gatherer-collector changed into filter-collector predominantly in lacustrine zone. With the cascading dams operation, the biotic index indicated that the water quality of reservoir in 2016 was better than in 2011. The evolution of benthic macroinvertebrate assemblages in the Manwan Reservoir was related to the operation of Xiaowan dam in the upper reach, the hydrological regime and siltation in the reservoir, and would continue with dynamic changes with the operation of the cascading hydropower dam.

Reviews

Eco-economic thinking for developing carbon sink industry in the de-farming regions

WANG Ji-jun, WANG Zheng-shu, CHENG Si-min, GU Wen, LI Yue, LI Mao-sen

2017, 28(12):  4109-4116.  doi:10.13287/j.1001-9332.201712.013

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Based on the potential and the law that plants absorb carbon dioxide, carbon sink industry means certain appropriate artificial intervention to obtain clean air, and to meet people’s production and life demand for ecological environment industry. Carbon sink industry is considered as a breakthrough point and a new growth point for optimizing and upgrading of the original relatively balanced or stable agricultural industry-resources system. Among the ecosystem services in the de-farming regions, the rapid increase of the economic manifestation of carbon fixation and oxygen release function and the carbon sink potential, as well as the rise of carbon trading and carbon market both in domestic and international, have established a theoretical and practical basis for the deve-lopment of carbon industry. With the development of the carbon sink industry, improving the carbon sequestration output will become the core of the carbon sink industry. The producers or marketers will form the controlling of the carbon source, the development of the path for carbon storage increasing and re-layout of agricultural industry-resources structure, and thus bring new vitality to regional sustainable development in the de-farming regions. This indicates the emphasis for the future research and development, that is, allocating the agricultural industry-resources structure and their benign coupling mechanism after integrating the carbon sink industry.

Interactive effects of temperature, CO₂ concentration and precipitation on growth and yield of crops

MENG Fan-chao, GUO Jun, ZHOU Li, XIONG Ming-ming, ZHANG Lei

2017, 28(12):  4117-4126.  doi:10.13287/j.1001-9332.201712.023

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Temperature, CO₂ concentration and precipitation are the key climate factors affecting crop growth and yield. The effects of different climate factors on crops are not independent, and their interactive effects on crops have become a focus in this research field. The study of interactive effects of multiple climate factors on crops could more reliably reflect the actual situations of crop growth, which could help us to understand the crop growth and even the ecosystem response to climate change, and optimize agricultural production managements in the future. In recent years, there are a lot of reports about the effects of different climate factors on crops both in China and abroad, and thus it is quite difficult to conduct a comprehensive review for interactive effects of all climatic factors on crops. Therefore, this review only focused on the results of the interactive effects of warming, elevated CO₂ concentration and changing precipitation on crop growth, photosynthetic physio-logy, and yield in recent years, and identified the knowledge gaps of the relevant studies and the key issues that urgently need to be solved in future research. This would be useful for the researches elucidating the influence of climate change on crop growth and yield.

Progress in decoding the impact of abiotic stress on spikelet fertility in rice

ZHOU Xiao-dong, ZHOU Juan, ZHANG Xue-song, JIANG Xiao-dong, YANG Lian-xin, WANG Yu-long

2017, 28(12):  4127-4133.  doi:10.13287/j.1001-9332.201712.026

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Recent research progress in the impact of abiotic stress on florets sterility was summarized in this review to reveal key processes in determining the floret sterility resulted from abiotic stress and their coherent connections. The spikelet fertility was mainly determined by four key processes, including behavior of tapetum, anther dehiscence and pollen release, pollen germination and fertilization. Abiotic stress affected these processes and led to the spikelet sterility. Abnormal changes at the early-stage of anther growth could impact the development of germ cell and fertilization. Damages of floret fertility caused by abiotic stress could be mitigated via some practices such as spraying exogenous plant growth substances or silicon fertilizer. Some research topics were suggested for future investigation, including the interactions of multiple stress factors on fertility, morphological and physiological effects on floral organ formation, differential responses of rice varieties to abiotic stress, and molecular mechanism of abiotic stress on floral organ development.

Effect of agricultural application of municipal sewage sludge on plant-soil system: A review

LIU Meng-jiao, XIA Shao-pan, WANG Jun, MA QING-xu, WANG Zhong-qiang, WU Liang-huan

2017, 28(12):  4134-4142.  doi:10.13287/j.1001-9332.201712.023

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Currently, reasonable disposal of municipal sewage sludge is one of the important issues in the field of resources and environmental science. Sludge is rich in large amounts of organic matter and available nutrients, promoting soil fertility, soil physical structure and biological properties. However, sludge contains a variety of heavy metals, organic contaminants and other hazardous substance, especially heavy metals, which are the bottlenecks of agricultural application of sludge. To improve the sewage sludge utilization efficiency and decrease the effect on soil, this essay made a summary on domestic and foreign studies on plant-soil interaction ecosystem with sewage sludge to provide a theoretical basis and scientific guidance for advancing sewage sludge utilization efficiency.

Progress of heterotrophic studies on symbiotic corals

YANG Yang-chu-qiao, HONG Wen-ting, WANG Shu-hong

2017, 28(12):  4143-4149.  doi:10.13287/j.1001-9332.201712.032

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Heterotrophy of zooxanthellae symbiotic corals refers to the nutrition directly coming from food absorption, not the nutrition obtained from photosynthesis. Most ex situ propagation of symbiotic corals focused on the effects of irradiation, flow rate and water quality on corals, few of them involved in the demand and supply of coral heterotrophic nutrition. This paper reviewed the significance of heterotrophic nutrient supply to symbiotic corals from the sources of coral heterotrophic nutrition, the factors affecting the supply of coral heterotrophic nutrient, and the methods of how to study the coral heterotrophy. In general, the research of coral heterotrophy is just at the beginning stage, and future studies should focus on the inherent mechanism of coral feeding selection and developing more effective research methods.

Review on enterprises’ eco-innovation

LIAO Zhong-ju, HUANG Chao

2017, 28(12):  4150-4156.  doi:10.13287/j.1001-9332.201712.031

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Eco-innovation is an important way to realize sustainable development. It has the dual positive externality of “knowledge spillover” and “environmental spillover”, which has attracted much attention from theory and practice. In order to systematically grasp the current situation of eco-innovation, this study collected the relevant foreign literatures on eco-innovation in the past ten years, and made a systematic review of the definition, characteristics and dimensions of eco-innovation. Focusing on the theory of institutional theory, stakeholder theory and resource-based view, this paper explored the antecedents of eco-innovation. Then, this paper also demonstrated the positive and negative effects of eco-innovation on corporate financial performance, and the meditating and moderating mechanisms between eco-innovation and financial performance. Finally, based on the limitations of existing research, the future research direction was put forward.