2014 Vol. 22, No. 9

  Previous Issue | Next Issue 
Display Method:
Assessment on capacities of ecosystem monitoring, research and management in Africa
WU Bingfang, LIU Jian, ZHANG Linxiu, YU Xiubo, LI Fadong, LI Xiaosong
2014, 22(9): 995-1001. doi: 10.13930/j.cnki.cjea.140843
Abstract(1342) PDF(1967)
Abstract:
Based on the comprehensive comparisons of serial ecosystem research networks all over the world, this paper evaluated the capacity of ecosystem research and monitoring in Africa and gaps to the developed networks, proposed the frameworks and programs for building Africa ecosystem monitoring network. The paper also advanced to form the continental ecosystem assessment methods, finish the Africa Ecological Research Network (AERN) layout design, and build a typical station, as a demonstration and training base for Africa ecosystem monitoring network. These jobs provide a model for ecosystem management and enhance the Africa's ability to respond to climate change.
Advances in the effects of bisphenol A on plants
WANG Qingqing, NIE Lijun, WANG Shengman, WANG Lihong, ZHOU Qing
2014, 22(9): 1002-1009. doi: 10.13930/j.cnki.cjea.140388
Abstract(1438) PDF(3621)
Abstract:
As a representative endocrine-disrupting chemical, bisphenol A (BPA) is a raw material used in industrial production of resin, plastic and coatings. These BPA-containing products are used in feeding bottles, food and drink packaging, water-supply pipes and teeth enclosed agents. It has been estimated that BPA production will exceed 3.7 million tons per year and global demand for BPA will increase substantially. Because of its large-scale production and extensive application, a large amount of BPA is continuously released into the environment. Thus BPA has been found ubiquitously in the environment, causing potential harm to living organisms. In contrast to vast literature on the effects of BPA on animals, only limited reports have dealt with the effects of BPA on plants. This paper reviewed the detection methods of BPA in plants, the effects of BPA on plants (including seed germination and growth of aboveground and underground organs of higher plants, and on the growth of algae), the mechanisms of BPA action on plants (including changes in cytokinin, nitrogen nutrients, photosynthesis and antioxidant systems), and the phytoremediation of BPA pollution. Finally, the focus of future research in the field of BPA was proposed. This included the effects of BPA on plant metabolism, cellular morphology and ultrastructure, mineral elements and signal transduction. This review provided relevant references on understanding the effects of BPA on plants. It also provided valuable insights into the action mechanisms of BPA on plants.
Research progress on the effects of land consolidation on ecosystem services
LIU Shiliang, AN Nannan, WANG Jun
2014, 22(9): 1010-1019. doi: 10.13930/j.cnki.cjea.140375
Abstract(1409) PDF(1549)
Abstract:
Land consolidation has been a vital process of realizing the intensive use of land resources and improving land productivity and utilization rate. Regional economic output and level of protection have been improved through land consolidation. However, land consolidation has also influenced regional ecological environment. With growing attention to the ecological effects of land consolidation, evaluation of ecological benefits of land consolidation has gained significant momentum in recent years. In this paper, we analyzed the economic valuation models of the ecological benefits of regional land consolidation based on the theories of ecosystem services value. Then in view of different land consolidation projects, the features and ecological effects of the projects were discussed and the influences of land consolidation on different ecosystem services highlighted. Energy analysis of current research progress and ecosystem services were compared with material and value assessment methods for different land consolidation projects. Furthermore, different quantitative methods corresponding to the land consolidation projects were discussed and their strengths and weaknesses analyzed. Meanwhile, the paper showed the application of the assessment methods in land consolidation along with different cases of land consolidation projects. Based on the introduction of the importance of ecological assessment and the application of landscape ecological design in land consolidation, we put forward the problems of ecosystem services valuation in the present land consolidation systems and the future development trends.
Effects of nitrogen and sulfur interaction on their accumulation, translocation and use efficiency in winter wheat
ZHAO Yuxia, ZHOU Fang, LI Xuefang, LI Na, WANG Linquan
2014, 22(9): 1020-1028. doi: 10.13930/j.cnki.cjea.140274
Abstract(1323) PDF(1238)
Abstract:
A field experiment was conducted in Guanzhong Plain of China to identify the effects of the interactions of nitrogen and sulfur on the absorption, translocation and use efficiency of nitrogen and sulfur by winter wheat ('Xiaoyan 22'). A two-factor (nitrogen and sulfur) central composite rotatable design was used in the experiment with five levels of nitrogen (75 kg·hm-2, 108 kg·hm-2, 187.5 kg·hm-2, 267 kg·hm-2 and 300 kg·hm-2) and five levels of sulfur (75 kg·hm-2, 97.5 kg·hm-2, 150 kg·hm-2, 202.5 kg·hm-2 and 225 kg·hm-2). The results showed that dry matter, N and S contents reached peak values during jointing to anthesis stage, accounting for 43.33%-48.42% dry matter, 28.71%-44.77% N and 40.11%-50.43% S contents of the entire winter wheat growth season. Translocation rates of nitrogen (63.61%-70.64%) were much higher than those of sulfur (10.63%-30.98%). The application of nitrogen and sulfur fertilizers increased nitrogen and sulfur contents and translocation from vegetative organs to grains after anthesis. The application of nitrogen and sulfur fertilizers also increased the contribution of both nitrogen and sulfur translocation to grain yield. Under N level of 108 kg·hm-2 and S level of 97.5 kg·hm-2, nitrogen and sulfur contents increased significantly with increasing sulfur or nitrogen application levels. At N level of 187.5 kg·hm-2 and S level of 150 kg·hm-2, nitrogen and sulfur contents increased initially before stabilizing with increasing sulfur or nitrogen input. Sulfur content was positively correlated with nitrogen appliction. The combined fertilizaton of nitrogen (170.64-204.52 kg·hm-2) and sulfur (97.35-139.32 kg·hm-2) had higher fertilizer use efficiency and apparent recovery. In conclusion, N & S uptake, translocation and use efficiency were increasable through optimizing the application rates of nitrogen and sulfur.
Effects of fertilizer application regimes on soil N2O emissions in the croplands of purple soil in the Sichuan Basin during wheat season
LIU Wenli, LI Xipeng, SHEN Xi, ZHU Bo
2014, 22(9): 1029-1037. doi: 10.13930/j.cnki.cjea.140067
Abstract(2210) PDF(1649)
Abstract:
Nitrous oxide (N2O) was undoubtedly a key element with respect to global warming and climate change. As about 60% of global anthropogenic N2O emissions have originated from agricultural soils, it has been a huge challenge to maintain high crop yields while reducing N2O emissions under the continued application of nitrogen fertilizers. Limited available field data have explored the effects of fertilizer application regimes on soil N2O emissions in the Sichuan Basin, one of the most intensive agricultural regions in China. Thus the objective of this research was to compare the effects of different N fertilizer application regimes on soil N2O emissions so as to find the best N fertilizer management practice which not only decreased N2O emission, but also maintained high crop yields. Static chamber-gas chromatographic techniques were used to measure soil N2O emissions from purple soil croplands with long-term N fertilization in treatments of pure synthetic N fertilizer (N), pig manure (OM), synthetic NPK fertilizer (NPK), pig manure combined with synthetic NPK fertilizer (OMNPK) and returned crop residues combined with synthetic NPK fertilizer (CRNPK). No fertilizer was applied under the control experiment (NF). The in situ field measurements were conducted during wheat season from November 2012 to May 2013. The results showed that cumulative N2O fluxes in different fertilization regimes were significantly different (P < 0.05) even when the same rates of total N were applied [130 kg(N)·hm-2]. Cumulative N2O fluxes in treatments of N, OM, NPK, OMNPK and CRNPK were 0.38 kg(N)·hm-2, 0.36 kg(N)·hm-2, 0.29 kg(N)·hm-2, 0.33 kg(N)·hm-2 and 0.19 kg(N)·hm-2, respectively. N2O emission factors in the respective treatments were 0.25%, 0.23%, 0.18%, 0.21% and 0.10%. Cumulative N2O flux in treatment of NF was 0.06 kg(N)·hm?2. Nitrogen fertilizer application significantly enhanced N2O emission. Inorganic N (ammonium and nitrate) content was the main controlling factor of soil N2O emission. Also rainfall significantly enhanced soil N2O emission. Wheat grain yields in treatments of N, OM, NPK, OMNPK and CRNPK were 1.34 t·hm-2, 3.71 t·hm-2, 2.80 t·hm-2, 3.13 t·hm-2 and 3.40 t·hm-2, respectively. Wheat grain yield in CRNPK treatment was not significantly different from that of OM treatment, which had the maximal yield that was much higher than yields of all the other treatments (P < 0.05). Furthermore, we assessed the global warm potential (GWP) of soil N2O emission on the basis of crop grain yield under the different treatments. The results showed that the yield-based GWPs of treatments of N, OM, NPK, OMNPK and CRNPK were 132.57 kg(CO2 eq)·t-1, 45.70 kg(CO2 eq)·t-1, 49.07 kg(CO2 eq)·t-1, 48.92 kg(CO2 eq)·t-1 and 26.41 kg(CO2 eq)·t-1, respectively. The yield-based GWP of soil N2O emissions in CRNPK treatment was the lowest of all the treatments. In contrast with conventional fertilization regime (NPK), the yield-based GWP decreased by 46%. This implied that returned crop residues combined with synthetic NPK fertilizer not only increased grain yield, but also decreased soil N2O emission due to the application of N fertilizer. For wheat season, the fertilizer application regime of returned crop residues with reduced synthetic fertilizer was therefore recommended as the best fertilization measure in purple soil croplands.
N2O emission characteristics and mitigation methods in South Loess Plateau under rain-fed winter wheat conditions
HU Teng, TONG Yan'an, GAO Pengcheng, GAO Bing, JU Xiaotang
2014, 22(9): 1038-1046. doi: 10.13930/j.cnki.cjea.140442
Abstract(1358) PDF(1291)
Abstract:
Quantifying N2O emissions and searching for appropriate emission-reduction measures have gained high international interest in global climate change studies. Therefore understanding the impacts of human activities on N2O emissions from arable soils was vital for mitigating any negative effects on climate change. In this paper, N2O emissions from soil under different nitrogen treatments: no nitrogen (CK), conventional treatment of 220 kg(N)·hm-2 (CON), optimized treatment with 150 kg(N)·hm-2 and straw return (OPT), optimized treatment with DCD (OPT+DCD) and optimized treatment by coated slow release fertilizer [OPT(SR)], in central Shaanxi of South Loess Plateau were observed during winter wheat season using the static opaque chamber/gas chromatography (GC) method. Results showed that in the first month of winter wheat growth, emissions were of large amount and lasted for longer times. In the last month, emission peaks rapidly occurred and disappeared after precipitation. Then during other times of winter wheat season, emissions were generally low. During seedling to re-greening stage, OPT+DCD and OPT(SR) significantly reduced N2O emission. Then during re-greening to maturing stage, emissions under the three optimized treatments were not significantly different. In terms of total emissions of different treatments of winter wheat, all the three optimized treatments reduced N2O emission, increased crop yield and decreased N2O intensity (N2O emission for per unit grain yield). Compared with CON, the optimized treatments of OPT, OPT+DCD and OPT(SR) reduced N2O emission by 29.2% (P < 0.01), 38.7% (P < 0.01) and 39.3% (P < 0.01), respectively, with not significant differences among the three optimized treatments. Compared with CON, the optimized treatments of OPT, OPT+DCD and OPT(SR) increased crop yield by 3.8% (P > 0.05), 15.2% (P < 0.05) and 9.5% (P < 0.05), respectively. Also compared with CON, the optimized treatment of OPT reduced N2O intensity by 31.7% (P < 0.05). Then compared with OPT, OPT+DCD and OPT(SR) reduced N2O intensity by 22.1% (P < 0.05) and 18.9% (P < 0.05), separately. The results suggested that returning straw to soils in combination with reducing nitrogen application rate to 150 kg(N)·hm-2 most reduced N2O emission. Using slow release fertilizer or adding certain amounts of DCD increased crop yield.
Dynamic characteristics of soil nutrients and soil microbial biomass of field-returned straws at different decay accretion conditions
CAI Liqun, NIU Yi, LUO Zhuzhu, WU Jun, YUE Dan, ZHOU Huan, DONG Bo, ZHANG Renzhi
2014, 22(9): 1047-1056. doi: 10.13930/j.cnki.cjea.140194
Abstract(1456) PDF(1574)
Abstract:
This paper used basin pot culture with plastic film method to study the dynamic characteristics of soil nutrients and soil microbial biomass during 120 d decomposition of different proportions of wheat and corn straws with different decomposing agents (F1: organic waste fermentation bacteria; F2: microbial agent; F3: "Manyuanchun" bio-fermentation). The results showed that during 120 d composition of wheat and corn straws, the increasing rates of soil organic matter, available nitrogen and total nitrogen in each treatment was rapid at the early stage and slow at the latter stage. The changes of increasing rates of soil phosphorus and potassium followed rapid-slow-rapid-slow trend. Throughout the trial stage, the soil microbial biomass carbon (SMBC) content of wheat treatments were increased first and then decreased. However, soil microbial biomass nitrogen (SMBN) content showed an alternating changing trend. Change in SMBC content of corn straw treatments was quite different from that of wheat treatments after 100 d composition. Treatments with decomposing agents improved soil nutrients, SMBC and SMBN contents, showed significant effects on soil fertility improvement. Among three decomposing agents, F3 (containing bacillus, filamentous fungi, actinomycetes and yeasts with special features) was the best in enhancing soil nutrients contents. The performance of different straw decomposing agents for wheat and corn straws were wheat > corn for F1, wheat ≥ corn for F2 and wheat < corn for F3. Therefore, F1 (training by multiple aerobic complex strains with a strong ability to decompose the cellulose, hemicelluloses, lignin and other organic ingredients of organic waste) and F3 most promoted wheat and corn straw decomposition, respectively. F2 (rich in microbial flora which decomposes cellulose, hemicelluloses, lignin and other bio-organic substances) equally promoted wheat and corn straw decomposition. For different decomposing agents, the order of SMBC and SMBN contents in wheat treatments was F2 > F3 > F1. The orders SMBC and SMBN in corn treatments were F2 > F3 ≈ F1 and F3 > F2 ≈ F1. SMBC in each corn straw treatment was greater than that in wheat straw treatments, for SMBN it was inverse. This was consistent with the amount of C/N ratio of the straws, the greater the C/N ratio the greater the SMBC content and the smaller the SMBN content.
Effects of different seedling nursery substrates and water management modes on seedling quality and yield of mechanically transplanted rice
WU Wenge, ZHOU Yongjin, CHEN Gang, CAI Haitao, WU Ranran, LI Xiahong, SUN Ruyin
2014, 22(9): 1057-1063. doi: 10.13930/j.cnki.cjea.140171
Abstract(1216) PDF(1061)
Abstract:
In order to develop a suitable technology for mechanical transplanted rice, a middle-season hybrid rice 'Huiliangyou6' was used to study the effects of nutrient soil dry bed nursery (ND), nutrient soil wet bed nursery (NW) and silt-water nursery (SW) on seedling quality and grain yield. The study also analyzed the effects of different seedling nursery methods on seedling flexibility, re-greening and spike formation stages. The results showed that for three seedling nursery treatments, seedling quality in ND was the best and SW the worst on 21 days after sowing. Compared with SW, seedling in ND and NW treatments had higher root-shoot ratio, stronger root development and higher dry matter accumulation. In ND treatment, seedling age range suitable for mechanical transplanting was 18-30 days. Also among the three seedling nursery methods, seedling flexibility was highest in ND. The nutrient soil dry bed nursery not only stabilized seed setting rate and 1000-grain weight, but also significantly increased the number of effective panicles and population total spikelets; significantly increasing yield. Seedlings re-greened very fast under ND method and also exhibited early tiller development and strong root development. This seedling nursery method was better for coordinating rice growth among the different growth stages in the field. It was also beneficial for construction of excellent population and high-yield.
Effects of removing low fresh leaf on the quality and economic characteristics of flue-cured tobacco
JIANG Houlong, CHEN Daiming, XU Anding, SHEN Zheng, SUI Xiaoning, DING Wei
2014, 22(9): 1064-1068. doi: 10.13930/j.cnki.cjea.140463
Abstract(1033) PDF(1219)
Abstract:
The objectives of this study were to investigate the effects of removing low fresh leaf on the chemical component, aroma composition, hierarchical structure and economic benefits of flue-cured tobacco. A field experiment was carried out to study the effects of four treatments - removing 0 (CK), 2 (T1), 3 (T2), 4 (T3) fresh leaves in lower part of the tobacco plant - on the chemical component, aroma composition, hierarchical structure and economic benefits of 'Yunyan 97' flue-cured tobacco in Wulong of Chongqing. The results indicated that with increasing number of removed fresh leaf, the contents of starch, total nitrogen and nicotine increased while K content decreased. Ratios of reducing sugar/nicotine and K/Cl in the upper and middle leaves of tobacco were significantly negatively correlated with the number of removed fresh leaf. However, the ratios of total nitrogen/nicotine of upper and middle leaves of tobacco were significantly positively correlated with the number of removed fresh leaf. For middle leaves, the highest content of aroma composition was in T2 treatment. However, the highest content of aroma composition for upper leaves was in T1 treatment. The economic benefits and hierarchical structure of flue-cured tobacco improved with different numbers of removed fresh leaves. The highest improvement was in T2 treatment, followed by T1 treatment and the lowest was in T3 treatment. Based on the comprehensive consideration of chemical components, aroma composition, hierarchical structure and economic benefits, it was recommended to remove lower fresh leaves in moderately fertile soils in Wulong ecological conditions. The number of leaf removal for the best effect on flue-cured tobacco was three.
Analysis of allelopathic effects and resource competition of weed suppression ability of wheat (Triticum aestivum) under low nitrogen stress condition
CHEN Shan, XIE Huiling, LI Yuanping, WANG Wei, XIAO Qingtie, LIN Ruiyu, LIN Wenxiong
2014, 22(9): 1069-1073. doi: 10.13930/j.cnki.cjea.140242
Abstract(1126) PDF(1194)
Abstract:
Allelopathic effects and resource competition are critical factors of weed suppression ability of crops. To separate the allelopathic effects from resource competition of weed suppression ability of wheat under low nitrogen stress condition, two strong allelopathic wheat accessions ('115/Q' and '92L89') and one weak allelopathic wheat accession ('K10103') were used in two sets of separate experiments (co-cultivated Alopecurus aequalis with wheat and treating Alopecurus aequalis with hydroponic solutions of co-cultured wheat root exudates) to evaluate bio-interference, allelopathy and resource competition effects. The experiments were conducted in gradient N concentration hydroponic solutions with N levels of 25 mg·L-1, 50 mg·L-1, 100 mg·L-1 and 200 mg·L-1. The results showed significantly differences in the abilities of inhibition to the growth of Alopecurus aequalis in the three wheat accessions in both experiments. Weed suppression ability (inhibitory rate, IR) increased with decreasing N level in all the wheat accessions. The rank order of IR for different wheat accessions was '115/Q' (55.1%?73.9%) > '92L89' (48.9%?65.9%) > 'K10103' (15.4%?45.5%). Generally, IR increased with decreasing N level in hydroponic solutions. Both allelopathic effects and resources competition were critical for wheat weed suppression. Different ecological strategies were noted in different allelopathic potential wheat accessions under low N stress condition. Weed suppression ability improved by increasing allelopathic effects of strong allelopathic wheat accessions. This was triggered by enhanced resources competition of weak allelopathic wheat accessions. Allelopathic effects increased with decreasing N level and the changes in inhibitory rate with N level well fitted quadratic equations.
Effects of partial root salt stress on seedling growth and photosynthetic characteristics of winter wheat
YANG Ting, XIE Zhixia, YU Qiong, LIU Xiaojing
2014, 22(9): 1074-1078. doi: 10.13930/j.cnki.cjea.140373
Abstract(1153) PDF(1074)
Abstract:
Most studies on plant salt stress have generally been conducted under uniform salinity in the root zone. However, the distribution of salinity in the soil is not always uniform under natural settings. Winter wheat is one of the main crops grown in salt-affected soils in China, with seedlings sensitive to salt stress. The effects of partial root salt stress on the growth and photosynthetic characteristics of winter wheat seedlings were investigated in this study using a split-root system in hydroponic culture. Each half root of the wheat seedlings was treated with either uniform (0|0 mmol L-1, 75|75 mmol L-1 and 150|150 mmol L-1) or non-uniform (0|150 mmol L-1) concentrations of NaCl, resulting in total or partial root salt stress. The results showed that salt stress significantly inhibited the growth of winter wheat seedlings, which inhibition increased with increasing NaCl concentration. Compared with total root salt stress treatments 150|150 mmol L-1 and 75|75 mmol L-1, partial root salt stress (0|150 mmol L-1) increased shoot dry weight by 23.5% and 17.2%, respectively. Partial root salt stress compensated for root growth in none salt-stress conditions by increasing root length, lateral root number and lateral root length respectively by 195.2%, 206.2% and 237.8% over that in 150 mmol L -1 NaCl condition. In the 0|150 mmol L-1 treatment, root Na+ content in 150 mmol L-1 NaCl side of the treatment dropped significantly by 12.1% than that in either sides of 150|150 mmol L-1 treatment. Also root Na+ content in salt-free side of 0|150 mmol L-1 increased significantly over that in either sides of the 0|0 treatment. These results indicated that increased [Na+] in roots in the salt-free side was possibly transported from the 150 mmol L-1 NaCl side of the treatment. Partial root salt stress treatment also decreased Na+ concentration in roots and leaf Na+/K+ content. Also Pn, Gs, Ci, Tr and chlorophyll fluorescence parameters (Fv/Fm) were higher in 0|150 mmol L-1 treatment than in total root salt stress. The improvement in plant growth under partial root salt stress was attributed to the reduction in leaf Na+ concentration and Na+/K+ ratio and the related increase in photosynthesis.
Effects of transgenic Bt-Cry1Ac cotton on activities of Bemisia tabaci enzymes
HU Qijing, ZHOU Fucai, YANG Yizhong, YANG Aimin, ZHANG Jianjun, HE Jing, ZHOU Jianhua, SHAO Jiuzhi
2014, 22(9): 1079-1085. doi: 10.13930/j.cnki.cjea.140050
Abstract(1219) PDF(1074)
Abstract:
To determine whether Bemisia tabaci population in transgenic Bt cotton exceeded that in conventional cotton and driven by Bt toxalbumin, and whether this was related to the change in the activity of protective enzymes and detoxification enzymes in B. tabaci, the study used transgenic Bt cotton 'Xinmian33B' and the conventional parental cotton '33' for the case study, and used the ELISA method and enzyme activity determination method to separately analyze Bt toxalbumin content, changes of activities of SOD, CAT and POD protective enzymes and of AChE, CarE and GSTs detoxification enzymes after B. tabaci feeding on transgenic Bt cotton. The results showed that Cry1Ac protein was detectable in B. tabaci after fed for 4 h on transgenic Bt cotton 'Xinmian33B', getting relatively stable after 12 h. The activities of SOD and GSTs were significantly inhibited (P < 0.05) after B. tabaci fed on 'Xinmian33B'. SOD activity steadily declined with the extension of the feeding time, declining 37.8%, 32.1%, 32.0% and 31.9% after feeding for 8 h, 12 h, 24 h and 36 h, respectively. Meanwhile, the activities of CAT, POD and CarE increased significantly (P < 0.05) and the enzyme activity steadily increased with the extension of feeding time. CAT activity was respectively 1.54 times, 1.55 times and 1.42 times; POD activity 1.59 times, 1.39 times and 1.53 times; and CarE activity 1.32 times, 1.34 times and 1.39 times those of the control after feeding for 12 h, 24 h and 36 h. The activity of AChE was not significantly affected after feeding on 'Xinmian33B'. These results suggested that the activities of protective enzymes of B. tabaci increased overall. The activities of detoxification enzymes were significantly affected by transgenic Bt-Cry1Ac cotton. Thus the addition of protective enzyme activity to B. tabaci could increase B. tabaci population. Further study was recommended to determine whether or not this effect was conclusive.
Vertical distribution patterns of genetic diversity of Xanthomonas oryzae pv. oryzae in Southwest China
GAO Lingling, HUANG Qiong, CHEN Xiaolong
2014, 22(9): 1086-1092. doi: 10.13930/j.cnki.cjea.140100
Abstract(1217) PDF(1066)
Abstract:
Based on the specific agro-ecological system and vertical climate in Southwest China, two polymerase chain reaction- based assays (rep-PCR and IS-PCR) were used to evaluate the population structure of Xanthomonas oryzae pv. oryzae (Xoo) from different elevation ranges (150 to 2 600 m) in Southwest China, which belong to six climate zones - north tropical climate zone, south subtropical climate zone, central subtropical climate zone, north subtropical climate zone, south temperate climate zone and cold temperate zone. A total of 218 isolates were tested in the research, out of which 73 isolates were collected from low elevation range (150?1 200 m), 90 isolates from medium elevation range (1 200?1 800 m) and 55 isolates from high elevation range (1 800? 2 600 m). The genetic diversity of Xoo was high in Southwest China, a total of 56 haplotypes were identified. The Xoo haplotypes in different elevation ranges were different, of which 18 were tested in high elevation range, 28 in low elevation range and 34 in medium elevation range. Although genetic diversity of Xoo was high, only H10 and H39 of haplotypes were tested in all the three different elevation ranges. Significant differences in the genetic diversity (Shannon Wiener index) of Xoo were observed among different elevation ranges. According to t-test, Shannon Wiener index in low and medium elevation ranges was significantly higher (P < 0.05) than that in high elevation range. However, no significant difference (P > 0.05) existed between medium and low elevation ranges. The genetic diversity of Xoo gradually reduced with decreasing temperature in different climate zones. Basis on cluster analysis of UPGMA, the 56 haplotypes of Xoo strains constituted nine putative genetic lineages. While strains from low elevation occurred under lineage 1 and lineage 2, strains from medium and high elevations occurred under lineage 3 to lineage 6 and lineage 3 to lineage 5. There were visible differences in Xoo strains from different elevation ranges. It was therefore recommended to take into account genetic diversity and variation degree of Xoo when laying out resistant genes based on haplotypes. This could slow down the rate of variability of Xoo strains on host selection pressure and avoid rapid lose of rice resistance.
Soil aggregate stability and erodibility under forest vegetation in the Loess Plateau using the Le Bissonnais method
ZENG Quanchao, DONG Yanghong, LI Xin, LI Yayun, LIU Lei, AN Shaoshan
2014, 22(9): 1093-1101. doi: 10.13930/j.cnki.cjea.140039
Abstract(1283) PDF(1336)
Abstract:
The composition and stability of soil aggregates are the main indicators of soil structure and quality. For sustainable ecological restoration, soil aggregates stability under different vegetation types in the forest zones of the Loess Plateau was studied using the Le Bissonnais (LB) method. Three sieving methods of LB (SW: slow-wetting sieving method; FW: fast-wetting sieving method; WS: wet-stirring sieving method) were used to simulate light rain, heavy rain and disturbance. Soil samples were collected from 10 types of vegetation in Yanhe Catchment of Yan'an City. The mean weight diameter (DMW), geometric mean diameter (DGM), mass fractal dimension (D) of soil aggregates and soil erodibility (K) were calculated. The results showed that FW treatment was the most destructive to soil aggregate stability, under which soil water-stable aggregate particle size was mainly concentrated in the <0.2 mm size group. The SW treatment showed the least destructiveness to soil aggregate stability with soil water-stable aggregate particle size mainly concentrated in the >2 mm size group. It then explained that light rains had no strong damaging effects on soil aggregates. The orders of DMW, DGM, D and K were SW > WS > FW, SW > FW > WS, WS > FW > SW, and FW > WS > SW, respectively, in both 0-10 cm and 10-20 cm soil layers. Under SW, Artemisia gmelinii community and Rosa xanthina community had greater DMW and DGM, and smaller K, indicating the two vegetation types had advantages in soil protection under light rain. Under WS and FW, Platycladus orientalis community and Acer buergerianum communities had DMW and DGM, and smaller K. They were appreciate vegetation types for soil protection under heavy rain and strong disturbance. The results suggested that LB method was appropriately applicable in measuring soil aggregate structure in the Loess Plateau. The LB method not only simulated traditional wet sieving results, but also explained the mechanisms involved in the disintegration of soil aggregates under different conditions in terms of soil structure stability. The results also suggested that the vegetation types significantly influenced soil water-stable aggregates in the region. In summary, the stability of soil aggregates was improved by vegetation restoration in the forest zones of the Loess Plateau.
Influence of spatial heterogeneity of climatic and socio-economic factors on soil organic matter-A case study of the central Heilongjiang Province, China
SHI Shuqin, CAO Qiwen, LI Zhengguo, XU Hengzhou
2014, 22(9): 1102-1112. doi: 10.13930/j.cnki.cjea.140097
Abstract(1206) PDF(1243)
Abstract:
The aim of this paper was to provide methodological support for understanding the response mechanism of soil properties to external factors and the related spatial distribution, which could also serve as a decision-making reference for farmers and agricultural management authorities. Using geostatistical theory, spatial analysis in GIS and geographically weighted regression (GWR) model, the study analyzed the response of soil organic matter to climatic and socio-economic factors in the central Heilongjiang Province in years of 2000 to 2005. For the period 2005, soil organic matter was spatially interpolated along with auxiliary soil type and pH datasets using Co-Kriging in GIS and the temporal variability analyzed. The result showed that in the western region of the study area, organic matter was higher in the east than in the west. Then in the eastern region of the study area, organic matter was higher in the central zone than in the northern and southern zones. Based on conventional regression model and variance inflation factor (VIF), the paper selected suitable variables for GWR model. Spatial autocorrelation analysis of soil organic matter content yielded global Moran's I index of 0.433 (P = 0.00), indicating that significant spatial autocorrelation in soil organic matter. Thus the GWR model was considered to be suitable for local parameter estimation and was used to determine the relationship between organic matter content and its driving factors. The CV method was used to determine the optimal bandwidth and to establish an adaptive kernel-type GWR model. Results showed that the GWR model accounted for over 57% of the total variance in soil organic matter content in the region. The spatial stability of the strength of the influence of each variable on organic matter content was analyzed. It showed that all variables had significant spatial instability. In addition, the minimum, maximum, upper quartile and lower quartile of the regression coefficients of the variables were largely different, and with both positive and negative correlations. This showed that the influence of each variable on soil organic matter content was spatially variable and was either positive or negative. Results from the GWR model showed that precipitation and annual average temperature negatively influenced organic matter content. Annual sunshine hours positively influenced organic matter content in most areas, except southwest Nenjiang Plain and south Songjiang Plain. The influence of mechanized farming level (as a socio-economic factor) on soil organic matter was positive in both north and west Nenjiang Plain and also in some parts of the Kebai Hills. Irrigation areas had relatively large positive effect on soil organic mat-ter in the study area. Fertilizer had negative effect on soil organic matter in areas of south Nenjiang Plain, northwest Songjiang Plain and northeast Sanjiang Plain, but positive effects in other areas. Mulch film consumption had a large positive effect on soil organic matter. The effect of pesticide consumption on soil organic matter was mainly positive in the west of the study area, while it was mainly negative in the east (all significant at the 0.01 level). It was concluded that the effects of climatic factors (which reflect dif-ferences in natural conditions) and socio-economic factors (which reflect agricultural inputs) on soil organic matter were largely het-erogeneous.
Using GGE biplot and comprehensive selection index to investigate mega-environments of cotton cultivar
XU Naiyin, LI Jian
2014, 22(9): 1113-1121. doi: 10.13930/j.cnki.cjea.140475
Abstract(1262) PDF(1342)
Abstract:
The application of cultivar selection index in crop variety breeding program could improve simultaneous selection efficiency of multiple target traits. Also genotypes derived from explorations of interactions with the environment and investigations of mega-environments using selection index contribute to rational utilization of specific adaptations of certain cultivars and environments, which could eventually enhance the reliability of variety breeding and multi-trait applications. As the most useful statistical and visualizing tool for mega-environment investigation, GGE biplot technique has been extensively used in the analysis of regional crop-trial datasets. Nevertheless, reports on cotton mega-environment identification using comprehensive cultivar selection index have to date remained scarce. The objective of this study was: 1) to construct a set of practicable cultivar selection index in line with national cotton variety registration criteria and 2) to investigate mega-environments using multi-trait selection index based on GGE biplot analysis. Datasets were collected from 39 sets of regional trials of cotton varieties, including 585 single-site cultivar comparison tests in the Yangtze River Valley (YaRV) in 2000-2013. Based on the results, the constructed cotton cultivar selection index (SI) was SI = 0.40 × lint cotton yield + 0.13 × fiber strength + 0.09 × (fiber length + micronaire value) + 0.11 × Fusarium wilt + 0.09 × Verticillium wilt + 0.10 × harvesting ratio of seed cotton before frost. Based on GGE biplot analysis, cotton planting region in YaRV was divided into four mega-environments for selection index. The four mega-environments included Sichuan Basin, Nanxiang Basin, Zhejiang Province Coastal Region and YaRV Middle/Lower Reaches. YaRV Middle/Lower Reaches mega-environemnt was most representative of the entire region. It covered the main cotton planting regions in YaRV, including the area around Dongting Lake in Hunan Province, the Jianghan Plains, the Southeast Downland in Hubei Province, the area around Poyang Lake in Jiangxi Province, the area along Yangtze River in Anhui Province, the Ningzhen Hilly Region, the area along Yangtze River and the Coastal Region in Jiangsu Province. However, the mega-environments of Sichuan Basin, Nanxiang Basin and Zhejiang Province Coastal Region were identified as special sub-regions with distinct ecological conditions. This set of environments was less representative of cotton planting region in YaRV. Subsequently, it was beneficial to promote breeding efficiency in order to realize broad adaptation selection of multi-trait across the entire cotton planting region in YaRV via preferential arrangements of breeding locations in the YaRV Middle/Lower Reaches maga-environment. Although the other mega-environments were not conducive for selection to represent the entire region for broad breeding adaptation programs, they were suitable for focusing on specific adaptive cultivar selections. This study showed the effectiveness of GGE biplot analysis in ecological regionalization. It was successfully used to divide the mega-environments in RaRV based on cultivar selection index. The study provided the scientific basis for decision-making on multi-trait cotton selections and recommendation of new cultivar policies in YaRV. It also provided a good example for implementation of similar ecological analyses in other cotton planting regions or even other crops.
A soil erosion model built on Machine Learning Theory
CAI Liangliang, YAN Lijiao, XU Huan
2014, 22(9): 1122-1128. doi: 10.13930/j.cnki.cjea.131098
Abstract(1224) PDF(1157)
Abstract:
In the aporia of environment problems, soil erosion is a critical element. Because of the many influencing factors, traditional prediction models of soil erosion are limited, including limitations such as difficulty in data collection, small-scale application, long research cycle, etc. These limitations make the prediction of soil erosion highly slow and inconvenient. Support Vector Machine (SVM) is one of the most important machine learning models. SVM has advantages such as non-linear mapping, self-learning ability, global minimum, insensitivity to input data. In contrast to traditional prediction models, SVM is highly beneficial in building relevant soil erosion models. Rainfall data were obtained from Puyang River Hydrologic Station of Zhuji City, Zhejiang Province. The layout research was developed in ArcMap and it included the upland catchment of Puyang River Hydrologic Station. The rainfall data and geographic data (including slope length, slope degree, soil type and land use type) were input into the SVM model as influencing factors of soil erosion. After screening, a total of 4 018 rainfall data were used. The proportions of the different slope degrees and slope lengths were calculated and land use types classified in study area using ERADS. After the data processing, the model input data were then ready, and divided into five groups, four of which were used as training data and the other used as examination data. The training data were input into the SVM model and the results compared. When the accuracy rate of the predicted results reached the maximum value, the model was accepted as attaining the optimum parameters. After confirmation of the optimal parameters, the soil erosion prediction model was inspected using the influencing factors and soil erosion data (i.e., the examination data). The highest accuracy rate of the model exceeded 75%. Among influencing factors, rainfall had the highest impact on soil erosion. The accuracy rate of the model reached 70% when only rainfall data were used, and was 3.5% when other influencing factors used together. At last, a relevant soil erosion prediction model was built with prediction accuracy rate of over 75%. The model could predict soil erosion from only rainfall data or rainfall in combination with geographic data. Although the prediction accuracy of model was relatively low under severe soil erosion, it provided a new and alternative method for predicting soil erosion on a large scales and extreme frequencies.

  冀ICP备05003362号-2

Address：286 Huaizhong Road, Shijiazhuang 050022, China

Tel：86-311-85818007E-mail：editor@sjziam.ac.cn

Supported by: Beijing Renhe Information Technology Co., Ltd.