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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2013 Vol. 21, No. 2
Display Method:
2013, 21(2): 141-148.
doi: 10.3724/SP.J.1011.2013.00141
Abstract:
Various kinds of endophytic and rhizospheric micro-organisms were closely related with various plants. Most of these micro-organisms were potential promoters of plant growth and development as they produced phytohormones that increased available nutrients to plants, controlled plant pathogens, etc. These microbes were collectively defined as plant growth-promoting micro-organisms. Furthermore, volatiles released by these plant growth-promoting micro-organisms were critical for mutual symbiosis of the host plants and plant-associated micro-organisms. Many endophytic and rhizospheric micro-organisms were reported to be capable of producing varieties of volatiles as secondary metabolites. Volatiles produced by plant growth-promoting micro-organisms had many essential ecological functions and the relationships among the functions were often quite complex. Some volatiles produced by plant growth-promoting micro-organisms were capable of promoting growth and development of plants. These volatiles induced systemic resistance in plants such that survival rates of plants in negative conditions improved. Also these compounds altered the constituents and contents of valuable secondary metabolites in plants, which in turn enhanced plants biotic resistance. Finally, some volatiles inhibited growth or reproduction of pathogens or insects and prevented herbivores from grazing on the host plants. Given these functions and several more, these critical metabolites enhanced host plants' competitive advantages over non-host plants. Because of these valuable ecological functions, further research studies needed to be done on beneficial effects of mutual symbiosis of micro-organisms and host plants. Several volatiles produced by plants affected signaling pathways or gene expression of host plants. In summary, studies on volatiles produced by plant growth-promoting micro-organisms enabled us to better understand the complex relationships among plants and micro-organisms. For in-depth research on volatiles produced by plant growth-promoting micro-organisms, this review summarized the results of current studies and discussed further development in this field.
Various kinds of endophytic and rhizospheric micro-organisms were closely related with various plants. Most of these micro-organisms were potential promoters of plant growth and development as they produced phytohormones that increased available nutrients to plants, controlled plant pathogens, etc. These microbes were collectively defined as plant growth-promoting micro-organisms. Furthermore, volatiles released by these plant growth-promoting micro-organisms were critical for mutual symbiosis of the host plants and plant-associated micro-organisms. Many endophytic and rhizospheric micro-organisms were reported to be capable of producing varieties of volatiles as secondary metabolites. Volatiles produced by plant growth-promoting micro-organisms had many essential ecological functions and the relationships among the functions were often quite complex. Some volatiles produced by plant growth-promoting micro-organisms were capable of promoting growth and development of plants. These volatiles induced systemic resistance in plants such that survival rates of plants in negative conditions improved. Also these compounds altered the constituents and contents of valuable secondary metabolites in plants, which in turn enhanced plants biotic resistance. Finally, some volatiles inhibited growth or reproduction of pathogens or insects and prevented herbivores from grazing on the host plants. Given these functions and several more, these critical metabolites enhanced host plants' competitive advantages over non-host plants. Because of these valuable ecological functions, further research studies needed to be done on beneficial effects of mutual symbiosis of micro-organisms and host plants. Several volatiles produced by plants affected signaling pathways or gene expression of host plants. In summary, studies on volatiles produced by plant growth-promoting micro-organisms enabled us to better understand the complex relationships among plants and micro-organisms. For in-depth research on volatiles produced by plant growth-promoting micro-organisms, this review summarized the results of current studies and discussed further development in this field.
2013, 21(2): 149-156.
doi: 10.3724/SP.J.1011.2013.00149
Abstract:
A large number of plant residues enters into soil on a daily basis in nature. The decomposition of these residues forms the foundation of nutrient cycles, especially carbon/nitrogen cycle. Several physical, chemical and biological factors (and interactions) contribute to the degradation processes. Among biological factors, micro-organisms which act as consumers and decomposers directly accelerate degradation processes or indirectly use acids and enzymes to do so. As micro-organisms, mycorrhizas have been recognized with special importance due to their especial microhabitat requirements. Arbuscular mycorrhizal (AM) fungi can form mutualistic symbiosis with more than 80% of higher plant species. The contribution of AM to plant residue degradation processes have varied at different hierarchical levels (plant root, mycorrhizas and soil mycelium), of course with mentioning accompanying bacteria. Most experiments have been carried out in pot or single compartment device conditions, which have made it difficult to clarify different effects of mycorhiza symbiosis on plant residue degradation. In this study, a di-compartment split-root device was used to quantitatively compare the changes in degradation processes in mycorrhizosphere and rhizosphere conditions. In the experiment, maize straw was used as representative plant residue and two different AM fungi (Glomus mosseae and Glomus etunicatum) inoculated. Samples were respectively harvested in 20 d, 30 d, 40 d, 50 d and 60 d after inoculation, analyzed for soil enzymatic activity, soil microbial biomass carbon and nitrogen, soil respiration and qCO2 and the mechanism of how mycorrhizal inoculation accelerated maize straw degradation discussed. The results showed that by inoculation with two different AM fungi, maize straw degradation mass and coefficient in mycorrhizosphere compartment were higher than in root compartment. Mycorrhizal inoculation enhanced carbon degradation but limited nitrogen degradation. It also decreased carbon/nitrogen ratio which facilitated further degradation. For soil biological performance, it was noted that catalase, protease, acid phosphatase, microbial biomass carbon, nitrogen and soil respiration were more enhanced in mycorrhizosphere compartment than in root compartment. This initiated the next step of forming more active microbial community. The increased indices involved in the degradation process were the main reasons behind mycorrhizal acceleration of degradation. Different ability to accelerate maize straw degradation lied in function diversity of AM fungi. More AM fungal species and soil types were suggested for consideration in future studies.
A large number of plant residues enters into soil on a daily basis in nature. The decomposition of these residues forms the foundation of nutrient cycles, especially carbon/nitrogen cycle. Several physical, chemical and biological factors (and interactions) contribute to the degradation processes. Among biological factors, micro-organisms which act as consumers and decomposers directly accelerate degradation processes or indirectly use acids and enzymes to do so. As micro-organisms, mycorrhizas have been recognized with special importance due to their especial microhabitat requirements. Arbuscular mycorrhizal (AM) fungi can form mutualistic symbiosis with more than 80% of higher plant species. The contribution of AM to plant residue degradation processes have varied at different hierarchical levels (plant root, mycorrhizas and soil mycelium), of course with mentioning accompanying bacteria. Most experiments have been carried out in pot or single compartment device conditions, which have made it difficult to clarify different effects of mycorhiza symbiosis on plant residue degradation. In this study, a di-compartment split-root device was used to quantitatively compare the changes in degradation processes in mycorrhizosphere and rhizosphere conditions. In the experiment, maize straw was used as representative plant residue and two different AM fungi (Glomus mosseae and Glomus etunicatum) inoculated. Samples were respectively harvested in 20 d, 30 d, 40 d, 50 d and 60 d after inoculation, analyzed for soil enzymatic activity, soil microbial biomass carbon and nitrogen, soil respiration and qCO2 and the mechanism of how mycorrhizal inoculation accelerated maize straw degradation discussed. The results showed that by inoculation with two different AM fungi, maize straw degradation mass and coefficient in mycorrhizosphere compartment were higher than in root compartment. Mycorrhizal inoculation enhanced carbon degradation but limited nitrogen degradation. It also decreased carbon/nitrogen ratio which facilitated further degradation. For soil biological performance, it was noted that catalase, protease, acid phosphatase, microbial biomass carbon, nitrogen and soil respiration were more enhanced in mycorrhizosphere compartment than in root compartment. This initiated the next step of forming more active microbial community. The increased indices involved in the degradation process were the main reasons behind mycorrhizal acceleration of degradation. Different ability to accelerate maize straw degradation lied in function diversity of AM fungi. More AM fungal species and soil types were suggested for consideration in future studies.
2013, 21(2): 157-163.
doi: 10.3724/SP.J.1011.2013.00157
Abstract:
To clarify a suitable fertilization mode for optimized yield and medicinal quality of Schizonepeta tenuifolia Briq., a single-factor random block design field experiment with three replications was conducted. The seven treatments in the experiment included three levels of organic manure (chicken compost manure 5 250 kg·hm-2, 10 500 kg·hm-2 and 15 750 kg·hm-2, respectively), three levels of chemical fertilizers (with the same ratios and quantities of nitrogen, phosphorus and potassium as the three manure treatments, respectively), and the control treatment without any fertilization. Leaf photosynthetic pigments and soluble protein, total flavonoid contents in different above-ground parts during different periods, and total dry-matter yield of S. tenuifolia after harvest were determined. The results showed that under the experimental conditions, both total dry-matter yield and photosynthetic pigment contents of S. tenuifolia under manure and chemical fertilizer treatments were significantly higher than those of the control (P < 0.05). Significant differences in dry-matter yield and photosynthetic pigment contents existed among different levels of manure and chemical fertilizer─ high level > medium level > low level. The differences between manure and chemical fertilizer with the same quantities of available nutrients were insignificant. Organic manure enhanced the accumulation of total flavonoids in stems, leaves and spikes of S. tenuifolia. The contents of total flavonoids varied in the order of low level > medium level > high level of manure treatments. Chemical fertilizer decreased the accumulation of total flavonoids in stems, leaves and spikes. Total dry-matter yield, total flavonoid contents of plants under high organic manure treatment were significantly higher than those of the other treatments and CK. Based on the results, it was concluded that chemical fertilizers with nitrogen, phosphorus and potassium increased yields and decreased both the total flavonoid content and medicinal quality of S. tenuifolia. Suitable quantities of organic manure increased both the dry-matter yield and total flavonoid contents in stems, leaves and spikes of S. tenuifolia. Hence organic manure was a better alternative to chemical fertilizers in the production of S. tenuifolia. The recommended amount of chicken compost manure for S. tenuifolia production in Hebei Province was 15 750 kg·hm-2.
To clarify a suitable fertilization mode for optimized yield and medicinal quality of Schizonepeta tenuifolia Briq., a single-factor random block design field experiment with three replications was conducted. The seven treatments in the experiment included three levels of organic manure (chicken compost manure 5 250 kg·hm-2, 10 500 kg·hm-2 and 15 750 kg·hm-2, respectively), three levels of chemical fertilizers (with the same ratios and quantities of nitrogen, phosphorus and potassium as the three manure treatments, respectively), and the control treatment without any fertilization. Leaf photosynthetic pigments and soluble protein, total flavonoid contents in different above-ground parts during different periods, and total dry-matter yield of S. tenuifolia after harvest were determined. The results showed that under the experimental conditions, both total dry-matter yield and photosynthetic pigment contents of S. tenuifolia under manure and chemical fertilizer treatments were significantly higher than those of the control (P < 0.05). Significant differences in dry-matter yield and photosynthetic pigment contents existed among different levels of manure and chemical fertilizer─ high level > medium level > low level. The differences between manure and chemical fertilizer with the same quantities of available nutrients were insignificant. Organic manure enhanced the accumulation of total flavonoids in stems, leaves and spikes of S. tenuifolia. The contents of total flavonoids varied in the order of low level > medium level > high level of manure treatments. Chemical fertilizer decreased the accumulation of total flavonoids in stems, leaves and spikes. Total dry-matter yield, total flavonoid contents of plants under high organic manure treatment were significantly higher than those of the other treatments and CK. Based on the results, it was concluded that chemical fertilizers with nitrogen, phosphorus and potassium increased yields and decreased both the total flavonoid content and medicinal quality of S. tenuifolia. Suitable quantities of organic manure increased both the dry-matter yield and total flavonoid contents in stems, leaves and spikes of S. tenuifolia. Hence organic manure was a better alternative to chemical fertilizers in the production of S. tenuifolia. The recommended amount of chicken compost manure for S. tenuifolia production in Hebei Province was 15 750 kg·hm-2.
2013, 21(2): 164-170.
doi: 10.3724/SP.J.1011.2013.00164
Abstract:
Light intensity is an important ecological factor that greatly influences rice grain formation and quality. This study discussed the effects of light intensity on rice quality at grain-filling stage and the differences in variety types and spikelets at different panicle positions. To do this, two pot-grown super rice cultivars, "Yangliangyou 6" (indica) and "Wuyunjing 23" (japonica), were subjected to three light intensity treatments (71%, 55% and 40% of normal light intensity respectively) at post-anthesis grain-filling stage, with normal outdoor growth as the control. The study aimed to throw more light on the physiological mechanisms of rice grain formation to lay the theoretical basis for improved rice quality. The results suggested that light intensity during grain-filling greatly influenced rice quality. Compared with the control, rice grain quality under the three treatments worsened with the weakening of light intensity. Grain quality response to light intensity varied with light intensity degrees, variety genotypes and grain positions on rice panicles. While grain quality on spikelets with late flower formation was poorly stability, that on spikelets with early flower formation was relatively stable. Milled rice and rice amylose content decreased and chalkiness increased with the weakening of light intensity. Amplitude change in grains on primary tillers was relatively larger than in grain on secondary tillers. Also the weaker the light intensity, the lower was the breakdown value, the higher were the setback value and crud protein content, and the worse were the rice cooking and eating qualities. Reasonable sowing times based on variety type and scientific cultivation practices for improved light conditions and rice growth likely mitigated any negative impacts of low light intensity on rice quality.
Light intensity is an important ecological factor that greatly influences rice grain formation and quality. This study discussed the effects of light intensity on rice quality at grain-filling stage and the differences in variety types and spikelets at different panicle positions. To do this, two pot-grown super rice cultivars, "Yangliangyou 6" (indica) and "Wuyunjing 23" (japonica), were subjected to three light intensity treatments (71%, 55% and 40% of normal light intensity respectively) at post-anthesis grain-filling stage, with normal outdoor growth as the control. The study aimed to throw more light on the physiological mechanisms of rice grain formation to lay the theoretical basis for improved rice quality. The results suggested that light intensity during grain-filling greatly influenced rice quality. Compared with the control, rice grain quality under the three treatments worsened with the weakening of light intensity. Grain quality response to light intensity varied with light intensity degrees, variety genotypes and grain positions on rice panicles. While grain quality on spikelets with late flower formation was poorly stability, that on spikelets with early flower formation was relatively stable. Milled rice and rice amylose content decreased and chalkiness increased with the weakening of light intensity. Amplitude change in grains on primary tillers was relatively larger than in grain on secondary tillers. Also the weaker the light intensity, the lower was the breakdown value, the higher were the setback value and crud protein content, and the worse were the rice cooking and eating qualities. Reasonable sowing times based on variety type and scientific cultivation practices for improved light conditions and rice growth likely mitigated any negative impacts of low light intensity on rice quality.
2013, 21(2): 171-178.
doi: 10.3724/SP.J.1011.2013.00171
Abstract:
Water transport is a fundamental aspect of crop physiology and an active area of research. Also water budget research under different maize cultivation patterns has been largely inadequate, especially on the area of maize cultivars intercropping and water balance. To determine the impacts of maize cultivars intercropping on plant-level water balance, "Zhengdan958" and "Shendan16" maize cultivars were planted in inter-lacing rows at two different inter-planting densities (45 000 plants·hm-2 and 60 000 plants·hm-2) in a total of four treatments. Grain yield, soil water content, stem sap flow (SSF) and root water conductivity (RHC) at different growth stages were investigated. The combined effects were analyzed for different characteristics of plant water consumption and transpiration. This enabled the efficient analysis of all the relevant factors of plant water transport. The results showed that intercropping improved root water conductivity, enhanced root water absorption vigor and functional continuity. Just as RHC, SSF obviously increased with increasing intercrop density. Daily variations in SSF followed an M-shaped curve under high density, but inverted a V-shaped curve under low density. Because of interplant density, maximum SSF appeared earlier in high than in low density treatments. Based on the changes in RHC and SSF, daily plant transpiration was extremely higher in high than low density plants. The maximum transpiration value for high-density plants occurred at grain filling and waxing stages. It occurred at tasseling and milking stages in low-density plants. Consequently, water use efficiency (WUE) was in the order of: low-density monoculture < intercropping < high-density monoculture. The above sequence was directly driven by yield differences. Cultivar intercropping improved root water absorption, extended root vigor and enhanced WUE. However, WUE distinctly varied with cultivar type and intercropping density. Further research was needed to build more understanding into these plant processes.
Water transport is a fundamental aspect of crop physiology and an active area of research. Also water budget research under different maize cultivation patterns has been largely inadequate, especially on the area of maize cultivars intercropping and water balance. To determine the impacts of maize cultivars intercropping on plant-level water balance, "Zhengdan958" and "Shendan16" maize cultivars were planted in inter-lacing rows at two different inter-planting densities (45 000 plants·hm-2 and 60 000 plants·hm-2) in a total of four treatments. Grain yield, soil water content, stem sap flow (SSF) and root water conductivity (RHC) at different growth stages were investigated. The combined effects were analyzed for different characteristics of plant water consumption and transpiration. This enabled the efficient analysis of all the relevant factors of plant water transport. The results showed that intercropping improved root water conductivity, enhanced root water absorption vigor and functional continuity. Just as RHC, SSF obviously increased with increasing intercrop density. Daily variations in SSF followed an M-shaped curve under high density, but inverted a V-shaped curve under low density. Because of interplant density, maximum SSF appeared earlier in high than in low density treatments. Based on the changes in RHC and SSF, daily plant transpiration was extremely higher in high than low density plants. The maximum transpiration value for high-density plants occurred at grain filling and waxing stages. It occurred at tasseling and milking stages in low-density plants. Consequently, water use efficiency (WUE) was in the order of: low-density monoculture < intercropping < high-density monoculture. The above sequence was directly driven by yield differences. Cultivar intercropping improved root water absorption, extended root vigor and enhanced WUE. However, WUE distinctly varied with cultivar type and intercropping density. Further research was needed to build more understanding into these plant processes.
2013, 21(2): 179-183.
doi: 10.3724/SP.J.1011.2013.00179
Abstract:
Hexaploid triticale (a new species) was artificially synthesized by crossing tetraploid wheat with rye. Its processing quality was related to its HMW-GS composition. To provide reference for the processing and utilization of hexaploid triticale germplasm resources, HMW-GS composition at Glu-1 locus was investigated in 101 samples from Xinjiang and 11 accessions from Poland using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Results showed that 3 [1(a), 2*(b), Null(c) ]; 8 [7(a), 7+8(b), 7+9(c), 6+8(d), 20(e), 13+19(g), 7+18(r), 6.8+20y(s)] and 6 [1r+4r(a), 2r+6.5r(b), 6r+13r(c), 2r+9r(d), 6.5r(e), 0.8r+6r(f)] alleles were encoded by Glu-A1, Glu-B1 and Glu-R1, respectively. This indicated that alleles at Glu-R1 were the richest. Null(c) at Glu-A1, 7+18(r) at Glu-B1 and 6r+13r(c) at Glu-R1 were found to be the main subunits, occupying 58.93%, 67.90% and 58.00%, respectively. Other subunits such as 1(a) at Glu-A1; 7(a), 6+8(d), 13+19(g) and 6.8+20y(s) at Glu-B1; and 1r+4r(a) and 0.8r+6r(f) at Glu-R1 were only detected in a few varieties. 30 HMW glutein patterns were found in 121 accessions of Null, 7+18, 6r+13r (c, r, c) and 2*. Also only 7+18, 6r+13r (b, r, c) were the main accessions, occupying 16.91% and 16.02%, respectively. Some distinctive glutein patterns such as [2*, 7+18, 2r+9r(b, r, d)] and [2*, 6.8+20y, 2r+6.5r(b, s, b)] were detected. Genetic variations index at Glu-1 locus of triticales from Xinjiang and Poland were in the order of Glu-R1 > Glu-A1 > Glu-B1 and Glu-R1 > Glu-B1 > Glu-A1, respectively. This indicated that genetic variation at Glu-R1 locus was richer than those at Glu-A1 and Glu-B1 in all detected materials. Analysis of genetic polymorphism revealed that genetic variation in the Poland accessions was richer than that in the Xinjiang accessions. Moreover, 7+18(r) and 6.8+20y(s) at Glu-B1 were new and special subunits formed during artificial evolution of triticale. It provided rich gene resources for improving wheat processing qualities.
Hexaploid triticale (a new species) was artificially synthesized by crossing tetraploid wheat with rye. Its processing quality was related to its HMW-GS composition. To provide reference for the processing and utilization of hexaploid triticale germplasm resources, HMW-GS composition at Glu-1 locus was investigated in 101 samples from Xinjiang and 11 accessions from Poland using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Results showed that 3 [1(a), 2*(b), Null(c) ]; 8 [7(a), 7+8(b), 7+9(c), 6+8(d), 20(e), 13+19(g), 7+18(r), 6.8+20y(s)] and 6 [1r+4r(a), 2r+6.5r(b), 6r+13r(c), 2r+9r(d), 6.5r(e), 0.8r+6r(f)] alleles were encoded by Glu-A1, Glu-B1 and Glu-R1, respectively. This indicated that alleles at Glu-R1 were the richest. Null(c) at Glu-A1, 7+18(r) at Glu-B1 and 6r+13r(c) at Glu-R1 were found to be the main subunits, occupying 58.93%, 67.90% and 58.00%, respectively. Other subunits such as 1(a) at Glu-A1; 7(a), 6+8(d), 13+19(g) and 6.8+20y(s) at Glu-B1; and 1r+4r(a) and 0.8r+6r(f) at Glu-R1 were only detected in a few varieties. 30 HMW glutein patterns were found in 121 accessions of Null, 7+18, 6r+13r (c, r, c) and 2*. Also only 7+18, 6r+13r (b, r, c) were the main accessions, occupying 16.91% and 16.02%, respectively. Some distinctive glutein patterns such as [2*, 7+18, 2r+9r(b, r, d)] and [2*, 6.8+20y, 2r+6.5r(b, s, b)] were detected. Genetic variations index at Glu-1 locus of triticales from Xinjiang and Poland were in the order of Glu-R1 > Glu-A1 > Glu-B1 and Glu-R1 > Glu-B1 > Glu-A1, respectively. This indicated that genetic variation at Glu-R1 locus was richer than those at Glu-A1 and Glu-B1 in all detected materials. Analysis of genetic polymorphism revealed that genetic variation in the Poland accessions was richer than that in the Xinjiang accessions. Moreover, 7+18(r) and 6.8+20y(s) at Glu-B1 were new and special subunits formed during artificial evolution of triticale. It provided rich gene resources for improving wheat processing qualities.
2013, 21(2): 184-191.
doi: 10.3724/SP.J.1011.2013.00184
Abstract:
Using the Static Chamber/IRGA, water vapor concentrations in tea plantations with different growth durations (3, 9 and 12 years) were measured and compared for diurnal variations in evapotranspiration (ET) before and after pruning. The study aimed to evaluate the water regulating ability of tea trees which is the dominant land use type in Yixing City, west of Tai Lake watershed. The results showed that diurnal variations in ET rate of tea tree tracked uni-peak curve. ET rose from 6:00, reached peak value at 12:00 and dropped rapidly or slowly afterwards. After pruning, tea tree ET rate dropped considerably. Mean ET rates for the 3-year and 9-year tea trees were respectively measured at 6:00, 9:00, 12:00 and 15:00 on April 23 - the day before first pruning. These rates were higher than those measured on May 17 - the day after the first pruning. Daily mean ET rates for 3-year and 9-year tea trees before first pruning were 3.11 mmol·m-2·s-1 and 73.74% higher than that after first pruning (1.79 mmol·m-2·s-1). Also amplitude decline in ET for the 3-year tea trees was 36.73% and that in the 9-year tea trees was 48.32%. ET decline range increased with increasing growth duration of the tea trees. The influencing factors of ET were discussed as follows: (1) Although ET trend was similar to that of temperature and tea tree ET closely related with temperature (P＜0.01), air temperature was not obviously different between before and after pruning, 34.46 ℃ on April 23 (the day before first pruning) and 34.30 ℃ on June 14 (the day after pruning). This suggested that air temperature was not the main driving factor of ET in the study area. (2) The study area was in a humid region where soil water content was relatively high but changed with rainfall and tea tree cover. There was no close relationship between ET and soil moisture, a trend different from that noted in semiarid and arid regions. This also suggested that soil humidity was not a main driving factor of ET in the study area. (3) Tea tree height after pruning was almost half of that before pruning, which height change was similar to the change in ET. As a roughness factor of aerodynamics, air near leaf was much influenced by the ambient atmospheric conductance, inducing less boundary layer conductance at lower plant heights. Also as water transport in the soil-plant-atmosphere continuum (SPAC) was inefficient, the tea tree height dwarfing rapidly decreased ET rate. (4) Air temperature was similar and soil moistures relatively higher before than after pruning. As the 20-year tea crop coverage (without pruning) increased by 9.41%, shadow area widened and soil evaporation weakened. While vegetation coverage of the 3-year and 9-year tea trees (with pruning) decreased respectively by 15.85% and 24.93%, bare soil area didn't increase and soil evaporation became smaller. As pruned debris of tea trees covered soil surface, especially for the 9-year tea trees, soil water retention capacity increased, and at the same time ET rate range decreased.
Using the Static Chamber/IRGA, water vapor concentrations in tea plantations with different growth durations (3, 9 and 12 years) were measured and compared for diurnal variations in evapotranspiration (ET) before and after pruning. The study aimed to evaluate the water regulating ability of tea trees which is the dominant land use type in Yixing City, west of Tai Lake watershed. The results showed that diurnal variations in ET rate of tea tree tracked uni-peak curve. ET rose from 6:00, reached peak value at 12:00 and dropped rapidly or slowly afterwards. After pruning, tea tree ET rate dropped considerably. Mean ET rates for the 3-year and 9-year tea trees were respectively measured at 6:00, 9:00, 12:00 and 15:00 on April 23 - the day before first pruning. These rates were higher than those measured on May 17 - the day after the first pruning. Daily mean ET rates for 3-year and 9-year tea trees before first pruning were 3.11 mmol·m-2·s-1 and 73.74% higher than that after first pruning (1.79 mmol·m-2·s-1). Also amplitude decline in ET for the 3-year tea trees was 36.73% and that in the 9-year tea trees was 48.32%. ET decline range increased with increasing growth duration of the tea trees. The influencing factors of ET were discussed as follows: (1) Although ET trend was similar to that of temperature and tea tree ET closely related with temperature (P＜0.01), air temperature was not obviously different between before and after pruning, 34.46 ℃ on April 23 (the day before first pruning) and 34.30 ℃ on June 14 (the day after pruning). This suggested that air temperature was not the main driving factor of ET in the study area. (2) The study area was in a humid region where soil water content was relatively high but changed with rainfall and tea tree cover. There was no close relationship between ET and soil moisture, a trend different from that noted in semiarid and arid regions. This also suggested that soil humidity was not a main driving factor of ET in the study area. (3) Tea tree height after pruning was almost half of that before pruning, which height change was similar to the change in ET. As a roughness factor of aerodynamics, air near leaf was much influenced by the ambient atmospheric conductance, inducing less boundary layer conductance at lower plant heights. Also as water transport in the soil-plant-atmosphere continuum (SPAC) was inefficient, the tea tree height dwarfing rapidly decreased ET rate. (4) Air temperature was similar and soil moistures relatively higher before than after pruning. As the 20-year tea crop coverage (without pruning) increased by 9.41%, shadow area widened and soil evaporation weakened. While vegetation coverage of the 3-year and 9-year tea trees (with pruning) decreased respectively by 15.85% and 24.93%, bare soil area didn't increase and soil evaporation became smaller. As pruned debris of tea trees covered soil surface, especially for the 9-year tea trees, soil water retention capacity increased, and at the same time ET rate range decreased.
2013, 21(2): 192-198.
doi: 10.3724/SP.J.1011.2013.00192
Abstract:
Soil aggregate is an key soil fertility identification index which determines the quality and erosion resistance of soils. Soil organic carbon content somehow influences soil stability and soil water-stable aggregate forms. It is a critical driving factor of soil fertility and soil cushioning property. Farming measures also influence changes in soil organic carbon pool and different farming measures have different effects on soil physical and chemical property. To find proper tillage measures on slope croplands in purple soils, the effects of across- and along-slope ploughs on soil aggregate stability in purple soils were studied. Through plot runoff experiments, the characteristics of water-stable aggregates and organic carbon contents in top soils (0~20 cm) were studied. On the slope-land of South China, peasants preferred doing along-slope plough than across-slope plough because ease of along-slope plough. However, rill erosion easily occurred in along-slope plough conditions, especially in big rainfall events. This worsened the degree of soil erosion in the region. On the other hand, research on soil nutrient loss in across-slope plough conditions has sown that due to high risks and inputs, across-slope plough farming was unacceptable to most peasants. Studies have shown that soil aggregate organic carbon content accounts for 90% of surface soil nutrients and agricultural production activities occurred mostly in surface soils. This research studied the effects of across- and along-slope ploughs on water-stable aggregates and organic carbon in surface purple soils. The study offered some theoretical bases for effective utilization of soil management measures in slope-land conditions. Results showed that compared with along-slope plough, across-slope plough increased aggregate water stability index by 38.99%. Aggregate dispersion index in along-slope plough was 1.64 times that in across-slope plough. This suggested that erosion resistance in across-slope plough was stronger than in along-slope plough conditions. Compared with along-slope plough, the average content of >0.25 mm water-stable aggregate in across-slope plough increased by 3.62%. Meanwhile, the average contents of water stable aggregate in >5 mm, 5~3 mm and 3~2 mm sizes in across-slope plough were higher than in along-slope plough. This suggested that across-slope plough significantly improved the >2 mm water-stable aggregate content. Percent destruction of soil aggregates in across-slope plough decreased by 3.05%, compared with along-slope plough. Also mean weight diameter (MWD) in across-slope plough was 1.39 times that in along-slope plough conditions. Organic carbon contents in 0.5~2 mm aggregates of the two tillage types were the highest. Under the two tillage measures, percent organic carbon contents in >0.25 mm aggregates decreased with decreasing diameter, reaching the lowest value in 0.5~0.25 mm aggregates. There was no significant difference between the two tillage measures in organic carbon contents in 2~1 mm aggregates, but significant differences existed in the other sizes aggregates. Across-slope plough significantly improved water-stable aggregate contents. It also had a better effect on soil retention capacity of organic carbon and better improved soil structure.
Soil aggregate is an key soil fertility identification index which determines the quality and erosion resistance of soils. Soil organic carbon content somehow influences soil stability and soil water-stable aggregate forms. It is a critical driving factor of soil fertility and soil cushioning property. Farming measures also influence changes in soil organic carbon pool and different farming measures have different effects on soil physical and chemical property. To find proper tillage measures on slope croplands in purple soils, the effects of across- and along-slope ploughs on soil aggregate stability in purple soils were studied. Through plot runoff experiments, the characteristics of water-stable aggregates and organic carbon contents in top soils (0~20 cm) were studied. On the slope-land of South China, peasants preferred doing along-slope plough than across-slope plough because ease of along-slope plough. However, rill erosion easily occurred in along-slope plough conditions, especially in big rainfall events. This worsened the degree of soil erosion in the region. On the other hand, research on soil nutrient loss in across-slope plough conditions has sown that due to high risks and inputs, across-slope plough farming was unacceptable to most peasants. Studies have shown that soil aggregate organic carbon content accounts for 90% of surface soil nutrients and agricultural production activities occurred mostly in surface soils. This research studied the effects of across- and along-slope ploughs on water-stable aggregates and organic carbon in surface purple soils. The study offered some theoretical bases for effective utilization of soil management measures in slope-land conditions. Results showed that compared with along-slope plough, across-slope plough increased aggregate water stability index by 38.99%. Aggregate dispersion index in along-slope plough was 1.64 times that in across-slope plough. This suggested that erosion resistance in across-slope plough was stronger than in along-slope plough conditions. Compared with along-slope plough, the average content of >0.25 mm water-stable aggregate in across-slope plough increased by 3.62%. Meanwhile, the average contents of water stable aggregate in >5 mm, 5~3 mm and 3~2 mm sizes in across-slope plough were higher than in along-slope plough. This suggested that across-slope plough significantly improved the >2 mm water-stable aggregate content. Percent destruction of soil aggregates in across-slope plough decreased by 3.05%, compared with along-slope plough. Also mean weight diameter (MWD) in across-slope plough was 1.39 times that in along-slope plough conditions. Organic carbon contents in 0.5~2 mm aggregates of the two tillage types were the highest. Under the two tillage measures, percent organic carbon contents in >0.25 mm aggregates decreased with decreasing diameter, reaching the lowest value in 0.5~0.25 mm aggregates. There was no significant difference between the two tillage measures in organic carbon contents in 2~1 mm aggregates, but significant differences existed in the other sizes aggregates. Across-slope plough significantly improved water-stable aggregate contents. It also had a better effect on soil retention capacity of organic carbon and better improved soil structure.
2013, 21(2): 199-206.
doi: 10.3724/SP.J.1011.2013.00199
Abstract:
Arbuscular mycorrhizal (AM) fungi is important in maintaining the functions and biodiversity of arid-land ecosystems and is also an indispensable factor in the restoration and reestablishment of vegetation. In particular, AM fungi are ubiquitous symbiotic fungi and plants. Clonal plants possess wider ecological neighborhoods than non-clonal plants. Clonal plants constitute a form of resource for the restoration of the Mu Us Sandy Land. Clonal plants have been identified as the driver of change in community environments and greatly contribute to the maintenance of community functions in the restoration process of vegetation. Clonal plants considerably enhance the ability of self-rehabilitation of sandy landscapes. To elucidate species diversity and ecological distribution of AM fungi associated with 3 kinds of clonal plants (Psammochloa villosa, Hedysarum leave, Artemisia ordosica) in Mu Us Sandy Land, two representative sites (Research Station and Yulin) were selected from the northeast and southwest of Mu Us Sandy Land. Soil samples at 50 cm depth of rhizosphere of clonal plants were collected in 4 replicates at each location and divided into sections corresponding to 0~10 cm, 10~20 cm, 20~30 cm, 30~40 cm, 40~50 cm depths in May, July and October 2006. A total of 23 AM fungal species belonging to 4 genera were isolated and identified. Of these, 15 species belonged to Glomus, 5 to Acaulospora, 2 to Gigaspora, and 1 to Scutellospora. G. mosseae was the dominant species in the P. villosa rhizosphere; G. melanosporum was the common species in the rhizosphere of 3 kinds of clonal plants. The ecological distributions were different among species and AM fungi genera. AM fungi spore density, species richness and species diversity index were highest in H. leave rhizosphere in the Research Station. The results showed that AM fungal species diversity was rich in clonal plant rhizospheres in Mu Us Sandy Land. Also the spatial distribution dynamics of AM fungal species in Mu Us Sandy Land was significant. This paper described the diversity and distribution of AM fungi in the rhizospheres of three kinds of clonal plants, which provided the basis for reestablishing ecosystems and sustaining economic development in Mu Us Sandy Land.
Arbuscular mycorrhizal (AM) fungi is important in maintaining the functions and biodiversity of arid-land ecosystems and is also an indispensable factor in the restoration and reestablishment of vegetation. In particular, AM fungi are ubiquitous symbiotic fungi and plants. Clonal plants possess wider ecological neighborhoods than non-clonal plants. Clonal plants constitute a form of resource for the restoration of the Mu Us Sandy Land. Clonal plants have been identified as the driver of change in community environments and greatly contribute to the maintenance of community functions in the restoration process of vegetation. Clonal plants considerably enhance the ability of self-rehabilitation of sandy landscapes. To elucidate species diversity and ecological distribution of AM fungi associated with 3 kinds of clonal plants (Psammochloa villosa, Hedysarum leave, Artemisia ordosica) in Mu Us Sandy Land, two representative sites (Research Station and Yulin) were selected from the northeast and southwest of Mu Us Sandy Land. Soil samples at 50 cm depth of rhizosphere of clonal plants were collected in 4 replicates at each location and divided into sections corresponding to 0~10 cm, 10~20 cm, 20~30 cm, 30~40 cm, 40~50 cm depths in May, July and October 2006. A total of 23 AM fungal species belonging to 4 genera were isolated and identified. Of these, 15 species belonged to Glomus, 5 to Acaulospora, 2 to Gigaspora, and 1 to Scutellospora. G. mosseae was the dominant species in the P. villosa rhizosphere; G. melanosporum was the common species in the rhizosphere of 3 kinds of clonal plants. The ecological distributions were different among species and AM fungi genera. AM fungi spore density, species richness and species diversity index were highest in H. leave rhizosphere in the Research Station. The results showed that AM fungal species diversity was rich in clonal plant rhizospheres in Mu Us Sandy Land. Also the spatial distribution dynamics of AM fungal species in Mu Us Sandy Land was significant. This paper described the diversity and distribution of AM fungi in the rhizospheres of three kinds of clonal plants, which provided the basis for reestablishing ecosystems and sustaining economic development in Mu Us Sandy Land.
2013, 21(2): 207-211.
doi: 10.3724/SP.J.1011.2013.00207
Abstract:
Organophosphorus pesticides have been widely used to control insect pests in agriculture. These compounds have been implicated in several nerve and muscular diseases in humans. Large-scale manufacturing and handling of organophosphate insecticides have caused the contamination of soils, air, surface water and groundwater across the globe. Chlorpyrifos degradation has become an increasingly important area of research in recent years. The current focus has been on the development of cost effective and eco-friendly technologies for treating polluted environments. Biodegradation has offered an efficient and cheap option for such decontamination process. Similarly, biodegradation has also been the main mechanism for removed chlorpyrifos residue, especially in the treatment of discharged wastewater from the varied processes of chlorpyrifos production. The study of the degradation kinetics was useful for understanding biodegradation processes as well as estimating pollutant concentrations. The degradation of high concentration pollutants was critical for developing practical applications of degrading bacteria. In this study, two pure Bacillus cereus strains (HY-1 and HY-2) were used in chlorpyrifos biodegradation in a batch of shake-flasks. The rate and extent of biodegradation were quantified at different chlorpyrifos initial concentrations (in the range of 40~200 mg·L 1) by B. cereus through adding chorpyrifos to mineralized medium and analyzing chlorpyrifos residue at a definite time. At the same time, the effects of incubation times and size of inoculum on chlorpyrifos degradation rate were determined. The degradation rate of high chlorpyrifos concentration by B. cereus was also measured. The results showed that the appropriate incubation time of inoculum of HY-1 and HY-2 strains were 10 h and 19 h respectively. The data suggested that inoculum incubation time significantly influenced chlorpyrifos degradation efficiency. Optimum inoculum amount for the two strains was 8% (v/v) of total volume. The effect of inoculum size on HY-1 degradation function was greater than that of HY-2 as the ratio increased from 4% to 8%. The simulated results suggested that the fit of the first-order kinetics model [ln(C0/Ct)=kt] was good for initial chlorpyrifos concentrations of 40 mg·L-1, 80 mg·L-1, 100 mg·L-1 and 120 mg·L-1. With further increases in chlorpyrifos concentration, only HY-2 followed the first-order kinetics model in terms of chlorpyrifos degradation. When chlorpyrifos concentration was within 40~120 mg·L-1, HY-1 degradation efficiency constant was within 0.013 5~0.015 7. Similarly, HY-2 degradation efficiency constant was within 0.008 0~0.015 3 when the chlorpyrifos concentration was 40~200 mg·L-1. HY-2 strain was possibly more suitable for higher chlorpyrifos concentration than HY-1 in terms of chlorpyrifos degradation, with HY-2 degradation rate relatively higher as well. The results suggested that further research was needed on the two microbes to fully understand their use as potential bio-agents in chlorpyrifos water contaminated remediation.
Organophosphorus pesticides have been widely used to control insect pests in agriculture. These compounds have been implicated in several nerve and muscular diseases in humans. Large-scale manufacturing and handling of organophosphate insecticides have caused the contamination of soils, air, surface water and groundwater across the globe. Chlorpyrifos degradation has become an increasingly important area of research in recent years. The current focus has been on the development of cost effective and eco-friendly technologies for treating polluted environments. Biodegradation has offered an efficient and cheap option for such decontamination process. Similarly, biodegradation has also been the main mechanism for removed chlorpyrifos residue, especially in the treatment of discharged wastewater from the varied processes of chlorpyrifos production. The study of the degradation kinetics was useful for understanding biodegradation processes as well as estimating pollutant concentrations. The degradation of high concentration pollutants was critical for developing practical applications of degrading bacteria. In this study, two pure Bacillus cereus strains (HY-1 and HY-2) were used in chlorpyrifos biodegradation in a batch of shake-flasks. The rate and extent of biodegradation were quantified at different chlorpyrifos initial concentrations (in the range of 40~200 mg·L 1) by B. cereus through adding chorpyrifos to mineralized medium and analyzing chlorpyrifos residue at a definite time. At the same time, the effects of incubation times and size of inoculum on chlorpyrifos degradation rate were determined. The degradation rate of high chlorpyrifos concentration by B. cereus was also measured. The results showed that the appropriate incubation time of inoculum of HY-1 and HY-2 strains were 10 h and 19 h respectively. The data suggested that inoculum incubation time significantly influenced chlorpyrifos degradation efficiency. Optimum inoculum amount for the two strains was 8% (v/v) of total volume. The effect of inoculum size on HY-1 degradation function was greater than that of HY-2 as the ratio increased from 4% to 8%. The simulated results suggested that the fit of the first-order kinetics model [ln(C0/Ct)=kt] was good for initial chlorpyrifos concentrations of 40 mg·L-1, 80 mg·L-1, 100 mg·L-1 and 120 mg·L-1. With further increases in chlorpyrifos concentration, only HY-2 followed the first-order kinetics model in terms of chlorpyrifos degradation. When chlorpyrifos concentration was within 40~120 mg·L-1, HY-1 degradation efficiency constant was within 0.013 5~0.015 7. Similarly, HY-2 degradation efficiency constant was within 0.008 0~0.015 3 when the chlorpyrifos concentration was 40~200 mg·L-1. HY-2 strain was possibly more suitable for higher chlorpyrifos concentration than HY-1 in terms of chlorpyrifos degradation, with HY-2 degradation rate relatively higher as well. The results suggested that further research was needed on the two microbes to fully understand their use as potential bio-agents in chlorpyrifos water contaminated remediation.
2013, 21(2): 212-216.
doi: 10.3724/SP.J.1011.2013.00212
Abstract:
Justicia procumbens is traditional Chinese medicine herb. To confirm fungicidal and insecticidal activity of J. procumbens extracts, methanol, chloroform, acetone, ethyl acetate and hexane extracts were obtained from J. procumbens by the combined method of cold-soaking and ultrasonic extraction. Extract inhibitory effects were studied using the inhibition zone method involving five species of plant pathogenic fungus-Colletotrichum gloeosprioides, Phomopsis asparagi, Pyricularia grisea, Fusarium graminearum and Botrytis cinerea. Methanol extract toxicity against four species of plant pathogenic fungus and bacteria (C. gloeosprioides, P. asparagi, B. cinerea and Xanthomonas campestris) and three species of insects (Aedes albopictus, Musca domestica and Pieris rapae) were also assayed. Results showed that 8 mg?mL-1 extracts of J. procumbens with different polar solvents had some inhibitory effects on five species of plant pathogenic fungus. The inhibition rates of methanol extract against C. gloeosprioides, P. asparagi and B. cinerea were over 50%. Methanol extract from J. procumbens had better fungicidal and insecticidal activity. EC50 of methanol extract against mycelium growth of C. gloeosprioides, P. asparagi and B. cinerea were 5.94 mg?mL-1, 4.61 mg?mL-1 and 5.27 mg?mL-1, respectively. The corresponding EC90 were 63.69 mg?mL-1, 58.01 mg?mL-1 and 54.57 mg?mL -1, respectively. Methanol extract at 0.25~1.00 mg?mL-1 showed strong inhibitory activity against X. campestris. The resultant extract at 0.125 mg?mL-1 showed moderate inhibitory activity. Methanol extract MIC was 0.062 5 mg?mL-1. Methanol extract LC50 against A. albopictus, M. domestica and P. rapae were 0.195 8 mg?mL-1, 0.351 4 mg?mL-1 and 0.287 7 mg?mL-1, respectively. The corresponding EC95 were 0.988 4 mg?mL-1, 3.053 2 mg?mL-1 and 2.584 4 mg?mL-1, respectively. This suggested that J. procumbens extracts had better application prospects as a biological pesticide in agricultural production.
Justicia procumbens is traditional Chinese medicine herb. To confirm fungicidal and insecticidal activity of J. procumbens extracts, methanol, chloroform, acetone, ethyl acetate and hexane extracts were obtained from J. procumbens by the combined method of cold-soaking and ultrasonic extraction. Extract inhibitory effects were studied using the inhibition zone method involving five species of plant pathogenic fungus-Colletotrichum gloeosprioides, Phomopsis asparagi, Pyricularia grisea, Fusarium graminearum and Botrytis cinerea. Methanol extract toxicity against four species of plant pathogenic fungus and bacteria (C. gloeosprioides, P. asparagi, B. cinerea and Xanthomonas campestris) and three species of insects (Aedes albopictus, Musca domestica and Pieris rapae) were also assayed. Results showed that 8 mg?mL-1 extracts of J. procumbens with different polar solvents had some inhibitory effects on five species of plant pathogenic fungus. The inhibition rates of methanol extract against C. gloeosprioides, P. asparagi and B. cinerea were over 50%. Methanol extract from J. procumbens had better fungicidal and insecticidal activity. EC50 of methanol extract against mycelium growth of C. gloeosprioides, P. asparagi and B. cinerea were 5.94 mg?mL-1, 4.61 mg?mL-1 and 5.27 mg?mL-1, respectively. The corresponding EC90 were 63.69 mg?mL-1, 58.01 mg?mL-1 and 54.57 mg?mL -1, respectively. Methanol extract at 0.25~1.00 mg?mL-1 showed strong inhibitory activity against X. campestris. The resultant extract at 0.125 mg?mL-1 showed moderate inhibitory activity. Methanol extract MIC was 0.062 5 mg?mL-1. Methanol extract LC50 against A. albopictus, M. domestica and P. rapae were 0.195 8 mg?mL-1, 0.351 4 mg?mL-1 and 0.287 7 mg?mL-1, respectively. The corresponding EC95 were 0.988 4 mg?mL-1, 3.053 2 mg?mL-1 and 2.584 4 mg?mL-1, respectively. This suggested that J. procumbens extracts had better application prospects as a biological pesticide in agricultural production.
2013, 21(2): 217-226.
doi: 10.3724/SP.J.1011.2013.0021
Abstract:
Pond aquaculture was a critical fishery production system in China. At present, eco-service value research focused on the positive aspects while negative service values (e.g., environmental cost) were neglected. Pond aquaculture performed multiple functions, including aquatic product supply, air conditioning and temperature adjustment, culture recreation services, etc. At the same time, this system can also bring forth environmental costs. For further clarification of changes in eco-service values and to realize sustainable development of pond aquaculture, this paper established a comprehensive eco-service value evaluation system. On this basis, eco-service values and their the spatial-temporal variations in pond aquaculture eco-service values in Shanghai (including Jiading, Qingpu and Fengxian Districts) were estimated by Market Valuation Method (MVM), Travel Cost Method (TCM), Contingent Valuation Method (CVM) and Shadow Engineering Method (SEM). The main results of the paper were summarized as follows: 1) The total values of pond aquaculture eco-service in Jiading, Qingpu and Fengxian Districts were approximately 8.228×107 Yuan·a-1, 8.462 8×108 Yuan·a-1 and 1.558 84×109 Yuan·a-1, respectively. This respectively amounted to 9.408×105 Yuan·hm-2·a-1, 2.000×105 yuan·hm-2·a-1 and 3.273×105 yuan·hm-2·a-1; which were 2.69, 1.94 and 2.17 times of pond aquaculture economic values in 2011. This showed that significant differences existed among the spatial-temporal variations in pond aquaculture. 2) Pond aquaculture eco-service values were high, but this huge potential values were not optimally exploited. Unrealized eco-service values were respectively about 5.46, 1.23 and 0.46 times of net food supply values in the Jiading, Qingpu and Fengxian Districts. 3) Driven by temporal variations in economic efficiency, pond aquaculture varieties were adjusted from 2010 to 2011. Conventional fish aquaculture reduced significantly while freshwater shrimp and Penaeus vannamei became the main aquaculture species in the studied districts. 4) There was significant difference and flucturation in temporal variations in eco-service values due to different spatial distributions among eco-services. Recreation culture service value was highest from April to September, air conditioning value highest from July to December and temperature adjustment value highest from May to September. 5) Pond scales had significant impact on spatial-temporal variations in eco-service values. Pond aquaculture eco-service value was subjected to scale economy. Spatial-temporal distributions of different types of eco-service values were dissimilar and no clear general mechanism was noted. It was necessary to adjust and optimize management strategies of pond aquaculture based on the eco-service value distributions and to develop recreational fisheries to improve eco-service values. It is important for government to develop and implement necessary ecological compensation policy to achieve environmental equity and sustainable development.
Pond aquaculture was a critical fishery production system in China. At present, eco-service value research focused on the positive aspects while negative service values (e.g., environmental cost) were neglected. Pond aquaculture performed multiple functions, including aquatic product supply, air conditioning and temperature adjustment, culture recreation services, etc. At the same time, this system can also bring forth environmental costs. For further clarification of changes in eco-service values and to realize sustainable development of pond aquaculture, this paper established a comprehensive eco-service value evaluation system. On this basis, eco-service values and their the spatial-temporal variations in pond aquaculture eco-service values in Shanghai (including Jiading, Qingpu and Fengxian Districts) were estimated by Market Valuation Method (MVM), Travel Cost Method (TCM), Contingent Valuation Method (CVM) and Shadow Engineering Method (SEM). The main results of the paper were summarized as follows: 1) The total values of pond aquaculture eco-service in Jiading, Qingpu and Fengxian Districts were approximately 8.228×107 Yuan·a-1, 8.462 8×108 Yuan·a-1 and 1.558 84×109 Yuan·a-1, respectively. This respectively amounted to 9.408×105 Yuan·hm-2·a-1, 2.000×105 yuan·hm-2·a-1 and 3.273×105 yuan·hm-2·a-1; which were 2.69, 1.94 and 2.17 times of pond aquaculture economic values in 2011. This showed that significant differences existed among the spatial-temporal variations in pond aquaculture. 2) Pond aquaculture eco-service values were high, but this huge potential values were not optimally exploited. Unrealized eco-service values were respectively about 5.46, 1.23 and 0.46 times of net food supply values in the Jiading, Qingpu and Fengxian Districts. 3) Driven by temporal variations in economic efficiency, pond aquaculture varieties were adjusted from 2010 to 2011. Conventional fish aquaculture reduced significantly while freshwater shrimp and Penaeus vannamei became the main aquaculture species in the studied districts. 4) There was significant difference and flucturation in temporal variations in eco-service values due to different spatial distributions among eco-services. Recreation culture service value was highest from April to September, air conditioning value highest from July to December and temperature adjustment value highest from May to September. 5) Pond scales had significant impact on spatial-temporal variations in eco-service values. Pond aquaculture eco-service value was subjected to scale economy. Spatial-temporal distributions of different types of eco-service values were dissimilar and no clear general mechanism was noted. It was necessary to adjust and optimize management strategies of pond aquaculture based on the eco-service value distributions and to develop recreational fisheries to improve eco-service values. It is important for government to develop and implement necessary ecological compensation policy to achieve environmental equity and sustainable development.
2013, 21(2): 227-235.
doi: 10.3724/SP.J.1011.2013.00227
Abstract:
Climate change has changed agro-climatic resources, especially the degree of heat and the spatio-temporal distributions of resources. Against global warming, temperature has increased in arid Northwest China. Also arid Northwest China has been most influenced by climate change. Using daily meteorological data from 67 stations in arid Northwest China, this paper analyzed change patterns and trends of temperature, accumulated temperature, frost over the period for 1961-2011. The results showed that in the arid northwest region, temperature increased at 0.33 ℃·10a-1, higher than the national average. The warming trend in Northern Xinjiang was larger than in other areas and winter season having the highest yearly variation in temperature. Accumulated temperature higher than 0 ℃ and 10 ℃ increased by 67.8 ℃·10a-1 and 68.8 ℃·10a-1. Accumulated temperature duration also increased over the 1961-2011 period. The increased days with ≥0 ℃ and ≥10 ℃ accumulated temperature were mainly caused by the delayed ending dates and the earlier initial dates, respectively. In the study area, there was delayed first frost, earlier last frost and lengthened frost free period. The rates of change in the first and last frost were 2 d·10a-1 and 1.4 d·10a-1, respectively. In the region, the longer frost-free period was mainly driven by delayed first frost. Inter-annual fluctuation in the first frost was less than that in the last frost in the arid Northwest China. The last frost date was more or less 10 days later than it used to be; even though climate warming caused no change in frost condition. Mostly, the last date of ≥10 ℃ accumulated temperature occurred earlier than the first frost date.
Climate change has changed agro-climatic resources, especially the degree of heat and the spatio-temporal distributions of resources. Against global warming, temperature has increased in arid Northwest China. Also arid Northwest China has been most influenced by climate change. Using daily meteorological data from 67 stations in arid Northwest China, this paper analyzed change patterns and trends of temperature, accumulated temperature, frost over the period for 1961-2011. The results showed that in the arid northwest region, temperature increased at 0.33 ℃·10a-1, higher than the national average. The warming trend in Northern Xinjiang was larger than in other areas and winter season having the highest yearly variation in temperature. Accumulated temperature higher than 0 ℃ and 10 ℃ increased by 67.8 ℃·10a-1 and 68.8 ℃·10a-1. Accumulated temperature duration also increased over the 1961-2011 period. The increased days with ≥0 ℃ and ≥10 ℃ accumulated temperature were mainly caused by the delayed ending dates and the earlier initial dates, respectively. In the study area, there was delayed first frost, earlier last frost and lengthened frost free period. The rates of change in the first and last frost were 2 d·10a-1 and 1.4 d·10a-1, respectively. In the region, the longer frost-free period was mainly driven by delayed first frost. Inter-annual fluctuation in the first frost was less than that in the last frost in the arid Northwest China. The last frost date was more or less 10 days later than it used to be; even though climate warming caused no change in frost condition. Mostly, the last date of ≥10 ℃ accumulated temperature occurred earlier than the first frost date.
2013, 21(2): 236-242.
doi: 10.3724/SP.J.1011.2013.00236
Abstract:
Maize, as a major grain crop in Sichuan, has contributed significantly to total grain production in the province. Sichuan Province has a complex topography and various landforms where droughts have posed serious threat to crop production. Drought is therefore a critical factor that has limited the development, growth and yield formation of maize in Sichuan. It has frequently occurred with an increasing severity in the spring and summer, and has caused the unstable yearly maize production. This paper analyzed spatio-temporal distribution of drought at different maize growth stages in order to lay the scientific basis for relevant departmental development of agricultural production programs and disaster prevention and mitigation strategies which would guide insurance agencies in formulating agricultural insurance premium rates. Daily meteorological data, collected from 144 stations in main corn production regions in Sichuan during 1970-2010, were used to calculate water budget index as an indicator for drought during corn growth season. Spatio-temporal variations in drought frequency and drought risk distribution were analyzed for each corn growth stage in 6 six main production regions (hilly area of southern basin, hilly area of central basin, plain and hill areas of western basin, mountain area around basin, equal ridge-valley region of eastern basin and mountain area of southwest Sichuan) of Sichuan Province. The results showed that since the late 1990s, drought frequency had increased in most corn production regions. The changes in drought frequency with time, however, varied from region to region. With the exception of the eastern basin, station-based mean drought frequency during maize jointing to milk-ripening stage increased across the regions. Also station-based mean drought frequency during maize milk-ripening to maturity stage increased in the southern and western basins and the basin edge. For the entire maize cultivation region in Sichuan, mild to strong drought was more prevalent than severe drought. While mild drought was most common in the hilly area of the southern basin, strong drought was prevalent in the shallow hilly area of the central basin. More severe droughts were less frequent in the low hilly areas of the western basin and in the paralleled ridge valley areas of the eastern basin. Severe drought was most frequent in the hilly areas of the southern basin of Sichuan. The risk of drought was high in the central basin and across most of the eastern basin and parts of the southern basin during corn growth season. Between jointing and milking stage, the risk of drought was high in the northern basin and across most of the central basin. From milk to maturity, there was high risk of drought during corn growth season in the north and southeast of the basin and parts of the central basin.
Maize, as a major grain crop in Sichuan, has contributed significantly to total grain production in the province. Sichuan Province has a complex topography and various landforms where droughts have posed serious threat to crop production. Drought is therefore a critical factor that has limited the development, growth and yield formation of maize in Sichuan. It has frequently occurred with an increasing severity in the spring and summer, and has caused the unstable yearly maize production. This paper analyzed spatio-temporal distribution of drought at different maize growth stages in order to lay the scientific basis for relevant departmental development of agricultural production programs and disaster prevention and mitigation strategies which would guide insurance agencies in formulating agricultural insurance premium rates. Daily meteorological data, collected from 144 stations in main corn production regions in Sichuan during 1970-2010, were used to calculate water budget index as an indicator for drought during corn growth season. Spatio-temporal variations in drought frequency and drought risk distribution were analyzed for each corn growth stage in 6 six main production regions (hilly area of southern basin, hilly area of central basin, plain and hill areas of western basin, mountain area around basin, equal ridge-valley region of eastern basin and mountain area of southwest Sichuan) of Sichuan Province. The results showed that since the late 1990s, drought frequency had increased in most corn production regions. The changes in drought frequency with time, however, varied from region to region. With the exception of the eastern basin, station-based mean drought frequency during maize jointing to milk-ripening stage increased across the regions. Also station-based mean drought frequency during maize milk-ripening to maturity stage increased in the southern and western basins and the basin edge. For the entire maize cultivation region in Sichuan, mild to strong drought was more prevalent than severe drought. While mild drought was most common in the hilly area of the southern basin, strong drought was prevalent in the shallow hilly area of the central basin. More severe droughts were less frequent in the low hilly areas of the western basin and in the paralleled ridge valley areas of the eastern basin. Severe drought was most frequent in the hilly areas of the southern basin of Sichuan. The risk of drought was high in the central basin and across most of the eastern basin and parts of the southern basin during corn growth season. Between jointing and milking stage, the risk of drought was high in the northern basin and across most of the central basin. From milk to maturity, there was high risk of drought during corn growth season in the north and southeast of the basin and parts of the central basin.
2013, 21(2): 243-250.
doi: 10.3724/SP.J.1011.2013.00243
Abstract:
This paper used Yongchuan District in Chongqing City as a case study to address the issues of method disunity, information shield and subjectivity of evaluation processes of eco-security of cultivated land requisition-compensation balance in China with the context and theory of entropy weight and matter element model. The entropy weight method included building systems of assessment factors; setting up factor fields for classifications of eco-security, entropy construction model and matter element analysis; relevancy calculations of factors and eco-securities of cultivated land requisition-compensation balance; and mapping out factor weights. The results showed that eco-security grade of cultivated land requisition-compensation balance for 2005 and 2009 was generally safe and for 2015 and 2020 was safe. The overall trend in eco-security of cultivated land requisition-compensation balance in Yongchuan District improved from general security to high security over the period from 2005, 2009, 2015 onto 2020. The key driving factors of eco-security of cultivated land requisition-compensation balance in the study area included population density, forest cover ratio, pesticide load per unit-area of cultivated land, chemical fertilizer load per unit-area cultivated land, etc. Also the key driving factors of eco-security of cultivated land requisition-compensation balance in Yongchuan District included per-capita cultivated land, cultivated/uncultivated land ratio, annual farmers' per-capital net income growth rate, annual GDP growth rate, primary industry annual growth rate, population natural growth rate, etc. Compared with fuzzy comprehensive evaluation, entropy weight and matter element analysis results were largely consistent. Although differences existed in individual years, leapfrog phenomenon was not apparent. This showed that the evaluation results of matter element analysis were visualized, reasonable and reliable. Also the matter element analysis was practical and the scientific evaluation method more meticulously described the evaluation process of eco-security of cultivated land requisition-compensation balance.
This paper used Yongchuan District in Chongqing City as a case study to address the issues of method disunity, information shield and subjectivity of evaluation processes of eco-security of cultivated land requisition-compensation balance in China with the context and theory of entropy weight and matter element model. The entropy weight method included building systems of assessment factors; setting up factor fields for classifications of eco-security, entropy construction model and matter element analysis; relevancy calculations of factors and eco-securities of cultivated land requisition-compensation balance; and mapping out factor weights. The results showed that eco-security grade of cultivated land requisition-compensation balance for 2005 and 2009 was generally safe and for 2015 and 2020 was safe. The overall trend in eco-security of cultivated land requisition-compensation balance in Yongchuan District improved from general security to high security over the period from 2005, 2009, 2015 onto 2020. The key driving factors of eco-security of cultivated land requisition-compensation balance in the study area included population density, forest cover ratio, pesticide load per unit-area of cultivated land, chemical fertilizer load per unit-area cultivated land, etc. Also the key driving factors of eco-security of cultivated land requisition-compensation balance in Yongchuan District included per-capita cultivated land, cultivated/uncultivated land ratio, annual farmers' per-capital net income growth rate, annual GDP growth rate, primary industry annual growth rate, population natural growth rate, etc. Compared with fuzzy comprehensive evaluation, entropy weight and matter element analysis results were largely consistent. Although differences existed in individual years, leapfrog phenomenon was not apparent. This showed that the evaluation results of matter element analysis were visualized, reasonable and reliable. Also the matter element analysis was practical and the scientific evaluation method more meticulously described the evaluation process of eco-security of cultivated land requisition-compensation balance.
2013, 21(2): 251-260.
doi: 10.3724/SP.J.1011.2013.00251
Abstract:
Sericulture production technology has gradually changed from dispersed small-scale mode to intensive large-scale mode in China. This has greatly increased not only labor force production efficiency in sericulture, but also rural sericulture production income. Concurrently, however, the ecological effectiveness has been insufficient for intensive sericulture technology system. Sericultural production waste has polluted rural ecological environments. To resolve the issue of ecological inefficiency in sericulture technology system and low used efficiency of sericulture resource material, a research was conducted on intensive sericulture technology framework using utilization ratio of annually biosynthesized dry matter in mulberry as a measurement index. For evaluation, the balance was set for technology productivity efficiency and ecological efficiency. Under an integrated eco-sericulture technology system, individual technological balance was evaluated in terms of three efficiencies - technological efficiency, economic efficiency and ecological efficiency. This innovative application of production mode and reflux mode in sericulture resource material optimized sericulture resource material use mode, controlled pollution degree of production wastes in rural ecological environments and formed eco-sericulture technology system frameworks. The frameworks included mulberry branch edible fungus industry production chain, silkworm excrement biogas control pollution and recycled link of filature waste water. Application of eco-sericulture technology system in rural Qin-Ba Mountain Area improved ecological efficiency of sericulture production technology, significantly increased use efficiency of sericulture resource material and environmental water resource and improved rural ecological environment conditions. The estimates for Shiquan County in Shaanxi Province suggested that production and utilization efficiency of sericulture resource material increased by 20.8%, mulberry branch edible fungus industry production was at 10 million bag·a-1, reflux utilization increased by 52.9%, avoided loss of sericulture resource materials, recycled environment water resources ratio was at 70.4% and total circulation water recovery/utilization was at 992 m-3·d-1. Discharged waste water CODCr (the chemical oxygen demand was used by potassium dichromate as oxidant) was <85 mg·L-1, which met national standards - Integrated Wastewater Discharge Standard (GB8978-96). Eco-sericulture technology system therefore not only reduced pollution from sericulture production in rural ecological environments, but also stabilized sustainable development of sericulture production in the Qin-Ba Mountain Area.
Sericulture production technology has gradually changed from dispersed small-scale mode to intensive large-scale mode in China. This has greatly increased not only labor force production efficiency in sericulture, but also rural sericulture production income. Concurrently, however, the ecological effectiveness has been insufficient for intensive sericulture technology system. Sericultural production waste has polluted rural ecological environments. To resolve the issue of ecological inefficiency in sericulture technology system and low used efficiency of sericulture resource material, a research was conducted on intensive sericulture technology framework using utilization ratio of annually biosynthesized dry matter in mulberry as a measurement index. For evaluation, the balance was set for technology productivity efficiency and ecological efficiency. Under an integrated eco-sericulture technology system, individual technological balance was evaluated in terms of three efficiencies - technological efficiency, economic efficiency and ecological efficiency. This innovative application of production mode and reflux mode in sericulture resource material optimized sericulture resource material use mode, controlled pollution degree of production wastes in rural ecological environments and formed eco-sericulture technology system frameworks. The frameworks included mulberry branch edible fungus industry production chain, silkworm excrement biogas control pollution and recycled link of filature waste water. Application of eco-sericulture technology system in rural Qin-Ba Mountain Area improved ecological efficiency of sericulture production technology, significantly increased use efficiency of sericulture resource material and environmental water resource and improved rural ecological environment conditions. The estimates for Shiquan County in Shaanxi Province suggested that production and utilization efficiency of sericulture resource material increased by 20.8%, mulberry branch edible fungus industry production was at 10 million bag·a-1, reflux utilization increased by 52.9%, avoided loss of sericulture resource materials, recycled environment water resources ratio was at 70.4% and total circulation water recovery/utilization was at 992 m-3·d-1. Discharged waste water CODCr (the chemical oxygen demand was used by potassium dichromate as oxidant) was <85 mg·L-1, which met national standards - Integrated Wastewater Discharge Standard (GB8978-96). Eco-sericulture technology system therefore not only reduced pollution from sericulture production in rural ecological environments, but also stabilized sustainable development of sericulture production in the Qin-Ba Mountain Area.
2013, 21(2): 261-266.
doi: 10.3724/SP.J.1011.2013.00261
Abstract:
Acute and diffuse contamination of soil and water by heavy metals, radionuclides, explosives and organic/inorganic pollutants have caused extensive, environmental and social concerns across the globe. Among the techniques used for cleaning up environmental pollution, phytoremediation has emerged as a more recent innovative, cost-effective and environment-friendly alternative. Phytoremediation utilizes plants and microbes to remove, transform or stabilize a whole lot of contaminants in water bodies, sediments or soils. This review focused on the types, advantages and limitations of current state of knowledge and future directions of plant-based cleanup techniques. Phytoremediation technologies included phytoextraction, phytostabilization, phytodegradation, phytostimulation and rhizofiltration. Phytoremediation also had limitations especially when toxicity levels and bioavailability of the pollutants limited its applicability. Or, long cleanup periods had been the greatest shortfall of phytoremediation. The past years had seen notable advances in understanding hyperaccumulator plant selection and breeding; processes that affected pollutant availability, rhizosphere processes, pollu-tant uptake, translocation, degradation and volatilization. There had, however, been still areas that were quite underdeveloped. To further enhance the efficiency of phytoremediation, a number of research directions needed attention. These included molecular biology and genetic engineering in breeding hyperaccumulators, agronomic practices for maximized pollutant uptake by plants, mechanisms of plant-microbe interactions in rhizosphere, integrated remediation technologies, field validated remediation efficiency, integrated landscape architecture, and bioenergy/seeding production of ornamental plants.
Acute and diffuse contamination of soil and water by heavy metals, radionuclides, explosives and organic/inorganic pollutants have caused extensive, environmental and social concerns across the globe. Among the techniques used for cleaning up environmental pollution, phytoremediation has emerged as a more recent innovative, cost-effective and environment-friendly alternative. Phytoremediation utilizes plants and microbes to remove, transform or stabilize a whole lot of contaminants in water bodies, sediments or soils. This review focused on the types, advantages and limitations of current state of knowledge and future directions of plant-based cleanup techniques. Phytoremediation technologies included phytoextraction, phytostabilization, phytodegradation, phytostimulation and rhizofiltration. Phytoremediation also had limitations especially when toxicity levels and bioavailability of the pollutants limited its applicability. Or, long cleanup periods had been the greatest shortfall of phytoremediation. The past years had seen notable advances in understanding hyperaccumulator plant selection and breeding; processes that affected pollutant availability, rhizosphere processes, pollu-tant uptake, translocation, degradation and volatilization. There had, however, been still areas that were quite underdeveloped. To further enhance the efficiency of phytoremediation, a number of research directions needed attention. These included molecular biology and genetic engineering in breeding hyperaccumulators, agronomic practices for maximized pollutant uptake by plants, mechanisms of plant-microbe interactions in rhizosphere, integrated remediation technologies, field validated remediation efficiency, integrated landscape architecture, and bioenergy/seeding production of ornamental plants.
Editor-in-chief：LIU Changming
Competent Authorities：Chinese Academy of Sciences
Sponsored by：Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society
Organizer：Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
ISSN 2096-6237
CN 13-1432/S
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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