The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and...The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.展开更多
[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity...[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.展开更多
Biochar is a soil amendment for increasing soil quality and decreasing nutrient leaching. However, there is little information on the impact of biochar-based fertilizer(BF) on soil nutrient leaching in agricultural so...Biochar is a soil amendment for increasing soil quality and decreasing nutrient leaching. However, there is little information on the impact of biochar-based fertilizer(BF) on soil nutrient leaching in agricultural soils. We conducted a soil column leaching experiment to study the effects of BF on the leaching of total nitrogen(TN), total phosphorus, and total potassium(TK) in tobacco soils. The distribution characteristics of NH_4^+-N, available P, and available K in soil profiles were analyzed after the application of BF. Biochar was prepared by pyrolysis of fluecured tobacco stems. It was applied at four levels, 0%, 3%,9%, and 15%(w/w), respectively, to the compound fertilizer. Compared with the control, the leaching loss of soil TN decreased by 8.36%, 6.72%, and 6.45%, and the loss of soil TK decreased by 9.18%, 9.31% and 11.82% in the 3%,9%, and 15% BF treatments, respectively. However, BF had no significant effect on the P leaching due to the low movement of P in the soil profile. In addition, the BF addition increased the immobilization of NH_4^+-N, available P, and available K in the soil profile. These results indicate that addition of BF to a tobacco-planting soil reduced nutrient leaching, and suggest that BF could be an effective method of applying biochar to agriculture fields.展开更多
The simple-shear condition is closer to reality than the direct-shear condition for simulating the mechanical behavior of vegetated soil slope under shallow failure.However,study on simple-shear characteristics for ve...The simple-shear condition is closer to reality than the direct-shear condition for simulating the mechanical behavior of vegetated soil slope under shallow failure.However,study on simple-shear characteristics for vegetated slope is still insufficient,and there lacks intuitive comparison of characteristics between these two shear conditions.In this study,large-scale simple-shear and direct-shear experiments were conducted on soil permeated by roots of Amorpha fruticosa to investigate the shear strength and stiffness.The stress-displacement relationship of each sample was obtained and further normalized to unify the influence of root content.The results reveal that the direct-shear condition overestimates the shear strength of root-permeated soils(by 41%)and thus the estimation of slope stability based on the parameters of direct-shear condition is not conservative.Furthermore,the initial stiffness of root-permeated soil under simple-shear condition is 34%lower than that under direct-shear condition.The higher strength and stiffness under direct-shear condition are caused by the following reasons:the shear plane does not have the lowest strength,the shear area is decreasing,and the shear zone is thinner.The significant deformation(lower stiffness)revealed by the simple-shear condition facilitates the application of early warning for vegetated shallow landslides.展开更多
A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use i...A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate.展开更多
Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass,respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric mi...Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass,respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric microorganisms, especially nitrogen-fixers, and intensify soil respiration in proportion to the dose and fertilizing time of the conditioner, leading to the increase in the number of nitrogen fixing bacteria and the decrease in the number of bacteria with special nutrition demands.展开更多
This work demonstrates the possibility to make a full valuation of a solid waste such as turkey manure, to obtain methane and a soil conditioner/fertilizer from turkey manure anaerobic digestion in a mesophilic pilot-...This work demonstrates the possibility to make a full valuation of a solid waste such as turkey manure, to obtain methane and a soil conditioner/fertilizer from turkey manure anaerobic digestion in a mesophilic pilot-scale continuous stirred tank reactor at different organic loading rates (OLR) (from 0.5 to 2.5 kgVS/m3d). The application of the anaerobic mono-digestion for the turkey manure treatment was an efficient alternative, because high volatile solids removal and methane were obtained in addition to obtaining a stabilized solid waste that can be applied as soil conditioner, based on its nutritional parameters and humic substances content. In this way, the turkey manure anaerobic digestion can be applied avoiding the co-digestion of the manure with other wastes and allows a process devoid of pollutant emissions, obtaining two products. The reactor operation depends on the OLR, and its operation does not allow an OLR above 1.5 kgVS/m3d. Higher OLR produced a decrease in the TS and VS removals and methane productivity.展开更多
[Objectives] In order to solve the problem of heavy metal pollution in paddy fields,field experiments were carried out to study the effect of Ca-Si soil conditioner on heavy metal remediation in paddy fields. [Methods...[Objectives] In order to solve the problem of heavy metal pollution in paddy fields,field experiments were carried out to study the effect of Ca-Si soil conditioner on heavy metal remediation in paddy fields. [Methods] A conventional planting mode( CK) was used as the control,and a Ca-Si soil conditioner( Ca-Si) treatment was set to analyze the differences in soil pH and heavy metal contents in different treatments. [Results]The content of cadmium in the paddy field exceeded the soil pollution risk control value of agricultural land by 59. 33%. The Ca-Si soil conditioner increased the pH value of paddy field soil by 0. 58 unit. The fixation rates of Ca-Si soil conditioner on chromium,arsenic,cadmium and plumbum reached 75. 96%,14. 09%,18. 93% and 7. 81% compared with the CK,respectively,and the available cadmium and lead contents were reduced by 82. 35% and 80. 00%,respectively. [Conclusions]This study provides ideas and references for the remediation of heavy metal pollution in paddy soil.展开更多
In the present study,reference is made to a pigsty with an estimated total animal weight of 500,000 kg.The quantities and quality(typical characteristics)of the generated waste are calculated.The total waste occurs af...In the present study,reference is made to a pigsty with an estimated total animal weight of 500,000 kg.The quantities and quality(typical characteristics)of the generated waste are calculated.The total waste occurs after the cleaning washes in the premises of the breeding unit.Semi-liquid waste is treated in solid-liquid phase mechanical separation plants.The resulting solids,waste(reduced humidity),go to storage areas,manure.These areas are shaped concrete basins,in which there is aerobic digestion“composting”.This process results in odorless organochumic material which is further used as a soil conditioner.展开更多
Moisture regime plays a crucial role in the mineralization of soil organic carbon (SOC). In this paper, the dynamics of SOC mineralization in typical paddy soils of Changshu, Jiangsu Province, China, was investigate...Moisture regime plays a crucial role in the mineralization of soil organic carbon (SOC). In this paper, the dynamics of SOC mineralization in typical paddy soils of Changshu, Jiangsu Province, China, was investigated by incubation test in laboratory. The differences in SOC mineralization under aerobic and submerged conditions of paddy soils were also studied. Results showed that the daily mineralization of SOC under different moisture regimes was significantly different in the whole incubation period, at the beginning of the incubation, it decreased quickly under aerobic condition, but increased rapidly under submerged condition, and both remained constant after 10 d of incubation. The differences in SOC mineralization were found to be mainly at the beginning period of the incubation and decreased along with the incubation time. Thus, the difference was not significantly different at the later incubation period. The respiration intensity, daily and cumulative mineralization of SOC under aerobic condition was 2.26-19.11, 0.96-2.41, and 0.96-2.41 times than those .under submerged condition, respectively. Statistic analyses showed that the higher the contents of microbial biomass carbon and nitrogen, the more significant difference in respiration intensity between aerobic and submerged conditions, but the higher the contents of microbial biomass nitrogen and dissolved organic carbon, the more significant difference in daily mineralization of SOC between the two conditions. The decrease in soil microbial activity under submerged condition was the main reason leading to the decrease in respiration intensity, but the decrease in SOC mineralization was also correlated with the changes in dissolved organic carbon over the whole incubation period.展开更多
This study deals with the seismic fragility of elastic structural systems equipped with single concave sliding(friction pendulum system(FPS)) isolators considering different soil conditions. The behavior of these ...This study deals with the seismic fragility of elastic structural systems equipped with single concave sliding(friction pendulum system(FPS)) isolators considering different soil conditions. The behavior of these systems is analyzed by employing a two-degree-of-freedom model, whereas the FPS response is described by means of a velocity-dependent model. The uncertainty in the seismic inputs is taken into account by considering artificial seismic excitations modelled as timemodulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. In particular, the filter parameters, which control the frequency content of the random excitations, are calibrated to describe stiff, medium and soft soil conditions. The sliding friction coefficient at large velocity is also considered as a random variable modelled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities of exceeding different limit states related to both the reinforced concrete(RC) superstructure and isolation level, defining the seismic fragility curves within an extensive parametric study carried out for different structural system properties and soil conditions. The abovementioned seismic fragility curves are useful to evaluate the seismic reliability of base-isolated elastic systems equipped with FPS and located in any site for any soil condition.展开更多
Leaf wetness provides a wide range of benefits not only to leaves,but also to ecosystems and communities.It regulates canopy eco-hydrological processes and drives spatial differences in hydrological flux.In spite of t...Leaf wetness provides a wide range of benefits not only to leaves,but also to ecosystems and communities.It regulates canopy eco-hydrological processes and drives spatial differences in hydrological flux.In spite of these functions,little remains known about the spatial distribution of leaf wetness under different soil water conditions.Leaf wetness measurements at the top(180 cm),middle(135 cm),and bottom(85 cm)of the canopy positions of rainfed jujube(Ziziphus jujuba Mill.)in the Chinese loess hilly region were obtained along with meteorological and soil water conditions during the growing seasons in 2019 and 2020.Under soil water non-deficit condition,the frequency of occurrence of leaf wetness was 5.45%higher at the top than at the middle and bottom of the canopy positions.The frequency of occurrence of leaf wetness at the top,middle and bottom of the canopy positions was over 80%at 17:00‒18:00(LST).However,the occurrence of leaf wetness at the top was earlier than those at the middle and bottom of the canopy positions.Correspondingly,leaf drying at the top was also latter than those at the middle and bottom of the canopy positions.Leaf wetness duration at the middle was similar to that at the bottom of the canopy position,but about 1.46-3.01 h less than that at the top.Under soil water deficit condition,the frequency of occurrence of leaf wetness(4.92%-45.45%)followed the order of top>middle>bottom of the canopy position.As the onset of leaf wetness was delayed,the onset of wet leaf drying was advanced and the leaf wetness duration was shortened.Leaf wetness duration at the top was linearly related(R^(2)>0.70)to those at the middle and bottom of the canopy positions under different soil water conditions.In conclusion,the hydrological processes at canopy surfaces of rainfed jujube depended on the position of leaves,thus adjusting canopy structure to redistribute hydrological process is a way to meet the water need of jujube.展开更多
Dissipation kinetics of chlorpyrifos in the near-neutral paddy soils of a vegetable cropping system under greenhouse, screenhouse and field conditions was studied using a rapid analytical method. The recoveries of chl...Dissipation kinetics of chlorpyrifos in the near-neutral paddy soils of a vegetable cropping system under greenhouse, screenhouse and field conditions was studied using a rapid analytical method. The recoveries of chlorpyrifos were between 86.5% and 105.5% with relative standard deviations for repeatability between 6.6% and 9.1% at fortification levels of 0.01, 0.1 and 1 mg/kg in the soil. The limit of detection of the method was 0.004 mg/kg and the limit of quantification was found to be 0.01 mg/kg. The dissipation rates of chlorpyrifos followed the first-order kinetics and the half-life was 6.96, 6.04 and 5.20 days in the soil under greenhouse, screenhouse and field conditions, respectively. The dissipation rates of chlorpyrifos in the soil varied with different cultivation conditions. Chlorpyrifos in the soil dissipated slower in a greenhouse and screenhouse than in the open field, which was likely attributed to the hermetic environment in the greenhouse and screenhouse.展开更多
This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation c...This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation characteristics of PE (potential evapotransph'ation) were analyzed based on the Penman-Monteith method recommended by FAO (the Food and Agriculture Organization of the United Na- lions). The contributions of dynamic, thermal and water factors to PE were discussed, and the wet-dry condition of the plateau region was further studied. The results indicated that daily PE was between 0.52 mm and 6.46 mm for the whole year. Monthly PE was over 107 mm from May to September, but decreased to less than 41 mm from November to February. Annual PE was 1,037.8mm. In the summer, thermal PE was significantly more than dynamic PE, but conversely in the winter. Annual variation of thermal PE was of sine wave pattern. In addition, drought and semi-drought climate lasted for a long time while semi-humid climate was short. The effect of water and dynamic factors on PE varied considerably with the seasons. Annual variation of thermal PE was of sine wave pattern.展开更多
Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT6746...Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulphate and urea) and ions (Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup>) added to these five strains were the elements favouring the good production of cellulase.展开更多
基金supported by the National Natural Science Foundation of China(31560122)the Guangxi Key Laboratory of Agro-Environment and Agric-Products Safety,China。
文摘The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.
基金Supported by Key R&D Program of the Ministry of Science and Technology of China(2017YFC0505102-4)。
文摘[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.
基金supported by the National Natural Science Foundation of China (Nos. 41773144 U1612441+5 种基金 41503080)the Key Technologies R&D Project in Agriculture of Guizhou province (Nos. NY [2013] 3019 NY [2015] 3001-1)the Major S&T Special Project of Guizhou province (No. [2014] 6015-21)the Opening Fund of the State Key Laboratory of Environmental Geochemistry (SKLEG2018905)Innovative Plan of Guizhou province and the Science and Technology Project of Guizhou Tobacco Company (201614)
文摘Biochar is a soil amendment for increasing soil quality and decreasing nutrient leaching. However, there is little information on the impact of biochar-based fertilizer(BF) on soil nutrient leaching in agricultural soils. We conducted a soil column leaching experiment to study the effects of BF on the leaching of total nitrogen(TN), total phosphorus, and total potassium(TK) in tobacco soils. The distribution characteristics of NH_4^+-N, available P, and available K in soil profiles were analyzed after the application of BF. Biochar was prepared by pyrolysis of fluecured tobacco stems. It was applied at four levels, 0%, 3%,9%, and 15%(w/w), respectively, to the compound fertilizer. Compared with the control, the leaching loss of soil TN decreased by 8.36%, 6.72%, and 6.45%, and the loss of soil TK decreased by 9.18%, 9.31% and 11.82% in the 3%,9%, and 15% BF treatments, respectively. However, BF had no significant effect on the P leaching due to the low movement of P in the soil profile. In addition, the BF addition increased the immobilization of NH_4^+-N, available P, and available K in the soil profile. These results indicate that addition of BF to a tobacco-planting soil reduced nutrient leaching, and suggest that BF could be an effective method of applying biochar to agriculture fields.
基金the financial supports from the National Natural Science Foundation of China(Grant No.41925030 and 4179043)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019QZKK0904)the Natural Science Foundation of Shaanxi Province(2020JQ-041)。
文摘The simple-shear condition is closer to reality than the direct-shear condition for simulating the mechanical behavior of vegetated soil slope under shallow failure.However,study on simple-shear characteristics for vegetated slope is still insufficient,and there lacks intuitive comparison of characteristics between these two shear conditions.In this study,large-scale simple-shear and direct-shear experiments were conducted on soil permeated by roots of Amorpha fruticosa to investigate the shear strength and stiffness.The stress-displacement relationship of each sample was obtained and further normalized to unify the influence of root content.The results reveal that the direct-shear condition overestimates the shear strength of root-permeated soils(by 41%)and thus the estimation of slope stability based on the parameters of direct-shear condition is not conservative.Furthermore,the initial stiffness of root-permeated soil under simple-shear condition is 34%lower than that under direct-shear condition.The higher strength and stiffness under direct-shear condition are caused by the following reasons:the shear plane does not have the lowest strength,the shear area is decreasing,and the shear zone is thinner.The significant deformation(lower stiffness)revealed by the simple-shear condition facilitates the application of early warning for vegetated shallow landslides.
基金Project partly supported by a grant from Expressway International Ltd., USA.
文摘A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate.
基金support from the 863 National High-Technology Program of China(819-07-10).
文摘Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass,respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric microorganisms, especially nitrogen-fixers, and intensify soil respiration in proportion to the dose and fertilizing time of the conditioner, leading to the increase in the number of nitrogen fixing bacteria and the decrease in the number of bacteria with special nutrition demands.
文摘This work demonstrates the possibility to make a full valuation of a solid waste such as turkey manure, to obtain methane and a soil conditioner/fertilizer from turkey manure anaerobic digestion in a mesophilic pilot-scale continuous stirred tank reactor at different organic loading rates (OLR) (from 0.5 to 2.5 kgVS/m3d). The application of the anaerobic mono-digestion for the turkey manure treatment was an efficient alternative, because high volatile solids removal and methane were obtained in addition to obtaining a stabilized solid waste that can be applied as soil conditioner, based on its nutritional parameters and humic substances content. In this way, the turkey manure anaerobic digestion can be applied avoiding the co-digestion of the manure with other wastes and allows a process devoid of pollutant emissions, obtaining two products. The reactor operation depends on the OLR, and its operation does not allow an OLR above 1.5 kgVS/m3d. Higher OLR produced a decrease in the TS and VS removals and methane productivity.
基金Supported by Natural Science Foundation of Guangdong Province(2018A030307075)Special Fund for Science and Technology Innovation Strategy of Guangdong Province(135-99000206,432-99000228)+2 种基金Science and Technology Planning Project of Shaoguan City(2018sn038)School-level Project of Shaoguan University(SY2016KJ04)Undergraduate Innovation and Entrepreneurship Project(Sycxcy2017-041,201810576009)。
文摘[Objectives] In order to solve the problem of heavy metal pollution in paddy fields,field experiments were carried out to study the effect of Ca-Si soil conditioner on heavy metal remediation in paddy fields. [Methods] A conventional planting mode( CK) was used as the control,and a Ca-Si soil conditioner( Ca-Si) treatment was set to analyze the differences in soil pH and heavy metal contents in different treatments. [Results]The content of cadmium in the paddy field exceeded the soil pollution risk control value of agricultural land by 59. 33%. The Ca-Si soil conditioner increased the pH value of paddy field soil by 0. 58 unit. The fixation rates of Ca-Si soil conditioner on chromium,arsenic,cadmium and plumbum reached 75. 96%,14. 09%,18. 93% and 7. 81% compared with the CK,respectively,and the available cadmium and lead contents were reduced by 82. 35% and 80. 00%,respectively. [Conclusions]This study provides ideas and references for the remediation of heavy metal pollution in paddy soil.
文摘In the present study,reference is made to a pigsty with an estimated total animal weight of 500,000 kg.The quantities and quality(typical characteristics)of the generated waste are calculated.The total waste occurs after the cleaning washes in the premises of the breeding unit.Semi-liquid waste is treated in solid-liquid phase mechanical separation plants.The resulting solids,waste(reduced humidity),go to storage areas,manure.These areas are shaped concrete basins,in which there is aerobic digestion“composting”.This process results in odorless organochumic material which is further used as a soil conditioner.
基金supported by the National Natural Science Foundation of China (40471066)the Natural Science Foundation of Jiangsu Province,China (BK2007266)
文摘Moisture regime plays a crucial role in the mineralization of soil organic carbon (SOC). In this paper, the dynamics of SOC mineralization in typical paddy soils of Changshu, Jiangsu Province, China, was investigated by incubation test in laboratory. The differences in SOC mineralization under aerobic and submerged conditions of paddy soils were also studied. Results showed that the daily mineralization of SOC under different moisture regimes was significantly different in the whole incubation period, at the beginning of the incubation, it decreased quickly under aerobic condition, but increased rapidly under submerged condition, and both remained constant after 10 d of incubation. The differences in SOC mineralization were found to be mainly at the beginning period of the incubation and decreased along with the incubation time. Thus, the difference was not significantly different at the later incubation period. The respiration intensity, daily and cumulative mineralization of SOC under aerobic condition was 2.26-19.11, 0.96-2.41, and 0.96-2.41 times than those .under submerged condition, respectively. Statistic analyses showed that the higher the contents of microbial biomass carbon and nitrogen, the more significant difference in respiration intensity between aerobic and submerged conditions, but the higher the contents of microbial biomass nitrogen and dissolved organic carbon, the more significant difference in daily mineralization of SOC between the two conditions. The decrease in soil microbial activity under submerged condition was the main reason leading to the decrease in respiration intensity, but the decrease in SOC mineralization was also correlated with the changes in dissolved organic carbon over the whole incubation period.
文摘This study deals with the seismic fragility of elastic structural systems equipped with single concave sliding(friction pendulum system(FPS)) isolators considering different soil conditions. The behavior of these systems is analyzed by employing a two-degree-of-freedom model, whereas the FPS response is described by means of a velocity-dependent model. The uncertainty in the seismic inputs is taken into account by considering artificial seismic excitations modelled as timemodulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. In particular, the filter parameters, which control the frequency content of the random excitations, are calibrated to describe stiff, medium and soft soil conditions. The sliding friction coefficient at large velocity is also considered as a random variable modelled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities of exceeding different limit states related to both the reinforced concrete(RC) superstructure and isolation level, defining the seismic fragility curves within an extensive parametric study carried out for different structural system properties and soil conditions. The abovementioned seismic fragility curves are useful to evaluate the seismic reliability of base-isolated elastic systems equipped with FPS and located in any site for any soil condition.
基金funded by the National Natural Science Foundation of China(32060301).
文摘Leaf wetness provides a wide range of benefits not only to leaves,but also to ecosystems and communities.It regulates canopy eco-hydrological processes and drives spatial differences in hydrological flux.In spite of these functions,little remains known about the spatial distribution of leaf wetness under different soil water conditions.Leaf wetness measurements at the top(180 cm),middle(135 cm),and bottom(85 cm)of the canopy positions of rainfed jujube(Ziziphus jujuba Mill.)in the Chinese loess hilly region were obtained along with meteorological and soil water conditions during the growing seasons in 2019 and 2020.Under soil water non-deficit condition,the frequency of occurrence of leaf wetness was 5.45%higher at the top than at the middle and bottom of the canopy positions.The frequency of occurrence of leaf wetness at the top,middle and bottom of the canopy positions was over 80%at 17:00‒18:00(LST).However,the occurrence of leaf wetness at the top was earlier than those at the middle and bottom of the canopy positions.Correspondingly,leaf drying at the top was also latter than those at the middle and bottom of the canopy positions.Leaf wetness duration at the middle was similar to that at the bottom of the canopy position,but about 1.46-3.01 h less than that at the top.Under soil water deficit condition,the frequency of occurrence of leaf wetness(4.92%-45.45%)followed the order of top>middle>bottom of the canopy position.As the onset of leaf wetness was delayed,the onset of wet leaf drying was advanced and the leaf wetness duration was shortened.Leaf wetness duration at the top was linearly related(R^(2)>0.70)to those at the middle and bottom of the canopy positions under different soil water conditions.In conclusion,the hydrological processes at canopy surfaces of rainfed jujube depended on the position of leaves,thus adjusting canopy structure to redistribute hydrological process is a way to meet the water need of jujube.
文摘Dissipation kinetics of chlorpyrifos in the near-neutral paddy soils of a vegetable cropping system under greenhouse, screenhouse and field conditions was studied using a rapid analytical method. The recoveries of chlorpyrifos were between 86.5% and 105.5% with relative standard deviations for repeatability between 6.6% and 9.1% at fortification levels of 0.01, 0.1 and 1 mg/kg in the soil. The limit of detection of the method was 0.004 mg/kg and the limit of quantification was found to be 0.01 mg/kg. The dissipation rates of chlorpyrifos followed the first-order kinetics and the half-life was 6.96, 6.04 and 5.20 days in the soil under greenhouse, screenhouse and field conditions, respectively. The dissipation rates of chlorpyrifos in the soil varied with different cultivation conditions. Chlorpyrifos in the soil dissipated slower in a greenhouse and screenhouse than in the open field, which was likely attributed to the hermetic environment in the greenhouse and screenhouse.
基金the funding received from the National Key Programme for Developing Basic Sciences of China (2010CB951701)Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-01)+3 种基金Natural Science Foundation of China (40875005)Natural Science Foundation of China for International Cooperation (40810059006)European Commission CEOP-AEGIS (Call FP7-ENV-2007-1 Grant No. 212921)Gansu Science and Technology Key Project (1001JKDA001)
文摘This study was based on the CEOP/CAMP-Tibet observed data at AWS (Automatic Weather Station) of MS3478 in the seasonal frozen soil region of northern Tibetan Plateau from March 2007 to February 2008. The variation characteristics of PE (potential evapotransph'ation) were analyzed based on the Penman-Monteith method recommended by FAO (the Food and Agriculture Organization of the United Na- lions). The contributions of dynamic, thermal and water factors to PE were discussed, and the wet-dry condition of the plateau region was further studied. The results indicated that daily PE was between 0.52 mm and 6.46 mm for the whole year. Monthly PE was over 107 mm from May to September, but decreased to less than 41 mm from November to February. Annual PE was 1,037.8mm. In the summer, thermal PE was significantly more than dynamic PE, but conversely in the winter. Annual variation of thermal PE was of sine wave pattern. In addition, drought and semi-drought climate lasted for a long time while semi-humid climate was short. The effect of water and dynamic factors on PE varied considerably with the seasons. Annual variation of thermal PE was of sine wave pattern.
文摘Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulphate and urea) and ions (Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup>) added to these five strains were the elements favouring the good production of cellulase.