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
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
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
The growing concern with the quality of life and the environment, due to the degradation of natural resources and their contamination, mainly with agrochemicals, led to the emergence of a sustainable or alternative ag...The growing concern with the quality of life and the environment, due to the degradation of natural resources and their contamination, mainly with agrochemicals, led to the emergence of a sustainable or alternative agriculture. The objective of this study was to evaluate the effect of the addition of increasing doses of bentonite and MB4 on the availability of nutrients to the soil. The experiment consisted of a 4 × 4 factorial, bentonite doses (0, 30, 60 and 90 t⋅ha−1) and MB4 doses (0, 3, 6 and 9 t⋅ha−1) with three replications. The soil mixtures with the treatments were conditioned in the plastic pots, incubated for 90 days in a greenhouse, and chemically analyzed. Data were submitted to analysis of variance and comparison of means by the Tukey test. Increasing doses of bentonite and MB4 promoted an increase in the calcium (Ca), magnesium (Mg) in the soil sample either alone or the mixture of two factors, except for the mixture of the Ca Mg doses. Increasing doses of bentonite increased the cation exchange capacity of the soil, favoring the availability of nutrients in the soil. The increasing doses of MB4 favored the increase of the pH values and, consequently, decreased the soil potential acidity values for the applied bentonite doses. On the other hand, these treatments decreased the cation exchange capacity of the soil.展开更多
The clay in the aquatic environment begins to precipitate depending on the saturation level of the solution.The purpose of this work is to monitor this subsidence of the clay and to see its course with photographs.The...The clay in the aquatic environment begins to precipitate depending on the saturation level of the solution.The purpose of this work is to monitor this subsidence of the clay and to see its course with photographs.The photos are then analyzed with the Adobe Photoshop program,so that the students of the 3rd grade of the High School are able to follow the evolution of the precipitation phenomenon through the analysis of the photos and the probability density distribution function of the three pigments(RBG(Red-Blue-Green)in the technology course).The rate of clay settling as shown in the photos requires a prerequisite for the use of soil conditioners in specific clay soils.The students who participated in the workshop had the opportunity to get in touch with the phenomenon of subsidence,the processing of the brightness of the images with the program Adobe Photoshop and the study of soil improvement alternatives.展开更多
Water conveyance tunnels usually experience high internal water pressures and complex soil conditions.Therefore,shield tunnels with double-lining structure have been adopted because of their high bearing capacity.The ...Water conveyance tunnels usually experience high internal water pressures and complex soil conditions.Therefore,shield tunnels with double-lining structure have been adopted because of their high bearing capacity.The effect of the interface between the segmental and inner linings on the bearing capacity has been widely investigated;however,the effect of soil on the internal water pressure bearing capacity has not been emphasized enough.Therefore,in this study,model tests and an analytical solution are presented to elucidate the effect of soil on the internal water pressure bearing capacity.First,model tests are conducted on double-lining models under sandy soil and highly weathered argillaceous siltstone conditions.The internal force and earth pressure under these different soil conditions are then compared to reveal the contribution of soil to the internal water pressure bearing capacity.Following this,an analytical solution,considering the soil–double-lining interaction,is proposed to further investigate the contribution of the soil.The analytical solution is verified with model tests.The analytical solution is in good agreement with the model test results and can be used to evaluate the mechanical behavior of the double-lining and soil contribution.The effect of soil on the bearing capacity is found to be related with the elastic modulus of the soil and the deformation state of the double-lining.Before the double-lining cracks,the sandy soil contributes 3.7%of the internal water pressure but the contribution of the soil rises to 10.4%when it is the highly weathered argillaceous siltstone.After the double-lining cracks,the soil plays an important role in bearing internal water pressure.The soil contributions of sandy soil and highly weathered argillaceous siltstones are 10.5%and 27.8%,respectively.The effect of soil should be considered in tunnel design with the internal water pressure.展开更多
Aims Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest ecosystems.the ob-jective of this study is to examine the effects of soil depth and root diameter ...Aims Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest ecosystems.the ob-jective of this study is to examine the effects of soil depth and root diameter on root decomposition and to analyze the relationship of root decomposition with factors such as soil environmental conditions and initial litter quality.Methods two decomposition experiments were conducted in natural pine(Pinus densiflora)and oak(Quercus serrata)forests over a 2-year period using the litterbag technique.For the soil depth experiment,216 litterbags containing fine roots(∅=0-2 mm)were buried at 0-10-,10-20-and 20-30-cm soil depths.Soil properties and soil enzyme activities and microbial biomass at each soil depth were analyzed.For the root diameter experiment,216 litterbags containing roots 0-1-,1-2-and 2-3-mm in diameter were buried at 10-cm soil depth.the initial litter qualities(carbon(c),nitrogen(N),calcium(ca)and phosphorus(P)concentrations)for each of the root diameter classes were analyzed.Litterbags were retrieved after 3,6,12 and 24 months in each forest type.Important Findingsthe root decomposition rate was significantly altered by soil depth and root diameter.After 2 years,the root decay constant at 0-10-cm depth(pine:0.35 and oak:0.41)was significantly higher than that at 10-20-cm(0.31 and 0.37)and 20-30-cm(0.32 and 0.33)depths in the P.densiflora and Q.serrata forests.Enzyme activities and microbial biomass declined with soil depth,which may be associated with decreasing soil moisture and organic matter.the decay constant for the 0-1-mm roots(pine:0.32 and oak:0.37)was higher than that of 1-2-mm(0.29 and 0.33)and 2-3-mm roots(0.26 and 0.33)for the P.densiflora and Q.serrata forests.Difference in initial P concentration and c/N ratio among the different diameter roots were linearly related with root decomposition.In particular,the increasing c/N ratio with root diameter resulted in decreases in the decomposition rate.these results indicate the surface soil microbial activities and initial c/N ratio of root litter as important drivers of c dynamics in temperate pine and oak forests.展开更多
The aims of this study are to determine the effect of Sabah ragi on food waste and dry leaves composting as well as to compare the composting performance from a previous study that had no addition of Sabah ragi.The co...The aims of this study are to determine the effect of Sabah ragi on food waste and dry leaves composting as well as to compare the composting performance from a previous study that had no addition of Sabah ragi.The composting process was conducted using an in-vessel passive aerated bioreactor with turning every 3 days for 40 days.Based on the physiochemical analysis,the stability and maturity of the compost were evaluated.Parameters such as temperature,total organic carbon,moisture content,pH,conductivity,and C/N were monitored.During the composting process,the highest temperature of 54.2℃ and the highest heat generation rate per initial mass of compost dry matter of 4098 kJ kg^(-1) day^(-1) was achieved on day 7.Furthermore,when compared to previous studies,this study achieved a faster thermophilic phase(≥45℃),a longer thermophilic period(4 days),and a higher cumulative temperature.Elementary kinetic analysis was performed based on the TOC profile and evaluated using coefficient correlation(R^(2)).In this study,application of the second-order model resulted in good responses.Low pathogen levels and higher nitrogen content were detected in the final compost,while some of the nutrients were not in the recommended range.An estimated ragi cost of RM 1.22 was required for every 1 kg of compost with a selling price of RM 6.00/kg of compost.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.
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The growing concern with the quality of life and the environment, due to the degradation of natural resources and their contamination, mainly with agrochemicals, led to the emergence of a sustainable or alternative agriculture. The objective of this study was to evaluate the effect of the addition of increasing doses of bentonite and MB4 on the availability of nutrients to the soil. The experiment consisted of a 4 × 4 factorial, bentonite doses (0, 30, 60 and 90 t⋅ha−1) and MB4 doses (0, 3, 6 and 9 t⋅ha−1) with three replications. The soil mixtures with the treatments were conditioned in the plastic pots, incubated for 90 days in a greenhouse, and chemically analyzed. Data were submitted to analysis of variance and comparison of means by the Tukey test. Increasing doses of bentonite and MB4 promoted an increase in the calcium (Ca), magnesium (Mg) in the soil sample either alone or the mixture of two factors, except for the mixture of the Ca Mg doses. Increasing doses of bentonite increased the cation exchange capacity of the soil, favoring the availability of nutrients in the soil. The increasing doses of MB4 favored the increase of the pH values and, consequently, decreased the soil potential acidity values for the applied bentonite doses. On the other hand, these treatments decreased the cation exchange capacity of the soil.
文摘The clay in the aquatic environment begins to precipitate depending on the saturation level of the solution.The purpose of this work is to monitor this subsidence of the clay and to see its course with photographs.The photos are then analyzed with the Adobe Photoshop program,so that the students of the 3rd grade of the High School are able to follow the evolution of the precipitation phenomenon through the analysis of the photos and the probability density distribution function of the three pigments(RBG(Red-Blue-Green)in the technology course).The rate of clay settling as shown in the photos requires a prerequisite for the use of soil conditioners in specific clay soils.The students who participated in the workshop had the opportunity to get in touch with the phenomenon of subsidence,the processing of the brightness of the images with the program Adobe Photoshop and the study of soil improvement alternatives.
基金the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-0700-07-456 E00051)the National Natural Science Foundation of China(Nos.51978517,52090082,and 52108381)the Shanghai Science and Technology Committee Program(Nos.21DZ1200601 and 20DZ1201404)。
文摘Water conveyance tunnels usually experience high internal water pressures and complex soil conditions.Therefore,shield tunnels with double-lining structure have been adopted because of their high bearing capacity.The effect of the interface between the segmental and inner linings on the bearing capacity has been widely investigated;however,the effect of soil on the internal water pressure bearing capacity has not been emphasized enough.Therefore,in this study,model tests and an analytical solution are presented to elucidate the effect of soil on the internal water pressure bearing capacity.First,model tests are conducted on double-lining models under sandy soil and highly weathered argillaceous siltstone conditions.The internal force and earth pressure under these different soil conditions are then compared to reveal the contribution of soil to the internal water pressure bearing capacity.Following this,an analytical solution,considering the soil–double-lining interaction,is proposed to further investigate the contribution of the soil.The analytical solution is verified with model tests.The analytical solution is in good agreement with the model test results and can be used to evaluate the mechanical behavior of the double-lining and soil contribution.The effect of soil on the bearing capacity is found to be related with the elastic modulus of the soil and the deformation state of the double-lining.Before the double-lining cracks,the sandy soil contributes 3.7%of the internal water pressure but the contribution of the soil rises to 10.4%when it is the highly weathered argillaceous siltstone.After the double-lining cracks,the soil plays an important role in bearing internal water pressure.The soil contributions of sandy soil and highly weathered argillaceous siltstones are 10.5%and 27.8%,respectively.The effect of soil should be considered in tunnel design with the internal water pressure.
基金National Research Foundation of Korea(2018R1A2B6001012).
文摘Aims Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest ecosystems.the ob-jective of this study is to examine the effects of soil depth and root diameter on root decomposition and to analyze the relationship of root decomposition with factors such as soil environmental conditions and initial litter quality.Methods two decomposition experiments were conducted in natural pine(Pinus densiflora)and oak(Quercus serrata)forests over a 2-year period using the litterbag technique.For the soil depth experiment,216 litterbags containing fine roots(∅=0-2 mm)were buried at 0-10-,10-20-and 20-30-cm soil depths.Soil properties and soil enzyme activities and microbial biomass at each soil depth were analyzed.For the root diameter experiment,216 litterbags containing roots 0-1-,1-2-and 2-3-mm in diameter were buried at 10-cm soil depth.the initial litter qualities(carbon(c),nitrogen(N),calcium(ca)and phosphorus(P)concentrations)for each of the root diameter classes were analyzed.Litterbags were retrieved after 3,6,12 and 24 months in each forest type.Important Findingsthe root decomposition rate was significantly altered by soil depth and root diameter.After 2 years,the root decay constant at 0-10-cm depth(pine:0.35 and oak:0.41)was significantly higher than that at 10-20-cm(0.31 and 0.37)and 20-30-cm(0.32 and 0.33)depths in the P.densiflora and Q.serrata forests.Enzyme activities and microbial biomass declined with soil depth,which may be associated with decreasing soil moisture and organic matter.the decay constant for the 0-1-mm roots(pine:0.32 and oak:0.37)was higher than that of 1-2-mm(0.29 and 0.33)and 2-3-mm roots(0.26 and 0.33)for the P.densiflora and Q.serrata forests.Difference in initial P concentration and c/N ratio among the different diameter roots were linearly related with root decomposition.In particular,the increasing c/N ratio with root diameter resulted in decreases in the decomposition rate.these results indicate the surface soil microbial activities and initial c/N ratio of root litter as important drivers of c dynamics in temperate pine and oak forests.
基金The authors acknowledge University Malaysia Sabah for the financial aid(SDG03-2020)Dana Inovasi Sekolah(DIS0005-2020)postdoctoral awarded to Dr.Junidah Lamaming.
文摘The aims of this study are to determine the effect of Sabah ragi on food waste and dry leaves composting as well as to compare the composting performance from a previous study that had no addition of Sabah ragi.The composting process was conducted using an in-vessel passive aerated bioreactor with turning every 3 days for 40 days.Based on the physiochemical analysis,the stability and maturity of the compost were evaluated.Parameters such as temperature,total organic carbon,moisture content,pH,conductivity,and C/N were monitored.During the composting process,the highest temperature of 54.2℃ and the highest heat generation rate per initial mass of compost dry matter of 4098 kJ kg^(-1) day^(-1) was achieved on day 7.Furthermore,when compared to previous studies,this study achieved a faster thermophilic phase(≥45℃),a longer thermophilic period(4 days),and a higher cumulative temperature.Elementary kinetic analysis was performed based on the TOC profile and evaluated using coefficient correlation(R^(2)).In this study,application of the second-order model resulted in good responses.Low pathogen levels and higher nitrogen content were detected in the final compost,while some of the nutrients were not in the recommended range.An estimated ragi cost of RM 1.22 was required for every 1 kg of compost with a selling price of RM 6.00/kg of compost.
