To find a new way treating the wastewater from biogas reactors in a pig farm, vegetated floating bed was built for observing the water-purifying capability of water spinach (Ipomoea aquatic) planted on the water surfa...To find a new way treating the wastewater from biogas reactors in a pig farm, vegetated floating bed was built for observing the water-purifying capability of water spinach (Ipomoea aquatic) planted on the water surface. Experiments were carried out to record the growth and biomass accumulation of water spinach and its effect on purification of biogas wastewater. The results show that the water which mixed with biogas wastewater has been purified significantly by water spinach on the floating bed. During its growth season within four months, the overall length of water spinach reached 199 ± 35 cm, while its root length reached 63 ± 28.6 cm. The average weight of individual fresh plant is of 1285 ± 619.7 g. Meanwhile, the concentration of total nitrogen (TN) in water under the floating bed decreased from 8.9 ± 0.062 mg·L-1 to 0.5 ± 0.011 mg·L-1;the concentration of total phosphorus (TP) decreased from 4.4 ± 0.236 mg·L-1 to 0.92 ± 0.024 mg·L-1;the concentration of chemical oxygen demand (COD) decreased from 87.3 ± 6.68 mg·L-1 to 0.74 ± 0.46 mg·L-1. It suggests that the water spinach removed more than 90% of pollutants in terms of TN, TP, and COD from the water. Results show that the vegetated floating bed technique is a feasible way to dispose the biogas slurry.展开更多
Most previous researches have focused on biochar application in agricultural soils; however, limited information is available concerning the effects of biochar amendment on greenhouse substrate properties. A greenhous...Most previous researches have focused on biochar application in agricultural soils; however, limited information is available concerning the effects of biochar amendment on greenhouse substrate properties. A greenhouse experiment was conducted to investigate effects of wheat straw biochar(0–160 m L L-1) and super absorbent polymer(SAP, 0.8 g L-1) on physical and chemical properties of a substrate based on spent pig litter compost and the growth of water spinach(Ipomoea aquatica Forsk). Total porosity, water-holding capacity, p H and electrical conductivity(EC) of the substrate significantly increased with increasing biochar rates, especially in the substrate without SAP. The values of p H and EC were significantly lower in the substrate with SAP than those without SAP at the high biochar application rates(100–160 m L L-1). The germination rates of water spinach decreased with increasing biochar rates when biochar was added alone(76.9%–83.7%), whereas the rates increased to 83.6%–85.8% when biochar was added in combination with SAP. Growth parameters of water spinach and nutrient uptake by shoots and roots increased with increasing biochar rates and reached the maximum values at the biochar rate of 100 m L L-1. There were significant cubic relationships between the uptake of nutrients(N, P, and K) and biochar rates, both with and without SAP addition. In order to avoid negative effects on plant growth,the biochar application rate should be controlled at an optimal level(100 m L L-1). The SAP addition not only enhanced the positive effects of biochar application on the properties of the substrate, but also inhibited the excessive rise of p H and EC following biochar additions, which led to better plant growth and enhanced nutrient uptakes by water spinach.展开更多
Effects of conventional and optimized water and nitrogen managements on spinach (Spinacia olerocea L.)growth and soil mineral N (Nmi.) residues were compared in an open field experiment in which water balancemethod an...Effects of conventional and optimized water and nitrogen managements on spinach (Spinacia olerocea L.)growth and soil mineral N (Nmi.) residues were compared in an open field experiment in which water balancemethod and N recommendation with the KNS-system were included. It was shown that the conventionalwater treatment (seasonal irrigated amount: 175 mm) reduced spinach growth compared to the water balancetreatments (seasonal irrigated amount: 80 and 85 mm) at the same N supply level due to N loss throughleaching caused by excessive water supply. Although 309 kg N ha-1 was applied in the conventional Ntreatment, compared to 82 and 66 kg N ha-l in the optimum N treatments, no significant difference in cropyield was investigated between the N treatments with the same irrigation practice. N uptake in spinach andsoil residual Nmin contents were also significantly affected by the irrigation practices. The conventional watersupply not only decreased water use efficiency, but also展开更多
Lead is a toxic and naturally occurring substance with documented neurotoxin, toxic, and long-lasting adverse health effects globally. Lead exposure can cause impaired physical and mental development in children. Expo...Lead is a toxic and naturally occurring substance with documented neurotoxin, toxic, and long-lasting adverse health effects globally. Lead exposure can cause impaired physical and mental development in children. Exposure to high lead levels affects the intestinal tract, kidneys, joints and reproductive system in adults. This study evaluates the removal of 1500 PPM of lead from contaminated aqueous solution using Celite, Louisiana Red Clay, Charcoal, and supernatants from aqueous extracts of Mustard Green (Brassica juncea), and Spinach (Spinacea oleracea). After shaking triplicate reaction mixtures for each substrate for 22 hours at room temperature, lead removal by the five substrates were analyzed by EPA Method 6010, using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Results suggest that the order of lead removal is Spinach (98%) > Charcoal (96%) > LA Red Clay (88%) > Mustard Green (87%) > Celite (4%). The study concludes that liquid substrates such as the supernatants from pureed spinach and mustard green can effectively remove lead from contaminated water.展开更多
文摘To find a new way treating the wastewater from biogas reactors in a pig farm, vegetated floating bed was built for observing the water-purifying capability of water spinach (Ipomoea aquatic) planted on the water surface. Experiments were carried out to record the growth and biomass accumulation of water spinach and its effect on purification of biogas wastewater. The results show that the water which mixed with biogas wastewater has been purified significantly by water spinach on the floating bed. During its growth season within four months, the overall length of water spinach reached 199 ± 35 cm, while its root length reached 63 ± 28.6 cm. The average weight of individual fresh plant is of 1285 ± 619.7 g. Meanwhile, the concentration of total nitrogen (TN) in water under the floating bed decreased from 8.9 ± 0.062 mg·L-1 to 0.5 ± 0.011 mg·L-1;the concentration of total phosphorus (TP) decreased from 4.4 ± 0.236 mg·L-1 to 0.92 ± 0.024 mg·L-1;the concentration of chemical oxygen demand (COD) decreased from 87.3 ± 6.68 mg·L-1 to 0.74 ± 0.46 mg·L-1. It suggests that the water spinach removed more than 90% of pollutants in terms of TN, TP, and COD from the water. Results show that the vegetated floating bed technique is a feasible way to dispose the biogas slurry.
基金supported by the National Natural Science Foundation of China (No.41401259)the General Financial Grant from the China Postdoctoral Science Foundation (No.2014M551528)+1 种基金the Independent Innovation Project of Jiangsu Province,China (No.CX(14)2035)the Special Scientific Research Fund of Agricultural Public Welfare Profession of China (No.201203050)
文摘Most previous researches have focused on biochar application in agricultural soils; however, limited information is available concerning the effects of biochar amendment on greenhouse substrate properties. A greenhouse experiment was conducted to investigate effects of wheat straw biochar(0–160 m L L-1) and super absorbent polymer(SAP, 0.8 g L-1) on physical and chemical properties of a substrate based on spent pig litter compost and the growth of water spinach(Ipomoea aquatica Forsk). Total porosity, water-holding capacity, p H and electrical conductivity(EC) of the substrate significantly increased with increasing biochar rates, especially in the substrate without SAP. The values of p H and EC were significantly lower in the substrate with SAP than those without SAP at the high biochar application rates(100–160 m L L-1). The germination rates of water spinach decreased with increasing biochar rates when biochar was added alone(76.9%–83.7%), whereas the rates increased to 83.6%–85.8% when biochar was added in combination with SAP. Growth parameters of water spinach and nutrient uptake by shoots and roots increased with increasing biochar rates and reached the maximum values at the biochar rate of 100 m L L-1. There were significant cubic relationships between the uptake of nutrients(N, P, and K) and biochar rates, both with and without SAP addition. In order to avoid negative effects on plant growth,the biochar application rate should be controlled at an optimal level(100 m L L-1). The SAP addition not only enhanced the positive effects of biochar application on the properties of the substrate, but also inhibited the excessive rise of p H and EC following biochar additions, which led to better plant growth and enhanced nutrient uptakes by water spinach.
基金Natural Science Foundation of Beijing(No.6991004)Joint Lab between theInstitute of Soil Science, CAS, +1 种基金 Hong Kong Baptist University (No. 99122202) Federal Ministry of Education and Research, Germany.
文摘Effects of conventional and optimized water and nitrogen managements on spinach (Spinacia olerocea L.)growth and soil mineral N (Nmi.) residues were compared in an open field experiment in which water balancemethod and N recommendation with the KNS-system were included. It was shown that the conventionalwater treatment (seasonal irrigated amount: 175 mm) reduced spinach growth compared to the water balancetreatments (seasonal irrigated amount: 80 and 85 mm) at the same N supply level due to N loss throughleaching caused by excessive water supply. Although 309 kg N ha-1 was applied in the conventional Ntreatment, compared to 82 and 66 kg N ha-l in the optimum N treatments, no significant difference in cropyield was investigated between the N treatments with the same irrigation practice. N uptake in spinach andsoil residual Nmin contents were also significantly affected by the irrigation practices. The conventional watersupply not only decreased water use efficiency, but also
文摘Lead is a toxic and naturally occurring substance with documented neurotoxin, toxic, and long-lasting adverse health effects globally. Lead exposure can cause impaired physical and mental development in children. Exposure to high lead levels affects the intestinal tract, kidneys, joints and reproductive system in adults. This study evaluates the removal of 1500 PPM of lead from contaminated aqueous solution using Celite, Louisiana Red Clay, Charcoal, and supernatants from aqueous extracts of Mustard Green (Brassica juncea), and Spinach (Spinacea oleracea). After shaking triplicate reaction mixtures for each substrate for 22 hours at room temperature, lead removal by the five substrates were analyzed by EPA Method 6010, using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Results suggest that the order of lead removal is Spinach (98%) > Charcoal (96%) > LA Red Clay (88%) > Mustard Green (87%) > Celite (4%). The study concludes that liquid substrates such as the supernatants from pureed spinach and mustard green can effectively remove lead from contaminated water.
