Germany and China use different stable systems for fattening pigs. Widespread systems in Germany are closed stables with slatted or partly slatted floor, which produce liquid manure (a mixture of urine, faeces, and c...Germany and China use different stable systems for fattening pigs. Widespread systems in Germany are closed stables with slatted or partly slatted floor, which produce liquid manure (a mixture of urine, faeces, and cleaning water) whereas in China open stables with closed concrete floors are used with separate collection of faeces and urine. Based on data from literature and own analyses nutrient flows of both systems are calculated. The Chinese manure system or mechanized belt or V-shaped pit floor systems with faeces/urine separation are more effective to separate solids, nutrients, carbon, and heavy metal than mechanical separation from liquid manure. The separation rates can be up to 88% for the solids, 67% for nitrogen, 93% for phosphorus, 60% for potassium, 94% for magnesium, 97% for cupper, and 98% for zinc. The faeces can be used for composting to produce a market product.展开更多
The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments...The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi'om High EC & Low CR to Low EC & High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values: irradiated by blue and red light-emitting diode lighting with PPFD (photosynthetic photon flux density) value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.展开更多
Soil nitrogen balance assessment (SNBA) serves as an effective tool for estimating the magnitude of nitrogen loss/gain of the agro-eco systems and to appraise their sustainability. SNBA brings forth awareness of soil ...Soil nitrogen balance assessment (SNBA) serves as an effective tool for estimating the magnitude of nitrogen loss/gain of the agro-eco systems and to appraise their sustainability. SNBA brings forth awareness of soil fertility problems, besides providing information relating to the resultant release of nitrogen into the environment consequent to agricultural practices. Quantitative information relating to nitrogen escape into the environment through such exercises can be gainfully utilized for identification of causative factors, enhancing fertilizer use efficiency and formulating programmes aimed at plugging N leakages. An overview of nitrogen balance approaches and methodologies is presented. A deeper understanding and insight into the agro-eco systems provided by the SNBA exercises can lay the basis for the formulation of effective agronomic interventions and policies aimed at promoting sustainable agriculture and a benign environment.展开更多
To separate and concentrate NH4+ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration...To separate and concentrate NH4+ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration between electrode chamber and middle chamber.In recent years, the research on electrochemical processes have been focused on phosphate and ammonium removal and recovery. Among the wide range of possibilities with regards to electrochemical processes, capacitive deionization (CDI) saves the most energy while at the same time does not have continuity and selectivity. In this study, a new electrochemical reactor with electrolyte cyclic flowing in the electrode chambers was constructed to separate and concentrate phosphate and ammonium continuously and selectively from wastewater, based on the principle of CDI. At the concentration ratio of NaCI solution between the electrode chambers and the middle chamber (r) of 25 to 1, phosphate and ammonium in concentration level of domestic wastewater can be removed and recovered continuously and selectively as struvite. Long-term operation also indicated the ability to continuously repeat the reaction and verified sustained stability. Further, the selective recovery at the certain r could also be available to similar technologies for recovering other kinds of substances.展开更多
The Sino-German research collaboration project,"Recycling of organic residues from agricultural and municipal origin in China"(2008–2012),comprising different interdisciplinary research groups,and also Germ...The Sino-German research collaboration project,"Recycling of organic residues from agricultural and municipal origin in China"(2008–2012),comprising different interdisciplinary research groups,and also German small and medium-sized enterprises,aimed at developing integrated strategies and solutions for the recycling of organic residues in China.In an intensive crop-livestock agricultural region in the Shunyi District of Beijing,five typical cropping systems were investigated.The research was conducted in the form of analyses of phosphorus(P)in soil,plants,animal feed,animal products,manures,mineral and organic fertilizers and the derivation of the corresponding nutrient balances and P flows.The mean annual P balance surplus was492 kg·ha–1·yr–1 P for the vegetable production system,significantly higher(P<0.05)than that for orchards(130 kg·ha–1·yr–1 P)and cereal crops(83 kg·ha–1·yr–1 P).Plant-available P(Olsen-P)concentrations of topsoils(0–20 cm)had good correlations with the amounts of P applied(from mineral and organic sources).Compared to results from the Second Chinese National Soil Survey of 1981,mean concentrations of available P in soils of 19 plots investigated in Shunyi District increased 10-fold(from 7.3 to 60 mg·kg–1)from 1981 to 2009.On average,the critical limit for Olsen-P concentrations(>30 mg·kg–1)that can lead to increased risk of P loss was exceeded in all five cropping systems.With feed additives,the"natural background value"(Chinese Environmental Quality Standard for Soils)of copper and zinc in topsoils was exceeded at several sites.Screening for several substances in the veterinary antibiotic classes of sulfonamides,tetracyclines,and fluoroquinolones revealed widespread topsoil contamination.Calculated livestock densities were 10.6 livestock units per ha arable land in 2007.Animal husbandry is increasingly conducted in large operations,making traditional ways of reuse difficult to apply.Comparing three management systems for treatment of organic residues from a pig farm via aerobic(composting)or anaerobic(biogas)treatment in a life cycle assessment,the resulting cropland demand for a sustainable land application of biogas effluent varied between 139 and 288 ha·yr–1,well above the cropland area owned by the farm(10 ha).The mismatch problems in the above context between business-as-usual and improving performance are framed and discussed as(1)the mismatch between centralized animal husbandry and smallholder farming,(2)the mismatch between livestock density and cropland,(3)nutrient(including P)recycling and increasing organic matter content versus energy production,(4)subsidies for compost production and biogas,as well as(5)advances in the regulatory framework in China.展开更多
基金The authors would like to thank the German Ministry for Education and Research (BMBF) (project No. 0330847G), the National Natural Science Foundation of China (project No. 40971177), and the Ministry of Science and Technology of the People's Republic of China (MOST) for financing the project.
文摘Germany and China use different stable systems for fattening pigs. Widespread systems in Germany are closed stables with slatted or partly slatted floor, which produce liquid manure (a mixture of urine, faeces, and cleaning water) whereas in China open stables with closed concrete floors are used with separate collection of faeces and urine. Based on data from literature and own analyses nutrient flows of both systems are calculated. The Chinese manure system or mechanized belt or V-shaped pit floor systems with faeces/urine separation are more effective to separate solids, nutrients, carbon, and heavy metal than mechanical separation from liquid manure. The separation rates can be up to 88% for the solids, 67% for nitrogen, 93% for phosphorus, 60% for potassium, 94% for magnesium, 97% for cupper, and 98% for zinc. The faeces can be used for composting to produce a market product.
文摘The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi'om High EC & Low CR to Low EC & High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values: irradiated by blue and red light-emitting diode lighting with PPFD (photosynthetic photon flux density) value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.
文摘Soil nitrogen balance assessment (SNBA) serves as an effective tool for estimating the magnitude of nitrogen loss/gain of the agro-eco systems and to appraise their sustainability. SNBA brings forth awareness of soil fertility problems, besides providing information relating to the resultant release of nitrogen into the environment consequent to agricultural practices. Quantitative information relating to nitrogen escape into the environment through such exercises can be gainfully utilized for identification of causative factors, enhancing fertilizer use efficiency and formulating programmes aimed at plugging N leakages. An overview of nitrogen balance approaches and methodologies is presented. A deeper understanding and insight into the agro-eco systems provided by the SNBA exercises can lay the basis for the formulation of effective agronomic interventions and policies aimed at promoting sustainable agriculture and a benign environment.
基金This research was supported by the Key Program of the National Natural Science Foundation of China (Grant Nos. 51238004 & 21521064).
文摘To separate and concentrate NH4+ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration between electrode chamber and middle chamber.In recent years, the research on electrochemical processes have been focused on phosphate and ammonium removal and recovery. Among the wide range of possibilities with regards to electrochemical processes, capacitive deionization (CDI) saves the most energy while at the same time does not have continuity and selectivity. In this study, a new electrochemical reactor with electrolyte cyclic flowing in the electrode chambers was constructed to separate and concentrate phosphate and ammonium continuously and selectively from wastewater, based on the principle of CDI. At the concentration ratio of NaCI solution between the electrode chambers and the middle chamber (r) of 25 to 1, phosphate and ammonium in concentration level of domestic wastewater can be removed and recovered continuously and selectively as struvite. Long-term operation also indicated the ability to continuously repeat the reaction and verified sustained stability. Further, the selective recovery at the certain r could also be available to similar technologies for recovering other kinds of substances.
基金funded by the German Federal Ministry of Education and Research (BMBF) project “Recycling of organic residues from agricultural and municipal origin in China” (0330847A-H)the Ministry of Science and Technology of China (MOST) (2009DFA32710)the German Academic Exchange Service (DAAD)–China Scholarship Council (CSC)
文摘The Sino-German research collaboration project,"Recycling of organic residues from agricultural and municipal origin in China"(2008–2012),comprising different interdisciplinary research groups,and also German small and medium-sized enterprises,aimed at developing integrated strategies and solutions for the recycling of organic residues in China.In an intensive crop-livestock agricultural region in the Shunyi District of Beijing,five typical cropping systems were investigated.The research was conducted in the form of analyses of phosphorus(P)in soil,plants,animal feed,animal products,manures,mineral and organic fertilizers and the derivation of the corresponding nutrient balances and P flows.The mean annual P balance surplus was492 kg·ha–1·yr–1 P for the vegetable production system,significantly higher(P<0.05)than that for orchards(130 kg·ha–1·yr–1 P)and cereal crops(83 kg·ha–1·yr–1 P).Plant-available P(Olsen-P)concentrations of topsoils(0–20 cm)had good correlations with the amounts of P applied(from mineral and organic sources).Compared to results from the Second Chinese National Soil Survey of 1981,mean concentrations of available P in soils of 19 plots investigated in Shunyi District increased 10-fold(from 7.3 to 60 mg·kg–1)from 1981 to 2009.On average,the critical limit for Olsen-P concentrations(>30 mg·kg–1)that can lead to increased risk of P loss was exceeded in all five cropping systems.With feed additives,the"natural background value"(Chinese Environmental Quality Standard for Soils)of copper and zinc in topsoils was exceeded at several sites.Screening for several substances in the veterinary antibiotic classes of sulfonamides,tetracyclines,and fluoroquinolones revealed widespread topsoil contamination.Calculated livestock densities were 10.6 livestock units per ha arable land in 2007.Animal husbandry is increasingly conducted in large operations,making traditional ways of reuse difficult to apply.Comparing three management systems for treatment of organic residues from a pig farm via aerobic(composting)or anaerobic(biogas)treatment in a life cycle assessment,the resulting cropland demand for a sustainable land application of biogas effluent varied between 139 and 288 ha·yr–1,well above the cropland area owned by the farm(10 ha).The mismatch problems in the above context between business-as-usual and improving performance are framed and discussed as(1)the mismatch between centralized animal husbandry and smallholder farming,(2)the mismatch between livestock density and cropland,(3)nutrient(including P)recycling and increasing organic matter content versus energy production,(4)subsidies for compost production and biogas,as well as(5)advances in the regulatory framework in China.