The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers＇ fields in Ward 5, Shurugwi. Th...The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers＇ fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging （PETR）, Rip ＆ Pot-Holing （RPH） and Conventional Mouldboard Ploughing （CMP） were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate （34.5% N） at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage （water management） as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers＇ common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially （2003/4） but had beneficial effects in subsequent seasons （2004/5 and 2005/6） with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure ＋ AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.展开更多
Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly...Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefit for plants and soils. Sludge samples were collected over a 12 month period from sewage treatment plants （STP＇s）, i.e, Khairathabad and Meeralam Tank, Hyderabad, India and analyzed for C, H, N, S by elementar analyzer, P, K, Ca, Mg by spectrophotometer and heavy metals like Zn, Pb, Ni, Cu, Cd by atomic absorption spectrophotometer. The sludge contained approximately 50% organic matter and 1-4% inorganic carbon. Organic and inorganic carbon, organic nitrogen, inorganic phosphorous, Ca and Mg were found to be present in sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time when sludge produced from different STP＇s.展开更多
An in-situ benthic device to measure nutrient fluxes across the sediment-water interface has been developed and successfully used to study both static and dynamic fluxes of nutrients in Dianshan Lake, China. The resul...An in-situ benthic device to measure nutrient fluxes across the sediment-water interface has been developed and successfully used to study both static and dynamic fluxes of nutrients in Dianshan Lake, China. The result shows that the surface sediments of Dianshan Lake were resuspended under wind-driven waves. DOC entered into overlying water only when sediments were resuspended. The average DOC flux was 105.78 mg/（mEd）, while the static and dynamic POC fluxes were 48.22 mg/（mEd） and 10 273.20 mg/（m2d）, respectively. Ammonia and nitrate had no significant release, and the dynamic flux of TN was 87.11 mg/（m2d）. The release of phosphorus was the most evident, and the dynamic fluxes of SRP and DTP were 20.22 mg/（m2d） and 21.78 mg/（mEd）, 2.2 and 2.0 times higher than the static fluxes, respectively. Dissolved phosphorus was released mainly as SRP, and phosphorus release from the sediments in Dianshan Lake cannot be ignored.展开更多
文摘The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers＇ fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging （PETR）, Rip ＆ Pot-Holing （RPH） and Conventional Mouldboard Ploughing （CMP） were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate （34.5% N） at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage （water management） as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers＇ common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially （2003/4） but had beneficial effects in subsequent seasons （2004/5 and 2005/6） with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure ＋ AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.
文摘Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefit for plants and soils. Sludge samples were collected over a 12 month period from sewage treatment plants （STP＇s）, i.e, Khairathabad and Meeralam Tank, Hyderabad, India and analyzed for C, H, N, S by elementar analyzer, P, K, Ca, Mg by spectrophotometer and heavy metals like Zn, Pb, Ni, Cu, Cd by atomic absorption spectrophotometer. The sludge contained approximately 50% organic matter and 1-4% inorganic carbon. Organic and inorganic carbon, organic nitrogen, inorganic phosphorous, Ca and Mg were found to be present in sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time when sludge produced from different STP＇s.
基金supported by the National Natural Science Foundation of China(Grant Nos.11032007,11472168)the Technology Innovation Foundation of Institute(Grant No.CX201408)+1 种基金the Science and Technology Commission of Shanghai(Grant No.15DZ1205604)Shanghai Municipal Oceanic Bureau(Grant No.Huhaike 2014-01)
文摘An in-situ benthic device to measure nutrient fluxes across the sediment-water interface has been developed and successfully used to study both static and dynamic fluxes of nutrients in Dianshan Lake, China. The result shows that the surface sediments of Dianshan Lake were resuspended under wind-driven waves. DOC entered into overlying water only when sediments were resuspended. The average DOC flux was 105.78 mg/（mEd）, while the static and dynamic POC fluxes were 48.22 mg/（mEd） and 10 273.20 mg/（m2d）, respectively. Ammonia and nitrate had no significant release, and the dynamic flux of TN was 87.11 mg/（m2d）. The release of phosphorus was the most evident, and the dynamic fluxes of SRP and DTP were 20.22 mg/（m2d） and 21.78 mg/（mEd）, 2.2 and 2.0 times higher than the static fluxes, respectively. Dissolved phosphorus was released mainly as SRP, and phosphorus release from the sediments in Dianshan Lake cannot be ignored.
