Thirteen sediment core samples(0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus(P) fractions in the sedime...Thirteen sediment core samples(0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus(P) fractions in the sediments of the shallow lakes in the area.The organic P fractions in the sediments were in the order of moderately labile organic P(MLOP) > moderately resistant organic P(MROP) > highly resistant organic P(HROP) > labile organic P(LOP),with average proportional ratios of 13.2:2.8:1.3:1.0.LOP,MLOP,and MROP were significantly related to the contents of total organic carbon(TOC),water-soluble P(WSP),algal-available P(AAP),NaHCO3-extractable P(Olsen-P),total P(TP),organic P(OP),and inorganic P(IP).However,HROP was significantly related to OP and weakly correlated with TOC,WSP,AAP,Olsen-P,TP or IP.This suggested that organic P,especially LOP and MLOP in sediments,deserved even greater attention than IP in regards to lake eutrophication.In terms of organic P,sediments were more hazardous than soils in lake eutrophication.Although OP concentrations were higher in moderately polluted sediment than those in heavily polluted sediment,LOP and MLOP were higher in the heavily polluted sediment,which indicated that heavily polluted sediment was more hazardous than moderately polluted sediment in lake eutrophication.展开更多
Seventy organic compounds including various organophosphorus esters, amines and oxygen-based ligands were investigated as extractants. The experiment results show that amines are excellent extractants for W and Mo. Th...Seventy organic compounds including various organophosphorus esters, amines and oxygen-based ligands were investigated as extractants. The experiment results show that amines are excellent extractants for W and Mo. Their sequence of extraction ability for W is as follows: quarternary amine > tertiary amine > secondary amine > primary amine. Acidic organophosphorus extractants do not extract W, but can extract Mo with high extraction ability from the acidic solution. These extractants could provide a potential process for separating W from Mo.展开更多
Information on soil test phosphorus (P) in soil treated with organic amendments is important to a sound management of manure additions to agricultural fields. This study compared the recovery of cow manure, chicken ma...Information on soil test phosphorus (P) in soil treated with organic amendments is important to a sound management of manure additions to agricultural fields. This study compared the recovery of cow manure, chicken manure, city compost P relative to triple super phosphate P (TSP) for an acidic soil with different antecedent soil test P (STP). Phosphorus was added at rates of 0, 100, 200, 400 and 800 mg P kg-1 soil based on total P. The soil was incubated at field capacity for 1, 4, 8 and 16 weeks (wk) after which they were extracted using NaHCO3 (Olsen) Mehlich-3, Kelowna and Bray & Kurtz-1 extractants. Regardless of extractants, after 1 wk incubation, the highest STP source was the TSP and the least was the city compost. Soil Test P increased with the addition of amendments from different P sources. Among the amendments, soil test P in TSP amended soil gradually decreased but in the city compost amended soil slightly in- creased with incubation time, whereas the changes of soil test P with time in the cow and chicken manures amended soil was very negligible. Across the amendments and rates of P additions, the value of extractable P with Olsen was of 55 mg ?kg-1 (16%), with Mehlich-3 was of 112 mg ?kg-1 (32%), with Kelowna was of 88 mg ?kg-1 (24%) and with Bray & Kurtz was of 104 mg ?kg-1 (29% of total added P). The P extraction efficiency was in the order: NaHCO3 Kelowna < Bray & Kurtz-1 < Mehlich-3. This study indicates that P in organic amendments reflects plant available P through the entire incubation period but P in the TSP are likely to under estimate after 8 wk of incubation.展开更多
基金the China’s National Basic Research Program:"Studies on the Process of Eutrophication of Lakesand the Mechanism of the Blooming of Blue Green Alga" (No2002CB412304)
文摘Thirteen sediment core samples(0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus(P) fractions in the sediments of the shallow lakes in the area.The organic P fractions in the sediments were in the order of moderately labile organic P(MLOP) > moderately resistant organic P(MROP) > highly resistant organic P(HROP) > labile organic P(LOP),with average proportional ratios of 13.2:2.8:1.3:1.0.LOP,MLOP,and MROP were significantly related to the contents of total organic carbon(TOC),water-soluble P(WSP),algal-available P(AAP),NaHCO3-extractable P(Olsen-P),total P(TP),organic P(OP),and inorganic P(IP).However,HROP was significantly related to OP and weakly correlated with TOC,WSP,AAP,Olsen-P,TP or IP.This suggested that organic P,especially LOP and MLOP in sediments,deserved even greater attention than IP in regards to lake eutrophication.In terms of organic P,sediments were more hazardous than soils in lake eutrophication.Although OP concentrations were higher in moderately polluted sediment than those in heavily polluted sediment,LOP and MLOP were higher in the heavily polluted sediment,which indicated that heavily polluted sediment was more hazardous than moderately polluted sediment in lake eutrophication.
文摘Seventy organic compounds including various organophosphorus esters, amines and oxygen-based ligands were investigated as extractants. The experiment results show that amines are excellent extractants for W and Mo. Their sequence of extraction ability for W is as follows: quarternary amine > tertiary amine > secondary amine > primary amine. Acidic organophosphorus extractants do not extract W, but can extract Mo with high extraction ability from the acidic solution. These extractants could provide a potential process for separating W from Mo.
文摘Information on soil test phosphorus (P) in soil treated with organic amendments is important to a sound management of manure additions to agricultural fields. This study compared the recovery of cow manure, chicken manure, city compost P relative to triple super phosphate P (TSP) for an acidic soil with different antecedent soil test P (STP). Phosphorus was added at rates of 0, 100, 200, 400 and 800 mg P kg-1 soil based on total P. The soil was incubated at field capacity for 1, 4, 8 and 16 weeks (wk) after which they were extracted using NaHCO3 (Olsen) Mehlich-3, Kelowna and Bray & Kurtz-1 extractants. Regardless of extractants, after 1 wk incubation, the highest STP source was the TSP and the least was the city compost. Soil Test P increased with the addition of amendments from different P sources. Among the amendments, soil test P in TSP amended soil gradually decreased but in the city compost amended soil slightly in- creased with incubation time, whereas the changes of soil test P with time in the cow and chicken manures amended soil was very negligible. Across the amendments and rates of P additions, the value of extractable P with Olsen was of 55 mg ?kg-1 (16%), with Mehlich-3 was of 112 mg ?kg-1 (32%), with Kelowna was of 88 mg ?kg-1 (24%) and with Bray & Kurtz was of 104 mg ?kg-1 (29% of total added P). The P extraction efficiency was in the order: NaHCO3 Kelowna < Bray & Kurtz-1 < Mehlich-3. This study indicates that P in organic amendments reflects plant available P through the entire incubation period but P in the TSP are likely to under estimate after 8 wk of incubation.
