The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined...The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined, so as to provide techni- cal guidance for reasonable use and improving use efficiency of nitrogen fertilizer for different types of crops. Compared with the control with nitrogen but unplanted crop, growing soybean, cotton, maize, sorghum significantly decreased the soil available N contents by 53. 48%, 51.54%, 33.10%, 55.03%,and influenced the constitution of soil available N. Thereinto, growing soybean, cotton, maize and sorghum significantly decreased soil inorganic N contents by 85.41%, 83.09%, 70.89% and 83.35%,but increased soil hydrolysable organic N contents by 1.41, 1.53, 2.11 and 1.28 times, respectively; growing soybean, cotton, maize and sorghum significantly decreased the rate of soil inorganic N to available N by 68.61%, 65.09%, 56.47% and 63.00%, but increased the rate of soil hydrolysable organic N to available N by 4.18, 4.21, 3.66 and 4.08 times, respectively. Compared with the control, growing soybean, cotton, maize and sorghum significantly increased the transform rate of ammonium nitrogen fertilizer by 93.66%, 38.19%, 32.58% and 38.31% respectively, and growing soybean treatment had the highest increasing range; the nitrification rates of ammo- nium nitrogen fertilizer of growing soybean, cotton, maize and sorghum treatments were negative values, and growing soybean treatment had the highest decreasing amplitude. The ammonium nitrogen fertilizer use efficiency of growing soybean, cot- ton, maize and sorghum treatments were 52.01%, 28.31%, 24.16% and 28.40% re- spectively and growing soybean treatment had the highest value. In conclusion, growing crops suppressed the soil nitrification and accelerated the development of soil hydrolysable organic nitrogen by the utilization of soil available nitrogen and the alteration of soil environment, and hence impacted the constitution of soil available nitrogen and the transform and use of ammonium nitrogen applied in soil. Legumi- nous crops had stronger ability of suppressing nitrification, making use of ammonium compared with non-Leguminous crops.展开更多
The effect of ammonium fixation on the estimation of soil microbial biomass N was studied bv thestandard fumigation-incubation (FI) and fumigation-extraction (FE) methods. NO_3-N content of fumigatedsoil changed littl...The effect of ammonium fixation on the estimation of soil microbial biomass N was studied bv thestandard fumigation-incubation (FI) and fumigation-extraction (FE) methods. NO_3-N content of fumigatedsoil changed little during incubation, while the fixed NH in soils capable of fixing NH increased withthe increase of K_2SO_4-extractable NH_4-N. One day fumigation increased both extractable NH and fixedNH. However, prolonged fumigation gave no further increase. One day fumigation caused significant loss ofNO_3-N, while prolonged fumigation caused no further loss. For soils tested, the net increases of fixed NHin fumigated soil equaled to 0-94% of NH_4-N flush measured by the FI method, and 1-74% of extractable Nmeasured by the FE method, depending on different soils. It is concluded that the ammonium fixation wasone of the processes taking place in soils during fumigation as well as incubation after fumigation and shouldnot be neglected in the estimation of microbial biomass nitrogen by either FI or FE method.展开更多
Two soils with relatively high (Soil 1) and low (Soil 2) ammonium fixation capacities were used in thisstudy to extalne the effect of ammonium fixation on the determination of N mineralised from soil ndcrobialbiomass....Two soils with relatively high (Soil 1) and low (Soil 2) ammonium fixation capacities were used in thisstudy to extalne the effect of ammonium fixation on the determination of N mineralised from soil ndcrobialbiomass. organism suspellsioll was quantitatively introduced to Soil 1 at various rates. Both fumigation-incubation (FI) and fumigation-ext raction (FE ) met hods were used to t reat t he soil. The amount of ffeedNH4+-N increased with increasing rate of organism-N addition. A close correlation was found between theamoun of fixed aznmonium and the rate of organism-N addition. The net increso of fixed NH4+-N wereequivalent to 38% and 12% of the added organism-N for FI and FE treatments, respectively in this specificsoil. To provide isotopic evidence, 15N-labelled organism-N was added to Soils 1 and 2 at 121.4 mg N kg-1.In FI treatment, 22 and 3 mg N kg-1 of labelled N were found in the fraction of fixed NH4+-N in Soils 1 and2 respectively; while in FE treatment, 9 mg N kg-1 of labelled N was found in the fraction of fixed NH4+-Nin Soil 1 only. There was no labelled N in the fraction of fixed NH4+-N in Soil 2. In all of the unfumigated(check) soils, there was little or no labelled N in the fixed fractions, probably because the organism-N addedwas easily mineralized and nitrified. A mean of 0.64 for KN value, the fraction of N ndneralized in the killedmicrobial biomass, was obtained with inclusion of the net increase of fixed NH4+-N. The corresponding valuecalculated with exclusion of the net increase of fixed NH4+-N was 0.46. It was concluded that ammniumfixation was a problem in determination of KN, particularly for soils with a high ammonium fixation capacity.Results also showed that microbial biomass N measurement by FE method was less affected by ammoniumprocess than that by FI method.展开更多
Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw ...Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg -1 respectively. Three treatments were designed to keep the soil saturated with water: A) a 2 cm water layer on soil surface (with beaker mouth open); B) a 2 cm water layer and a 1 cm liquid paraffin layer (with beaker mouth open); and C) water saturated under O 2 free Ar atmosphere. The soils were incubated at 28 oC for 5 days. There was almost no 15 N labelled NH + 4 N detected in Treatment A. However, there was 1.4 to 3.4 mg N kg -1 15 N labelled NH + 4 N in Treatment B and 2.1 to 13.8 mg N kg -1 in Treatment C. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non labelled NH + 4 N in the original soils, 15 N labelled NH + 4 N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. DRNA process in soil suspension seemed to start after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms,did not facilitate DRNA process. DRNA occurred only when glucose was available and at the C/NO 3 - N ratio of over 12. It seemed that both availability and quality of the carbon sources affected DRNA.展开更多
The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing g...The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing glu-cose and (NH4)2HPO4, the strain could convert 137.0g of glucose into 52.4g of 2,3-butanediol and 8.4g of acetoin in shaking flasks. The diol yield amounted to 90% of its theoretical value and the productivity was 1—1.5g·L-1·h-1. In fed-batch fermentation, the yield and productivity of diol were further enhanced by maintaining the pH at 6.0. Up to 92.4g of 2,3-butanediol and 13.1g of acetoin per liter were obtained from 215.0g of glucose per liter. The diol yield reached 98% of its theoretical value and the productivity was up to 2.1g·L-1·h-1.展开更多
Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen aft...Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment. Treatment effect of anaerobic ammonium oxidation （anammox） process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%, 74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. Thc,dcmand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the inftuent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.展开更多
基金Supported by National Natural Science Foundation of China(41371259)Hubei Natural Science Foundation(2014CFB545)~~
文摘The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined, so as to provide techni- cal guidance for reasonable use and improving use efficiency of nitrogen fertilizer for different types of crops. Compared with the control with nitrogen but unplanted crop, growing soybean, cotton, maize, sorghum significantly decreased the soil available N contents by 53. 48%, 51.54%, 33.10%, 55.03%,and influenced the constitution of soil available N. Thereinto, growing soybean, cotton, maize and sorghum significantly decreased soil inorganic N contents by 85.41%, 83.09%, 70.89% and 83.35%,but increased soil hydrolysable organic N contents by 1.41, 1.53, 2.11 and 1.28 times, respectively; growing soybean, cotton, maize and sorghum significantly decreased the rate of soil inorganic N to available N by 68.61%, 65.09%, 56.47% and 63.00%, but increased the rate of soil hydrolysable organic N to available N by 4.18, 4.21, 3.66 and 4.08 times, respectively. Compared with the control, growing soybean, cotton, maize and sorghum significantly increased the transform rate of ammonium nitrogen fertilizer by 93.66%, 38.19%, 32.58% and 38.31% respectively, and growing soybean treatment had the highest increasing range; the nitrification rates of ammo- nium nitrogen fertilizer of growing soybean, cotton, maize and sorghum treatments were negative values, and growing soybean treatment had the highest decreasing amplitude. The ammonium nitrogen fertilizer use efficiency of growing soybean, cot- ton, maize and sorghum treatments were 52.01%, 28.31%, 24.16% and 28.40% re- spectively and growing soybean treatment had the highest value. In conclusion, growing crops suppressed the soil nitrification and accelerated the development of soil hydrolysable organic nitrogen by the utilization of soil available nitrogen and the alteration of soil environment, and hence impacted the constitution of soil available nitrogen and the transform and use of ammonium nitrogen applied in soil. Legumi- nous crops had stronger ability of suppressing nitrification, making use of ammonium compared with non-Leguminous crops.
文摘The effect of ammonium fixation on the estimation of soil microbial biomass N was studied bv thestandard fumigation-incubation (FI) and fumigation-extraction (FE) methods. NO_3-N content of fumigatedsoil changed little during incubation, while the fixed NH in soils capable of fixing NH increased withthe increase of K_2SO_4-extractable NH_4-N. One day fumigation increased both extractable NH and fixedNH. However, prolonged fumigation gave no further increase. One day fumigation caused significant loss ofNO_3-N, while prolonged fumigation caused no further loss. For soils tested, the net increases of fixed NHin fumigated soil equaled to 0-94% of NH_4-N flush measured by the FI method, and 1-74% of extractable Nmeasured by the FE method, depending on different soils. It is concluded that the ammonium fixation wasone of the processes taking place in soils during fumigation as well as incubation after fumigation and shouldnot be neglected in the estimation of microbial biomass nitrogen by either FI or FE method.
文摘Two soils with relatively high (Soil 1) and low (Soil 2) ammonium fixation capacities were used in thisstudy to extalne the effect of ammonium fixation on the determination of N mineralised from soil ndcrobialbiomass. organism suspellsioll was quantitatively introduced to Soil 1 at various rates. Both fumigation-incubation (FI) and fumigation-ext raction (FE ) met hods were used to t reat t he soil. The amount of ffeedNH4+-N increased with increasing rate of organism-N addition. A close correlation was found between theamoun of fixed aznmonium and the rate of organism-N addition. The net increso of fixed NH4+-N wereequivalent to 38% and 12% of the added organism-N for FI and FE treatments, respectively in this specificsoil. To provide isotopic evidence, 15N-labelled organism-N was added to Soils 1 and 2 at 121.4 mg N kg-1.In FI treatment, 22 and 3 mg N kg-1 of labelled N were found in the fraction of fixed NH4+-N in Soils 1 and2 respectively; while in FE treatment, 9 mg N kg-1 of labelled N was found in the fraction of fixed NH4+-Nin Soil 1 only. There was no labelled N in the fraction of fixed NH4+-N in Soil 2. In all of the unfumigated(check) soils, there was little or no labelled N in the fixed fractions, probably because the organism-N addedwas easily mineralized and nitrified. A mean of 0.64 for KN value, the fraction of N ndneralized in the killedmicrobial biomass, was obtained with inclusion of the net increase of fixed NH4+-N. The corresponding valuecalculated with exclusion of the net increase of fixed NH4+-N was 0.46. It was concluded that ammniumfixation was a problem in determination of KN, particularly for soils with a high ammonium fixation capacity.Results also showed that microbial biomass N measurement by FE method was less affected by ammoniumprocess than that by FI method.
文摘Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg -1 respectively. Three treatments were designed to keep the soil saturated with water: A) a 2 cm water layer on soil surface (with beaker mouth open); B) a 2 cm water layer and a 1 cm liquid paraffin layer (with beaker mouth open); and C) water saturated under O 2 free Ar atmosphere. The soils were incubated at 28 oC for 5 days. There was almost no 15 N labelled NH + 4 N detected in Treatment A. However, there was 1.4 to 3.4 mg N kg -1 15 N labelled NH + 4 N in Treatment B and 2.1 to 13.8 mg N kg -1 in Treatment C. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non labelled NH + 4 N in the original soils, 15 N labelled NH + 4 N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. DRNA process in soil suspension seemed to start after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms,did not facilitate DRNA process. DRNA occurred only when glucose was available and at the C/NO 3 - N ratio of over 12. It seemed that both availability and quality of the carbon sources affected DRNA.
文摘The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing glu-cose and (NH4)2HPO4, the strain could convert 137.0g of glucose into 52.4g of 2,3-butanediol and 8.4g of acetoin in shaking flasks. The diol yield amounted to 90% of its theoretical value and the productivity was 1—1.5g·L-1·h-1. In fed-batch fermentation, the yield and productivity of diol were further enhanced by maintaining the pH at 6.0. Up to 92.4g of 2,3-butanediol and 13.1g of acetoin per liter were obtained from 215.0g of glucose per liter. The diol yield reached 98% of its theoretical value and the productivity was up to 2.1g·L-1·h-1.
基金Project (20377013) supported by the National Natural Science Foundation of China project (020959) supported by Department of Science and Technology of Guangdong Province
文摘Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment. Treatment effect of anaerobic ammonium oxidation （anammox） process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%, 74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. Thc,dcmand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the inftuent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.
