Monoammonium phosphate （MAP） is produced from crude phosphoric acid which contains Fe （III）, AI （III） and Mg （II） ions. In general, the fertilizers MAP was obtained by including various heavy metal micronutrie...Monoammonium phosphate （MAP） is produced from crude phosphoric acid which contains Fe （III）, AI （III） and Mg （II） ions. In general, the fertilizers MAP was obtained by including various heavy metal micronutrients （Co, Cu, Fe, Mn, Mo, Ni and Zn）, fluorine and heavy metals considered toxic （Al and Cd） in. The long-continued application of phosphate fertilizers （MAP） and their by products can redistribute and elevate heavy metal and fluorine concentrations in soil profiles. However, they are subsequently transferred into the human food chain because of their availability to plants, mainly in acid soils. Thus, it is important to eliminate the impurities in MAP. Purified MAP is three times more expensive than the same product before purification and is commonly used in a number of applications such as flame proofing （building materials, pulp and paper） and agriculture. Purified MAP is a key ingredient in specialty all-soluble dry fertilizers, waste water-nutrient for biological purification, fermentation and biotechnology-nutrient. The procedure for purification of industrial MAP is a recrystallization, by using several mixtures of solvents. The physicochemical characterization of this fertilizer upstream and downstream from the purification, through spectroscopic analyses and chemical analyses, shows that recrystallization can eliminate impurities. The physicochemical properties of the purified MAP obtained by recrystallization are comparable to those of the MAP obtained with a pure phosphoric acid.展开更多
The maximum rate of carboxylation （Vcax） is a key photosynthetic parameter for gross primary produc- tion （GPP） estimation in terrestrial biosphere models. A set of observation-based Vcax values, which take the ni...The maximum rate of carboxylation （Vcax） is a key photosynthetic parameter for gross primary produc- tion （GPP） estimation in terrestrial biosphere models. A set of observation-based Vcax values, which take the ni- trogen limitation on photosynthetic rates into consideration, are used in version 4.5 of the Community Land Model （CLM4.5）. However, CLM4.5 with carbon-nitrogen （CN） biogeochemistry （CLM4.5-CN） still uses an inde- pendent decay coefficient for nitrogen after the photosyn- thesis calculation. This means that the nitrogen limitation on the carbon cycle is accounted for twice when CN bio- geochemistry is active. Therefore, to avoid this double nitrogen down-regulation in CLM4.5-CN, the original Vcmax scheme is revised with a new one that only accounts for the transition between Vcmax and its potential value （without nitrogen limitation）. Compared to flux tower- based observations, the new Vcmax scheme reduces the root-mean-square error （RMSE） in GPP for China's Mainland by 13.7 g C m-2 yr-1, with a larger decrease over humid areas （39.2 g C m 2 yr-1）. Moreover, net primary production and leaf area index are also improved, with reductions in RMSE by 0.8% and 11.5%, respectively.展开更多
文摘Monoammonium phosphate （MAP） is produced from crude phosphoric acid which contains Fe （III）, AI （III） and Mg （II） ions. In general, the fertilizers MAP was obtained by including various heavy metal micronutrients （Co, Cu, Fe, Mn, Mo, Ni and Zn）, fluorine and heavy metals considered toxic （Al and Cd） in. The long-continued application of phosphate fertilizers （MAP） and their by products can redistribute and elevate heavy metal and fluorine concentrations in soil profiles. However, they are subsequently transferred into the human food chain because of their availability to plants, mainly in acid soils. Thus, it is important to eliminate the impurities in MAP. Purified MAP is three times more expensive than the same product before purification and is commonly used in a number of applications such as flame proofing （building materials, pulp and paper） and agriculture. Purified MAP is a key ingredient in specialty all-soluble dry fertilizers, waste water-nutrient for biological purification, fermentation and biotechnology-nutrient. The procedure for purification of industrial MAP is a recrystallization, by using several mixtures of solvents. The physicochemical characterization of this fertilizer upstream and downstream from the purification, through spectroscopic analyses and chemical analyses, shows that recrystallization can eliminate impurities. The physicochemical properties of the purified MAP obtained by recrystallization are comparable to those of the MAP obtained with a pure phosphoric acid.
基金supported by the National Natural Science Foundation of China(Grant Nos.91125016 and 41305066)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05110102)
文摘The maximum rate of carboxylation （Vcax） is a key photosynthetic parameter for gross primary produc- tion （GPP） estimation in terrestrial biosphere models. A set of observation-based Vcax values, which take the ni- trogen limitation on photosynthetic rates into consideration, are used in version 4.5 of the Community Land Model （CLM4.5）. However, CLM4.5 with carbon-nitrogen （CN） biogeochemistry （CLM4.5-CN） still uses an inde- pendent decay coefficient for nitrogen after the photosyn- thesis calculation. This means that the nitrogen limitation on the carbon cycle is accounted for twice when CN bio- geochemistry is active. Therefore, to avoid this double nitrogen down-regulation in CLM4.5-CN, the original Vcmax scheme is revised with a new one that only accounts for the transition between Vcmax and its potential value （without nitrogen limitation）. Compared to flux tower- based observations, the new Vcmax scheme reduces the root-mean-square error （RMSE） in GPP for China's Mainland by 13.7 g C m-2 yr-1, with a larger decrease over humid areas （39.2 g C m 2 yr-1）. Moreover, net primary production and leaf area index are also improved, with reductions in RMSE by 0.8% and 11.5%, respectively.
