The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the opti...The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the optimal concentrations for better nutrient release was proposed. The characteristics of nutrient release of film-coated urea were evaluated by soil column leaching experiment. Organic-inorganic compound film-coated urea showed good characteristics of nutrient release, which could be well simulated by Logistic curve. The two parameters in this curve, a and r, can be used to present nutrient release of film-coated urea, and followed the order of B 〉 C 〉 A and C 〈 B 〈 A, respectively, indicating that the release was stronger with the increasing concentration of natural macromolecular compound in the membrane, which implied better controllability of nutrient release. The concentration of 5% of natural macromolecular compound showed better characteristic of nutrient release and can be utilized as a membrane material combined with inorganic mineral powders to develop film-coated slow-release fertilizer.展开更多
A preliminary assessment of the Wujiangdu Reservoir examined nutrient distribution and transport.Water samples were collected in the summer(July) of 2004, during the high-flow season. Inorganic nutrients(N,P, Si) and ...A preliminary assessment of the Wujiangdu Reservoir examined nutrient distribution and transport.Water samples were collected in the summer(July) of 2004, during the high-flow season. Inorganic nutrients(N,P, Si) and chlorophyll a(chl a) concentrations of the Wujiangdu Reservoir and its inflow rivers were analyzed.Other water parameters(dissolved oxygen, p H, temperature, and electrical conductivity) were measured as well.The results show gradually decreasing concentrations of NO_3^--N and dissolved silicate in the surface water moving downstream to the dam of the Wujiangdu Reservoir.Additionally, soluble reactive phosphorus concentrations measured very low, with most falling below the sensitivity threshold of the method used in surface waters. Particulate phosphorus and NO_3^--N were the predominant species of phosphorus and nitrogen in the reservoir, respectively. The concentration of nutrients in the Yeji River was the largest of all inflow rivers. The maximum concentration of chl a was found near the dam. These results reflect upstream conditions similar to that of a river, and reservoir conditions near the dam similar to that of a natural lake system.展开更多
As a kind of biological fertilizer sources, green manure can improve soil fertility and the quality of agricultural products. This paper introduced the germplasm resource of green manures in the major provinces in Chi...As a kind of biological fertilizer sources, green manure can improve soil fertility and the quality of agricultural products. This paper introduced the germplasm resource of green manures in the major provinces in China, mainly summarized the characteristics of decomposition and nutrients release of returning green manures to soils, as well as the influence on soil fertility and succeeding crops, with the aim to provide references for rational utilization of green manures and the scientific management of farmland nutrients.展开更多
基金supported by a key project of Liaoning Province (2006215005)China Ministry of Education (209032)
文摘The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the optimal concentrations for better nutrient release was proposed. The characteristics of nutrient release of film-coated urea were evaluated by soil column leaching experiment. Organic-inorganic compound film-coated urea showed good characteristics of nutrient release, which could be well simulated by Logistic curve. The two parameters in this curve, a and r, can be used to present nutrient release of film-coated urea, and followed the order of B 〉 C 〉 A and C 〈 B 〈 A, respectively, indicating that the release was stronger with the increasing concentration of natural macromolecular compound in the membrane, which implied better controllability of nutrient release. The concentration of 5% of natural macromolecular compound showed better characteristic of nutrient release and can be utilized as a membrane material combined with inorganic mineral powders to develop film-coated slow-release fertilizer.
基金funded by the Ministry of Science and Technology of China through Grant No.2016YFA0601000the Natural Science Foundation of China(No.423456700)+3 种基金youth fund from the Sichuan provincial education department(2006B077)basic research program from Sichuan Province of technology(2008JY0121)educational reform program of Neijiang Teachers College(JG200912-162)self key scientific research program of Sichuan provincial education department(14ZA0247)
文摘A preliminary assessment of the Wujiangdu Reservoir examined nutrient distribution and transport.Water samples were collected in the summer(July) of 2004, during the high-flow season. Inorganic nutrients(N,P, Si) and chlorophyll a(chl a) concentrations of the Wujiangdu Reservoir and its inflow rivers were analyzed.Other water parameters(dissolved oxygen, p H, temperature, and electrical conductivity) were measured as well.The results show gradually decreasing concentrations of NO_3^--N and dissolved silicate in the surface water moving downstream to the dam of the Wujiangdu Reservoir.Additionally, soluble reactive phosphorus concentrations measured very low, with most falling below the sensitivity threshold of the method used in surface waters. Particulate phosphorus and NO_3^--N were the predominant species of phosphorus and nitrogen in the reservoir, respectively. The concentration of nutrients in the Yeji River was the largest of all inflow rivers. The maximum concentration of chl a was found near the dam. These results reflect upstream conditions similar to that of a river, and reservoir conditions near the dam similar to that of a natural lake system.
基金Supported by the Natural Science Foundation of Guangxi(2017GXNSFBA198204)the Key Science and Technology Project of Guangxi(Guike AA17204059-9&AA172040459-10)+1 种基金the Planning Project for Scientific Research and Technological Development of Xixiangtang District,Nanning City(2017-2-10309)the Special Fund for the Fundamental Research of Guangxi Academy of Agricultural Sciences(Guinongke 2018YT07&2018YM28)
文摘As a kind of biological fertilizer sources, green manure can improve soil fertility and the quality of agricultural products. This paper introduced the germplasm resource of green manures in the major provinces in China, mainly summarized the characteristics of decomposition and nutrients release of returning green manures to soils, as well as the influence on soil fertility and succeeding crops, with the aim to provide references for rational utilization of green manures and the scientific management of farmland nutrients.
