Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea gran...Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 μm were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.展开更多
The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpr...The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpregnated woodchips from tropical plant biomass(oil palm frond and rubberwood),was developed.The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry.When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h,release was slow and steady,although the release rate was lower in distilled water than in the soil solution.展开更多
After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed,...After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.展开更多
The anionic polymer γ-polyglutamic acid(γ-PGA) was used to coat urea and slow its dissolution. Three types of slow release urea(SRU) fertilizers(polymer coated urea with pore constriction, polymer coated urea with e...The anionic polymer γ-polyglutamic acid(γ-PGA) was used to coat urea and slow its dissolution. Three types of slow release urea(SRU) fertilizers(polymer coated urea with pore constriction, polymer coated urea with enzyme inhibitor and polymer coated urea with pore constriction and enzyme inhibitor) were prepared and tested for the N-release rate. After using SRU, the effect on the tomato growth was analyzed. The extracts of SRU were analyzed for NH3/NH4+-N and NO3--N. The N-release rate was used to determine the optimum ratio of ingredients. The results show that the three types of SRU met the dissolution rate standards recommended by the Committee of European Normalization. γ-PGA SRU increased the chlorophyll content of tomato(flowering stage) by an average of 100% compared with that grew in untreated urea. The results from soil analysis(0-60 cm in tomato pots) indicate that the content of NH3/NH4+-N in SRU-treated pots was 25%-61% higher than that in soil from urea-treated pots during the growing period,while the content of NO3--N was nearly 50% lower after the tomato had been harvested. Newly formulated SRU fertilizer increases nitrogen uptake and reduces loss of applied nitrogen. Plant growth is enhanced, a valuable resource is conserved, and the aquatic environment benefits from decreased level of nitrate in agricultural run-off.展开更多
应用固-液反应包膜工艺,采用4种改性的无机包膜材料,试制出了成本较低的包膜缓释尿素,用水中溶出率法测定了包膜缓释尿素的养分释放特征,应用盆栽水稻评价了包膜缓释尿素的肥效,并与国外的有机缓释氮肥(M ethy lene U rea)和高聚物包膜...应用固-液反应包膜工艺,采用4种改性的无机包膜材料,试制出了成本较低的包膜缓释尿素,用水中溶出率法测定了包膜缓释尿素的养分释放特征,应用盆栽水稻评价了包膜缓释尿素的肥效,并与国外的有机缓释氮肥(M ethy lene U rea)和高聚物包膜复合肥(O sm ocotte)进行了比较,表明固-液反应型包膜尿素具有较好的养分缓释效果,4种包膜尿素与等氮和等重常规尿素相比,栽培水稻都有一定的增产作用,并提高了肥料利用率,其中LU增产最显著,比等氮和等重尿素处理分别增产41.5%和35.7%,肥料当季利用率达到43.9%,好于国外的有机缓释氮肥和高聚物包膜复合肥,养分释放特征与水稻氮素营养特征较为接近,可为水稻一次性施肥所用。展开更多
基金the National Key Technology R&D Program of the 11th Five-Year Period (No.2006BAD10B08)
文摘Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 μm were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.
基金supported by Research University Grant Scheme(RUGS)University Putra Malaysia(No.03-02-12-2293RU)
文摘The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpregnated woodchips from tropical plant biomass(oil palm frond and rubberwood),was developed.The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry.When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h,release was slow and steady,although the release rate was lower in distilled water than in the soil solution.
文摘After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.
基金Supported by the National Water Pollution Control and Management Science and Technology Major Projects of China(2012ZX07104-002-04)Natural Science Foundation for Innovation Group of Hubei Province,China(2009CDA020,T200703)
文摘The anionic polymer γ-polyglutamic acid(γ-PGA) was used to coat urea and slow its dissolution. Three types of slow release urea(SRU) fertilizers(polymer coated urea with pore constriction, polymer coated urea with enzyme inhibitor and polymer coated urea with pore constriction and enzyme inhibitor) were prepared and tested for the N-release rate. After using SRU, the effect on the tomato growth was analyzed. The extracts of SRU were analyzed for NH3/NH4+-N and NO3--N. The N-release rate was used to determine the optimum ratio of ingredients. The results show that the three types of SRU met the dissolution rate standards recommended by the Committee of European Normalization. γ-PGA SRU increased the chlorophyll content of tomato(flowering stage) by an average of 100% compared with that grew in untreated urea. The results from soil analysis(0-60 cm in tomato pots) indicate that the content of NH3/NH4+-N in SRU-treated pots was 25%-61% higher than that in soil from urea-treated pots during the growing period,while the content of NO3--N was nearly 50% lower after the tomato had been harvested. Newly formulated SRU fertilizer increases nitrogen uptake and reduces loss of applied nitrogen. Plant growth is enhanced, a valuable resource is conserved, and the aquatic environment benefits from decreased level of nitrate in agricultural run-off.
文摘应用固-液反应包膜工艺,采用4种改性的无机包膜材料,试制出了成本较低的包膜缓释尿素,用水中溶出率法测定了包膜缓释尿素的养分释放特征,应用盆栽水稻评价了包膜缓释尿素的肥效,并与国外的有机缓释氮肥(M ethy lene U rea)和高聚物包膜复合肥(O sm ocotte)进行了比较,表明固-液反应型包膜尿素具有较好的养分缓释效果,4种包膜尿素与等氮和等重常规尿素相比,栽培水稻都有一定的增产作用,并提高了肥料利用率,其中LU增产最显著,比等氮和等重尿素处理分别增产41.5%和35.7%,肥料当季利用率达到43.9%,好于国外的有机缓释氮肥和高聚物包膜复合肥,养分释放特征与水稻氮素营养特征较为接近,可为水稻一次性施肥所用。
