| It is water and fertilizer restricted the sustainable development of agriculture in our country. On the one hand, conventional water-soluble fertilizer is low-recovery, high-losses, and pollutes the environment; on the other hand, the contradictions of water supply and demand is more and more prominent due to the uneven distribution, relatively poor and heavy waste of fresh water in our country. Enhancing the efficiency of water and fertilizer is the key of sustainable development of agriculture in china. Super absorbent polymer was one kind of high-molecular compounds which has the function of absorbent, water retention and nutrient release function. With the continuous research and development realises of it, SAP, as sustained-release matenal, which used to develop slow-release fertilizer of water security’s type, was paid more and more attention, and has becoming the hotsport by researchers all round the world. On the basis of conventional polymerizable monomer of acrylic acid, acrylamide,2-acrylamide group-methyl propane sulfonic acid(AMPS) was used to prepare three kinds of SAP. Through the determination of physical and chemical characteristics, SAP’s performance of water absorption and retention, SAP’s processing conditions with the monomers of acrylamide was explored, acrylic acid and2-acrylamido-2-methylpropane sulfonic acid were evaluated. What’s more, Surface polymerization process was also used to prepare a new kind of urea which coater with SAP successfully. This kind of fertilicer has the function of absorbent, retention water and nutrient release. In addition, SAP coated urea’s water absorption, nutrient release properties and regulation effect between water and fertilization were studied.The main conclusions are as follows:1) As the main materials,acrylic acid,acrylamide,2-Acrylamido-2-Methyl Propane Sulfonic acid were used to prepare three types of SPA, and all of them did well in water absorption,water retention,salt repeated and repeated water absorption In pure water and salt water, water absorption ratio of P(AA-AM),P(AA-AMPS), P(AA-AM-AMPS) were348g/g,517g/g,397g/g and55g/g,58g/g,56g/g respectively, With the concentration of external mediun ion increased,SAP’s water sorporbency declining,and the higher the valence of cation,the greater the decline.When dried for3hours in65℃for3h and45℃for7hours respectivily, water retention rate was still higher than60%,and by adding SPA for0.1%(wt%),holding a water rate increase by37%; repeated absorbent5h later, absorbency rate in pure water and salt water were83.3%,81.6%and79.6%,74.5%,70.7%and76.4%, respectively.2) Using the surface polymenzation mechanism,SAP coated urea were prepared In this study,three kind of SAP were used as outsourcing film,theoretical envelope volume were5%,8%and10%respectively,and each reaction were optimized. AA and AMPS’s degree of neutralization were50%, crosslinking agent0.16%and initiator1.0%on the basis of the mass of both monomers, respectively..3) SAP collated urea did well in water absorption and nutrient release properties.Water absorption ratio was determined by the nature of outsourcing film.When the volume theoretical envelope was10%, P(AA-AM),P(AA-AMPS) and P(AA-AM-AMPS)’s water absorption ratio in pure water were8.5g/g,9.1g/g and8.8g/g respectively. Whether in water or soil, sustained release’s effect was proportional to the, inversely proportional to the dissolved out, and the bigger the amount of coated,the better effect of sustained release;the amsller the dissolution rate,the better the sustained release.When theoretical envelope volume was10%, P(AA-AM),P(AA-AMPS) and P(AA-AM-AMPS)’s dissolution rate in water were78.82%,74.85%and74.81%respectively. All kind of fertilizer’s nutrients released in7d in water;Under4weeks cultivateing,three kinds of coated urea’s soil leaching rate were30.44%,33.39%and30.58%with10%’s throretical envelope volume, which were27.81%,20.82%and27.48%lower than ordinary urealeaching respectively.4) SAP coated urea could integrated regulation water and fertilizer very well.Compared with ordinary urea,corn’s biomass which teained with SAP coated urea increased from7.46%～11.41%, water use efficiency increased by9.039%～16.430%,The nitrogen utilization efficiency was increased by23.552%～41.922%.5) P(AA-AM-AMPS)’s release properties and effect of water and fertilizer’s integrated effects was better than P(AA-AM) and P(AA-AMPS)’s。... |
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