Study On Preparation And Fertilizer Efficiency Of The Slow-release Polymer Fertilizer

In this paper, a new kind of slow-release polymer fertilizer was synthesized by the condensation polymerization. The main chain of slow-release polymer fertilizer was consisting of nitrogen, phosphorus, potassium, carbon, hydrogen and oxygen. It solved the two problems of "multi-nutrient" and "controlled and released" of the fertilizer developing industry.Firstly, phosphoryl thiourea potassium was synthesized with the urea and potassium dihydrogen phosphate; Then the urea-formaldehyde oligomers was also synthesized by condensation polymerization between the formaldehyde and urea; eventually, the polymer slow-release fertilizer was obtained by the condensation reaction between urea-formaldehyde oligomers and phosphoryl thiourea potassium. The prior synthesis conditions were obtained by using the orthogonal experiment. By amplificatory in further experiments, we verified the conditions of the synthesis process craft. The molecular structure of the polymer slow-release fertilizer was determined by the FTIR. And the molecular structure was shown in following:The slow-release polymer fertilizer is a degradable polymer material. Its solubility is about 20% in cold water. After 120 days, its dissolution rate was still less than 40%. As a result, it can reduce the losses due to the slow-release property. The loss can cause the water to be polluted. In the soil, the degradation rate of the polymer fertilizer will be substantially improved in the presence of micro-organisms and plants. The release of nutrients showed a slow-fast-slow dynamics change. The release of nutrients was slow at first. It did not "burn" seedlings. Consequently, we can be no longer a top-dressing fertilizer to reduce the agricultural labor input, reducing the cost of agricultural production; In the medium-term, the release rate became more faster, which meet crop nutrient needs; In the last stage, the release rate became slow, and was broadly consistent with the crop growth rule. Accordingly, it can enhance the fertilizer utilization rate substantially.About the fertilizer efficiency study on the polymer slow-release fertilizer, the results show: Compared with the general compound fertilizer treatments, the tomato yield of the polymer slow-release fertilizer treatments increased by 11.2%; But the application amount of the polymer slow-release fertilizer is half of the general compound fertilizer. Compared with the enveloped fertilizer treatments, the soybean yield of the polymer slow-release fertilizer treatments increased by 6%; But the application amount of the polymer slow-release fertilizer is one-third of the general compound fertilizer. It showed that the polymer slow-release fertilizer utilization rate than ordinary fertilizer compound fertilizer and enveloped had a substantial increase. Compared with the general compound fertilizer treatments, the tomato sugar contents of the polymer slow-release fertilizer treatments increased by 10.1%.It showed the polymer slow-release fertilizer could enhance the utilization rate of fertilizers, but also improve the product quality.