Nutrients Release Characters Of Melamine Waste And Its Effects On Ryegrass Growth

Melamine waste is the solid waste that is generated in the production process of melamine, with the recovery of melamine market over the past two years, the market demand is increasing. Therefore recycling of melamine waste has an important economic and ecological significance. In recent years, many studies have shown that nitrogen content in the melamine waste is very high and it has a low levels of pollutants,so the melamine waste can be used as nitrogen fertilizer to realize the reusing of resources. In this paper, indoor simulation and a pot experiment were used to study the character of nutrition release and influence factors of melamine waste in brown soil. Ryegrass,a common kind of turfgrass was used to study the effect of different proportions of urea and melamine waste on the growth and the effect on soil enzyme activity in cinnamon soil. The main results were as follows:1. The melamine waste contained 50.01% of nitrogen and the available nitrogen content was only 0.03%, it released very slowly, so it could be reuse as the material to produce the slow-release nitrogen fertilizer. The nitrogen release was promoted with the increase of temperature and soil moisture content,the total nitrogen , the available nitrogen and NH4+-N content were enhanced. The amplitude of total nitrogen and available nitrogen were remarkable between the different processing levels. Under the alkalinity condition,it was conducive to hydrolysis of melamine waste, so the total nitrogen improved obviously,when pH was 5.0,total nitrogen content was separately decreased by 2.49% and 5.17% compared to pH 7.8 and pH 8.5, the change of NH4+-N was extremely tiny. The organic fertilizer promoted the nitrogen releasing of melamine waste,and with the content of organic fertilizer increasing,the nitrogen released faster. 2. The application of the melamine waste significantly promoted the growth of ryegrass,the height and fresh weight increased by 5.73% and 5.64%,it had an obviously difference compared to CK. With the urea fertilizer, the effect was better than separately handling of melamine waste,when the level of the waste and urea was at the ratio of 1:3, it was the most close to the level of urea treatment. After waste employment , it was significantly improved the nitrogen,nitrate-N content, decreased soluble sugar content. With the ratio of waste and urea reduction, this trends were becoming evident. The fertilizer improved the CAT and NR activity of the ryegrass with a varying degrees , but it did not harm their growth.3. In whole application rates of fertilizer, the recovery rate of N in three crops was extremely low for treatment of the single application of the waste,it was only 11.79%. With the application of urea could substantially improve their recovery,when the level of waste and total nitrogen was at the ratio of 1:4,the recovery rate of nitrogen was 80.70%,with the most similar to chemical nitrogen fertilizer. As the adding of harvest times, the relative performance recovery of the four treatments increased obviously compare with A5. In half application of fertilizer,all targets displayed the same changes. But the amount of nitrogen that was recoveried was lower than the whole application of fertilizer in same allocated proportions.4. Soil urease activity was improved with the ratio of waste and urea reduction,it was increased by 9.42 to 26.09% compared to CK. The half quantity processing's urease activities were slightly lower than the whole quantity processing's .The soil CAT activities were decreased,but it would not cause pollution of soil environment.