包膜尿素在不同介质中氮素释放特性研究

Studies on Nitrogen Release Characteristics of Coated Urea in Different Medium

培养不同膜材用量的包膜尿素(CRU1,CRU2)在25℃静水及不同土壤(白浆土、黑土、黑钙土)中的释放规律,研究介质及膜材用量对包膜尿素氮素释放的影响。结果表明:氮素释放期方面,CRU1和CRU2在25℃静水中的释放期分别为30 d和100 d,在白浆土中的释放期分别为37 d和182 d,在黑土中的释放期分别为36 d和209 d,在黑钙土中的释放期分别为34 d和213 d。无机氮变化规律方面,CRU1处理下土壤中NO_(3)^(-)-N含量呈现先平稳再升高后下降的趋势,NH_(4)^(+)-N含量呈现先升高后降低的趋势;CRU2处理下土壤中NO_(3)^(-)-N、NH_(4)^(+)-N含量均呈现先平稳再升高后降低的趋势。相关结果表明,介质类型显著影响包膜尿素的氮素释放期,与水相比土壤中的氮素释放期明显增加,且不同土壤类型间差异显著。随着膜材用量的增加,包膜尿素的氮素释放期明显增加,同时介质中的无机氮含量变化趋势也存在差异。

Incubation experiments were conducted to study the release patterns of coated urea(CRU1;CRU2) with different membrane dosage in water and soils. The aim of this study was to investigate the effects of medium and membrane dosage on nitrogen release from coated urea. Our results showed that, at 25 ℃ hydrostatic conditions, the release period of CRU1 and CRU2 was 30 days and 100 days, respectively. Under the soil culture conditions, the nutrient release period of CRU1 in planosol, black soil and chernozem was 37 days, 36 days and 34 days, respectively. While the nutrient release period of CRU2 on planosol, black soil and chernozem was 182 days, 209 days, and 213 days, respectively. The content of NO_(3)^(-)-N in CRU1 in different types of soils first showed a trend of decreasing and then increasing, however, the content of NH_(4)^(+)-N increased first and then decreased. The contents of NO_(3)^(-)-N and NH_(4)^(+)-N of CRU2 in different types of soil all showed a trend of being stable at first and then increased and then decreased. These results indicated that nitrogen release period of coated urea was significantly affected by the type of medium, the nitrogen release period in soil was significantly longer than that in water, and there were significant differences among different soil types. With the increase of the amount of membrane material, the nitrogen release period of coated urea increased obviously, and the change trend of inorganic nitrogen content in the medium also varied.