外加可溶性碳、氮对不同热量带土壤氨挥发的影响

在室内条件下采用静态吸收法,研究了外加可溶性碳、氮对不同热量带经长期施肥的3种农田土壤:黑土、潮褐土和红壤氨挥发的影响.结果表明,施用氮肥显著促进了土壤氨挥发,在单施氮肥和可溶性碳配施氮条件下,不同热量带土壤氨挥发量从高到低分别为潮褐土(14.3、 7.37 mg·kg~(-1)),黑土(1.52、 1.11 mg·kg~(-1)),红壤(0.998、 0.402 mg·kg~(-1)).添加可溶性碳显著减少土壤因施氮肥产生的氨挥发量,其中黑土减少27.0%,潮褐土减少48.5%,红壤减少60.0%.在黑土、潮褐土长期不同施肥土壤中,单施氮肥后氨挥发量均表现为无肥土壤 > 化肥土壤 > 化肥+有机肥土壤,与可溶性碳配施氮后氨挥发量变化规律相反;在红壤长期不同施肥土壤中,单施氮肥和可溶性碳配施氮后氨挥发量均表现为无肥土壤 > 化肥土壤 > 化肥+有机肥土壤.研究结果还表明,外加可溶性碳、氮后,潮褐土铵态氮含量的减少幅度和硝态氮含量的增加幅度均显著高于黑土和红壤,说明潮褐土中氮素损失潜能大.

Influence of Soluble Carbon and Nitrogen on Ammonia Volatilization from Different Thermal Zones Soil

A static absorption method was used to study the influence of soluble carbon and nitrogen on ammonia volatilization from different thermal zone soils, such as black soil, red soil and cinnamon soil, performed in laboratory. Results showed that nitrogen application enhanced ammonia volatilization significantly. The amount of ammonia volatilization in cinnamon soil ranged from 14.3 to 7.37 mg·kg^-1, which in black soil from 1.52 to 1.11 mg·kg^-1 and from 0.998 to 0.402 mg·kg^-1 in red soil applied with only nitrogen or nitrogen amended with soluble carbon. Moreover, soluble carbon decreased ammonia volatilization caused by nitrogen, and amounts of decrease were 27.0%, 48.5%, 60.0% in black soil, cinnamon soil and red soil separately. The amount of ammonia volatilization from black soil and cinnamon soil applied only nitrogen was in an order of CK > NPK > NPKOM, while contrary order appeared if nitrogen was amended with soluble carbon. However, it was the same order for red soil applied with only nitrogen or nitrogen amended with soluble carbon. In addition, the variances of NH⁺₄-N and NO^-₃-N contents in cinnamon soil were larger than other soils, which suggested that cinnamon soil had high potential of nitrogen loss.