Nitrogen transformations in a Chinese aquic cambisol applied urea with dicyandiamide or plant residues

作者：Ju XT; Liu XJ; Zhang FS^*

来源：Communications in Soil Science and Plant Analysis, 2004, 35(17-18): 2397-2416.

DOI：10.1081/LCSS-200030318

• nitrogen transformation
• dicyandiamide
• urea
• plant residues
• nitrification
• Chinese aquic cambisol

Understanding the effects on nitrogen (N) transformations and supply to crops of dicyandiamide (DCD) and the various plant residues applied with N fertilizer in China is vital for maximizing crop yields and minimizing environmental pollution. Nitrogen transformations were measured in a Chinese Aquic Cambisol following the application of urea (U), or U with DCD, wheat straw (WS), alfalfa straw (AS), and poultry manure (PM) by aerobic incubation in the laboratory. Nitrification was rapid in the 7 days after U or U with WS, AS, and PM were applied; almost all the applied N from U was nitrified by the 14th day, but only 20% by the 35th day, where DCD was applied with the U. The NH4-N concentrations in the soil with U+DCD was always much higher than those in the other treatments. The results thus showed that DCD significantly inhibited nitrification on this soil. The high C:N ratio of WS significantly decreased the amount of N-min (NH4-N plus NO3-N) in soil, while the low C:N ratio of AS and PM significantly increased N,in compared with the U treatment. The content of N,,g (organic N extracted by 0.01 M CaCl2 solution) in the soil was much lower than that of Nmin and was not significantly different between the treatments, except for the U + DCD treatment, where it measured as DCD. The N recovery and loss rate after 35 days'; incubation, as measured by 15 N tracer, was not significantly different in the U, U+WS, U+AS, and U+PM treatments, but recovery was significantly higher and loss correspondingly smaller when DCD was applied. With DCD, the N fertilizer was mostly fixed in soil after 35 days but without DCD was present as NO3-N. For effective use of fertilizers in the North China Plain, an understanding of the effects of applying inhibitors such as DCD and plant residues is needed.

• 出版日期2004-10
• 单位中国农业大学