HE-NIAN-ZU;YU SHEN;YE ZHI-QIAN;OUYANG HANG;XIONG JIN-SHAN

;Department of Land Science and Applied Chemistry, Zhejiang Agricultural University, Hangzhou 310029 (China)

lime nitrogen;nitrification inhibitor;urea;urease activity;urease inhibitor

Laboratory incubation experiment was conducted to study the effect of lime nitrogen(LN) on transformation of urea-N in three paddy soils. The results showed that LN had an inhibitory effect on urease activity in these soils especially in the first 5 days, and that in the first 20 days of incubation, the amount of NH_4~+-N derived from urea was lower in the soil with LN than in the soil without LN. While after 30 days the amount of NH_4~+-N was higher in the mature haplic paddy soil developed on Quaternary red clay(MHPS) with LN than that in the soil without LN. The amount of NH_3-N volatilized was decreased in the earlier stage and increased in the later stage of incubation in the MHPS by the addition of LN.