Effects of urease and nitrification inhibitors application on urea fate in soil and nitrate accumulation in lettuce

Abstract

The effects of amendment of urea with the urease inhibitor N‐(n‐butyl)‐thiophosphoric triamide (NBPT) and the nitrification inhibitor dicyandiamide (DCD) on urea trasformation in soil and nitrate accumulation in winter lettuce were studied in a cold greenhouse experiment. The DCD inhibited remarkably the nitrification process for more then two months, maintaining significantly higher levels of ammonium in soil solution compared to normal urea. The DCD did not decrease the ammonia volatilization but determined a significant reduction of plant nitrate concentration at final harvest. The treatment urea + NBPT showed a behavior slightly different from normal urea with a higher level of soil nitrate three weeks after nitrogen (N) fertilization. No effects on NO₃ plant accumulation were observed, but losses of NH₃ were significantly reduced.

Notes

Present address: Istituto Sperimentale Agronomico, Bari, Italy.

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