tailieunhanh - Agronomic efficiency of NBPT as a urease inhibitor: A review

Urea is the most widely used nitrogen (N) fertilizer, with a projected increase in annual demand of in the coming years. After its application to soil, urea undergoes hydrolysis via the urease enzyme, causing increases in the soil pH in the surrounding area of the granules and resulting in NH3 losses that average 16% of N applied worldwide and can reach 40% or more in hot and humid conditions. The use of urease inhibitors is an effective way to reduce NH3 losses. Several compounds act as urease inhibitors, but only N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide, being the most successful in a market that has grown 16% per year in the past 10 years. Only in the past three years other compounds are being commercially launched. In comparison to urea, NBPT-treated urea reduces NH3 loss by around 53%. Yield gain by NBPT usage is of the order of and varies from to depending on crop species. Nitrification inhibitors usually increase NH3 volatilization and mixing them with urease inhibitors partially offsets the benefits of the latter in reducing NH3 loss. The efficacy of NBPT to reduce NH3 loss is well documented, but there is a need for further improvement to increase the period of inhibition and the shelf life of NBPT-treated urea. | Journal of Advanced Research 13 2018 19-27 Contents lists available at ScienceDirect Journal of Advanced Research journal homepage locate jare Review Agronomic efficiency of NBPT as a urease inhibitor A review Heitor Cantarella a Rafael Otto b Johnny Rodrigues Soaresc Aijanio Gomes de Brito Silva b Check for updates a Soils and Environmental Resources Center Agronomic Institute of Campinas Avenida Barao de Itapura 1481 13020-902 Campinas SP Brazil b Luiz de Queiroz College of Agriculture University ofSão Paulo Av. Padua Dias 11 13418-900 Piracicaba SP Brazil c School of Agricultural Engineering University of Campinas Av. Cândido Rondon 501 13083-875 Campinas SP Brazil GRAPHICAL ABSTRACT Schematic diagram of urea dissolution diffusion and hydrolysis in the soil. a Without an inhibitor hydrolysis is fast dark blue color causing NH3 NH4 accumulation and increasing the pH close to the soil surface around the fertilizer granule driving NH3 volatilization. As the ammonia species are less mobile in soil diffusion is limited. b The inhibitor maintains urea unhydrolyzed for some time. Urea has no electrical charges and diffuses easily into the soil solution. When the effect of the inhibitor phases down and urea starts to hydrolyze both the pH and the NH3 NH4 concentrations are lower light blue color as a result of dilution. Part of the urea is incorporated into the soil before hydrolysis the NH3 produced inside the soil is retained by the negative charges of colloidal material and losses are reduced even if no rain or irrigation incorporates urea into the soil. ARTICLE INFO ABSTRACT Article history Received 11 January 2018 Revised 22 May 2018 Accepted 23 May 2018 Available online 24 May 2018 Keywords NBPT NPPT Ammonia volatilization Soil urease Nutrient use efficiency Urea Nitrogen fertilizer Urea is the most widely used nitrogen N fertilizer with a projected increase in annual demand of in the coming years. After its application to soil urea undergoes

• Hoá học
• Ammonia volatilization
• Nutrient use efficiency
• Nitrogen fertilizer
• Agronomic efficiency
• NBPT as a urease inhibitor