Comparison of nitrification inhibitors to restrict nitrate leaching in a maize crop irrigated under mediterranean conditions

Abstract

The aim of this paper was to compare dicyandiamide (DCD) and 3,4 dimethylpyrazole phosphate (DMPP) as inhibitors of ammonium oxidation and nitrate leaching after applying fertilizer to a maize (Zea mays L.) crop grown under Mediterranean conditions. The effects of nitrification inhibitors were also compared to those of N fertilization without inhibitors and with split N application. In plots fertilized with ammonium sulphate nitrate (ASN), either DCD or DMPP lengthened ammonium presence in soil and produced lower soil NO 3 -concentrations (30% lower than in plots with no inhibitor). The use of DCD or DMPP achieved significant reductions in nitrate leaching. DCD showed excellent properties for controlling nitrate leaching, taking into account the fact that grain yield and N accumulated by plant were similar for the ASN-DCD and ASN treatments applied at the same N doses. The split N treatment did not offer any advantages in terms of leached nitrate, either with the use of single ammonium sulphate nitrate (ASN) or with single application of nitrification inhibitors. The nitrification inhibitors did not increase the yield but did not reduce it either. The drainage rate was the most important component of nitrate leaching. The low drainage values of the first year resulted in a sharp decline of nitrate leaching. However, the experiment of the second year, showed clear differences in nitrate leaching between treatments due to the greater drainage.Additional key words: dicyandiamide, dimethylpyrazolephosphate, N fertilization, split N application. ResumenComparación de dos inhibidores de la nitrificación para reducir la lixiviación de nitrato en un cultivo de maíz irrigado bajo condiciones mediterráneas El objetivo de este trabajo fue comparar el efecto de la diciandiamida (DCD) y el 3,4 dimetilpirazolfosfato (DMPP) como inhibidores de la nitrificación, en la fertilización nitrogenada de un cultivo de maíz (Zea mays L.) bajo condiciones mediterráneas. Se compararon los efectos de los inhibidores frente a la fertilización sin inhibidores y con aplicaciones divididas de nitrógeno. En parcelas fertilizadas con nitro sulfato amónico (ASN), tanto DCD como DMPP, prolongaron la presencia de amonio en el suelo, originando un descenso en las concentraciones de NO 3 -(30% menos que en parcelas fertilizadas sin inhibidor) y en consecuencia en la lixiviación de nitrato. El DCD mostró excelentes propiedades para controlar la lixiviación de nitrato, ya que la producción de grano y el N acumulado por la planta fueron similares para el tratamiento ASN-DCD y ASN, ambos aplicados a la misma dosis de N. El tratamiento de N en dosis divididas no ofreció ninguna ventaja sobre el nitrato lixiviado ni frente al uso de ASN solo, ni frente a la aplicación de ASN con alguno de los inhibidores de la nitrificación. En el experimento se observa que los inhibidores de la nitrificación no aumentan la producción pero tampoco la reducen. La dosis de drenaje fue el factor más importante en la lixiviación de nitrato. Los bajos valores de drenaje...

A Laboratory Evaluation of Ammonia Volatilization and Nitrate Leaching following Nitrogen Fertilizer Application on a Coarse‐Textured Soil

“…The UAN treatment had the greatest total leaching loss of 66% of fertilizer N applied whereas leaching from the UAN‐IN and UAN‐NS were not different from each other and both were significantly lower than that from the UAN treatment but greater than that from PCU. These results are consistent with other studies that also showed reduced NO 3 − leaching with specialized N fertilizers such as polymer‐coated urea, urea with urease or nitrification inhibitors or both inhibitors added compared to conventional N fertilizers (Diez et al, 2010; Zaman et al, 2008). These specialized products are designed to release N more gradually over time than conventional N fertilizers to improve synchrony between soil N availability and crop N demand to minimize N loss.…”

Fertilizer and Irrigation Management Effects on Nitrous Oxide Emissions and Nitrate Leaching

“…In a field experiment on a permanent pasture, Zaman et al (2008) found that urea with only urease inhibitor or with both urease and nitrification inhibitors (as in the IU in the current study) reduced NO 3 leaching compared with urea alone. Diez et al (2010) also reported significantly lower NO 3 leaching with the use of DCD with a traditional N source. In the current study, greater NO 3 leaching with PCU than with split-U and the trend for greater NO 3 leaching with IU compared with split-U were most likely due to better synchrony of the N application with crop demand for split-U.…”

Novel Investigation on Ammonium Thiosulphate (ATS) as an Inhibitor of Soil Urease and Nitrification

“…and other 2 NO − oxidizing microorganisms. In our experiment, we noticed that the rate of 4 NH + disappearance did not correspond to the rate of 3 NO − formation, suggesting that ATS led to the stabilization of N-4 NH + , and thus delaying the production of nitrate [51] [52]. In addition, our results are in accordance with those reported by Al Kanani et al [53] who attributed the non-concomitant 4 NH + to 3 NO − conversion to the accumulation of nitrite, adversely affecting the amount and the activity of soil microorganisms, thus retarding nitrification…”