Nitrogen Agronomic Efficiency and Estimated Losses in Potato with Enhanced-Efficiency Fertilizers

ABSTRACT

The objectives were to i) assess the effect of enhanced-efficiency nitrogen (N) fertilizers (EENF) [maleic itaconic acid copolymer (NSN) or 3,4-dimethylpyrazole phosphate (DMPP)] and urea on potato (Solanum tuberosum L.) tuber yield, N agronomic efficiency (NAE), N recovery efficiency in tuber (NRE_tuber) and plant (NRE_plant), N physiological efficiency, residual inorganic N in soil at harvest (N_residual) and N losses (N_losses) and ii) determine the impact of the amount of drainage water on NAE and N_losses. On-farm experiments were conducted in seven sites with two fertilizers (EENF and urea) and two N rates (0 and 100 kg N ha⁻¹). A N mass balance was used to calculate N_losses. At two sites (one with NSN and one with DMPP), tuber yield response to N was greater with EENF than urea (avg. 5.0 Mg ha⁻¹). NAE, NRE_tuber and NRE_plant were 17%, 31% and 25% higher with EENF than urea, respectively. These efficiencies decreased as drainage water increased. The estimated N_losses were 12% lower with EENF, being the reduction particularly relevant with increasing drainage water. Therefore, using EENF in combination with irrigation management that ensures low drainage water amounts is essential for maximizing the fertilizer use efficiency and minimizing N_losses in potato production systems.

KEYWORDS:

• DMPP
• drainage water
• medium-textured Mollisols
• NSN
• nitrogen recovery efficiency

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Funding

This work was supported by the Fondo para la Investigación Científica y Tecnológica [PICT 2016-0304]; Universidad Nacional de Mar del Plata [AGR583/19, 15/A587].