Abstract
Purpose: The use of nitrification inhibitors could be an interesting alternative to enhance nitrogen (N) fertilizer use efficiency in annual crops such as cotton, under tropical soil conditions. Thus, our aim was to evaluate the efficiency of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in a typical tropical soil, evaluating the fate of nitrogen (N-NO3-, N-NH4+ and total N in soil and leached water), N-accumulation and N recovery by cotton plants and soil. Methods: Leaching columns with cotton plants were used to access N-NO3- and N-NH4+ losses in drainage water. Treatments consisted in three N levels applied in side-dressing (corresponding to 50, 100 and 150 kg N ha-1) as 15N-urea with and without DMPP application. An additional treatment (absence of N application in side-dressing) was used as control. Results: 3,4-dimethylpyrazole phosphate was efficient to improve N recovery from applied urea fertilizer in plants and in the soil by reducing NO3- leaching, leading to enhanced N acquisition from fertilizer and soil, augmenting plants N-accumulation, mainly when high N levels above 100 kg N ha-1 were applied. We found that total N recovery increased 31% when 150 kg N ha-1 was applied as urea + DMPP source compared to conventional urea. In addition, DMPP application reduced NO3- leaching losses (c.a. of 11 to 20%), although had no significant effect on shoot and root dry matter yield. Conclusion: The reduction of NO3- leaching losses highlights the potential of DMPP to mitigate the impact of increased urea input on leaching losses thereby improving N use efficiency and N uptake in cotton crop.
Nitrification inhibitor 3,4-Dimethylpyrazole phosphate improves nitrogen recovery and accumulation in cotton plants by reducing NO3− leaching under 15N-urea fertilization
