Biomass Accumulation and Yield of Potato in Response to Management of Nitrogen with Nitrification Inhibitor DMPP.

Nitrogen is one of the most important nutrients for potato crop, which makes N management a key factor for the N availability. Thus, a study seeking the best strategy for the potato nitrogen use becomes necessary, mostly when it is grown in sandy soils. The objective of this study was to evaluate the effect of N fertilizer rate and application timing on biomass accumulation and tuber yield of potato cultivar Ágata produced in southeast Brazil. Three field experiments were carried out in São Paulo state, two were conducted in an experimental farm at São Manuel city (2011 and 2012), and one more in a commercial farm at Avaré city (2012). The treatments comprised two rates of N (120 and 160 kg ha^-1) as Ammonium sulfonitrate (N 26%) with nitrification inhibitor DMPP (3.4-dimethylpyrazole phosphate), which one is commercially known as ENTEC® 26 (registered trademark of EuroChem Agro Mannheim, Germany). The fertilizer was either totally applied at planting or it was split applied (40 kg ha^-1 at planting; remainder split applied). In addition, there was one more treatment without N application, as a control. Was verified better effects of N split application than the single one, this treatment has promoted higher biomass accumulation as well as higher tuber yield. Such results do not permit the exclusion of the split application of Entec on potato cultivated in sandy soil under irrigation system.

Keywords: Solanum tuberosum, nitrogen fertilization, nitrification inhibitor.