Nitrate and potassium concentration in fertigated soil cultivated with wine vines

Concentração de nitrato e potássio em solo fertirrigado e cultivado com videira de vinho

ABSTRACT

In the semiarid region of Brazil the use of irrigation systems for applying fertilizers in horticulture is the primary means for incorporating nutrients in the soil. However, this technique still requires its use in wine vines to be assessed. In view of this, this study aimed to assess nitrate and potassium concentrations in soil fertigated with nitrogen and potassium fertilizers in 3 wine grape growing cycles. A field experiment was conducted with 'Syrah' wine grapes, in Petrolina, Pernambuco, Brazil; it assessed five nitrogen doses (0, 15, 30, 60 and 120 kg ha^-1) and five K₂O doses (0, 15, 30, 60 and 120 kg ha^-1) applied by drip irrigation system with two emitters per plant, with a flow rate of 4 L h^-1. The experimental design used was the factorial split-plot, making up 13 combinations arranged in 4 randomized blocks. Soil solution samples were collected weekly with the aid of porous cup extractors for all treatments and at depths of 0.4 and 0.6 m by determining nitrate and potassium concentrations and electrical conductivity. Increased levels of both nutrients in the irrigation water increased the availability of nitrate and potassium in the soil solution. The highest nitrate and potassium concentrations were found in the second growing cycle at both depths studied.

Index terms:
Vitis vinifera L; soil solution; fertigation