Nitrate and potassium movement in a sandy loam soil cultivated with fertigated grapevine (Vitis vinifera /L.) in the Brazilian semiarid

Abstract Fertigation can increase the efficiency of fertilizer application and facilitate the nutritional management of a crop. Thus, nitrate and potassium movements in a sandy loam soil were evaluated as function of fertilizer doses during three growing seasons of the grapevine cv. Syrah grafted on Paulsen 1103 rootstock (June to October 2013, February to June 2014, and August to November 2014) in Petrolina, state of Pernambuco, Brazil. Five doses of N (0, 15, 30, 60 and 120 kg ha-1) and five doses of K2O (0, 15, 30, 60 and 120 kg ha-1) were combined in a fractional 52 factorial design, totaling 13 combinations, in a randomized blocks experiment with four replications. The concentrations of nitrate and potassium in the soil solution were determined. Samples were collected by porous cup extractors installed at 0.4 and 0.6 m depths. The movement of these ions was obtained by the product between their concentration in the soil solution and the soil water flux density. The increase in nitrogen fertilization promoted a greater movement of NO3- (62.2 kg ha-1) in the soil. The movement of K+ was also observed in two growing seasons .