NO 3 – , K + , and chlorophyll index in fertigated grapevines in the semi-arid region of Brazil

Evaluating the effects of N and K supply on grapevines ( Vitis vinifera L.) techniques for nutritional diagnosis is great importance fertigation management this crop. This study evaluated soluble concentrations NO 3 – + in petiole sap leaf chlorophyll index drip irrigated ‘Syrah’ grapevine (from 17 June 2013 to 25 Nov 2014). The treatments consisted five levels (0, 15, 30, 60 120 kg ha –1 ) 2 O ), combined an incomplete 5 factorial scheme 13 combinations arranged randomized blocks with four replications. We determined sap, index, cluster mass number per plant, mean mass, phenolic composition. High contributed positively yield; however, increased K+ caused a negative response sap. For rate, showed higher values at flowering stage, while high were observed during grape-ripening stage.