Metabolic responses of guava trees irrigated with different N and K levels in São Francisco valley.

The guava (Psidium guajava 1.) cv. Paluma has been cultivated in Sao Francisco Valley, Northeastern of Brazil, for in natura consumption and processing purposes. In spite of its importance, there are few scientific knowledge regarding guava physiology, nutrition, irrigation and fertigation. The objective of this work was to evaluate the effect of weather conditions and different concentrations of Nand K applied by fertigation in foliar contents of reducing sugars, total soluble sugars, starch, sucrose, amino acids, and proteins. The field experiment was carried out at Bebedouro Experimental Field and the biochemical evaluations at the Laboratory of Seed and Plant Physiology, both located at Embrapa Semi-Arido, Petrolina-PE. The doses of200 g N and 100 g Kp; 400 g Nand 200 g O; 600 g Nand 300 g O; and 800 g Nand 400 g O per plant were applied in an experiment field. The experimental design was totally randomized blocks, with four treatments and five blocks. The weather conditions influenced the plant photosynthesis, which affects the plants metabolism. Guava presented specific responses to Nand K fertigation for each parameter evaluated. The weather conditions during the evaluation period influenced guava responses to N and K.