Influence of calcium, magnesium and potassium in the soil on guava plants (<em>Psidium guajava</em> L.), cv. Paluma production

Abstract

The objective of the present research was to study the influence of application of calcium, magnesium and potassium in the soil on guava production. The experiment was carried out in São Tomé, PR. The guava plants were 2 years and nine months old. The randomized design was used as a statistical model consisting of 4 treatments (control, 450 g/plant of calcium, magnesium and potassium) with 4 replications. The parameters evaluated were the nutrients in soil and leaves and production (number of fruits per plant, weight of the fruits and total production per plant (kg per plant)). There were significant differences in relation to calcium, magnesium and potassium concentration in the soil. On the other hand, no significant differences in relation to the pH values, H+Al and P were observed. It was verified that the concentration values of nitrogen, calcium and magnesium in the guava leaves were significantly higher in relation to control. It was noticed that the concentration of potassium in the guava leaves reduced over time, and the reduction was of 28% in the third analysis in relation to the first one, characterizing its mobility and exportation by harvesting. At the first harvest, the production was more dependent on the treatment in which magnesium was added in the soil. At the second harvest, howewer, there was no significant difference in the production between the treatments. The increase in the number of fruits per plant resulted in a reduction of their weight