Óxido de cálcio e magnésio aplicados no fundo do sulco de plantio da cana-de-açúcar

Abstract

In the sugarcane crop, limestone (calcium and magnesium carbonate) has traditionally been used as a soil corrector and also as a source of calcium (Ca) and magnesium (Mg), however this material has low reactivity and depends on much of the incorporation into the soil which, in general, results in a slower reaction. Due to these limitations, new materials were sought through research that could provide more active forms of Ca and Mg, capable of promptly making these nutrients available to the culture, allowing their better establishment. Therefore, the objective was to evaluate the effect of doses of oxides of Ca and Mg applied at the bottom of the planting furrow, on the development, productivity and quality of the plant cane. Two experiments were set up, both in a randomized block design (DBC), with four replications. Thus, different increasing doses of Ca and Mg oxide (46% CaO and 33% MgO) were evaluated, as well as a control treatment without the use of oxide. At the Santo Ângelo Plant (experiment 1) there was an increase in production productivity for TCH and TAH due to the doses 100, 150 and 200 kg ha-1 of Ca and Mg oxide applied in the planting furrow, with the highest yields achieved with the dose of 150 kg ha-1 of Ca and Mg oxide, which provided increments of approximately 13% in TCH and 19% in TAH in relation to the control. At Usina Buriti (experiment 2), there was an increase in TAH production due to the 50, 100 and 200 kg ha-1 of Ca and Mg oxide applied in the planting furrow, with the highest yields achieved with the 100 kg dose ha-1 of Ca and Mg oxide, which provided increments of approximately 15% in TAH compared to the control. There was an increase in the levels of exchangeable Ca and Mg in the soil and in the foliar contents of these nutrients with the application of Ca and Mg oxide, also occurring an increase of pH in the sugarcane planting line in layers 0 to 20 and 20 to 40 cm deep in relation to the control.