Aplicação de escória siderúrgica e gesso no plantio de cana-de-açúcar: crescimento e produtividade em quatro ciclos

Abstract

Sugarcane is considered very important in Brazilian agribusiness, but its growth and quality characteristics are limited by irregular rainfall during cultivation and soil acidity coupled with high concentrations of Al+ 3 in the main producing areas of the country. Steel and gypsum slag are alternatives that minimize these limitations of the growing environment. The objective of this study was to evaluate the effect of metallurgic slag and gypsum on sugarcane planting on morphology, productivity and agricultural contribution over four crop cycles. For this, a field study with the variety RB92579 was carried out during four crop cycles using a randomized block design in a 4x4 factorial scheme, with four replications. The treatments were composed of a combination of four doses of metallurgic slag (0, 4, 8 and 16 t ha-1) and four doses of gypsum (0, 3, 6 and 12 t ha-1). The plot consisted of five lines of 10 m in length with spacing of 1 m between rows. The height of the sugarcane was higher in the interaction between the metallurgic slag and the first crop cycle. The doses of steel slag and gypsum promoted significant increases in the number of industrializable stalks. High and sugar yields increased as a result of increasing doses of metallurgic slag and gypsum during the four cycles. The technological analysis was not influenced by the application of metallurgic slag and gypsum, but the cultivation cycles promoted quadratic effect for ºbrix and purity and linearly increased the fiber content over the four cycles. Metallurgic slag and gypsum increased the agricultural contribution margin, which was more significant at the maximum doses of 16 and 12 t ha-1, with increases of 189.65 and 156.89 dollars ha-1, respectively. In the last year of harvest, the root system showed root density along the more uniform profile with gypsum and slag + gypsum, mainly in the 20-60 cm layer, and therefore important agricultural inputs to be applied at the moment of sugarcane, promoting residual effects.