Efeito da escória de siderurgia nos atributos químicos do solo, nutrição e produção de milho no nordeste paraense.

Abstract

The objective of this study was to evaluate the agronomic efficiency of slag in different particle sizes and doses, through the improvement of soil properties, nutrition and productivity of maize (Zea mays). The work was conducted in dystrophic Oxisol in the experimental field of Embrapa Amazônia Oriental, city of Terra Alta - PA. We used a randomized complete block design with three replications in a factorial 4x3x8 +2, four grain sizes (material retained between ABNT in 20-50, 50-100, 100-200 and <200), three different slag doses (1.65, 3.81 and 5.98 t ha-1) for lifting of base saturation of 40, 70 and 100%, respectively, eight different incubation times (15, 30, 45, 60, 90 , 120, 240 and 360 days), and two additional treatments, one with and one without lime scale and slag (control). For assessment of the chemical, collections were made in the soil at a depth of 0-20 cm in each plot, and each incubation period. Nutritional assessment and corn production, after 120 days of sowing performed the harvest of corn plants. After harvesting, the plants were measured with the aid of a tape measure to obtain the plant height (PH) and separated into leaf + stem and reproductive (spike, which was separated into straw, grain and cob). The plant material was dried at 70oC until reaching constant weight to determine the dry weight of (MSPA). To determine weight, ear of grain, and cob, all ears were harvested contained in the four central lines of all the main plots (Stand). The samples were ground and subjected to chemical analysis. It was determined the concentrations of macronutrients (N, P, K, Ca and Mg) and micronutrients (Cu, Mn, Fe and Zn). The finer size fractions (100-200 and <200) showed better results in some soil chemical properties. The treatments with the slag produced better results compared to the additional treatments (lime + control) on soil chemical properties. There was no significant effect of particle size fractions and neither of the doses in the levels of nutrients in plants. We observed a significant effect only in different parts of the plants in nutrient content. The nutrient uptake by the crop, as the macronutrients and micronutrients, presented the following decreasing order: N>K> Ca> P> Mg and Fe> Mn> Zn> Cu. There were no significant effect of particle size fractions and incubation time on plant height, ear production and weight cob. Shows higher PMSPA and grain yield in plots that were applied slag with smaller size fractions (ABNT in 100-200 and <200) and in higher doses 3.81 and 5.98 t ha-1.