Parâmetros agronômicos do algodoeiro em função de doses de calcário e adubo

Abstract

The cotton plant (Gossypium spp.) is extremely sensitive to the presence of aluminum in the soil, so liming is necessary to achieve success with the crop in acidic soils, which generally have nutrient deficiencies and limitations to productivity. Fertilization is extremely important to meet the cotton plant's needs so that it can express its full productive potential. The objective of this study was to evaluate the effect of limestone and fertilizer doses containing primary macronutrients on the productivity and growth parameters of cotton (Gossypium hirsutum L.) in the municipality of Monte Carmelo - MG. The experiment was carried out in an experimental area at the Federal University of Uberlândia, Monte Carmelo Campus, located at geographical coordinates 18º72'27.36'' S and 47º52'33.5'' O and an altitude of 903m. The crop was irrigated using a drip system, with emitters spaced 0.2 m apart and a drip flow rate of 1.6 L h-1. Sowing was carried with the FM 944 GL cultivar at a spacing of 0.8 m between rows and a density of 11 seeds per linear meter. The experiment was conducted in a randomized block design, with four replications, in a 3 x 3 factorial scheme, totaling 36 experimental plots. The treatments were a combination of three limestone levels (100%, 200% and 400% of the reference according to the base saturation elevation method) and three levels of fertilizer (50%, 100% and 150% of the reference, according to the soil analysis). The following parameters were evaluated: SPAD index, plant stem diameter (mm), height (cm), number of apples and tops per plant, weight of apples (g), tops (feather and seeds) per plot, and this data was extrapolated to kilos per hectare to obtain the yield in stone and feather. The data was analyzed using the F test and if significant differences were detected, the Tukey test was applied at 5% probability. Increasing the of limestone by 400% of the standard recommendation increases the height of the cotton plant, the number of apples per plant and the seed cotton yield compared to the standard recommendation of 100%. Fertilization based on 100% of the standard recommendation provides higher seed cotton productivity (kg ha-1) compared to the 50% fertilization level.