Doses de adubação nitrogenada no cultivo do milheto em ambiente semiárido

Abstract

Due rusticity and multifunctionality of millet plants, this culture adapts very well to semi-arid zone conditions and still requires little economic investment, associating its yields potential with nitrogen fertilization. The aimed was to analyze the growth, yield and of tissue mineral composition of millet (Pennisetum glaucum cv. BRS 1501) plant (Nome scientific + cultivar) in different nitrogen doses under greenhouse conditions. The experimental design was a completely randomized 5x4 factorial design and five replications. The main factor was composed of five nitrogen doses (without nitrogen fertilization - 100, 200, 300 and 400 kg ha- 1), while the second factor referred to the evaluation periods at 21, 42, 63 and 78 Days After the Sowing - DAS. The variables analyzed were plant growth (height, stem diameter, number of leaves and leaf area); Nutrient accumulation and forage yield and quality (Dry matter of shoot, leaf / stem ratio and dry matter). There was interaction of the N doses and withdrawal times for the vegetative growth variables, only the height of the plant had a decrease in the values with the increase of the doses of N. There were interaction of the N doses with the evaluation periods, except for the contents of Ca. Only N increased with the increase of the dose of N, with a maximum of 53.84 g kg-1. The other nutrients had linear decreasing behavior. The variables of leaf and stem fractions and leaf / stem ratio had a quadratic behavior for the interaction of the increase of N doses with the different seasons. The highest millet dry matter yield was observed at the dose 270.94 kg of N ha-1, obtaining the value of 1893, 46 kg ha-1 at 78 DAS. Nitrogen fertilization positively influences the production of millet, with a recommended dose of 271 kg ha-1 of N and cut of the plants at 63 DAS for the semi-arid region