Efeito da adubação nitrogenada em cobertura de variedades e híbridos de milho do cerrado de Humaitá-AM

Abstract

The region of the south of Amazon concentrates one of the largest human pressures of the state, they are areas of agricultural border that need technological information more and more. The planting of grains in the municipal district of Humaitá - AM has been accomplished in an empiric way. The area is still lacking of studies and agronomic recommendations, in that way, the rural producer one see forced to use of handlings recommended for his origin area and not always adapted to the Amazonian region, sometimes causing high economical damages. The present study was developed in the agricultural harvest of 2005/06 in the farm Brasília in the municipal district of Humaitá-AM of property of Mr Luiz Pareja. The objective of this work was to accomplish a competition among varieties and hybrid of corn, associated to the manuring of nitrogen covering in savannah of Humaitá. The tested cultivate was constituted of hybrid (simple, double and triple) and varieties of open pollination, totaling 22 cultivate. The experimental design was in randomized block in factorial plan with four replications, which the factors are: covering nitrogenated fertilization (80 kg.ha-1 and testify) and cultivars. The appraised variables were: income of grains, ear of corn length, diameter of ears of corn, number of arrays for ear of corn, number of grains for arrays, weight of 100 grains, initial and final stand, height of the insert of the 1st ear of corn, nº of tumbled ears of corn and open, total nº of ears of corn and masculine bloom. You cultivate them appraised they answered to the manuring nitrogenada in covering, being obtained an increment in the productivity medium of 95%, varying between 26% and 235%. The hybrid expressed better income of grains than the varieties as expected, among them, they stood out 2B619, BRS 2020, 2C599 and BRS1030. Among the varieties, the most productive was BR106 and for treating of a pollination variety open of low cost, it has demonstrated a good alternative in the corn planting in the area.