Produtividade Do Trigo Irrigado Submetido À Aplicação De Nitrogênio E À Inoculação Com Azospirillum brasilense

Abstract

Inoculating wheat seeds with nitrogen-fixing bacteria such as Azospirillum brasilense may be beneficial to the crop and reduce the need for N application Nevertheless few studies have measured the benefit of this practice on irrigated wheat with the expectation of high yield and demand for N The objective of this study was to evaluate the yield and N content of irrigated wheat under different N application rates with and without inoculation with A brasilense Two experiments were carried out in 2011 and reevaluated in 2012 In each crop year one experiment was set up in an area with low N availability in the soil (growing in succession to maize) and another with high availability (growing in succession to soybean or carrots) The treatments consisted of five N application rates and inoculation or no inoculation with A brasilense The N rates tested were 20 60 100 140 and 180 kg ha-1 in the area with low N availability and 20 50 80 110 and 140 kg ha-1 in the area with high N availability Yield grains per spike dry matter accumulation in the shoots N content in the index leaf and in the grain and N uptake and export were evaluated The N content in the index leaf increased through inoculation with A brasilense However the N taken up was not affected by inoculation of the bacteria The N applied increased wheat yield and this increase was more evident in the area with low N availability in the soil