Effects of wastes from co-inoculation with Azospirillum brasilense in soybeans and nitrogen fertilization on corn leaves by macronutrients

Abstract

Response of foliar rates of macronutrients in corn under nitrogen fertilization and the effects of waste of co-inoculation with Azospirillum brasilense in soybeans are evaluated. Soybean was planted in two treatments, namely, inoculation of seeds with Bradyrizobium japonicum, with and without co-inoculation with Azospirillum brasilense, followed by corn. Treatments for corn crop consisted of a combination of residual inoculation of Bradyrhizobium japonicum and the residual co-inoculation with Azospirillum brasilense within the band (main factor) applied to soybean seeds and five doses of N (0, 50, 100, 150 and 200 kg ha-1) applied to second harvest, consorted with Urochloa ruziziensis in the splits (secondary factor). Foliar rate of N, P, K, Ca, Mg and S for corn crops was determined. Efficiency of nitrogen usage (EUN), recovery of applied nitrogen (RNA), agronomic efficiency of applied N (EA) and physiological efficiency (EF) were determined. Data underwent analysis of variance and means of quality factor (inoculation) were compared by F test, whilst polynomial regression was applied for quantitative factor (N doses). Corn inoculation residue did not increase the rate of corn foliar N. However, there was an increase according to the dose of applied N. In the case of other nutrients (P, Ca, Mg), foliar increase of nutrients was detected in most doses when compared to co-inoculation and interaction between inoculation factors and N doses. There was no increase in K and S when compared to co-inoculation residue. Residual co-inoculation with Azospirillum brasilense in soybean improves corn physiology cultivated in succession and generates plants with greater production potential coupled to greater stress tolerance.