The efficiency of liquid source nitrogen for foliar absorption in oat

Abstract

The objective of the study is to estimate the technical, economic and stability of nitrogen use efficiency in oats intercropped with soybean and corn in conventional management using urea and nutrient spraying for foliar absorption, considering the expression of biomass and grain yields in different cropping systems, subsidizing the validation of this technology. The study was carried out in Augusto Pestana, RS, Brazil, in a soybean/oat and corn/oat system. In each system, two experiments were carried out, one to quantify biomass yield and another to estimate grain yield, totally four experiments. In all experiments the design was randomized blocks with four replications in a 2x4 factorial, for 2 nitrogen sources (liquid and solid) with 4 doses (0, 30, 60 and 120 kg ha-1), respectively. The solid source (urea) with 45% of nitrogen for root absorption and the liquid source (N-Top®) with 28% of the nutrient for foliar absorption were applied at the phenological stage of the fourth expanded oat leaf. The analyzed variables were biomass and grain productivity, obtained by cutting the three central rows of each plot at the physiological and harvest maturity stages, respectively. The efficiency of using nitrogen from a liquid source via foliar absorption in oats promotes similar results when using urea. Regardless of the nitrogen source, doses of 45 and 75 kg ha-1 are more efficient in soybean/oat and corn/oat systems, respectively. Although the technical efficiency of liquid source nitrogen is proven, the high cost does not allow recommendation on a commercial scale