Effect of nitrogen and potassium doses on growth, chemical composition and levels of ammonium and nitrate in the aerial part of yellow oat cultivated in greenhouse

Abstract

The present experiment was carried out in a greenhouse, at Jaboticabal, São Paulo, Brazil. A dark red latosol with medium texture was used in pots, aiming at evaluating the effects of levels of nitrogen and potassium on the production of dry matter and alterations in the chemical composition of the soil and of the plant. For mineral fertilization of the soil it was used urea, simple superphosphate, potassium chloride and heptahydrated zinc sulfate, in the doses of 0, 00, 200 and 400 mg dm-3 for nitrogen and potassium; 200 mg dm-3 for phosphorus and 5 mg dm-3 for zinc. The fertilizer N and K were parceled out in three applications, the first in the seeding, the second 0 days after, and the third 5 days after the second. The seeding of yellow oat (Avena byzantina C. Koch) was realized 30 days after incubation of the corrective. The samplings of the aerial part were taken 60 and 20 days after seeding with the following being determined: dry matter production, levels of crude protein, levels of macronutrients and of some micronutrients (Cu, Fe, Zn, and Mn) in the aerial part. Nitrogen promoted an increase of dry matter and levels of crude protein in the two cuts; N-NH4 + increased significantly until the dose of 200 mgdm-3 of K. A positive effect of N and K in the concentrations of N-NH4 + and N-NO3 - in the soil was verified.Additional keywords: Avena byzantina; mineral nutrition; fertilization; chemical composition.