Applications in sustainable production

Abstract

Capsicum plants (Capsicum annuum L. cv. Lamuyo) were grown in controlled greenhouse conditions in artificial soil. The plants received increasing levels of N (6, 12, 18 and 24 g/m²) and K (4, 8 and 12 g/m²), complemented with other nutrients. On plants leaves sampled fortnightly throughout their growth cycle to measure the cations (C⁺: NH₄ ⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺), anions (A: SO₄ ^2‐, Cl^‐, P₂O₄ ^‐, NO), protons (H⁺), ascorbic and citric acid, and total organic anions. Our results showed an increase in foliar inorganic anions proportionnai to the NK doses applied. In general, citric acid gave a lower values in the lower NK doses, whereas, the higher values were obtained with the higher doses. No clear response was observed of ascorbic acid to the doses of NK as the highest leaf value was achieved, with the low NK levels. The internal cationic excess led to an increase in hydrogen ions, either extruded or integrated into the tissue. The values of the H⁺/N_org and C⁺‐A^‐/N_org ratios increased as increased K₁ to K₃, with the combinations of N₁, N₂ and N₃, with an inverse trend in N₄.