Economic viability of Phaseolus vulgaris (BRS Estilo) production in irrigated system in a function of application of leaf boron

Abstract

ABSTRACTFoliar fertilization may be a viable strategy to boron supply in irrigated cropping systems with common beans (Phaseolus vulgaris), since it prevent B leaching. The aim of this work was to evaluate the economic viability and physiological parameters of the common beans production in irrigated cropping systems using sources and increasing foliar boron doses. A field experiment was carried out using an experimental block design in a factorial scheme 2 × 5 × 3, with two sources of B (boric acid and borax) and five doses: 0 (control), 2, 4, 6 e 8 kg ha−1, with three repetitions. Foliar B applications were performed at 40 days after seeds germination, in pre-flowering stage. Physiological process (transpiration, stomatal conductance, CO2 internal concentration, net photosynthesis, and relative chlorophyll index), B level in leaves and grain yield were measured. These data were used to determine the economic viability of B fertilization in common beans. Both boric acid and borax increased B levels in common beans leaves. Borax affected some physiological process reducing stomatal conductance and increasing net photosynthesis. Using borax, the highest net photosynthesis was observed at a rate of 4 kg ha−1, while the boric acid increased net photosynthesis linearly after increasing B doses application. An enhance of 311 kg ha−1 in the grain yield was observed using borax related to the control (without B application); however, grain yield decreased linearly after application of increasing B doses, as boric acid. Comparing the economic viability of sources and doses of B, the highest profitability is obtained using borax at a rate of 4 kg ha−1, which promoting a differential profit of US$534.44 per hectare compared to common beans cropping without B.