BIOFORTIFICAÇÃO COM ZINCO EM FORRAGEIRAS DE INVERNO

Abstract

Biofortification with zinc (Zn) in winter forage crops can be an efficient short-term strategy to alleviate malnutrition problems of this micronutrient in humans and animals. The objectives of this work were to study the effects of Zn application in the soil and via foliar spray on forage yield (ryegrass, rye and black oats), forage biofortification and nutrient exports from the cultivated area. For each forage species, ryegrass (Lolium multiflorum Lam.), rye (Secale cereale L.) and black oat (Avena strigosa Schreb.), the experimental design was in a randomized complete block, with four replications, in a split-plot design. In plots, the supply of Zn in the sowing fertilization (without and with Zn) was studied. In subplots, the application of doses (400 and 800 g ha-1 of Zn) and two times (T1 and T2) of foliar spraying were evaluated. At approximately 156 DAS, the shoot of the three forage species was collected in each subplot and the dry matter weight and the concentration of nutrients in the shoot materials were determined. Soil and foliar Zn application did not significantly affect biomass yield. Both soil Zn supply and foliar Zn sprays increased the Zn concentration in the shoot dry matter of the three forage species. The increase of Zn in plant biomass was greater in foliar sprays performed in T2. For the same spraying season, the highest Zn dose (800 g ha-1) had the greatest effect in increasing the Zn concentration in the shoot of the forages. Thus, the Zn supplies in the soil and via foliar sprays did not affect forage yield, but increased the element concentration in the biomass of the studied forages. Furthermore, the Zn supply in the soil increased the levels of N, Ca and decreased the levels of Cu and Mn in the shoot of the forage species.