Yield, nutritional status and soil fertility cultivated with common bean in response to amino-acids foliar application

Fertilization of common bean (Phaseolus vulgaris) plants with amino-acids (AAs) near the beginning of flowering may increase productivity. This procedure is aimed to avoid waste and increase nutrient use efficiency at the end of the crop cycle, improving the leaf area in the translocation of these nutrients to the common bean. In order to test this hypothesis, a field experiment was conducted on a typic Eutrortox (Oxisol) in randomized block design, with three replicates. Four rates of a solution composed of amino-acids (6.8% glycine, 4.4% proline, 3.3% glutamic acid, 2.7% alanine, 1.9% arginine, 1.7% aspartic acid, 1.3% lysine, 1.3% histidine, and 1.0% leucine) applied 45 days after plant emergence were studied. There was no interaction between years of cultivation × amino-acids. However, the productivity of common bean was significantly influenced by the AAs rates, with the highest seed yield obtained at estimated concentration in 0.0094% of the product in foliar sprays. The increases in the rates resulted in increased foliar nitrogen (N) and zinc (Zn) concentrations and decreased sulfur (S) concentration. The macronutrient uptake was nitrogen>potassium>phosphorus>magnesium > calcium > sulfur (N > K > P > Mg > Ca > S), while for micronutrients it was iron>zinc>boron>copper>manganese (Fe > Zn > B > Cu > Mn). In the soil, the concentrations of organic carbon (C) and available P were negatively affected by the AAs rates.