Agronomic Biofortification in Caupi Beans with Lithium

Biofortification of basic crops is ideal because of the broader consumption of staple foods by the majority of the population. Beans are one of the main constituents of many Brazilian dishes, for urban and rural populations. Li is essential to the mental and behavioral health of human beings. The objective of this work was to study the assimilation of Lithium (Li) by cowpea beans (Vigna unguiculata), with the application of lithium hydroxide (LiOH). The study was carried out in a greenhouse at the Federal University of Tocantins, Campus de Gurupi. The treatments were arranged in a completely randomized design in a 5 x 3 arrangement, with five doses of Li (0; 10; 20; 30 and 40 mg kg-1); and three cultivars of Caupi beans (BRS Cauame, BRS Itaim and BRS Nova Era) with four replicates. The application was performed via foliar, and the doses were divided into two applications of equal proportions, spaced in 15 days. Each experimental plot was represented by a vessel containing 10 kg of soil. Stem diameter, number of pods per plant, pod length, number of grains per pod, insertion of the first pod, plant height, mass of 100 grains, grain yield, lithium content, total nitrogen, crude protein and lipid content. The agronomic biofortification with Li occurred positively with the application of up to 26 kg Li ha-1 for the three cultivars, with up to 159.38% increase over the treatment without Li application. The results indicate that it is possible to increase the Li doses in Caupi with the use of lithium hydroxide (LiOH) in foliar fertilization.