Investigação sobre o aproveitamento da manipueira como fertilizante foliar.

Abstract

It was studied the utilization of the manipueira - liquid extract of the roots of the Manihot esculenta, a remainder of the industrialization of flour from mandioca - as a foliar fertilizer. This way, two experiments were settled in different places and times involving the crops of okra (Hibiscus esculentus) and sorghum (Sorghum bicolors). The experiment with okra took place in the plateau of Ibiapaba, state of Ceará, Brazil, in 1992/3. By using the manipueira in the concentrations 1:4, 1:6, 1:8 and 1:10, by making six pulverizations considering one by week, it was obtained a production (number and total weight of fruits) estatistically higher to the control plants (pulverizations with water), as well as that obtained with the utilization of the foliar comercial fertilizer used as referencial of nutritional comparisson. A second experiment, involving sorghum, was conducted in 1994, at Pici Campus Federal University of Ceará - in Fortaleza. It was used the same concentrations of manipueira except the first one (1:4), and the same foliar comercial fertilizer with identical sequence of aplications. None of these treatments provided a increasement of green weight estatistically significant in relation to the control. The lack of a better answer from sorghum to the manipueira as well as to the comercial fertilizer, shoued be considered, mainly to factors linked to the epidermical structure of the leaf (cerosity) and to the mechanism of working of its stomates making difficult the absortion of nutrients by using foliar way. This doesn't void the usefulness of manipueira as a foliar fertilizer as was demonstrated according to results obtained in the first experiment.