Use manipueira of cassava as biofertilizer and bioinsecticide in lettuce crop

Abstract

The state of Pará is the biggest producer of cassava flour in Brazil, however, the cassava cultivation in this state still primitive, using little added technology, both in cultivation, irrigation,
for example, and in waste treatment or generated effluents. The manipueira is the waste of the
flour production, highly toxic for the soil, for plants and for the microbiota, very important to the
ecological relation in the environment. The production of cassava flour generates high quantities
of manipueira to each ton of processed root. If done correctly, the aerobic and/or anaerobic
treatment of the manipueira can eliminate the effluent toxicity, besides making its use possible
in irrigation projects, allowing the productive chain circle of cassava flour to became, gradually,
ecologically correct. It’s recommended the prior treatment of manipueira, through the most
complete fermentation possible before add it to the soil, especially to reduce its organic load,
to avoid the fermentation of it on rhizosphere, accident that usually causes the death of plants.
In Santarém/PA the cultivation and manufacture of flour is intense, highlighting the Boa Esperança
community, located at 43rd km of Curuá-Una highway (PA – 370). The aim of this work
was the characterization of the effluent (manipueira) and its applicability as source of irrigation
water in horticulture with the intention of provide to the owners of flour houses and vegetable
producers the reuse of this waste in agroecological scope. The use of this natural organic waste
will sharply decrease the use of chemical fertilizers and insecticides by the community. To
get sample results, an experiment was set up at the premises of UFOPA. The lettuce (Lactuca
sativa) crop was used. Half of the experiment was daily irrigated with manipueira and, the other
half, only with water, in order to prove its action as a natural biofertilizer and bioinsecticide. At
the end of the experiment, it was found the beneficial effect on the crop, where plants irrigated
with manipuera seemed more vigorous and well nourished, with no pest insects when compared
to the plants irrigated only with water. The potential of this extract shows in experiment
and places as an alternative to its use and reuse by community farmers, aiming the non-use
of chemical products like fertilizers and insecticides, based on the use of organic products and
emphasizing the importance of agroecology.