Testing microalgae solutions (scenedesmus sp) as a natural biostimulant in the lettuce hydroponiccultivation (lactuca sativa)

Abstract

In order to make a first contribution in the use of nutrients coming from unicellular algae, a test was realized, its main purpose consisted on evaluate the nutritional contribution of live unicellular algae. (Scenedesmus sp) in a nutritive solution that is commonly used in hydroponic. Three doses of microalgae solution were evaluated as a natural bio stimulant in the lettuce production. (Lactuca sativa): in a low concentration of algae (40 x 104 cel. ml-1); medium concentration (80 x 104 cel. ml-1); and high (120 x 104 cél. ml-1); the witness was a nutritive solution without microalgae addition. There were used microalgae from the laboratory of Agricultural and Environmental Sciences School where the microalgae were produced to add them to the hydroponic production system later. A completely randomized block design was used in four treatments and three repetitions. The blocks were placed perpendicularly to the luminosity considered as a non-controllable factor. The hydroponic nutritive solution was evaluated daily, the pH was constant 6 to 7,3 and the electrical conductivity was 1,7 a dSm-1. At the end of the development cycle, the roots and leaves were weight. The variance analysis detected significant differences for the treatments (p<0.05). At the end of the essay, the aerial weight average per plant was 34.3 g. for the witness (without microalgae solution addition), while for the high microalgae solution (120 x 104 cel ml-1) was 46.32 g. Therefore, the use of live microalgae solutions during the hydroponic lettuce development cycle provokes a lettuce production increase without affecting the hydroponic solution or the plant.