Cultivo hidropônico da alface crespa sob diferentes níveis de salinidade.

Abstract

Water scarcity for irrigation is an obstacle to the agricultural and social development of arid and semi-arid regions. The use of lower quality water in agriculture, such as salt water, is a very adequate alternative to these places, since it will promote the increase of the supply of water boosting the agricultural activity and contributing to the economic and social development in the region. Despite the potential benefits, the use of saline water in agriculture is not without risk, since the presence of high salt concentrations can cause damage to irrigated crops. In this way it is important to study the efficiency of alternative techniques that allow the use of salt water in a way that allows its use in a safe way in the crops. In view of the above, the present work had the objective of evaluating the effects of different levels of salinity of the nutrient solution in the hydroponic cultivation of two lettuce cultivars. To this end, an experiment was set up in a protected environment at the Federal University of Campina Grande (UFCG), Campus I, during the period from 01 to 22 September 2016. The experimental design was completely randomized (CRD) which involved 4 × 2 factorial scheme with four levels of electrical conductivity of the nutrient solution (1,6; 3,6; 5,6 and 7,6 dS m-1) and two lettuce cultivars, Valentina (C1) and Alcione (C2), totaling 8 treatments with 3 replicates, resulting in 24 experimental units. The solution with lower salinity (S1) was prepared with rainwater and the other treatments (S2, S3 and S4) were prepared with water from the local supply system of Campina Grande - PB, whose electrical conductivity was 1,69 dS m-1, being therefore, an addition of NaCl (sodium chloride) is required to reach the CE values proposed in the research. According to the results, the use of saline water to prepare the nutrient solution in the hydroponic cultivation of the two lettuce cultivars studied in this research is beneficial, allowing to obtain well - nourished plants with adequate vegetative growth, resulting in good crop yield indexes.