Productivity of lettuce under proportions of bovine manure and levels of irrigation water salinity

Abstract

This study aimed to evaluate the effect of irrigation with different levels of water salinity and different levels of bovine manure on the growth and yield of lettuce. The experiment was conducted in randomized blocks in a 5 x 4 factorial design with three replicates and one plant/pot, characterizing the experimental unit. Four levels of salinity (S1 = 0.27; S2 = 1.5; S3 = 3.0; S4 = 4.5 dS m ^-1 ) were used and water from the supply system was adjusted by the addition of NaCl for irrigation, with five levels of bovine manure in the substrate with sand at five proportions (Sm1 = 0:1; Sm2 = 1:3; Sm3 = 1:1; Sm4 = 3:1 and
Sm5 = 1:0). The variables evaluated were: number of leaves, plant diameter, root length, fresh weight of shoots and roots and dry weight of shoots and roots at 35 days after transplanting. All variables were affected by the studied factors, with isolated effect of salinity levels and manure levels, but without significance in the interaction (S x Sm). The results showed that the development of lettuce was negatively affected by salinity above 3.0 dS m ^-1 and positively affected by increasing proportions of manure levels.