Morfofisiologia e produção de tomateiro tipo cereja sob salinidade hídrica e adubação organomineral.

Abstract

Water scarcity is a problem that is present in many parts of the world, especially in semiarid and arid regions, making the viability of lower quality waters in agriculture is necessary, especially saline waters. However, salinity is one of the abiotic factors that most affect the growth, physiology and yield of crops. Among the main techniques used to increase crop productivity, with records of alleviating the effects of salts to plants, there is the use of organic inputs and proper management of mineral fertilizer. Thus, the objective with the study was to evaluate the morphological and physiological characteristics and yield of cherry tomato subjected to irrigation with salinity water and mineral fertilizer and organic fertilizer. The experiment was conducted in a greenhouse (in pots of 11 L) at the Federal University of Campina Grande, on Campina Grande / PB. The treatments consisted of five levels of electrical conductivity of irrigation water (0.5, 1.5, 2.5, 3.5 and 4.5 dS m-1) and three fertilization treatments (unfertilized control; fertilizer with earthworm castings and chemical fertilizer), factorially combined in a 5 x 3 and arranged in a randomized complete block design (4 blocks). It was assessed growth-related variables, leaf gas exchange variables and fruit production variables, where the data collected were subjected to analysis of variance (by F test) and for the significant variables, regression analysis and mean comparison tests were performed (Tukey's test). It was found that the salinity water hindered the growth of cherry tomato, with reductions in height and stem diameter, and plant losses of biomass production throughout the cycle. The number of leaves was reduced only at 35 days after transplanting (DAT), indicating that the culture does not activate the mechanism of exclusion of salts by the process of leaf abscission at the beginning cycle. At 20 DAT, leaf area was reduced due to the high salinity level, as an adaptation mechanism to reduce the transpiring surface and prevent water loss. The stomatal conductance, leaf internal CO2 concentration, transpiration and net photosynthesis of culture were benefited for the organic fertilizer, at 20 DAT, and impaired with increasing water salinity at 20 and 40 DAT, however, due to the application of a second dose of mineral fertilizers, there was an attenuation of the salt's deleterious effects on stomatal conductance, transpiration and photosynthesis at 40 DAT. In plants without any fertilization happened lower growth, leaf gas exchange damage, higher rate of flowers's abortion and lower fruit production. Fruit production was reduced with increasing salinity. Although fertilization with earthworm compost has afforded a greater vegetative growth, fruit production was higher when plants were subjected to mineral fertilization.