Efficiency of Lithovit-Guano 25 as affected by foliar spray or fertigation on salt-stressed-tomato crop

Abstract: The application of small-scale fertilizers is among methods tested to reduce the salinity-caused reductions in crop production. The efficiency of a certain fertilizer was shown to be significantly affected by its application method or place. Therefore, in the current study, Lithovit-Guano25 (Guano) was applied with a concentration of 2 g.L^-1 through two methods of fertigation (ferti) and foliar spraying (foliar) on tomato salt-stressed crop irrigated by four different NaCl solutions (EC 2, 6, 10 and 14 dS.m^-1). Control plants were those irrigated by NaCl solutions with no Guano application. Leaf number, fresh weights of plant parts, yield components, nutrient content, and total chlorophyll content, were reduced with salt stress. Salinity increased total soluble solids, titratable acidity and cell electrolyte leakage. Compared to control, Guano-foliar caused a reduction in soil EC by 0.09, 0.13, 0.2 and 0.22 dS.m^-1 respectively at EC2, EC6, EC10 and EC14. Fresh weights of shoots and roots were optimized mainly in Guano-foliar by 12.5, 10, 4 and 7.5 g compared to control, respectively at EC2, EC6, EC10, and EC14. When comparing methods of application, no significant difference was found between both methods on fruit diameter, fruit TSS, TTA and Mg content. Leaf area and fruit weight in Guano-foliar-treated plants were significantly higher (by 20 cm² and 2.5 g) compared to Guano-ferti-treated plants at EC14. Moreover, fruit number and yield were also maximized following Guano-foliar treatment. Guano-foliar treated plants accumulated less sodium at EC6 (by 0.2 %) and more phosphorus at all ECs (by 0.2 %) than those of Guano-ferti. Additionally, nitrogen, calcium, and total chlorophyll content were maximized in Guano-foliar-treated plants. When compared to fertigation, foliar spraying of guano had a better effect on mitigating salt stress.