Tolerance of tomato to salinity under fertigation and calibration of cardy-ion meters for determination of nutrients in the soil solution and plant

Author(s)

Blanco, Flávio Favaro

• Document type: Doctoral Thesis
• Press: Piracicaba. [2004]. xviii, 115 f., gráficos, ilustrações, tabelas.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz
• Defense date: 08 mar. 2004

Examining board members

Folegatti, Marcos Vinicius; Boaretto, Antonio Enedi; Duarte, Sergio Nascimento; Gheyi, Hans Raj; Silva, Enio Farias de Franca e

• Advisor: Folegatti, Marcos Vinicius
• Field of knowledge: Agronomical Sciences - Agricultural Engineering
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca Central da Escola Superior de Agricultura Luiz de Queiroz; t635.642; B639t; 82875

Abstract

The concentration of salts in the water is one of the main aspects to be observed to define a strategy of irrigation management, which could take to damages due to the soil salinization, with consequent reduction of crops yield. Once tolerant crops to salinity present larger tenors of some nutrients in the leaves, then the fertilizing in sensitive crops could be conducted in order to increase the tenors of these nutrients in the leaves to increase the crop tolerance to salts. This work had the objective of studying the effects of three doses of N and K in the tomato tolerance to salinity, as well as to evaluate the performance of cardy-ion meters (CIM) in the determination of nutrients in the soil solution and in the sap of the plant. Tomato seedlings, hybrid Facundo, were transplanted in 10/23/2001 in vases containing 60 kg of a sandy-clay-loam soil, spaced 1.0 x 0.5 m, in a greenhouse covered with polyethylene film. The treatments were composed by the combination of three levels of N (7.5; 15.0 and 22.5 g plant-1) and three levels of K (8, 16 and 24 gK2O plant-1) applied by drip fertigation, in the 3x3 factorial scheme with five replications. Salts (sodium chloride and calcium chloride) were added to the irrigation water for obtaining an electric conductivity of 9.5 dS m-1. Soil solution and petiole sap were collected for determinations of the nutrients with the CIM, whose values were compared with the determinations by the standard methods. Significant effects of the treatments were not observed for the development and yield of the plants, as well as for the fruits quality. The concentrations of nutrients in the soil solution determined with CIM showed good correlations with the determinations by the standard methods, and the concentrations of nutrients in the petiole sap were well correlated to the tenors in the dry matter of the leaves... (AU)