Distribuição de sais no perfil do solo e produtividade do cafeeiro irrigado com água salino-sódica

Abstract

The objective of the present work was to study the relationship between the rain pattern and yield of coffee over a twenty-year period, as well to evaluate the distribution of salts in the profile of a soil and the productivity of the coffee (Coffea arabica L.) irrigated with saline-sodic water along three years, being used the variety Catuaí, with medium age twenty years old. The experiment was conducted in the Fazenda Lagoa do Morro, town of Brejões, State of Bahia. A surface drip irrigation system with 2.5 Lh-1 emitters was used to irrigate the area. The experiment followed a randomized complete block design where six irrigation depths (0, 2.0, 2.5, 3.0, 3.5, and 4.0 mm), replicated six times, were applied each two days. The following soil parameters were evaluated from surface to 80 cm depth at 20 cm increments: pH, electrical conductivity of soil paste (CEes), exchangeable sodium ratio (PST) and the sodium adsorption ratio (RAS). Results from hydroclimatological water balances presented annual total deficit for all evaluated sites, becoming worse in the periods of larger water demand by the coffee. All the appraised soil parameters presented increasing tendency; medium PST was high (> 30%) in all the irrigated treatments, indicating sodification. The soil pH increased slowly over the season from an average of 5,5 to 6,9 for all treatments. The average yield varied of 2100 kg/ha (2,0 mm) to 600 kg/ha (4,0 mm). The depth of 2,0 mm promoted increment of 44% in relation to the witness treatment. A reduction of ,8% was verified in the productivity of 2003 in relation to 2001, for the same treatment.