Efeito de corretivos químicos e matéria orgânica sobre características físicas e químicas de um solo salino-sódico

Abstract

To study the effects of chemical amendments and organic matter on physical and chemical characteristics of a saline-sodic soil (Vertic torrifluvents), located in the University of Ceará Experimental Farm at Pentecoste, Ceará, Brazil, samples were colected in depths of 0-25 cm and 25-50 cm and submited to the following treatments: gypsum (CaSO4.2H2O) and calcium chloride (CaCl2.2H2O) in rates calculated to substitute 50, 100, 150 and 200% of exchangeable sodium; organic residues - rice (Oryza sativa Linn.), carnaúba (Copernicia cerifera (Arr. Cam.) Mart.) and feijão de porco (Canavalia ensiformis DC.) were applied at the rate of 1%. The samples treated were incubated in controlled conditions of temperature and moisture (27°C and 1/3 bar) for 60 days. The experiment was conducted in soil columns and according to a complete random scheme with two repplications. Means were compared applying Tukey test at the 0,05 probability leveI. Treatments resulted in significant differences on the values of the water transmission characteristics, aggregate stability, exchangeable sodium and soluble salts, in relation to the untreated soil, being the effects proportional to the amount of amendment used. Chemical amendments were more effective than organic matter and among amendments grypsum was more effective than calcium chloride. No significant differences were detected among organic matter treatments. Application of concentrated electrolyte solutions increased saturated hydraulic conductivity of the soil. It is expected that the results obtained would be useful in planning and conducting field experimentation on management and reclamation of saline-sodic soils.