Salt Leaching Process in an Alkaline Soil Treated with Elemental Sulphur under Dry Tropic Conditions

Soil drainage is necessary at both the field and district level to prevent rising tables and to allow for leaching salt. The laboratory study described in this paper was designed to evaluate the effect of elemental sulphur application on salts leaching in a tropical alkaline soil under dry tropic conditions. Four treatments were applied: (i) no-S°, (T ), (ii) 0.5 mg S°g soil, (T ), (iii) 1.0 mg S°g soil, (T ), (iv) 2.0 mg S°g soil, (T ). After 01 2 3 1 1 1 mixing, subsamples of each soil mixture from each treatment were placed in plastic pots (30×30 cm, diameter × height) and maintained at 50% water holding capacity for 45 days at 28°C. After incubation, these soil subsamples were packed into polyvinyl chloride columns. Generally, cations with higher solubility (sodium and potassium) were strongly leached when the process was 1.3 pore volume, on the other hand, at the beginning of the process (0-0.25 pore volumes), calcium and magnesium cations were observed in higher quantities, although their values changed during the process. Anion composition in the effluent varied considerably during leaching, because carbonate quantities were low at the beginning of the process, although they later increased, contrary to sulphates, bicarbonates and chlorides. Sulphur application in soil increases anion and cation solubilization. This is evidenced by increase of electrical conductivity, as well as a higher pH in the soil without Sulphur application.