Influence of Cropping System on Salt Distribution in an Irrigated Vertisol1

Abstract

AbstractField studies were conducted to determine the influence of cotton (Gossypium hirsutum L.) and grain sorghum [Sorghum bicolor (L.) Moench.] on salt distribution in a vertisol profile. Electrical conductivity of soil saturated pastes taken from the root zone (0 to 90 cm) after 4 years of sorghum ranged from 2.6 to 4.8 mmhos/cm but ranged from 4 to 7.6 mmhos/cm at 0 to 90 cm after 4 years of cotton. Chloride concentrations showed similar trends in that CI‐ concentrations were 9 to 12 meq/liter at 0 to 90 cm after sorghum, but were from 18 to 30 meq/liter at the same depth after cotton. The differences in salt concentrations in the soil profile after the two crops were attributed mainly to higher water infiltration rate after sorghum (5.81 cm/hr) than after cotton (1.23 cm/hr). The indicate that cropping practice can be an important factor in salt accumulation in clay soils and that the crops should be alternated to avoid excessive salt accumulation in the root zone.