Effect of Sub-surface Drain Spacings on Soil Salinity, Soil Water Content and Growth of Wheat on a Saline Soil

A field study was conducted to evaluate the effects. of three sub-surface drain spacings (25, 50 and 75m) on soil salinity, soil water content and growth of wheat on a sandy loam saline soil (Camborthid). Installation of sub-surface drainage system resulted in appreciable reduction in salts due to monsoon leaching and continuous cropping. Decrease in soil salinity was more in 25m drain spacing than in 75m drain spacing. Residual soil water content was higher in 75m drain spacing than in 25 and 50m drain spacing and increased with the increasing distance from the drains. Root penetrated up to 90cm soil depth, but 76 and 88 per cent root mass were in 0–15 cm soil depth in 25 and 75m drain spacings, respectively. Root development in lower depths was restricted by the higher salinity of these layers. Grain andstraw yields decreased with the increasing drain spacings. Grain yield was higher near the drains and decreased as the distance from the drains increased.