Effect of saline drainage effluent on soil health and crop yield

Field trials were conducted in arid area of Pakistan with wheat–cotton rotation to evaluate the potential use of brackish drainage effluent for soil reclamation and crop production. The original drainage effluent was diluted with canal water before application. The treatments included: simple leaching with marginal water (electrical conductivity (EC) 1.25 dS m?1) without growing crop; irrigation with saline water (EC 2.25 dS m?1) alone; irrigation with saline water and green manure; and irrigation with saline water and farmyard manure. The changes in infiltration rate, soil salinity and sodicity along with crop yield were recorded. Maximum improvement of 88.9% was recorded in infiltration rate with green and farmyard manure application. In case of soil salinity and sodicity, the highest decrease of 2.8 and 41.3% was recorded with farmyard manure and an increase of 39.2 and 14.9% with simple leaching at 0–15 cm depth. At other three sampling depths, all treatments significantly increased EC of soil. Whereas sodium absorption ratio increased only at the lowest depth (60–90 cm) under all treatments. The application of farmyard manure produced the highest wheat and cotton yield with an average of 1925 and 1485 kg ha?1, respectively. The overall results showed that the application of farmyard manure was comparatively more effective than other treatments in overcoming the adverse effects of irrigation with poor quality water. However, the use of farmyard manure with drainage effluent is recommended under acute shortage of irrigation water.