Leaching behaviour of saline vertisols under paddy-paddy cropping sequence

A field experiment was conducted for six consecutive seasons from kharif, 1997 to rabi/summer, 1999–2000 on a saline Vertisol at Agricultural Research Station, Gangavati, Karnataka to study the effect of continuous and intermittent leaching methods under paddy-paddy cropping sequence on soil salinity distribution, leaching efficiency, crop performance and water-use efficiency. As observed after the harvest of 6^th season crop, continuous ponding was found to be better than intermittent ponding for achieving higher leaching efficiency. However, the leaching efficiency did not differ much between intermittent pondings. Continuous ponding resulted in cumulative desalinization throughout the profile and crop growth period but under intermittent ponding, after an initial marginal de-salinization, salts tend to build up in surface layers. Paddy yields improved considerably over the seasons in both continuous and intermittent leaching methods with highest yields under continuous ponding followed by intermittent ponding for two days and three days, respectively. Results indicated that intermittent pondings (2 and 3 days) were superior to continuous ponding in terms of water saving and water-use efficiency. Effective leaching depth was higher in case of continuous ponding during kharif as compared to intermittent pondings.