Determination of time frame for substitution of salt-tolerant varieties of rice (Oryza sativa) and wheat (Triticum aestivum) through crop diversification in sodic soils

Abstract

A field experiment was conducted during 2001–05 at Regional Research Station, Central Soil Salinity Research Institute, Lucknow to determine the time frame for substitution of salt-tolerant varieties of rice (Oryza sativa L.) and wheat (Triticum aestivum L. emend. Fiori & Paol.) through crop diversification. Under resource-scarce conditions, application of gypsum @ 25% gypsum requirement and growing salt-tolerant varieties of rice ‘CSR 13’ for 4 years and wheat ‘KRL 19’ for 3 years was found optimum time for substitution of salt-tolerant varieties through crop diversification. However, under resource-rich conditions where gypsum is available to fulfill 50% gypsum requirement, crop diversification under sodic soils may be initiated after growing of salt-tolerant varieties of rice for 3 years and of wheat for 2 years. After 4 years of rice (Oryza sativa L.)– wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system, the pH2 of surface soil with 25 and 50% gypsum requirement levels reduced to 9.12 and 8.87, respectively or say the soil is partially reclaimed. There are certain highly remunerative crops, like sweet basil (Ocimum basilicum L.), matricaria (Matricaria chamomilla L.), chilli (Capsicum spp) and garlic (Allium sativum L.) which may grow at this sodicity level and gave high economic returns. On the basis of crop diversification study, rice equivalent yield (14.21 tonnes/ha) and production efficiency (61.25 kg/ha/day) was higher with sweet basil–matricaria cropping system over the traditional rice–wheat system. Chilli–garlic cropping system recorded the highest water-expense efficiency (150.72 kg/ha cm), followed by sweet basil–matricaria but the total amount of water used was more (125.65 cm) in rice–wheat system. The water requirements of sweet basil–matricaria and chilli–garlic cropping systems were 19.8 and 31.8% less than that of rice–wheat cropping system. Energy-use efficiency of sweet basil–matricaria was higher (11.99) than that of the rice– wheat (11.43) cropping system. Highest benefit : cost ratio was recorded with sweet basil–matricaria (2.74), followed by chilli–garlic (2.42) cropping systems.