RESPONSE OF TWO LEGUME CROPS TO SOIL SALINITY IN GYPSIFEROUS SOILS

Competition for water resources, increasing land salinization and the need to feed a growing population are challenges facing irrigated agriculture in the Fergana Valley of Uzbekistan. Growing short-season legumes with water-saving irrigation technologies is one strategy for increasing food production and land productivity using relatively less water. However, little information is available to assess how these crops will respond when produced with deficit irrigation on the gypsiferous soils of the region. This greenhouse study evaluated various growth components of common bean and green gram irrigated with deficit irrigation in soils with and without gypsum and at three levels of soil salinity. Results showed that biomass and leaf area decreased by approximately 20% for both crops, as EC(e) increased from 2.8 to 7 dS m(-1). Yields were higher at all salinities for green gram than in common bean. However, relative yield reductions with increasing salinity were greater for green gram (43%) compared to common bean (19-31%). The presence of gypsum enabled both crops to maintain reasonable yield at EC(e) values which would be lethal in soils dominated both other salts. The effect of increasing salinity was the same at all levels of deficit irrigation. Copyright (C) 2008 John Wiley & Sons, Ltd.