Soybean response and ion accumulation under sprinkler irrigation with sodium-rich saline water

Abstract

The magnitude of crop growth and yield depends on the salinity level, the toxic ions present in the irrigation water and the irrigation system used. In order to study the effect of sprinkler irrigation with salty water on soybean growth, development parameters and yield, and ionic accumulation in plant tissues as pot experiment was set up. There were three treatments with different irrigation water quality (EC 0, 2 and 4 dSm-1), applied during the whole cycle. Soybean aerial biomass was 20-30% less than Control when irrigation water salinity was 4dSm-1. Clearly salinity entering via leaves affected the grain filling stage and severely reduced soybean grain production (80% reduction) when salinity in irrigation water surpassed 2 dSm-1. Sprinkler irrigation aggravate the low tolerance of soybean to salinity and limit its cropping in such conditions. Two linear relationships between leaf Cl- concentration (Y= 14.2-2x) or K/Na ratio (Y=5.3x-3.4) (both in early stages) and soybean grain yield were found. Both relationships may be used as diagnostic tools for estimating soybean yield loss when salinity is the main stress factor.