Experimental assessment of influence of soil moisture on the 137Cs accumulation in shoots of spring wheat

Abstract

The aim of this research was to analyze the effect of soil moisture regime on the intensity of 137Cs transfer into cereals using spring wheat as a model species. Accumulation of 137Cs in shoots of spring wheat grown on soil substrates differ by water and nutrients content was analyzed. The investigated water regimes were 40 % (insufficient moisture supply), 70 % (optimal moisture supply) and 85 % (excessive moisture supply) of full moisture capacity of the soils; substrates with optimal and low content of essential mineral nutrients were used in the experiment. The plants were grown in a chamber with controlled climate conditions. Increasing water content in the soil from 40 to 85 % of the total moisture capacity significantly reduces the 137Cs content in plants. The shape of the relationship between soil moisture and the soil-to-plant transfer of 137Cs depends on the agrochemical characteristics of the soil. The difference in the radioisotope accumulation in the shoots of wheat grown on extreme water regimes is about four times when substrate with optimum content of nutrients was used. The difference is less than two times when substrate with a low content of essential nutrients was used; moreover, there are no differences between the 70 and 85 % variants on a substrate with low content of nutrients. The revealed dependencies cannot be explained by the change in the share of bioavailable forms of 137Cs in the soil since it does not significantly change in soils with different moisture regimes.