Modification of the 137Cs, 90Sr, and 60Co transfer to wheat plantlets by NH4+ fertilizers.

Inorganic fertilizers are used as agricultural countermeasures intended to inhibit the soil to plant transfer of radionuclides after a radioactive fallout. Two NH4+ fertilizers, diammonium phosphate (DAP) and NPK, were applied to soil contaminated with a mixture of radionuclides to analyze whether they modify the transfer of 137Cs, 90Sr, and 60Co and stable elements (K, Na, Ca, and Mg) to wheat plantlets grown under controlled laboratory conditions. DAP introduced NH4+ in the soil, which can increase 137Cs transfer, while NPK also introduced K+, which can decrease it. The application of DAP increased the accumulation of 137Cs in wheat plantlets with increasing application rate, so did the 137Cs/K in plantlets. Regarding the NPK application, the 137Cs increased in all treatments, but at maximum rate, the available K introduced by the fertilizer was probably able to partially satisfy the nutritional requirements of the wheat plantlet and the 137Cs decreased relative to the recommended rate. The 137Cs/K ratio in plantlet decreased with increasing NPK rates. The transfer of 90Sr increased with increasing DAP rate and only at the maximum NPK rate. The 60Co transfer only increased at the maximum application rates for DAP and NPK. These modifications should be considered when using these fertilizers as agricultural countermeasures.