Mulching as a countermeasure for crop contamination within the 30 km zone of Chernobyl Nuclear Power Plant

The effect of mulch soil cover on crop contamination by Cs-137. was studied within the 30 km zone of Chernobyl Nuclear Power Plant. Experiments were p erformed with oats (Avena sativa) over a three year period. In 1992 soil su rface was covered by a plastic net In 1993 two straw mulch treatments were applied at a dose rate of 200 g m(-2) using Cs-137 contaminated and clean s traw, respectively. A similar mulch treatment was applied in 1994, and two mulch doses of clean straw were tested (200 and 50 g m(-2)). Protection of the soil with a plastic net significantly increased crop yield and reduced crop contamination (by about 30%). When clean straw was used as a mulch lay er, a significant decrease of about 30-40% in Cs-137 activity concentration was observed. Mulching with Cs-137 contaminated straw did not reduce crop contamination, probably due to an increase in soil available Cs-137 release d from the contaminated mulch. Mulching has been shown to be an effective t reatment both for reducing Cs-137 plant contamination and improving crop yi eld. Therefore, it can be considered as a potential countermeasure in a pos taccident situation.