Celem podjętych badań była ocena wpływu zanieczyszczenia gleby wzrastającymi dawkami kadmu (0, 10, 20, 30 i 40 mg Cd·kg⁻¹ gleby) na plonowanie wybranych roślin testowych oraz próba złagodzenia tego oddziaływania poprzez aplikację substancji neutralizujących, takich jak: wapno, kompost, węgiel brunatny i bentonit. Podstawę badań stanowiły doświadczenia wazonowe, w których roślinami testowymi były: łubin żółty, kukurydza, rzodkiewka i facelia błękitna. Statystyczna analiza uzyskanych wyników dowiodła istnienia korelacji pomiędzy dawkami kadmu a wysokością uzyskanych plonów roślin, której kierunek był zależny od rodzaju substancji inaktywujących. Obliczony indeks tolerancji najniższy zakres przyjmował w przypadku łubinu (0,02–0,90) i rzodkiewki (0,05-1,15), nieco wyższy w doświadczeniu z facelią (0,45–1,38), a zdecydowanie najwyższy w doświadczeniu z kukurydzą (0,59–1,77).
The purpose of the study has been to examine the effect of soil contamination by incremental doses of cadmium on yield of several crops grown in soil ameliorated with such inactivating substances as lime, compost, brown coal and bentonite. The research consisted of four pot experiments, in which yellow lupine, maize, radish and blue phacelia. Cadmium was introduced to soil in the form of aqueous solution of cadmium chlorite, in doses of 0, 10, 20, 30 and 40 mg Cd·kg⁻¹. Lime was applied in doses corresponding to 1 Hh; doses of compost and brown coal equaled 4% of the soil mass in a pot, while the amount of benotnite reached 4% in pots with yellow lupine and 2% in pots with maize, radish and phacelia. The substrate was composed of brown soil, sampled from the arable and humic horizon, with the texture of slightly loamy sand. The soil under yellow lupine, maize and radish was very acid, while that under phacelia was slightly acid in reaction. After harvest, fresh aerial and roots mass yields were determined for each pot separately. The results were analyzed statistically with an Anova test at α = 0.05, using the Statistica 9.0 software, while the r correlation coefficient between the analyzed factors was calculated with a Microsoft Excel package. The direction of the correlation between cadmium doses and yields depended on the species of plant ad type of inactivating substance. In a series without neutralizing substances, the soil contamination with the cadmium doses of 20, 30 and 40 mg Cd·kg⁻¹ had a strong adverse effect on the yield of yellow lupine aerial parts and the yield of radish roots and aerial parts, which declined by 84–98% versus the control. The same doses of cadmium caused much smaller loss of phacelia yields, which ranged between 44 and 55% relative to the control. In turn, the yield of useful parts of maize was depressed by the highest cadmium contamination levels, never exceeding 10% compared to the control. Compost, brown coal, lime or bentonite added to soil to alleviate the effect of cadmium pollution produced positive effects, such as higher average yields of lupine and phacelia aerial organs as well as radish roots. In the experiment on maize, the mean aerial yield was higher only in the series with compost. The inactivating substances led to another result, such as smaller yield reductions of all the crops exposed to increasing doses of cadmium in soil. Benotnite was most effective in reducing yield losses of yellow lupine and blue phacelia aerial mass as well as radish roots, while compost was best at limiting the yield loss of maize aerial organs.
