RELATIONS BETWEEN SOIL CHEMICAL PROPERTIES AND CADMIUM CONTENT IN GREEN MASS OF SILAGE MAIZE

UDK 631.41:633.15; 633.15:546.48 (497.6) Cadmium content in soil is an important factor which determines the content of this heavy metal in plants. However, many other factors including soil pH, content of organic matter, other trace minerals in soil which could reduce or enhance cadmium uptake by roots of plants as well as anthropogenic routes of cadmium contamination (mining, superphosphates and industry) can have an influence on the cadmium concentrations in plant tissue. A three years study was conducted to evaluate cadmium content in green mass of silage maize in certain areas of Central Bosnia region. A multiple linear regression (MLR) model was developed to predict maize tissues cadmium concentration as function of different factors such as soil cadmium content, pH of soil, organic matter in soil as well as phosphorus, potassium, zinc and iron content in soil. The results indicate huge variability of cadmium content in soil (maximum value was more than 3fold greater than the minimum value) and green mass of maize (maximum to minimum ratio greater than 100). Cadmium concentration in all investigated samples of maize was below maximum tolerable levels in ruminant nutrition. Using a stepwise multiple linear regression method, a significant model emerged (F2.14 = 55.193, p<0.001; R2 = 0.887). Significant variables were phosphorus (Beta = 0.813, p<0.001) and potassium (Beta = -0.401, p<0.005) content in soil. Soil pH, organic matter, cadmium, zinc and iron were not significant in this model. Insignificant correlation between soil and plant cadmium content (r=0.374, p=0.07) indicates that the presence of cadmium in the soil may not be the main determinant of its content in plants.