Effects of soil acidity on the uptake of trace elements in soybean and tomato plants

The effects of soil acidity on the uptake of trace elements (Co, Zn, Se, Rb, Sr, Y, Zr, Tc, Ru, Rh and Re) in soybean and tomato were studied by a multitracer technique. The soybean and tomato plants were cultivated on soils at pH 6.4 (normal soil) and 4.2 (acid soil) and administered with a multitracer for 15–60 d. In general, the uptake of cationic elements in the leaves and stems of soybean plants cultivated on acid soil became higher than those of plants cultivated on normal soil during the late period of growth. However, the effect of soil acidification on the uptake of the anionic element, Se, was quite different from that on the cationic elements. The uptake of Se by the plants cultivated on normal soil was higher than that of the plants cultivated on acid soil at all four harvest points. The uptake behavior of these elements in soybean was discussed in relation to their adsorption behavior on the same soil as was used for soybean cultivation. The growth of tomato plants was seriously affected by the soil acidity and lowering of uptake of elements was observed for the plants cultivated on acidified soil.