The Use of 32P to Study Root Growth of Soybean as Affected by Soil Compaction

THE USE OF 32p TO STUDY ROOT GROWTH OF SOYBEAN AS AFFECTED BY SOIL COMPACTION. Two greenhouse and two field experiments have been conducted to study the effect of soil compaction on root and plant growth of soybean, by using 32p in the form of carrier free KH/2p04 solution. In the greenhouse experiment it was clearly shown that by increasing soil compaction the growth of roots and shoots was increasingly inhibited. The growth of roots was expressed in f% Arcsin converted from 32p activity (counts per minute, cpm) in the shoots and 32p activity in the shoots (cpm) without convertion. Plant growth was expressed in plant height, number of leaves, dry weight of pods and shoots. In the field experiment, it was shown distinctively that root growth in the 15 cm soil depth was inhibited Whith the increase of soil compaction. Similar with the greenhouse experiments the growth of roots was expressed in cpm of 32p of roots, shoots, and pods, while, the growth of plants was expressed in plant height, number of pods. and dry weight of pods, seeds. and st over.