Adsorption strength of zinc for soil humus

Adsorption strength of zinc for soil humus

“…Obviously chela'ted zinc in soil is more difficult to be absorbed by plants than the exchangeable zinc. This result shows that the adsorption strength of chelated zinc in soil is higher than that of exchangeable zinc, and confirms the supposition in the previous paper (1).…”

“…The chelation properties of soil humus are important for their influence on the availability of metal elements in soil. Chelation properties appear to be closely related to the degree of humification (1). This problem is to be studied further.…”

“…The content of radioactive zinc in each plot of "Kuroboku" eoil which was treated with zinc sulfate and zinc-EDT A at both levels of calcium carbonate was observed to be lower than that of the plot of red-yellow soil in the second and third harvests. In the previous paper (1), the author reported that a large part of the zinc adsorbed by red-yellow soil existed as an exchangeable form and that the amount of chel~ted forms in "Kuroboku" soil was fairly higher 'than tha,t of the exchangeable form. Accordingly ziltc adsorbed by soil in chelated forms is thought to be more difficult to be absorbed by plants than that in the exchangeable form.…”

“…The next process was performed as shown in Experiment 1. (S) equivalent to 20 g and (R) equivalent to 8 g were air-dried and used as (S) and (R) which were treated with zinc sulfate and zinc-EDTA and adsorbed them in the forms of exchangeable and chelated zinc (1). The amounts of zinc adsorbed, as me per 100 g of soil and resin, were as follows: 0.44 for (S) treated with zinc sulfate «S) -zinc), 0.44 for (S) treated with zinc-EDT A «S) -zinc-EDT A), 1.…”