In order to carry out the large-scale afforestation in the dry lands, reservation of water required for plant growth serves as a point of the success. In the present study, we investigated fertilizer absorption and discharge capacities of bauxite calcined by a rapid heating, which had been demonstrated to give a large water restoration capacity in our previous study. The results are as followed.
(1) Phosphoric acid in liquefied fertilizer Hyponex decreased as a result of treatment to the non-calcinated bauxite with it. In the elution examination, both potassium and nitric ions were discharged gently. In addition in change in pH and EC value were slight.
(2) Values of EC and pH of liquefied fertilizer Hyponex decreased by 2mS/cm and increased to pH 9, respectively as a result of treatment of rapid calicined bauxite at 700°C. All of the phosphoric acid in the solution was absorbed. More eluent was required for elution of potassium ion and nitric ion than in case of non-calcined bauxite.
(3) Pretreatment of the rapid calcined bauxite with phosphoric acid increased the eluted amount of phosphate ion from hyponex treated bauxite by ten times or more.Furthermore, the elution duration was much enlarged. Thus, the validity of the calcined and pretreated bauxite as carrier of “ Gradually discharge fertilizer ” was demonstrated.
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