九州に於ける干拓地土壌の研究(第三報) : 熊本県八代郡文政村北新地

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In this paper the chemical properties of a very sandy reclaimed marsh soil enclosed by dyke in 1925,is dealt with. 1. The advance of drainage causes the oxidation of sulphide mineral in surface soils and some of these are changed acid of about pH 6. But the pH-values of water-logged subsoils are all over 8. 2. The salt contents of underground waters are low and amount to 0.248-0.644 grams in 100 cc. Cl and Na are dominant, and SO_4 and Mg stand next. 3. The water soluble salt contents of soils are relatively low and amount to 0.024-0.286%. With the advance of drainage decrease the percentage contents of Cl and Na, and increase those of SO_4,HCO_3,Ca and Mg. 4. The status of exchangeable cations differ much with localities. With the advance of drainage increase the percentage contents of H and Ca, and decrease those of Mg and (K + Na.). In a acid surface soil H occupy 55.4 parts of exchange capacity.
1940-09-25