Properties of five soils in Kagawa prefecture and growth of young Satsuma orange trees on them

Abstract

1. One-year-old Satsuma orange trees were planted singly in the 1/2, 000 a Wagner's pots with each of the five different soils which commonly distributed in the fruit growing areas in Kagawa prefecture. The name of soils used was as follows; diluvian soil, soil derived from Izumi sandstone, granitic soil, soil from biotite andesite, and soil from Sanuki andesite.Experiments were carried on from March 1957 to October 1959, applying ammonium sulfate, fused magnesium phosphate, and potassium sulfate as well as barnyard manure.2. On each kind of soils, trees grew better when planted with its surface soil than when planted with its subsoil. In the comparison of the growth among the five different soils, the Sanuki andesite soil was the best, then the Izumi sandstone soil, followed by the granitic soil, the biotite andesite soil, and the diluvian soil in order.3. On the Izumi sandstone soil, defoliation took place in the latter part of the experimental period. As one of the causes for it, the shortage of Ca supply in connection with the high soil acidity was considered, of which however a further study is necessary.4. The diluvian soil on which the tree growth was most inferior, was of poor moisture holding and base exchanging capacities, containing a high percentage of easily reducible Mn. The leaf analysis of trees grown on it, showed low Ca and extremely high Mn contents.5. The granitic soil was sandy and had poor moisture and nutrient holding capacities. However, the leaf analysis revealed neither nutrient deficiency nor surplus. So, the inferior tree growth on it might be mainly due to the poor physical conditions of the soil.6. Regardless of the high moisture and nutrient holding capacities, the biotite andesite soil had low pH value, extremely high y1 value, and very low percentage of Ca saturation. Therefore, the poor tree growth on it might be caused by limited Ca supply and high acidity of the soil.7. The Sanuki andesite soil on which trees grew best, had the high moisture holding and base exchanging capacities. Nevertheless, the soil was of fairly high acidity and contained a considerable amount of easily reducible Mn, trees grown on it showing the high Mn content of leaves. So, the best growth of trees on it might be due to the superior physical soil conditions.