The citrus soils in Kyushu comprise a variety of soils derived from various parent material, namely, andesite, granite, volcanic debris, paleozoie formation, Archaean, dilluvium etc. Soil textures range from light to very heavy, and mix plenty of gravel. The soils are deep and well drained The species of citrus cultivated is mainly "loose skin orange" (Citrus unschiu Marc.) Both the reaction and lime saturation of soils, collected from famous citrus regions in Kyushu, were determined. In these regions the adequate liming, for example, 1125 kg. slaked lime per hectare every other year, are commonly practised. Green manuring and mulching are also common. The analytical results are summarised as follows : Reaction and lime saturation of citrus soils. [table] It appears to be that the optimum soil pH is about 6 and its lime saturation is about 55 per cent., although the citrus makes a good growth within a wide range of both soil reaction and lime saturation.
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