(一)根据近几年的调查,发现江苏省西部及西南部丘陵地区和太湖北部及西部平原地区的瀦育性水稻土中,广泛分布有一种群众称为“白土”的土壤。这一土壤的共同特征是:上层颜色特别浅淡(表土由于施肥影响,色泽可稍深),质地如粉,缺乏结构;下层土体则粘重紧实。这种土壤稻麦产量均低。 (二)通过重点剖面的养分分析及微团粒测定,初步证实:各地“白土”的肥力是低于一般田;但从白土本身来说,表土以下的浅色土层(白土层)肥力又是最低的;白土层以下的底土,某些营养元素的含量却并不过低。(三)通过重点剖面的机械分析、粘粒部分硅铁铝及土壤游离铁的测定,并结合野外观察结果,初步证实:“白土”水稻田上层土壤颜色所以特别浅淡质地如粉,主要是由于缺乏粘粒和铁质;而上层土壤粘粒和铁质之所以缺乏,则主要是母质因素和人工灌溉因素所共同影响而造成的。(四)“白土”的改良途径是:对表土施用品质较高的有机肥及富含铁质的粘性土质肥料;对表土以下的粉质白土层和粘质底土层(B_1),则通过大力施用有机肥,实行拌和性的深耕深翻。 (I) According to the surveys conducted in recent years, it has been found that there are widely distributed soils called “Clay soils” in the hilly paddy soil in the hilly areas in western and southwestern Jiangsu and the northern and western Taihu lakes of Taihu Lake. Common characteristics of this soil are: the upper color is particularly pale (topsoil due to fertilization, the color may be slightly darker), the texture of powder, lack of structure; the underlying soil is sticky and tight. This soil rice yield are low. (B) Through the key section of nutrient analysis and micro-aggregate determination, initially confirmed: around the “clay” of the fertility is lower than the general field; but from the clay itself, the surface soil below the light-colored soil layer (soil layer) fertility is The lowest; below the clay soil, some nutrients are not too low levels. (3) Through the mechanical analysis of the key sections, the determination of iron and iron in the clay part and soil iron, combined with the field observation results, initially confirmed: “clay” upper paddy soil color so special light texture, such as powder, mainly Due to the lack of clay and iron; and the lack of clay and iron in the upper soil, it is mainly due to the combination of parental and artificial factors. (4) The improvement measures for “clay” are: applying high-quality organic fertilizers and iron-rich clay fertilizers to the topsoil; and by applying strong force to the silty clay and silty subsoil below the topsoil Application of organic fertilizer, the implementation of deep mixing deep plowing.