肥料の隨伴物質として土壤に加へられた硫酸根の移動及び集積並に之が石灰,鉄,滿俺,腐植等の移動に及ぼす影響に就て(農藝化學)

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In Japan, the amount of sulphate-ion applied to fields as an accompaniment of fertilizers, such as ammonium sulphate, calcium superphosphate and potassium sulphate has remarkably increased in recent years, and now we are apprehensive of the damage caused by the attack on rice root by free H_2S produced by the reduction of such sulphates, especially in so-called "degradated paddy soils" Thus we made a study of the absorption of sulphate-ion by soils, the state of its leaching by pot experiments and the quantity of sulphate-ion accumulated in field soils by the application of ammonium sulphate for long years, and we obtained the results such as follows. [I] Absorption of sulphate-ion: (1) When 10g. soil with 100cc of N/5 ammonium sulphate solution was shaken, and after twenty-four hours the SO_4 content of the supernatant clear liquid was analysed, the decrease of SO_4 was confirmed, though the general opinion of present days is that the sulphate and chloride ions, unlike phosphate ion, are not adsorbed by soil colloids. Thus, it was known that the original and Na-oxalate-treated soil absorbed SO_4 fairly well, but the soil washed with N/5 HCl solution to eliminate Ca-ion, absorbed SO_1 insignificantly (Fig. 1). (2) When Ca-satulated clay which had been prepared by treating bentonite with calcium chloride solution was treated with ammonium sulphate solution by the same method as described above, it absorbed a large quantity of SO_4. However, Na-clay hardly absorbed it. On the otherhand, the absorption-curves of ammonium ion in these cases were almost the same (Fig. 2). (3) The amount of sulphate ion absorbed increased almost linearly when the amount of Ca-clay added increased, while it was not so with Na-clay, H-clay and K-clay. (4) It is clear that a part of the sulphate ion is temporarily preserved in soil by combining chemically with calcium, the percentage of preservation being greater in concentrated solution than in dilute solution. From this fact, it may be supposed that this is one of the factors which cause the preserved amount of sulphate ion to be greater in paddy fields where ammonium sulphate has an opportunity of solving as comparatively concentrated solution than in ordinary farm fields. [II] Each 1 litre of penetrated water from pots of paddy state, fertilized with ammonium sulphate, calcium superphosphate and potassium sulphate was analysed weekly as for the contents of sulphate, Ca, Fe, sulphide, free H_2S etc., and the average results of two years (1951-1952) were as follows: (1) A greater part of sulphate leached within 45 or 50 days after the plantation of rice plant, and after that the remaining part went out slowly but steadily. The former seems to be a direct outgo from ammonium sulphate and potassium sulphate, whereas the latter is an outgo from Ca superphosphate applied. There was not a great difference between the leaching amounts of sulphate and chloride during the former period of growth. (2) The outgone amount of calcium was almost the same whether it might be added as sulphate or chloride, and in both cases a greater amount of calcium leached as compared with unfertilized plots. (3) The outgo of iron was greatly accelerated by the addition of sulphate, especially in planting plots during the latter period of growth. (4) The leaching amount of sulphide was extremely little as compared with the total amount of sulphates added, and the differences between the plots were not recongnized, except that the penetrating amount of sulphate plot was a little greater. [III] Soils fertilized with ammonium sulphate for 5 to 57 years and unfertilized soils in the neighborhood were collected from different parts of Japan, and compared by chemical analysis, and the following results were obtained. (1) Soils fertilized with ammonium sulphate for long years contained more sulphate when compared with unfertilized soils; the average difference being 0.017% in surface soil, 0.012% in subsoil of paddy soils and 0.02% in surface soil, 0.34% in subsoil of ordinary field soils. But the increased amount by long years fertilization with ammonium sulphate was less than ten percents of total amount of ammonium sulphate fertilized during respective period. (2) Soils fertilized with ammonium sulphate had lower Ca content and pH value, larger total acidity and lower degree of base saturation as compared with unfertilized soils and the difference is especially significant in ordinary field soils as it is naturally expected. (3) The free iron content of soils fertilized with ammonium sulphate was comparatively small, especially in paddy field soils. (4) Humus contents are generally higher in soils fertilized with ammonium sulphate as compared with unfertilized soils. This is considered to be a result of the fact that the growth of crops was better in the plots fertilized with ammonium sulphate than unfertilized plots accordingly the organic matter that remained in soils was greater in the former plots than in the latter ones. If the plots fertilized with N without sulphate were arranged, the humus contents of the plots might be higher like those of plots fertilized with ammonium sulphate, because the leaching of Ca and Fe might be violent in the latter soils.
大阪府立大学の論文
1954-02-25

肥料の隨伴物質として土壤に加へられた硫酸根の移動及び集積並に之が石灰,鉄,滿俺,腐植等の移動に及ぼす影響に就て(農藝化學)

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