To clarify the influence of phosphorus application and available phosphorus concentration in soil on phosphorus concentration in head or occurrence of head rot in Broccoli, phosphorus application test in the same nitrogen application rate and field research on plant and soil nutritional state were conducted. Besides of it, to investigate influence of nitrogen and phosphorus concentration on calcium concentration in head, we measured contents of these elements in foliage, stalk or head every week in nitrogen application test. The results are as follows: 1. Phosphorus application increased phosphorus contents in Broccoli, but had no consequence on phosphorus concentration in head and head weight. Similarly available phosphorus concentration in soil less than 450mg-P_2O_5kg^<-1> had no consequence on each of them. 2. In field research, there was no relation between available phosphorus concentration in soil and the occurrence of head rot or calcium concentration in head of Broccoli. 3. In head growing period, phosphorus and nitrogen probably translocated from leaves to head simultaneously. Nitrogen application increased phosphorus and calcium contents in head. The increasing ratio was lower in calcium than phosphorus. 4. In field research, phosphorus absorption affected neither calcium uptake nor calcium translocation to head. 5. It was concluded that phosphorus application rate, available phosphorus concentration in soil less than 450mg-P_2O_5kg^<-1> and phosphorus uptake amount have little influence on calcium concentration in head or occurrence of head rot. Nitrogen application decrease calcium concentration in head and enhance head rot.

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The fate of chemical fertilizer ammonium nitrogen (Nitrogen Derived from Fertilizer: NDF) that was applied together with composted cattle manure was investigated using vegetables cultivated lysimeter. The plots of 1) single application of chemical fertilizer and 2) combined application of chemical fertilizer and composted cattle manure were set for 2 different kinds of soil (Andosols and Gray Lowland soils). We designed the experiment so that the nitrogen supply to the crops was equal in each plot, taking into account the substitution rate and relative fertilizer efficiency of composted cattle manure. ^<15>N labeled chemical fertilizer N was applied during year one, whereafter unlabeled N was added during year two. Nitrogen leaching was greater in the single application plots than in the combined application plots, therefore it was concluded that the combined application was successful in reducing the nitrogen leaching from vegetable fields, in terms of a relatively short duration of one to two years. The amounts of NDF absorbed by the crops in year one were roughly proportional to the NDF application rate. The majority of NDF in the soil was retained in an upper soil layer (0-20cm) after one year of the experiment, and the most of them were in immobilized forms (e.g. organic form). Immobilization of NDF in the upper soil layer was enhanced by the combined application of composted manure. Highly negative correlation coefficients were observed between the percentage recoveries of NDF in leachate at the end of the experiment, and in immobilization in soil after one year of the experiment.

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A pot study was conducted to investigate characteristics of nitrogen mineralization from ten different organic fertilizers commonly available to organic producers. Komatsuna (Brassica rapa L.cv. Rakuten) was successively cultivated five times in a total period of 222 days in soil receiving each of the organic fertilizers and, as a control, a chemical fertilizer containing CDU-N and NH_4-N (1:1). The early growth of Komatsuna was seriously suppressed in soil where non-fermented fertilizers were added immediately before seeding. Plant materials including rice bran and oil meals of soybean and rape constitute the non-fermented fertilizers. The relative nitrogen uptake ratios (RUR) of compound organic fertilizer, fish meal, oil meals of soybean and rape, fermented organic fertilizer and dried poultry manure were 80, 70, 60, 55, 50 and 25%, respectively, while the RUR of composted cattle manure and rice bran were both only 17%. The number of days required to absorb 50% of total nitrogen uptake (NU50) was investigated. The NU50 of rice bran, oil meals of soybean and rape and fish meal were 109, 95, 72 and 57 days after the first seeding, respectively. The NU50 of these organic fertilizers were significantly longer than that of the compound chemical fertilizer. After the harvest of Komatsuna in the fifth cultivation, the residual nitrogen rates of composted cattle manure and rice bran were 65 to 70% and around 65%, respectively. Moreover, the amounts of nitrogen mineralization from composted cattle manure and rice bran were significantly higher than that from the compound chemical fertilizer.

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The chemical forms of K, Mn, Fe, Cu and Zn in soil of a vegetable cropping field of clay loam brown lowland soil which have received the two level of mono-application of cattle or pig feces compost for 29 planting times during 15 years was examined by a sequential extraction procedure. Reference field cropping management was mono application of chemical fertilizer without any organic matter. Total contents of these elements were analyzed by hydrofluoric acid digestion method. The dilute hydrochloric acid (0.1M) extraction was also carried out to assess what chemical forms of the sequential extraction were corresponding to the dilute acid extractable amount. Total content of K and Fe of the compost plot was not significantly different from the chemical fertilizer plot, but, that of Mn tended to be higher in the compost plot. Total content of Cu of the compost plot except for the plot of higher level of pig feces compost was almost same to the chemical fertilizer plot. Total content of Zn of the higher level of cattle feces compost plot and the both plot of lower and higher level application of pig feces compost was significantly higher than the chemical fertilizer plot. The most of K was in the form of crystalline for all treatment plot, and in comparison with the chemical fertilizer plot, the relative proportions of chemical form of exchangeable, inorganic matter- and organic matter-bound were larger in the compost plot. Manganese was found to be relatively higher proportion in organic matter-bound form, comparing to Fe, and the proportion of inorganic matter-bound form in the compost plot was higher than that of the chemical fertilizer plot. More than 99.7% of Fe was in the form of oxides bound and crystalline form, and compost application resulted in a larger proportion of organic matter-bound form. Cu was found to be predominantly in oxides bound and crystalline form, and the proportion of organic matter-bound form of the compost plot was certainly larger than the chemical fertilizer plot. Zn was dominated in crystalline form and the proportions of inorganic matter- and organic matter-bound form in the compost plot was significantly larger than those of the chemical fertilizer plot. The proportion of 0.1M-HCl extractable K in the compost plot was much higher than that of the chemical fertilizer plot, and the dilute acid extracted the amount comparable to the sum of exchangeable and inorganic matter-bound form, and did not extract organic matter-bound form. The proportion of dilute acid extractable Mn in compost plot was tended to be higher than that of the chemical fertilizer plot, but the extractable proportion was comparable to only exchangeable and inorganic matter-bound form. Only very small proportion of Fe was extracted by the dilute acid, and the proportion was larger than the sum of exchangeable, inorganic matter- and organic matter-bound form, indicating the dilute acid dissolve a portion of oxides bound form. Copper in soil of the chemical fertilizer plot was extracted at the proportion comparable to the sum of exchangeable, inorganic matter- and organic matter-bound form. But, Cu in soil of highly compost applied plot which had relatively higher proportion of organic matter-bound Cu, the dilute acid could not extract most of the organic matter-bound form. Zinc in chemical fertilizer plot soil was extracted only small portion by the dilute acid. But, Zn in soil of increased Zn concentration by compost application was extracted at most 37.7% for higher application of pig feces compost. The dilute acid extracted Zn at a rate of little over proportion than the sum of exchangeable, inorganic matter- and organic matter-bound form, which dose contrast with Cu extractability.

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On the western edge of the Omiya tableland, the soil-dressing practice known as "Dorotsuke" had been in place for a long time before second half of 20^<th> century. Dorotsuke involves carrying alluvial soil from the dry riverbed of the Arakawa River to fields on the tableland, where volcanic ash soil prevail. The present study aims to investigate anthropogenic pedogenesis by the practice of Dorotsuke. The soil profile of a field in Kitamoto City, Saitama Prefecture, having thick alluvial soil due to the practice of Dorotsuke was examined. The soil in this field was compared with the volcanic ash soil from the Omiya tableland, and also with the alluvial soil from the dry riverbed of the Arakawa River in order to clarify the changes in soil properties through the practice of Dorotsuke. Solid phase rate had increased, while the maximum water-holding capacity and water content had decreased in the soil of the Dorotsuke field due to the dressing of alluvial soil. Amounts of oxalate-soluble aluminum and silica in the alluvial soil were less than one-tenth of the amounts in the volcanic ash soil. The dressing of alluvial soil in the Dorotsuke field resulted in a decrease in the phosphate absorption coefficient and an increase in the relative amounts of calcium phosphate and the amounts of available phosphate. Alluvial soil contains a great deal of exchangeable calcium, which provides a supply of calcium and increases the soil pH of the Dorotsuke field. However, there was an apparent tendency for calcium to be leached from the Dorotsuke field, resulting in a lower pH in the upper horizon. The amount of alluvial soil brought into the field was assumed to be about 5000tons per 1 hectare, based on a calculation incorporating soil thickness, bulk density and amounts of oxalate-soluble silica.

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