Japanese Journal of Soil Science and Plant Nutrition

Ammonium nitrogen, which is generally not obtained in the common potassium chloride extraction method, was found to be present in cattle manure compost and swine manure compost. In preliminary chemical analyses, ammonium nitrogen dissolved as pH decreased in the extracted liquid, and magnesium and phosphate dissolved at a molar ratio equal to that of the ammonium ion. Moreover, the dissolution pattern of___ was similar to that of pure reagent. Based on these results, we identified the unknown ammonium nitrogen as magnesium ammonium phosphate (MAP). The formation of MAP in the composting process of swine feces was confirmed. Hydrochloric acid (0.5mol L^<-1>) is suitable for the extraction of ammonium nitrogen, including MAP, when the ratio of compost weight (g) and the amount of material extracted (ml) is 1:10. The amount of ammonium nitrogen obtained by this extraction method was at least twice that extracted by the common method (average of 110 samples). We examined the relationships among the amount of inorganic nitrogen obtained by potassium chloride extraction, MAP, and the amount of inorganic nitrogen present in a 4-week incubation (at 30℃) of cattle manure compost and swine manure compost produced by the piling method or the open-stirring method. No relationship was observed between the amount of inorganic nitrogen obtained from incubation and that obtained by potassium chloride extraction. When MAP was included, however, in many cases the total MAP and inorganic nitrogen from potassium chloride extraction corresponded to inorganic nitrogen obtained from incubation. Thus, rather than potassium chloride, hydrochloric acid should be used to extract ammonium nitrogen, including MAP, for the correct evaluation of compost nitrogen fertilizer efficiency.

View full abstract

Differences in the nitrogen fertilizer efficiency of cattle manure compost and swine manure compost were examined with regard to the concentration of acid-detergent-soluble organic matter (ADSOM). An incubation experiment was performed at 30℃, and there was little change in the amount of inorganic nitrogen content (including magnesium ammonium phosphate) in the samples containing ADSOM at concentrations of <250mg g^<-1> compost. However, after immobilization for approximately 7 days, inorganic nitrogen was mineralized in the samples containing ADSOM at concentrations of ≥250mg g^<-1> compost. These results suggest that nitrogen fertilizer efficiency can be predicted on the basis of inorganic nitrogen content in compost containing ADSOM at concentrations of <250mg g^<-1>. This prediction method was verified by experiments of komatsuna cultivation (〜30 days) and sorghum cultivation (〜150 days).

View full abstract

This study aimed to produce a highly functional compost containing high concentrations of Bacillus that control crop diseases by managing the composting process. At a 10-15% mixing ratio of waste clay to dairy manure, the temperature of the manure was controlled well. By mixing in waste clay at this ratio, the disease-controlling Bacillus concentration was maintained at 10^6g^<-1> in the manure compost of a local dairy farm. Experiments using a small vertical fermentation system showed that by mixing waste clay and recycled manure, the disease-controlling Bacillus concentration increased from____ to 7.5×10^7g^<-1>. Using dairy farm manure in the fermentation system, we found that the Bacillus concentration increased to 2.0×10^9g^<-1> and was maintained at >10^8g^<-1> throughout the year. Our findings show that compost containing high concentrations of disease-controlling Bacillus can be produced in a vertical fermentation system by adding waste clay and recycled compost to the dairy farm manure.

View full abstract

Show abstractHide abstract

Heavy application of phosphate fertilizer and subsequent phosphate accumulation in arable soils, especially Andosols, are critical issues for sustainable agriculture in Japan. The effects of fertilization and plant nutrient management on phosphate accumulation and its speciation in uncultivated virgin soils and cultivated upland soils of Tokachi district, Hokkaido, were investigated. Three pairs of virgin and arable soil profiles were collected from adjacent sites to evaluate the vertical distribution of total, sequentially extractable, and available phosphates in the soils. Net accumulated amounts of phosphate in the arable soils were calculated while accounting for bulk density and differences in the thickness of layers between upland and adjacent virgin soils. In soils classified as Low-humic Andosols (Typic Hapludands), Cumulic Andosols (Pachic Melanudands), and Haplic Brown Lowland soils (Fluventic Dystrudepts), surplus phosphates were accumulated at depths of 0〜40, 0〜30, and 0〜35cm, respectively, of the arable soil profiles. Phosphates were distributed homogeneously in the plow layer due to physical disturbance and mixing. The vertical distributions of phosphate in the paired virgin and arable soils indicated that most of the surplus phosphate accumulated without leaching in the plow layer of the Andosols, whereas some surplus phosphate leached out from the surface layer of the Brown Lowland soils. Net accumulated amounts of phosphate in the cultivated Andosols were remarkably large, with estimated annual accumulation rates of >130kg ha^<-1>. Most of the accumulated phosphate may be specifically adsorbed by active aluminum and iron, which could be extracted by fluoride through a strong ligand-exchange reaction. The net accumulated phosphate in the cultivated Lowland soil was relatively small. Most of the phosphate may accumulate through precipitation processes as calcium hydrogen phosphate and amorphous aluminum phosphate, which could be dissolved by weak acids and extracted by a weak ligand-exchange reaction, respectively.

View full abstract

Download PDF (1447K)

Register with J-STAGE for free!