Japanese Journal of Soil Science and Plant Nutrition

The effects of nitrogen fertilization and harvesting time on flour quality (protein content, maximum viscosity measured by rapid visco analyzer (RVA), color of flour, dough characteristics measured by Brabender farinograph) and baking quality of spring wheat, Haruyutaka, grown in Hokkaido Prefecture were investigated. The protein content of wheat flour increased remarkably with an increase of nitrogen fertilizer, but no significant correlation was found between the nitrogen fertilization and the yield of wheat. The maximum viscosity, measured by RVA, and the brightness (L^*) of flour, and the weakness (Wk), measured by farinograph, decreased with an increase of protein content of wheat flour. The co-ordinate of red-green color (a^*) of flour and the absorption (Ab), the development time (DT), the stability (Stab), and the valorimeter value (vv) increased with an increase of protein content of wheat flour. The maximum viscosity and the L^* of flour obtained from wheat harvested at a suitable time were higher than for that harvested at a late time. The a^* of flour obtained from wheat harvested at a suitable time was lower than for that harvested at a late time. The dough characteristic was not affected by harvesting time. The ratio of loaf volume to weight increased with an increase of protein content of wheat flour, but it was not affected by harvesting time. It was concluded that the maximum viscosity and the flour color were affected by both the protein content of wheat flour and the harvesting time. The quality of dough and the ratio of loaf volume to weight were mainly affected by the protein content of wheat flour when there was no heavy rainfall, which induced remarkable deterioration of maximum viscosity.

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The objectives of this study were to investigate the availability and balance of nitrogen from ^<15>N-labeled composted poultry manure and sawdust cattle manure by ^<15>N tracer technique and to compare these results to the ^<15>N-labeled rape cake and chemical fertilizer, ammonium sulfate. In the field experiment, ^<15>N recovery in rice plants from ammonium sulfate, rape cake, composted poultry and sawdust cattle manure at maturity were 41.7, 28.7, 15.7 and 4% respectively. On the other hand, the ^<15>N residual in the top soil (0-15 cm) from the same set were 35, 41, 47 and 91%, respectively. The mineral fertilizer equivalent (MFE) of composted poultry manure, composted sawdust cattle manure and rape cake were 40, 10 and 70%, respectively. The span of ^<15>N availability from these manures was from active tillering stage to panicle formation stage. The trend of change of organic ^<15>N recovery-derived from ^<15>N labeled matters in a laboratory incubation experiment was similar to that in the field experiment. It is suggested that the laboratory incubation experiment can characterize or predict the pattern of mineralization of organic matters in the actual field conditions.

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In order to characterize the chemical properties of the anaerobically digested slurry of dairy cow manure, in comparison with those of the aerated slurry and untreated slurry, we analyzed the composition of humic and non-humic components contained in these slurries. Fourier-transform infrared (FT-IR) spectra of the slurries were also compared. Among the slurry samples collected from various slurry treatment facilities in Hokkaido, Japan, seven samples of digested slurry, nine samples of aerated slurry, and eight samples of untreated slurry were included. The rates of low molecular weight fatty acids and neutral sugars in the total alkali extractable components of the digested slurries were much lower than those in untreated slurries and aerated slurries with low aeration intensity. The rates of humic substances differed considerably according to the type of slurry. In the digested slurries, the rates of humic acid were much higher, while the rates of PVP-adsorbed fulvic acid were much lower than those of untreated slurries and aerated slurries with low aeration intensity. In consequence, the rate of humic substances in the total alkali extractable substances (DH) was very high in the digested slurry.-In the aerated slurry, the rate of humic substances increased with the increase in the intensity of aeration, The FT-IR spectrum of digested slurry showed that the peaks representing aliphatic, protein, and carbohydrate components were extremely low and the peak representing aromatic, carboxylate, and hydrogen-bonded carbonyl group was very high. The ratios of the peak area of aromatic, carboxylate, and hydrogen-bonded carbonyl group over that of the aliphatic group or that of polysaccharides showed a highly significant positive correlation with DH. From these results, it became clear that digested slurry contained lower amounts of easily decomposable organic matter and larger amounts of humie substances independently of the conditions of treatments in comparison to untreated slurry and aerated slurry with low aeration intensity.

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In order to compare the chemical characteristics of humic acids and PVP-adsorbed fulvic acids extracted from the anaerobically digested slurry with those of the aerated slurry and untreated slurry of dairy cow manure, we analyzed ultraviolet and visible absorption spectra and FT-IR spectra of these fractions. Used slurries included 7 anaerobically digested slurries, 9 aerated slurries and 8 untreated slurries all collected from slurry treatment facilities in Hokkaido. Humic acids extracted from the three types of slurries used in this study all belonged to the Rp type with extremely high AlogK and low RF values compared with soil humic acid, indicating their very low degree of humification. The E_4/E_6 ratios of PVP adsorbed fulvic acids obtained from anaerobically digested slurries were very similar to those of aerated and untreated slurries. The absorbances at 340 and 280 nm per unit concentration of carbon of humic acids and those at 400, 340 and 280 nm per unit concentration of carbon of PVP adsorbed fulvic acids obtained from anaerobically digested slurries were larger than those of untreated slurries. Large and small values were observed for the visible and ultraviolet absorbance of PVP adsorbed fulvic acids obtained from aerated slurries depending on the intensity of aeration. Ultraviolet and visible absorption spectra and FT-IR spectra of humic acids from several slurries were extremely similar to those of lignin. It was suggested, therefore, that constituents derived from lignin were an important structural component in the humic substances of those slurries. On the other hand, FT-IR spectra indicated that humic acids from anaerobically digested slurries contained a lower proportion of aliphatic and polysaccharide components and larger proportions of aromatic components, carboxylate, and carbonyl groups than the humic acids of untreated slurries. Humic acids from aerated slurries contained a lower proportion of polysaccharide but almost the same proportion of aliphatic component compared with untreated slurries. FT-IR spectra of PVP adsorbed fulvic acids from anaerobically treated and aerated slurries indicated an increase in carboxyl and carbonyl groups as well as a decrease in phenolic groups and polysaccharide components compared with untreated slurries.

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