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2. Assessing the impact of phosphorus cycling on river water P concentration in Hokkaido

Author

Woli, Krishna Prasad, Hayakawa, Atsushi, Nagumo, Toshiyuki, Imai, Hiromu, Ishiwata, Teruo, Hatano, Ryusuke, Woli, Krishna Prasad, Hayakawa, Atsushi, Nagumo, Toshiyuki, Imai, Hiromu, Ishiwata, Teruo, and Hatano, Ryusuke

Abstract

We estimated the phosphorus (P) budgets for all 212 cities, towns and villages of Hokkaido, Japan. We also carried out water sampling from all major rivers flowing in the respective areas during the snowmelt season and measured total P (TP) concentration. Surplus P in the agricultural land was estimated by subtracting the amount of crop uptake from the input sources, such as the amount of chemical and compost fertilizers, crop residues, rainfall and irrigation. The livestock excreta P not utilized on farmland was assumed to be disposed P. Total P concentrations in most of the river water ranged from undetectable to 1 mg L-1, rarely reaching up to 2.32 mg L-1, and the areas surrounding the Funka Bay had comparatively higher concentrations. More than two-thirds of the areas had surplus P in farmland ranging from negative values to 30 kg ha-1 of farmland, and areas with mixed farmland and livestock husbandry had higher surplus values ranging from 31 to 72 kg ha-1, indicating that the source of the residual P was applied chemical and manure fertilizers. Total P concentration in river water was not correlated with the proportion of upland field and urban area or with the farmland surplus P resulting from the P cycling and the municipal waste P that mixes into the river water. However, TP concentration was positively correlated with the proportion of Andisol area occupied by farmlands (r = 0.25, P < 0.01). The TP concentration was also correlated with the topographic factors in areas (r = 0.49, P < 0.01) that possess more than 50% Andisols in farmlands. Multiple regression analysis showed that TP concentration was best explained by a combination of disposed excreta, the Andisol area occupied by farmland, the application rate of chemical fertilizers and topographic factors (r2 = 0.21, P < 0.001). Thus, P losses from farmlands to river water during the snowmelt season could mainly be attributed to fertilizer management and soil type along with the topographic condition of t

Published
2008

15. Stability Constants of Imidazole– and Alkylimidazole–Copper(II) Complexes

Author

Imai, Hiromu and Tamura, Hiroshi

Abstract

The stability constants of imidazole (HIm)– and alkylimidazoles–copper(II) acetate complexes were calculated from the potentiometric titration data with the aid of the SUPERQUAD computer program. The stability constants of ionic species of [CuALr]+type (A : CH3COO, L : HIm a, 1-CH3·Im b, 2-CH3·HIm c, 4-CH3·HIm d, 2-C2H5·HIm e, 2-(CH3)2CH·HIm f, r=1, 2, 3, and 4) detected from the complexes were ascertained to be decreased in the order of b(1-substituted)=d(4-substituted)>c(2-substituted) relating to the position of methyl group bonded to the imidazole ring, and c(2-CH3)>e(2-C2H5)>f(2-(CH3)2CH) relating to the kinds of alkyl group substituted on 2-position, respectively. The stability of these ionic species was discussed from the neutralization effect of the charge and the steric effect of alkyl group or acetate ion. The stability constants of the hydroxo species of [CuL2(OH)2] type indicated the extremely small values, and its order did not indicate a similar tendency with those of ionic species of [CuALr]+types. The distribution of these complex species was investigated as a function of pH.

Published
1991
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16. Properties and Configuration of Manganese(II), Cobalt(II), Nickel(II), Copper(II) and Zinc(II) Chelates of Acetoacetylferrocene

Author

Imai, Hiromu and Ota, Tadamasa

Abstract

Physical and chemical properties of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) chelates of acetoacetylferrocene were investigated. The solubility decreased in the order CHCl3>CH2Cl2>C6H5Cl>C6H4(CH3)2>C6H6, the chelates being more soluble in pyridine. It was found from magnetic data that the configuration is octahedral for the aquo or pyridine adduct of manganese(II), cobalt(II) and nickel(II) chelates, square planar for anhydride of copper(II) chelate, distorted octahedral for its pyridine adduct, and quasi-tetrahedral for the anhydride of manganese(II) chelate. The d-d transition of electronic spectra was analysed by Ohsymmetry for cobalt(II) and nickel(II) chelates, and by C2hsymmetry for copper(II) chelate. Assignment of the d-d transition for manganese(II) chelate was difficult.

Published
1974
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21. NIPPON KAGAKU KAISHI

Author

IMAI, Hiromu, primary, IKEUCHI, Kiyoshi, additional, SHIRAIWA, Tadashi, additional, and OIWA, Masayoshi, additional

Published
1976
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