| Project/Area Number |
06660070
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | Hirosaki University |
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Principal Investigator |
AOYAMA Masakazu Hirosaki University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (60150950)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Heavy metals / Apple orchard soil / Plant residue decomposition / Microbial biomass / Microbial activity / Copper / Lead / Arsenic / 土壌 / リンゴ園 / 有機物 / 微生物バイオマス |
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| Research Abstract |
The effects of heavy metals (Cu, Pb, As) accumulated in apple orchard surface soils associated with the continuous application of metal-based pesticides on the decomposition of plant residue and the size and activity of the microbial biomass were assessed. The results obtained were as follows :
1.The heavy metals accumulatedin apple orchard soils did not inhibit the decomposition of fresh plant residues, while inhibited considerably the decomposition of humified plant residues.
2.The heavy metals accumulated in apple orchard soils reduced the proportion of the microbial biomass in the soil organic matter and, further, increased the proportion of fungal biomass in the total microbial biomass.
3.The dehydrogenase activity and soil respiration measured as indications of microbial activity were reduced in the presence of heavy metals, when expressed on a soil organic matter basis.
4.The toxicity of the heavy metals accumulated in apple orchard soils was in the order of Cu>>Pb>As with respect to the plant residue decomposition, microbial biomass, and microbial activity.
5.The plant residue decomposition and microbial activity were adversely affected by the water-soluble and exchangeable Cu whose amount depended on the soil pH,whereas the microbial biomass by the slightly soluble heavy metals accumulated in apple orchard surface soils.
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