堆肥の施用による土壌物理性改良効果の評価
| Autor: | Tomonori, Fujikawa, Nakamura Takahiko, Komamura Masaharu |
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| Jazyk: | japonština |
| Předmět: | |
| Popis: | 堆肥による土壌物理性の改良効果については,改良に至るメカニズムや施用方法と効果の定量的な関係が十分に明らかにされているとは言えない。本研究では,より均質な間隙構造の試料を作成できる撹乱土壌と堆肥を混合して土壌物理性を測定し,堆肥の種類,量および土壌の締固め強度が混合後の土壌の物理性および間隙の量や大きさに与える影響を検討した。牛ふんを原料とする堆肥は,土壌への混合量の増加にともない,気相率や間隙率が低下するにも関わらず通気係数や飽和透水係数が大きくなった。保水性の測定からは混合量の増加に伴い大きな間隙の割合が増加することが示されており,大きな間隙が通気性や透水性の上昇に寄与したと考えられた。一方,腐葉土を混合した試料の飽和透水係数はもとの土壌より大きくなったものの,通気係数はほとんど変化しなかった。腐葉土を混合した試料では締め固めの強度が大きくなっても通気係数や飽和透水係数の低下の割合が小さかった。保水性の測定からは腐葉土の作り出す大きな間隙は圧縮されにくいことが示された。堆肥の形状や大きさによって,作り出される間隙の大きさや量,圧縮への耐性に違いがあることが示唆された。 A comprehensive understanding of changes in physical properties in soil after the mixing of compost is still lacking. The objectives of this study are to estimate the effects of the amount of cattle manure compost and leaf mold, and the compaction intensity of mixed soil, on soil physical properties and pore structure, such as pore volume and size distribution. Values of air permeability and saturated hydraulic conductivity increased with increase in the mixing compost, although the air filled porosity and total pore volume decreased. The inconsistency in the relationships between these porosities and air permeability and hydraulic conductivity is explained in terms of the increase in the fraction of large pores, which contributed to these conductivities greatly, increased by the compost mixing. The values of hydraulic conductivity of soils mixed with leaf mold increased with the increase of the mixing leaf mold but the changes in air permeability were negligibly small. The decreases in air permeability and hydraulic conductivity of the leaf mold-mixed soil with increases in the compaction intensity were smaller than those of the compost-mixed soil. The large pores made after mixing of leaf mold were more difficult to be compressed than those made by the compost. It is suggested that the shape and size of the mixing materials affect the structure of the pores that are made by the mixing and the physical properties of mixed soil. |
| Databáze: | OpenAIRE |
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