| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 87 === In this study, a modified centrifugation for obtaining soil solutions was developed and compared to vacuum extraction . Relationship between the composition of saturated extracts and different water/soil ratio extracts was also investigated. Finally, We studied the soil solution composition of fifty acid soils from Taiwan as affected by liming and incubations under dry-wet moisture regime .
The modified centrifugation apparatus offers a more rapid method than vacuum extraction. pH of soil solutions obtained by the modified centrifugation methods was consistently lower than that of vacuum extraction. Differences in the concentratios of Ca and Mg were also noticed.
Relationships between the electrical conductivity of saturated extracts and different water/soil ratio extracts from sixty soil solutions from Taiwan were：ECe＝1.75×EC1:1(R2＝0.988***), ECe＝3.70×EC2.5:1(R2＝0.984***), ECe＝6.42×EC5:1(R2＝0.978***).
Effects of liming and incubation were increases in soil solution pH, Cl-, NO3-, SO42-, and Ca2+, and reductions in Mg2+, K+, Na+. Besides，we found that the relationship between ionic strength and electrical conductivity of soil solutions from Taiwan were：IM=0.0166ECe,ds/m－0.0009(R2＝0.974***) and log(ImM)＝1.134log(ECe,dS/m)＋1.185(R2＝0.956***).
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