EFFECTS OF FREEZING AND THAWING ON SOME CHEMICAL PROPERTIES OF THREE SOILS
[摘要] Theeffectofcontinuousfreezingat−15 CandalternatefreezingandthawingonsomechemicalpropertiesofthreeSaskatchewansoilswasdetermined.Theresultsarebasedonsoilstreatedwhilemoistwithmethylbromideandfreeze-driedfollowingthefrosttreatments.Thefreezingeffectswereobtainedbycomparisonswithair-driedcontrolsamples.AlternatefreezingandthawingresultedinalargeincreaseinexchangeableNH4-NandasmallbutsignificantdecreaseinexchangeableK;therewasnoeffectoncationexchangecapacityorexchangeableCa++andMg++.FreezingandthawingdidnotaffectNO3-Ncontent.DiluteNaHCO3-extractableNandwater-solublecarbohydrates,asindicesofavailableN,increasedsharplyaftercontinuousfreezing,butalternatefreezingandthawinggaveafurtherincreaseinNaHCO3-extractableNonlyinonesoil.TherewasanincreaseinNaHCO3-extractablePaftercontinuousfreezingandafurthersignificantincreasefollowingalternatefreezingandthawing.Thelargeincreas...
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[效力级别] [学科分类] 农业科学（综合）
[关键词] [时效性]
