Chemical extraction methods for various K pools in a dynamic soil K model. A case study in intensive rice cropping in the Mekong Delta, Vietnam

N.M. Hoa, B.H. Janssen, O. Oenema

Research output: Chapter in Book/Report/Conference proceedingAbstract

Abstract

In the Mekong Delta, intensive triple rice cropping is depleting soil K. Analytical methods for characterization of various soil K pools need to be evaluated for prediction of soil K deficiency risk using a simulation model. Possible methods include solution K extracted by 0.01M CaCl2, exchangeable K by 1M NH4OAc pH7, non-exchangeable K by 1M boiling HNO3, 0.2M Na TetraPhenylBorate (5 min), and total K by concentrated HClO4-HF. Two greenhouse experiments were set up, each for 3 rice crops, to study changes in soil K pools: an exhaustion experiment with 19 soils and 5 weeks per crop, and an experiment with 4 soils without or with fertilizer K, and 3 months per crop. Soil K fractions including K(CaCl2), K(NH4OAc), K(HNO3), and K(NaTPB) were measured at the beginning and at the end of each crop in the first experiment and after 3 crops in the second experiment. K(HClO4-HF) was measured only at the beginning of the experiment
Original languageEnglish
Title of host publicationProceedings of the 18th World Congress of Soil Science, Philadelphia, Pennsylvania, U.S.A., 9-15 July 2006
Place of PublicationPhiladelphia
Pages168-23
Publication statusPublished - 2006
Event18th World Congress of Soil Science, Philadelphia, Pennsylvania, U.S.A., 9-15 July 2006 -
Duration: 9 Jul 200615 Jul 2006

Conference

Conference18th World Congress of Soil Science, Philadelphia, Pennsylvania, U.S.A., 9-15 July 2006
Period9/07/0615/07/06

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Hoa, N. M., Janssen, B. H., & Oenema, O. (2006). Chemical extraction methods for various K pools in a dynamic soil K model. A case study in intensive rice cropping in the Mekong Delta, Vietnam. In Proceedings of the 18th World Congress of Soil Science, Philadelphia, Pennsylvania, U.S.A., 9-15 July 2006 (pp. 168-23). Philadelphia.