 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Predicting Phosphorus Buffer Coefficients of Some Representative Soils for Maize Production in Lao PDR by Three Soil Analysis Methods) ผู้เขียน: ครปานี ดุ่นนาดี,  ดร.ทัศนีย์ อัตตะนันทน์, ศาสตราจารย์ , Russell Yost สื่อสิ่งพิมพ์:pdf AbstractPhosphorus buffer coefficient (PBC) is one of the important factors in the phosphorus fertilizer recommendation prediction by the use of Phosphorus Decision Support System (PDSS) program. A study on PBC of 7 representative maize soils in Laos and one Thai soil was conducted. The PBC determination was done by mixing the soils with potassium dihydrogen phosphate (KH2PO4) at the rates of 0, 25, 50, 100 and 200 mg P kg-1. All soil samples were kept in the incubator at 30 ?C for two weeks. The extractable P was analyzed by three methods: Bray-2, Mehlich-1 and iron oxide-impregnated filter paper method or Pi-test. The results showed different PBC values of soils with different extractants. Multiple regression analysis was used to determine the relationship between the PBC and soil properties. It revealed that PBCBray-2 was correlated with percentage of clay content with adjR2=0.64 and PBCPi-test was correlated with percentage of clay content and ammonium oxalate extractable aluminum, with adjR2 =0.89. The soil properties were substituted in the two models to predict the PBCBray-2 and PBCPitest, respectively. The predicted PBC was plotted against observed PBC to compare the prediction accuracy using soil properties by 1:1 line relationship. The result showed that the PBC should be estimated by Pitest for more accurate PBC prediction. |
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