Predicting phosphorus buffer coefficients of some representative soils for maize production in Lao PDR by three soil analysis methods | เธเธฒเธฃเธเธณเธเธงเธ phosphorus buffer coefficients เธเธญเธเธเธธเธเธเธดเธเธเธตเนเนเธเนเธเธเธฑเธงเนเธเธเนเธเธเธฒเธฃเธเธฅเธดเธเธเนเธฒเธงเนเธเธเนเธเธเธฃเธฐเนเธเธจเธฅเธฒเธงเนเธเธขเธเธฒเธฃเธงเธดเนเธเธฃเธฒเธฐเธซเนเธเธดเธ 3 เธงเธดเธเธต
2008
Khonpany Dounphady(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agriculture. Department of Soil Science) | Tasnee Attanandana(Kasetsart University. Bangkhen Campus, Bangkok (Thailand). Faculty of Agriculture. Department of Soil Science) E-mail:[email protected] | Yost, Russell(University of Hawii at Monoa. Hawii (USA). Department of Tropical Plant and Soil Sciences)
Phosphorus buffer coefficient (PBC) is one of the important factors in the phosphorus fertilizer recommendation prediction by PDSS program. The study on PBC of 7 representative maize soils from 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. All soil samples were kept in the incubator at 30 deg C for two weeks. The extractable P was analyzed by three methods: Mehlich 1 (PBC (Mehlich 1)), Bray-2(PBC (Bray-2)) and iron oxide-impregnated filter paper method or Pi-test (PBC(Pi-test)). The results showed different PBC values of soils with different extractants. Multiple regression analysis was used to study the relationship between the PBC and soil properties. It revealed that (PBC(Bray-2) was correlated with percentage of clay content with adj R sup (2) =0.64 and PBC (Pi-test) was correlated with percentage of clay content and ammonium oxalate extractable aluminum, with adj R sup (2) =0.89.
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