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Phosphorus forms and extractability from three sources in a recently exposed calcareous subsoil

Formas y Extracción de Fósforo de Tres Fuentes en un Subsuelo Calcáreo Recientemente Expuesto

Robbins, C.W. and Westermann, D.T. and Freeborn, L.L. (1999) Phosphorus forms and extractability from three sources in a recently exposed calcareous subsoil. Soil Science Society of America Journal. 63:1717-1724.

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Irrigation-induced erosion and land leveling have decreased crop
yields on - 800 000 ha of south-central Idaho silt loam soils because
of topsoil removal. Phosphorus availability is a known production
problem after topsoil removal. This study evaluated the effect of three
P sources on soil P solubility by three standard methods for calcareous
soils. A long-term study was initiated on a Portneuf silt loam (Coarse-silty,
mixed, superactive, mesic Durinodic Xeric Haplocalcid) by removing
the surface 0.3 m of topsoil from strips between undisturbed
topsoil strips. Phosphorus treatments applied across all strips were
conventional fertilizer (applied according to soil test), dairy manure,
and cheese whey. All treatments increased the freshly exposed subsoil
bicarbonate extractable ortho-P concentrations up to or greater than
the topsoil concentrations, which were more than adequate for economical
crop production. The high-whey and manure treatments increased
the subsoil saturation paste and 0.01 M CaCl2 extractable
ortho-P concentrations up to or greater than the untreated topsoil
ortho-P concentrations. The initial topsoil ortho-P solubility was along
the β-tricalcium phosphate (β-TCP) isotherm and the initial subsoil
was well below the β-TCP isotherm. The ortho-P solubility of the
subsoil monocalcium phosphate (MCP) treatment remained just below
the β-TCP isotherm. The cottage cheese whey treatment increased
subsoil P solubility up to the β-TCP isotherm and the manure treated
subsoil ortho-P solubilities were between the β-TCP and octacalcium
phosphate (OCP) isotherms. Most subsoil ortho-P concentrations by
all three extraction methods decreased from spring to fall and then
increased over winter in the subsequent spring samples. Soil solution
ortho-P concentrations decreased with time in the subsoil treatments
except immediately following treatment applications. The topsoil ortho-P
extract concentrations by all three methods varied among samplings
but remained about the same during the study period.

Item Type: Article
NWISRL Publication Number: 1000
Subjects: Soil > Calcareous soil
Soil > Chemistry > Phosphorous
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:50
Last Modified: 16 Nov 2016 17:47
Item ID: 93