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Phosphorus Runoff from Two Water Sources on a Calcareous Soil
- Aase, J.K., Bjorneberg, D.L., Westermann, D.T.
- Journal of environmental quality 2001 v.30 no.4 pp. 1315
- water pollution, phosphorus, losses from soil, calcareous soils, silt loam soils, irrigated soils, sprinkler irrigation, soil analysis, runoff, Idaho
- Phosphorus (P) in irrigation runoff may enrich offsite water bodies and streams and be influenced by irrigation water quality and antecedent soil surface conditions. Runoff, soil loss, and P fractions in runoff using reverse osmosis (RO) water or mixed RO and well water (RO/Tap) were studied in a laboratory sprinkler study to evaluate water source effects on P transport. A top- or subsoil Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid), either amended or not amended with manure and/or with cheese whey, with Olsen P from 20 to 141 mg kg and lime from 108 to 243 g kg, was placed in 1.5 × 1.2 × 0.2-m-deep containers with 2.4% slope and irrigated three times from a 3-m height for 15 min, applying 20 mm of water. The first irrigation was on a dry loose surface, the second on a wet surface, and the third on a dry crusted surface. Surface (ca. 2 cm) soil samples, prior to the first irrigation, were analyzed for Olsen P, water-soluble P (P), and iron-oxide impregnated paper–extractable P (FeO-P) analyses. Following each irrigation we determined runoff, sediment, dissolved reactive phosphorus (DRP) in a 0.45-μm filtered sample, and FeO-P and total P in unfiltered samples. Soil surface conditions had no effect on P runoff relationships. Water source had no significant effect on the relationship between DRP or FeO-P runoff and soil test P, except for DRP in RO runoff versus water-soluble soil P (= 0.90). Total P in RO runoff versus soil P were not related; but weakly correlated for RO/Tap (< 0.50). Water source and soil surface conditions had little or no effect on P runoff from this calcareous soil.