2007/09/01 by V. Steven Green, V. S. Green, Thanh H. Dao +8 · 24 citations
Agricultural and Biological Sciences · Chemistry · Environmental Science · #Agronomy #Biology #Chemistry #Dactylis glomerata #Ecology #Environmental science #Forage #Loam #Manure #Orchard #Phosphorus #Phosphorus and nutrient management #Poaceae #Red Clover #Soil Carbon and Nitrogen Dynamics #Soil and Water Nutrient Dynamics #Soil science #Soil water #Surface runoff
paper · doi:10.1097/ss.0b013e31809eda32
published in Soil Science 172(9), 721-732 (Lippincott Williams & Wilkins)
openalex publication_date 2007/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
Although runoff from phosphorus (P)-enriched soils contains more P than the functionally defined molybdate-reactive P, information on the biological significance of the remaining fraction is limited. A study was conducted to characterize distributions of inorganic and enzyme-labile P forms in simulated runoff from a silt loam soil (Typic Hapludults) under orchard grass (Dactylis glomerata L.)-red clover (Trifolium pratense L.) and no-till forage-type soybean (Glycine max [L.] Merr.)-wheat (Triticum aestivum L.) systems after the fall harvest. Forage management effects on runoff composition and on relationships between soil water-extractable P (WEP) in runoff and bioactive P pools were determined after eight annual manure applications. Concentration and mass distributions of P forms in runoff over time were lognormally distributed, and four parameters defined the distributions' amplitude and asymmetry. The more inclusive total bioactive P (EDTA-PHP) fraction was found in greater concentration and mass than WEP. Peak concentrations and mass loads were greater from soil amended with manure P than untreated soil and from soil under orchard grass-clover than soil under soybean-wheat rotation. The strength of correlations between predicted WEP mass loads and soil P pools was in the order EDTA-PHP > ligand-exchangeable inorganic P > Mehlich-3P, suggesting that runoff P forms were directly associated with soil available P fractions that were partly derived from enzyme-mediated processes. The results also suggested that knowledge of the P release pattern was as important a factor as mass load because management intensity and yield potentials of these forage systems can alter the characteristics of the loss process.