Phosphorus leaching from soils containing different phosphorus concentrations in the Broadbalk Experiment

A - Papers appearing in refereed journals

Heckrath, G., Brookes, P. C., Poulton, P. R. and Goulding, K. W. T. 1995. Phosphorus leaching from soils containing different phosphorus concentrations in the Broadbalk Experiment. Journal of Environmental Quality. 24 (5), pp. 904-910.

AuthorsHeckrath, G., Brookes, P. C., Poulton, P. R. and Goulding, K. W. T.
Abstract

Total P (TP), total particulate P (TPP), dissolved reactive P (DRP), and dissolved organic P (DOP) were determined in waters from pipe-drains (at 65-cm depth) from the Broadbalk Experiment at Rothamsted. Soils that have received either no P, P in farmyard manure (about 40 kg P ha(-1)) or superphosphate (up to 35 kg P ha(-1)) annually for >150 yr, now contain 0.5 M NaHCO3-extractable P concentrations (Olsen-P) in the plow layer (0- to 23-cm depth) between 5 and 100 mg kg(-1) soil. Our aim was to determine if significant quantities of P could be detected in the drainage water and their relationship to soil P concentrations. On five occasions between October 1992 and January 1994, both TP and DRP from plots receiving superphosphate frequently exceeded 1 mg L(-1) and were high compared with literature data. Ranging between 66 and 86% of TP, DRP was the largest fraction in drainage water. It remained low (<0.15 mg L(-1)) from plots below 60 mg Olsen-P kg(-1). There was then a rapid increase in DRP up to the maximum Olsen-P concentration. A simple linear Split-Line Model described this relationship very well for all drainage events. This implies that up to 60 mg Olsen-P kg(-1) soil (the change point), P was retained strongly in the plow layer. Above this, P losses in the drainage water were much more closely related to Olsen-P than commonly suggested. The mechanisms could either be preferential how or rapid transport of P in forms less susceptible to sorption but finally measured as DRP. The results suggest enhanced P losses through subsurface runoff on heavy soils, once a certain plow layer concentration of Olsen-P is exceeded. 

KeywordsRRES175; 175_Soil science; 175_Long-term experiments
Year of Publication1995
JournalJournal of Environmental Quality
Journal citation24 (5), pp. 904-910
Digital Object Identifier (DOI)doi:10.2134/jeq1995.00472425002400050018x
Open accessPublished as non-open access
Funder project or code220
Output statusPublished
PublisherAmerican Society of Agronomy, Crop Science Society of America and Soil Science Society of America

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