Field-scale phosphorus losses from a drained clay soil in Sweden

✍ Scribed by Barbro Ulén; Kristian Persson

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 165 KB
• Volume: 13
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(19991215)13:17<2801::aid-hyp900>3.0.co;2-g

✦ Synopsis

The objective of this study was to determine and discuss ®eld-scale phosphorus losses via subsurface tile drains. A total phosphorous (Tot-P) export, which averaged 0 . 29 kg ha À1 year À1 , was measured over a six-year period from the 4 . 43 ha drainage system of a Eutric Cambisol in Central Sweden. The main part (63%) was in particulate form (PP) while the remainder was either in phosphate form (PO 4 -P) or in other dissolved or colloidal forms. A very small area, less than 1% of the soil surface, was demonstrated to be hydraulically active by using a staining technique in soil monoliths taken from the ®eld. The stained macropores were few, but were continuous downward, and were relatively evenly distributed among the eight 7 dm 2 areas that were investigated. The transport from the ®eld mainly occurred in episodes during which the relationship between phosphorus concentration and discharge was characterized by hysteresis loops. On average, half of the yearly P transport occurred in 140 hours. Compared with ¯ow-proportional and frequent sampling, manual and fortnightly sampling underestimated the transport of Tot-P and suspended solids (SS) by 59 and 42%, respectively, during the six years studied. Amounts of dierent phosphorus forms exported through the tile drains were very similar to those reported from other clay soils in Northern Europe and North America.