RT Journal Article
SR Electronic
T1 Field-scale variation of soil phosphorus within small alberta watersheds
JF Journal of Soil and Water Conservation
FD Soil and Water Conservation Society
SP 414
OP 422
VO 62
IS 6
A1 S. C. Nolan
A1 J. L. Little
A1 J. P. Casson
A1 F. J. Hecker
A1 B. M. Olson
YR 2007
UL http://www.jswconline.org/content/62/6/414.abstract
AB Field-scale variation in soil-test phosphorus (STP) and the degree of soil phosphorus saturation (DPS) can affect predictions of phosphorus loss from agricultural soils. Our objectives were to characterize STP and DPS and relate these to topographic characteristics within eight small watersheds in Alberta, Canada. An ungrazed grassland site (2 ha [5 ac]) and seven cultivated sites (22 to 248 ha [54 to 613 ac]) represented a range of tillage and manured conditions. Soils were sampled by landform position at three depths (1 point per 1 to 5 ha [2 to 12 ac]) in fall 2003. Levels of STP in 0 to 2.5 cm (0 to 1 in) were up to two times greater than in 0 to 15 cm (0 to 6 in) at non-manured sites. Within-field variation in STP and DPS was not well related to landform class or topographic index, although some variation was attributable to previous management. Current agronomic sampling strategies should give adequate representations of STP and DPS where management and soil properties are similar.