RT Journal Article
SR Electronic
T1 Conservation practice effects on phosphorus losses from Southern Piedmont watersheds
JF Journal of Soil and Water Conservation
FD Soil and Water Conservation Society
SP 157
OP 161
VO 40
IS 1
A1 G. W. Langdale
A1 R. A. Leonard
A1 A. W. Thomas
YR 1985
UL http://www.jswconline.org/content/40/1/157.abstract
AB Conservation and conventional tillage systems were used on small, upland watersheds in the Southern Piedmont to determine P contributions to nonpoint-source water pollution. Six tillage/cropping systems were studied on three watersheds over a 10-year period. Each tillage/cropping system was repeated every 2 to 4 years over a range of conservation practices and related to both C and P factors of the USLE. Total P runoff losses varied from 0.1 to 4.0 kg ha−1 yr−1 and consistently related to soil loss within each tillage system, irrespective of watershed landscape and the conservation practice imposed, The soluble-P fraction, PO4-P, and total dissolved P increased dramatically from about 10% to 40% of total P as multiple croppping and the use of conservation tillage intensafied with respect to crop residue cover. Although higher concentrations of both soluble P and total P were usually associated with conservation tillage, total P losses declined 50% or more while soluble P losses were nearly equal to or less than those measured for conventional tillage. These reductions in total P were the result of lower runoff volume with conservation tillage.