TY - JOUR

T1 - The selective removal of phosphorus from soil: Is event size important?

AU - Quinton, John N.

AU - Catt, John A.

AU - Hess, Tim M.

PY - 2001

Y1 - 2001

N2 - Data from the Woburn Erosion Reference Experiment (Bedfordshire, UK) were used to test the hypothesis that losses of phosphorus (P) in small erosion events are as great as those in infrequent large events, and to examine the effect of storm characteristics on the selective enrichment of P in eroded sediment. For almost every plot event in the period 1988 to 1994, the clay-sized fraction of the sediment was enriched compared with the soil of the plots. There was more variation in clay enrichment for smaller erosion events than for larger ones. The clay and P contents of the sediment were strongly correlated (p < 0.01), and there was a wider range of P concentrations in the sediment derived from small events than in that from large events. However, individual events resulting in small soil losses (<100 kg) did not account for greater P losses than larger events (>100 kg). The greater frequency of smaller events, combined with the likelihood of higher P concentrations in the sediment, therefore accounted for a greater proportion of the P lost over the 6-yr period than the infrequent large events. Phosphorus concentrations generally increased with increasing peak discharge and decreased with increasing event duration. For the same return period, P losses were generally greater from plots cultivated up and down the slope than from those cultivated across the slope. Overall, our results suggest that small erosion events should be controlled to prevent P contamination of surface waters and that the most effective means of doing this are by the introduction of minimal tillage techniques and across-slope cultivations.

AB - Data from the Woburn Erosion Reference Experiment (Bedfordshire, UK) were used to test the hypothesis that losses of phosphorus (P) in small erosion events are as great as those in infrequent large events, and to examine the effect of storm characteristics on the selective enrichment of P in eroded sediment. For almost every plot event in the period 1988 to 1994, the clay-sized fraction of the sediment was enriched compared with the soil of the plots. There was more variation in clay enrichment for smaller erosion events than for larger ones. The clay and P contents of the sediment were strongly correlated (p < 0.01), and there was a wider range of P concentrations in the sediment derived from small events than in that from large events. However, individual events resulting in small soil losses (<100 kg) did not account for greater P losses than larger events (>100 kg). The greater frequency of smaller events, combined with the likelihood of higher P concentrations in the sediment, therefore accounted for a greater proportion of the P lost over the 6-yr period than the infrequent large events. Phosphorus concentrations generally increased with increasing peak discharge and decreased with increasing event duration. For the same return period, P losses were generally greater from plots cultivated up and down the slope than from those cultivated across the slope. Overall, our results suggest that small erosion events should be controlled to prevent P contamination of surface waters and that the most effective means of doing this are by the introduction of minimal tillage techniques and across-slope cultivations.

KW - Agriculture

KW - Conservation of Natural Resources

KW - Geologic Sediments

KW - Models, Theoretical

KW - Phosphorus

KW - Rain

KW - Soil

KW - Soil Pollutants

KW - Water Movements

U2 - 10.2134/jeq2001.302538x

DO - 10.2134/jeq2001.302538x

M3 - Journal article

C2 - 11285915

VL - 30

SP - 538

EP - 545

JO - Journal of Environmental Quality

JF - Journal of Environmental Quality

SN - 0047-2425

IS - 2

ER -