Partitioning the contributions of minerogenic particles and bioseston to particulate phosphorus and turbidity

The application of lanthanum modified bentonite (Phoslock®) and polyaluminium chloride (PAC) is popular in the restoration of European temperate lakes; however, the effects of the application on the concentrations of phosphorus (P) in both the water and the sediments have been poorly evaluated to date. We studied the effects of the application of Phoslock® + PAC on the concentrations of total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), total suspended solids (TSS) and chlorophyll a (Chla) in the water, and different P forms in the sediments, in an isolated part of Lake Yanglan. The results showed that the concentrations of TP, PP, SRP, TSS and Chla decreased significantly after the addition of Phoslock® + PAC. Moreover, the concentrations of labile-P, reductant-soluble-P and organic-P in the sediments were also significantly decreased after the Phoslock® + PAC application. However, the concentrations of both the stable apatite-P and residual-P in the sediments after application of Phoslock® + PAC were much higher than the pre-addition values, while the concentrations of metal-oxide-P did not differ significantly between the pre- and post- application conditions. Our findings imply that the combined application of Phoslock® and PAC can be used in the restoration of subtropical shallow lakes, to reduce the concentrations of P in the water and suppress the release of P from the sediments.

Download Full-text

Leaching of dissolved and particulate phosphorus via preferential flow pathways in a forest soil: An approach using zero-tension lysimeters

Journal of Plant Nutrition and Soil Science ◽

10.1002/jpln.201900216 ◽

2020 ◽

Vol 183 (2) ◽

pp. 238-247 ◽

Cited By ~ 2

Author(s):

Vera Makowski ◽

Stefan Julich ◽

Karl-Heinz Feger ◽

Lutz Breuer ◽

Dorit Julich

Keyword(s):

Forest Soil ◽

Preferential Flow ◽

Particulate Phosphorus ◽

Flow Pathways ◽

Preferential Flow Pathways

Download Full-text

The effect of rainfall intensity on soil erosion and particulate phosphorus transfer from arable soils

Water Science & Technology ◽

10.2166/wst.1999.0527 ◽

1999 ◽

Vol 39 (12) ◽

pp. 41-45 ◽

Cited By ~ 34

Author(s):

A. I. Fraser ◽

T. R. Harrod ◽

P. M. Haygarth

Keyword(s):

Soil Erosion ◽

Suspended Sediment ◽

Rainfall Intensity ◽

Overland Flow ◽

Agricultural Soils ◽

Arable Land ◽

Significant Proportion ◽

Particulate Phosphorus ◽

Arable Soils ◽

Flow Monitoring

Soil erosion, in the form of transported suspended sediment in overland flow, is often associated with high rates of particulate phosphorus (PP) (total P>0.45 μm) transfer from land to watercourses. Particulate P may provide a long-term source of P for aquatic biota. Twenty-two sites for winter overland flow monitoring were selected in south-west England within fields ranging from 0.2–3.8 ha on conventionally-managed arable land. Fields were situated on highly porous, light textured soils, lacking impermeable horizons and often overlying major aquifers. Long arable use and modern cultivation methods result in these soils capping under rain impact. Overland flow was observed when rainfall intensity approached the modest rate of 0.8 mm hr−1 on land at or near to field capacity. Low intensity rainfall (<2 mm hr−1) produced mean suspended sediment losses of 14 kg ha−1 hr−1, with associated PP transfer rates of 16 g ha−1 hr−1. In high intensity rainfall (>9 mm hr−1) mean PP losses of 319 g ha−1 hr−1 leaving the field were observed. As might be expected, there was a good relationship between PP and suspended sediment transfer in overland flow leaving the sites. The capacity of light soils to cap when in arable use, combined with heavy or prolonged rainfall, resulted in substantial discharges, soil erosion and associated PP transfer. Storms with heavy rain, typically of only a few hours duration, were characterised by considerable losses of PP. Such events, with return periods of once or twice a winter, may account for a significant proportion of total annual P transfer from agricultural soils under arable crops. However, contributions from less intense rain with much longer duration (around 100 hours per winter in many arable districts of the UK) are also demonstrated here.

Download Full-text