Preventing soil erosion by water
- Small dams between ploughing furrows
- Post-fire mulching in forests
- Terraces on mountainous agricultural land
In Switzerland the RECARE researchers are testing the effectivness of reducing soil erosion by using a Dyker to produce small dams between ploughing furrows in potato fields. Attached to the rear end of the planting machine, the Dyker digs holes into the bottom of the furrows between the potato dams.
Soil erosion: Photographs and furrow profile measurements show that furrows treated with the Dyker clearly displayed less signs of erosion compared to untreated furrows. In addition, their accumulation zones had collected less eroded soil than those of untreated furrows.
Waterlogging: In treated furrows, rainwater was evenly retained in the holes and infiltrated the soil locally. In untreated furrows, much of the water remained on the surface and ran off into the depression. Resulting anaerobic conditions prevented the plants from growing and ultimately led to crop failure.
Burnt areas in forests can reveal some extreme responses in runoff generation and associated sediment losses. Such responses exacerbate the direct effects of fire on vegetation and on the soil physical, chemical and biological properties, compromising their recovery from heat-induced changes. Post-fire soil erosion also represents a serious threat to off-site "values-at-risk", through flood generation and transfer of sediments, organic matter, nutrients and pollutants to downstream water bodies. Recent field trials in the Portugese case study area have clearly demonstrated that mulching with forest logging residues (widely available in the region) is highly effective in reducing erosion in recently burnt areas. The RECARE experiment is testing the effectiveness of mulching to reduce post-fire soil (fertility) losses. It involves mulching with eucalyptus logging slash at 2 contrasting application rates.
|Post-fire mulching experment|
a. the two mulch application rates tested in the field (2.5 vs. 8 Mg ha-1) had a statistically significant effect on various ground cover categories throughout the first year after the fire, including the litter cover that was targeted by the treatment. Immediately after mulching, the litter cover was, on average, 4% in the untreated plots and 48 and 77% in the little- and much-mulch treatments, respectively,corresponding to increases in protective cover of 12 and 19 times.
b. the two mulch application rates also produced major reductions in mineral soil losses over the first year after the fire as these losses amounted, on average, to 6.3 Mg ha-1 y-1 in the case of the untreated plots and to 0.9 and 0.2 Mg ha-1 y-1 in the plots with little- and much-mulch, respectively. As such, the overall effectiveness of the two mulch treatments in reducing soil loss was 86 and 97%, effectiveness in % being quantified as: (loss_untreated – loss_treated) / loss_untreated * 100. Similar results were obtained for organic matter losses (weight-loss-on-ignition method), with the two mulching treatments being, on average, highly effective (88 and 94 %) in reducing the 1.7 Mg ha- y-1 losses from the untreated plots.
J.J. Keizer, M.A.S. Martins, S.A. Prats, S.R. Faria, O. González-Pelayo, A.I. Machado, M.E. Rial-Rivas, L.F. Santos, D. Serpa, M.E.T. Varela (20015) Within-in flume sediment deposition in a forested catchment following wildfire and post-fire bench terracing, north-central Portugal. Cuadernos de Investigación Geográfica Vol 41, No. 1 doi: http://dx.doi.org/10.18172/cig.2700
A.I. Machadoa, D. Serpaa, R.V. Ferreiraa, M.L. Rodríguez-Blancob, R. Pintoa, M.I. Nunesa, M.A. Cerqueiraa, J.J. Keizera(2015) Cation export by overland flow in a recently burnt forest area in north-central Portugal Science of the Total Environment Volumes 524–525, 15 August 2015, Pages 201–212 doi: 10.1016/j.scitotenv.2015.04.026
Ferreira R.V., Serpa D., Cerqueira M.A., Keizer J.J. (2016) Short-time phosphorus losses by overland flow in burnt pine and eucalypt plantations in north-central Portugal: A study at micro-plot scale. Published in: Science of the Total Environment 551–552, 631–639 https://dx.doi.org/10.1016/j.scitotenv.2016.02.036
Campos I., Abrantes N., Keizer J.J., Vale C., Pereira P. (2016) Major and trace elements in soils and ashes of eucalypt and pine forest plantations in Portugal following a wildfire. Published in:Science of the Total Environment 2016 Dec 1;572:1363-1376 https://dx.doi.org/10.1016/j.scitotenv.2016.01.190
Tavares Wahren F., Julich S., Nunes J.P., Gonzalez-Pelayo O., Hawtree D., Feger K.-H., Keizer J.J. (2016) Combining digital soil mapping and hydrological modeling in a data scarce watershed in north-central Portugal. Published in: GEODERMA 264, part B, 350- 362 http://dx.doi.org/10.1016/j.geoderma.2015.08.023
The creation of agricultural terraces on steep terrain can provide an effective solution to preventing soil erosion. The experiment involves testing the effectiveness of maintenance/rehabilitation of dry-stone terraces. It involves a participatory monitoring process.
|mitigating erosion by water on mountainous agriculture land||Cyprus experimental site|
- Soil moisture indicates runoff reduction and more infiltration
- Peaks more pronounced for the top layer
- Higher soil moisture behind standing terrace wall than behind collapsed
wall (SM1 vs SM5)
- Soil loss reduction of 80% in restored (standing) terraces compared to degraded terraces (open)
- Soil loss reduction of 98% in restored (standing) terraces compared to degraded terraces (closed)
- Soil loss of 3.6 t ha-1 y-1 in degraded terraces (from closed plot)
- Soil loss of 0.06 t ha-1 y-1 in standing terraces (from closed plot)
Christos Zoumides, Adriana Bruggeman, Elias Giannakis, Corrado Camera, Hakan Djuma, Marinos Eliades, Katerina Charalambous (2016) Community-Based Rehabilitation of Mountain Terraces in Cyprus. Published in Land Degradation & Development (2016) August 1 DOI: 10.1002/ldr.2586
Hakan Djuma, Adriana Bruggeman, Corrado Camera, Christos ZoumidesDjuma, H., Bruggeman, A., Camera, C. and Zoumides (2016) Combining qualitative and quantitative methods for soil erosion assessments: an application in a sloping mediterranean watershed, Cyprus