The document summarizes research on wind erosion in alpine meadows. Wind tunnel experiments showed that sediment and PM10 transport decreased with increasing plant density. Field investigations found lower sediment transport rates in areas with 15-20% vegetation cover compared to bare soil. Tests also revealed that mycorrhizal fungi help reduce wind erosion by increasing plant growth and soil aggregate stability, thereby improving vegetation establishment and wind erosion control over the long term.

1. Wind erosion in an alpine meadow compared to
wind tunnel experiments with live plants
Wind tunnel results:
• Set-up of experiments
• Sediment, PM10 transport
Field investigations:
• Wind erosion test field
• Sediment transport
Mycorrhiza:
• Fungal wind erosion control
• Sediment transport
Conclusions …
Frank Graf, WSL Institute for Snow and Avalanche Research SLF, CH-7260 Davos Dorf, Switzerland www.slf.ch

2. Wind tunnel experiments with live plants
wind velocity: ~ 13.8 ms-1
humidity: 48.0 %
temperature: 9.8 C
time period: ~ 30.0 min

3. Effects of plant density on sediment and PM10 transport
a) bare soil (reference)
0.30 a)
b) vegetated soil with 0.3
cover of 16%
0.25 field: cover of 15-20% 0.25
sediment transport [kg m s ]
2 1
PM10 concentration [mg m ]
3
0.20 0.2
0.15 0.15
b)
0.10 0.1
0.05 0.05
0.00 0
sediment PM10 sediment PM10
bare soil veg. cover = 16%
Burri et al. 2009, 2011

4. Alpine wind erosion test field (Latschüelfurgga, 2409 masl)

5. Sediment transport data of experiment no 15
soil with ~15% vegetation cover bare soil (without vegetation cover)
3.0
5
2.5
number of sand grains [log10n]
number of sand grains [log10n]
4
2.0
3
20
1.5
20
18
2
1.0
18
]
th [m
]
th [m
12
leng
12
1
leng
0.5
8 8
7 7
0.0
0
10 5 0 5 10 10 5 0 5 10
width [m] width [m]
period of: wind erosion risk investigation
wind velocity range: 6.2 - 9.8 0.3 - 15.8 ms-1
humidity range: 43.9 - 61.6 43.8 - 100.0 %
temperature range: 14.2 - 14.6 -1.1 - 14.8 C
time period: ~ 200.0 min 4.0 days

6. Comparison of erosion rates: wind tunnel vs. field
3.0
log10-scale
])
vegetated
bare soil
2.5
] of protection effect [
2.0
1.5
wind tunnel
field test
1.0
log10( ratio [
0.5
90 699 5 15
39 650 2 6
57 288 4 23
0.0 st nd st st nd st st nd st st nd st
1 mid 2 lane 1 row 1 mid 2 lane 1 row 1 mid 2 lane 1 row 1 mid 2 lane 1 row
ex.15 (spring) ex.21 (summer) ex.33 (fall) all ex. (15, 21, 33)

7. Wind erosion control by mycorrhizal fungi
0.001-0.1 mm
suspension clay, silt
“sand storm”
X
0.1-1 mm
saltation
“jumping” X (fine) sand
> 1 mm
"rolling,
creeping" X (coarse) sand

8. Effect of mycorrhiza on sediment transport

9. Effect of mycorrhiza on sediment transport
60
B)
Burri et al. 2011
50
soil loss through wind erosion [%]
10 20 300 40
myc non-myc myc non-myc
A. vulneraria ssp. alpestris L. perenne

10. Correlation between erosion rate and mycorrhization
70
60 Burri et al. 2011
50
erosion rate [%]
40
30
20
10 Anthyllis
Lolium
0
10 20 30 40 50
degree of mycorrhization [%]

11. Soil aggregate stability by mycorrhizal fungi...

12. Conclusions ...
• The positive effect of natural vegetation in DRR is still
underestimated and often neglected
• Plants and mycorrhizal fungi jointly reduce sediment
transport and are most effective in long-term
(wind) erosion control
• Adapted plant-fungi combinations improve
and accelerate the re-establishment of a
protective vegetation cover
 Mycorrhizal fungi increase:
• plant (root) growth
• soil aggregate stability
 water and nutrient retention capacity
 plant (root) growth
 (re-) establishment of protective vegetation
Thank you for your attention …