Remediation of subsoil compaction by subsoiling and deep rooting crops

1. REMEDIATION OF SUBSOIL COMPACTION BY
SUBSOILING AND DEEP ROOTING CROPS
Adriaan Vanderhasselt, Tommy D’Hose, Wim Cornelis 26/11/2021
DEPARTMENT OF ENVIRONMENT
SOIL PHYSICS RESEARCH GROUP

2. SOIL COMPACTION
2

3. SUBSOIL COMPACTION
3
Topsoil
Subsoil
Plough pan
̶ Tyre-soil surface area
̶ Wheel load
Persistent effects
Tillage operations
+ natural remediation processes
Terranimo®

4. PROBLEM SITUATION
̶ Melle
̶ Sandy loam (Lcp)
̶ Plough pan (30-45 cm)
=> Barrier to:
- Root growth
4
75 cm
Penetration resistance (MPa)
0 1 2 3 4 5 6 7 8
Depth
(cm) -80
-70
-60
-50
-40
-30
-20
-10
0
Root density maize (# roots/cm2
)
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2
Depth
(cm) -80
-70
-60
-50
-40
-30
-20
-10
0
Rotation 1 - Control
Maize can grow 1.0-1.7 m into the soil,
if not restricted
Topsoil
Subsoil
Plough pan

5. EXPERIMENT
̶ Mechanical remediation – Subsoiling
̶ Biological remediation – Fodder radish & Alfalfa
̶ 3 maize-based cropping systems
5
↓↓ ↓↓ ↓↓
↓↓ ↓↓ ↓↓
↓↓ ↓↓ ↓↓
60m
1
2
3
15m
ROT1 ROT2 ROT3
Year 0 Year 1 Year 2 Year 3 Year 4
2019 2020 2021 2022 2023
ROT1 Maize ↓↓ Maize Maize Maize Maize WB: Winter barley
ROT2 Maize WW + fr ↓↓ Maize WB Maize WW: Winter wheat
ROT3 Maize WW ↓↓ Alfalfa Alfalfa Maize fr: fodder radish
↓↓: Subsoiling

6. ROTATION 1
6

7. ROTATION 1 - SUBSOILING
̶ Monoculture maize
̶ 29/10/2019
̶ 7 tines
̶ 50 cm depth
7

8. Rotation 1 - Subsoiling
6/11/2019
8 days after subsoiling
Lateral distance (cm)
0 10 20 30 40 50 60 70
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
(MPa)
0
1
2
3
4
5
6
7
ROTATION 1 – PENETRATION RESISTANCE
8
Rotation 1 - Control
29/10/2019
0 days before subsoiling
Lateral distance (cm)
0 10 20 30 40 50 60
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
(MPa)
0
1
2
3
4
5
6
7
Rotation 1 - Subsoiling
16/04/2020
170 days after subsoiling
Lateral distance (cm)
0 20 40 60 80 100 120
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
(MPa)
0
1
2
3
4
5
6
7
Wheel pass
Plough pan

9. ROTATION 1 – ROOT GROWTH MAIZE
9
Root density maize (# roots/cm2
)
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
Rotation 1 - Control
Rotation 1 - Subsoiling
=> Increased access to water and nutrients
Profile wall method

10. Control Subsoiling
Maize
yield
-
DM
(kg/ha)
0
5000
10000
15000
20000
25000
30000
ROTATION 1 – CROP YIELD 2020
10
+10%
a
b

11. ROTATION 1 – RECOMPACTION
11
Difference in Penetration resistance (MPa)
-7 -6 -5 -4 -3 -2 -1 0 1
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
Days after subsoiling
8
170
525
Recompaction
After: 2 x ploughing
2 x manure application
2 x sowing
1 x maize harvest

12. Control Subsoiling
Maize
yield
-
DM
(kg/ha)
0
5000
10000
15000
20000
25000
30000
ROTATION 1 – CROP YIELD 2021
12
+1%
a a

13. ROTATION 2
13

14. ROTATION 2 – SUBSOILING + COVER CROP
̶ Maize-winter cereal rotation
̶ 31/08/2020
̶ 4 tines
̶ 50 cm depth
̶ Followed by:
‒ Fodder radish
14

15. ROTATION 2 – PENETRATION RESISTANCE
15
Lateral distance (cm)
0 20 40 60 80 100 120 140 160
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
(MPa)
0
1
2
3
4
5
6
7
Rotation 1 - Subsoiling
6/11/2019
8 days after subsoiling
Lateral distance (cm)
0 10 20 30 40 50 60 70
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
(MPa)
0
1
2
3
4
5
6
7
Rotation 2 Rotation 1
90 cm 45 cm

16. ROTATION 2 – ROOT GROWTH FODDER RADISH
16
Root density fodder radish (# roots/cm2
)
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
Rotation 2 - Control
Rotation 2 - Subsoiling
0,0 0,4 0,8 1,2 1,5 1,9
Root density fodder radish (# roots/cm2
)
Lateral distance (cm)
10 20 30 40 50 60 70 75
10
20
30
40
50
60
70
75
Depth
(cm)
Tine subsoiler

17. ROTATION 2 – RECOMPACTION
17
Difference in Penetration resistance (MPa)
-7 -6 -5 -4 -3 -2 -1 0 1
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
Days after subsoiling
3
186
438
Difference in Penetration resistance (MPa)
-7 -6 -5 -4 -3 -2 -1 0 1
Depth
(cm)
-80
-70
-60
-50
-40
-30
-20
-10
0
Days after subsoiling
8
170
525
Rotation 2 Rotation 1
Recompaction
After: 2 x ploughing
2 x manure application
3 x sowing
1 x maize harvest
After: 2 x ploughing
2 x manure application
2 x sowing
1 x maize harvest

18. Control Subsoiling
Maize
yield
-
DM
(kg/ha)
0
5000
10000
15000
20000
25000
30000
ROTATION 2 – CROP YIELD (2021)
18
+1%
a a

19. CONCLUSIONS
̶ Short-term positive effects of subsoiling,
especially in dry year (2020)
̶ Recompaction after one year
̶ Potential for deep rooting crops (fodder radish) to bind loosened
structure after subsoiling, protecting subsoil from recompaction
19

20. Adriaan Vanderhasselt
PhD student
DEPARTMENT OF ENVIRONMENT
E Adriaan.Vanderhasselt@ugent.be
www.ugent.be