1) The document describes a study evaluating sustainable land management techniques at a farm in semi-arid southeast Spain, including green manure, reduced tillage, water harvesting systems, mulching, and reduced tillage for cereals. 2) Preliminary results show that water harvesting increases soil water content and almond yields, while green manure also increases almond yields and reduces soil and water loss compared to conventional practices. 3) Final conclusions on the effects of these techniques on sediment yields are uncertain due to challenges calculating runoff contribution areas from laser scan data. Mulching also did not clearly improve outcomes so far.

1. Sustainable land management
measures in semiarid SE Spain:
the Alagüeces farm (Murcia)
Albert Solé-Benet1
, Joris de Vente1
, Ashraf Afana1
,
Jorge López1
, Carolina Boix-Fayos2
1
EEZA-CSIC (Almería) 2
CEBAS-CSIC (Murcia)

2. Los Alagüeces
Zarzadilla de Totana
Lorca
Murcia
Spain
Land uses: rangeland,
dryland cereals,
almonds

3. Desertification indicators in the area:
- Soil erosion (rills, gullies)
- Water scarcity, droughts

4. - SLM 1: Green manure
Autumn 2008
Spring 2009)
SLM technologies under test

5. - SLM 2: reduced tillage in almonds
Reduced tillage = disks + cultivator (2 operations per year)
Conventional tillage = disks + cultivator (3 - 5 operations)

6. - SLM 3: boquera
= diversion from main channel
(water harvesting system)

7. - SLM 4: mulch
Mulch used: cereal straw

8. - SLM 5: reduced tillage in cereals
Mouldboard ploughing

9. Field A (almonds without terraces)
3 subplots, 3 replicates:
- green manure (AL1-AL2-AL3),
- rreduced tillage (AL4-AL5-AL6),
- control (AL7-AL8-AL9).
Implementation plan
Variables monitored:
- runoff
- sediment yield
- almond yield
- organic carbon sequestration.

10. Implementation plan
- Gerlach troughs for runoff and sediment
yield monitoring in field A and B

11. Field B (almonds in terraces):
- water harvesting (boquera)
- mulch.
- control.
Variables monitored:
- water height from boquera (capacitive
sensor) runoff rates
− θ at 30-35 cm continuously (4 probes /
SLM technique & control)
- θ manually after events at 0-20 cm
- almond yield.
Implementation plan

12. Field C (cereals in 2 subplots, 3 replicates):
- control (conventional tillage): CE1-CE2-CE3
- reduced tillage: CE4-CE5-CE6.
Variables monitored:
- runoff
- sediment yield
- cereal yield.
Implementation plan

13. © Joris de Vente
Implementation plan
- Meteorological station
Variables measured:
P, T & humidity air, wind
direction & velocity

14. - Sediment data: we need to know the contribution area to every Gerlach trough
© Joris de Vente
Preliminary results
Drainage accumulation flow at 5 cm
resolution generated by the D8 method using
IDRISI
3D representation of field site A. DEM
generated by ANUDEM at 5 cm resolution.
Original data from terrestrial laser scanner
Leica ScanStation 2

15. - First sediment data
© Joris de Vente
Preliminary results
Sediment yield in 1 year in site C
(cereals)
0
1
2
3
4
5
6
control reduced tillage
sedimentyield(kg)
Sediment yield in 1 year in site A
(almonds)
0
5
10
15
20
25
green manure reduced
tillage
control
sedimentyield(g/m²)

16. Field B - average soil water content in 3 SLM systems
0
5
10
15
20
25
30
35
40
45
18-11-08
18-12-08
17-01-09
16-02-09
18-03-09
17-04-09
17-05-09
16-06-09
16-07-09
15-08-09
14-09-09
14-10-09
13-11-09
13-12-09
12-01-10
11-02-10
13-03-10
12-04-10
12-05-10
11-06-10
11-07-10
10-08-10
09-09-10
Soilwatercontent(%vol)
Control
Water harvesting
Mulch
0
5
10
15
20
25
30
35
40
45
18-11-08
18-12-08
17-01-09
16-02-09
18-03-09
17-04-09
17-05-09
16-06-09
16-07-09
15-08-09
14-09-09
14-10-09
13-11-09
13-12-09
12-01-10
11-02-10
13-03-10
12-04-10
12-05-10
11-06-10
11-07-10
10-08-10
09-09-10
Soilwatercontent(%vol)
Control
Water harvesting
Mulch
Field B - maximum soil water content values in 3 SLM systems
- Soil moisture
Preliminary results

17. Preliminary results
- Almond yields
Almonds yield in site A
-1
1
3
5
7
9
11
13
15
Green manure Reduced tillage Control
annualyield(kg/tree)
Almonds yield in site B
-1
1
3
5
7
9
11
13
15
Boquera Mulch Control
annualyield(kg/tree)

18. Preliminary results
Magnitude and intensity during runoff events
0
10
20
30
40
50
60
70
80
90
100
21/09/09
30/09/09
16/12/09
12/01/10
02/02/10
24/02/10
21/04/10
04/06/10
18/06/10
25/08/10
P(mm)&Intensity(mm(h)
P P intensity
- weather
Daily Precipitatipon and Average Daily Temperature
'Los Alhagüeces'
0
5
10
15
20
25
30
22/08/2008
05/09/2008
19/09/2008
03/10/2008
17/10/2008
31/10/2008
14/11/2008
28/11/2008
12/12/2008
26/12/2008
09/01/2009
23/01/2009
06/02/2009
20/02/2009
06/03/2009
20/03/2009
03/04/2009
17/04/2009
01/05/2009
15/05/2009
29/05/2009
12/06/2009
26/06/2009
10/07/2009
24/07/2009
07/08/2009
21/08/2009
Precipitation(mm)
0
5
10
15
20
25
30
35
Temperature(ºC)

19. Conclusions (to be considered with caution)
- Water harvesting increases soil water content and consequently
almond yield.
- Clear results on sediment yield depend essentially on contribution
areas which calculations are not straightforward from laser scanner
data. Consequently final results on sediment yield might change with
regards preliminary ones.
- Mulch has not produced positive results so far. Possible causes:
technology not properly implemented and/or mulch type (cereal
straw). Is this mulching type affecting infiltration negatively causing
lower soil water content?
- Green manure has had a positive influence in almond yield with
regard reduced and conventional tillage and seem to reduce soil and
water loss.
- Results from field C (cereals) are still under process.