Long-term effectiveness of Sustainable Land Management practices to control runoff, soil erosion and nutrient loss in Mediterranean rainfed agroecosystems
Semelhante a Long-term effectiveness of Sustainable Land Management practices to control runoff, soil erosion and nutrient loss in Mediterranean rainfed agroecosystems
Semelhante a Long-term effectiveness of Sustainable Land Management practices to control runoff, soil erosion and nutrient loss in Mediterranean rainfed agroecosystems (20)
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Long-term effectiveness of Sustainable Land Management practices to control runoff, soil erosion and nutrient loss in Mediterranean rainfed agroecosystems
2. Long-term effectiveness of Sustainable Land
Management practices to control runoff, soil erosion
and nutrient loss in Mediterranean rainfed
agroecosystems
Martínez-Mena, M1., Carrillo-López, E1., Boix-Fayos, C1., Almagro, M2.,
García Franco, N3., Díaz Pereira, E1., Castillo, V1., de Vente, J1
1Soil erosion and conservation research Group CEBAS-CSIC
2Basque Centre for Climate Research BC3
3Technical University of Munich
2
3. • Soil erosion is recognized as a major threat to soil
functions in the Mediterranean region
• Soil erosion results in the loss of soil nutrients and
organic matter decreasing the productivity of soil and its
capacity to sustain life: that is particularly worrying for
rainfed crops
• Things can get worse
3
Scarce and torrential rainfall
Rugged relief
Shallow and poor soils
Long lasting human
interventions
Eekhout et al. https://doi.org/10.5194/hess-22-5935-2018
Introduction: The problem
4. 4
• Sustainable land use and management (SLM)
has the potential to reduce soil, organic carbon
and nutrient losses by erosion but…
• Response depend on local socio-environmental
conditions
• Poorly adopted
• Competition of spontaneous plant for water and
nutrient
• Not immediate positive effects on yield
• Lack of (socio-economic)incentives
Objectives:
• How effective are SLM in reducing runoff soil
erosion and associated losses in two Mediterranean
rain fed crops
• Is the efficiency depending on rainfall
characteristics?
Introduction: The solutions ?
5. • Duplicate the slide as needed
5
MethodsStudy areas
2009: Sustainable management practices implementation
Six years (2010-2015): Erosion monitorization and OC and
nutrients mobilization.
6. Reduced tillage (RT)
chisel ploughing (2 times yr-1)
15 cm depth
Implemented management practices in almond
Conventional tillage (CT)
chisel ploughing (4-5 times yr-1)
20 cm depth
Reduced tillage+green manure (RTG)
chisel ploughing (2 times yr-1) at 20 cm depth
Avena sativa & Vicia sativa 1:3 at 150 kg ha-1
Reduced tillage (RT)
chisel ploughing (2 times yr-1)
20 cm depth
7. Implemented management practices in Cereal
Conventional mouldboard
tillage after harvest 40 cm
3 times (chisel plough )
during fallow (20 cm)
Reduced contour
tillage
Labours/year : 2
Depth: 20 cm
8. Almond
orchard
Cereal
Lithology Limestones Marls
Clay (%) 17.76±3.7 30.65±3.9
Silt (%) 48.9±11.5 59.6±2.8
Sand (%) 33.2±14.8 9.6±5.9
OC (g/kg) 20.1 7.4
T N (g/Kg) 2.12 0.7
Polsen (ppm) 47 6.1
K (ppm) 815,18 126
CaCO3 (%) 44±9.2 56±10.1
pH 8.8±0.14 9.14±0.17
CE (S/cm) 90.8±14.7 73.3±5.9
Study areas: general characteristics
9. Experimental design: Open Erosion plots
Study period (2010-2015)
Slope: 10-15%
Three replicates per treatment: 15 plots (9 almond;6 cereal).
Drainage are: 25-126 m2 (almond) ; 44-265 m2 (cereal)
14. Results: effect of soil quality.
0
1
2
3
4
5
6
7
8
EROC ERN ERP
CT RT
Almond Orchard
OC (%) NT (%) P (ppm)
CT
1,94±0.13b 0.14±0.02b 40,19±4.58a
RT
2.38±0.10a 0.19±0.02a 53,20±6.76a
RTG
2.56±0.14a 0.23±0.01a 30,64±2.32a
OC (%) NT (%) P (ppm)
CT 0.59±0.03b 0.07±0.02a 3.46±0.16b
RT 0,85±0.04a 0.08±0.007a 5.0±0.31a
Cereal
Soil OC and nutrients
0
0.5
1
1.5
2
2.5
3
EROC ERN ERP
CT RT RTG
b
b
a
Enrichment ratios
15. 15
Results: Effectiveness and rainfall characteristics.
Season
Spring Summer Autumn Winter Total
Numberofeventsineacherosivityclass(%)
0
20
40
60
80
100
Class I
Class II
Class III
Effectiveness of RTG
Effectiveness of reduced tillage
Almond crops
Cereals
Almond crops
Runoff
Erosion
16. The SLM practices evaluated resulted in reduced runoff, erosion, and
mobilization of organic carbon and nutrients in sediments and subsequently
increased organic carbon (OC) and nutrients (N and P) contents in the soil.
Main remarks
Our results support the key role of SLM practices under semiarid conditions as
useful tools for climate change mitigation and adaptation, given the expected
increase in high-intensity rainfall events in semiarid areas
Highest (soil erosion and nutrient exportation) during the most intense rainfall
events, which are responsible for the highest erosion rates in Mediterranean
areas.
Short-term effect (18 months) of the evaluated SLM practices on erosion
control, making their implementation especially attractive for farmers.
• How effective are SLM in reducing runoff soil erosion and associated
losses in two Mediterranean rain fed crops
• Is the efficiency depending on rainfall characteristics?
17. Thank you for listening
http://www.soilwaterconservation.es/
This study site has been funded by several national (CYCIT AGL201125069//CGL2014-55-405-R), Regional projects
(Séneca Foundation: 08757/PI/08//19350/PI/14] and European projects (F6 DG RTD 037046 and DIVERFARMING
H2020 RUR-06-2016 728003).
UNCCD provided a grant for Victor M. Castillo to attend the Global Symposium on Soil Erosion
Notas do Editor
Scenarios of climate change predict for Segura basin in SE Spain decreasing annual average precipitation while increasing of heavy rainfall events
Almond crops is expanding because of subsidies but also increase value at market and development of late varieties. It is typically cultivated in tree rows spaced with bare soil between them.
Cereals is quite residual crop but still occupying significant area. Rotational system with long period of fallow
La cubierta verde se siembra en otoño y se siega en mayo/junio dependiendo de las precipitaciones y se incorpora al suelo: vicia sativa and barleyThe tested SLM practices were selected as result of a participatory exercise with relevant stakeholders
Muy brevemente las prácticas aplicadas consisten en:
Cereales sometidos a un sistema de rotación de barbecho (siembra en otoño y cosecha en junio) seguido por un periodo de descanso de un año donde los residuos de la cosecha se dejan en el campo a lo largo del otoño y el invierno. Laboreo en paralelo a las líneas de contorno.
El cereal: laboreo reducido (consistente en 2 labores al año a 20 cm depth) frente al laboreo tradicional con labores 4/5 veces al año y una vez vertedera con volteo del suelo en los primeros 40 cm.
The wheat field under CT was plowed with a moldboard plow to 40 cm depth following harvest in June, leaving the land fallow for one year. During the fallow period, the land was plowed three more times with a chisel plow before the seeding in the next autumn. Under RT, the wheat field was not plowed after harvest, leaving the stubble during the fallow year, until the next autumn, when the land was prepared for seeding with a chisel plow (0.20 m).
Ambas zonas tienen características litológicas contrastadas, texturas franco limosas pero con diferencias en los contenidos de arcilla y arena. Bajos contenidos de materia orgánica y alto contenido de carbonatos…
Aquí presentamos el diseño de las parcelas que se utilizan para cuantificar tasas de erosión y movilización de nutrientes por dicho proceso. Son parcelas abiertas de tipo caja gerlach donde se recoge el material más grueso las cuales están conectadas a un depósito que a su vez se conecta con un segundo.
La recogida de sedimento se realiza tras cada evento. La superficie de drenaje de las distintas parcelas oscila entre 82-54-27 en los almendros y 140 m2 en el cereal.
Variabilidad interanual
Descenso de P gradual del 2010 al 2014 y reducción en un 35% respecto de un periodo de 30 años (1940-2007).
Lluvias que generan escorrentía y erosión fluctuando entre un 39 y un 85% de la precipitación total anual (ligado con la intensidad). Años más secos producen menos eventos erosivos pero más fuertes
Total de 33 eventos en 6 años. Años más secos (2013 y 2014) tuvieron mayores intensidades y precipitaciones.
42% de los eventos que generaron erosion pertenecen a la clase 1 de erosividad; mientras que el 29% pertenecen a las clases 2 y 3.
Umbrales bajos de precipitación e intensidad generadores de erosión en las dos zonas de estudio y prácticamente todos los eventos que generan escorrentía movilizan sedimento (100% en cereal y entre 66 y 88% en el almendro)
Effect of reducing the number tillage operations on runoff was observed for both crops. But impact was greater in almond than in cereal ( not significant for this crop, maybe because of large (intrinsic) variability of runoff response along the measured events )
Impacts of SLM practices were greater on soil erosion. Cereal showed highest avaerage soil los rates due to managemnet practices ( long fallow period: bare , unprotected soil)
In terms of total soil losses a positive effect of implementing SLM can be observed in both crops. This positive effect was observed at soon as 1 and half year after the implementation of the practices and the effects are increasing as time goes by. By the end of the period of study, conventional tillage erodes four fold soil than reduced tillage in cereal and 2 and half ties the soil eroded by reduced tillage in almonds
We also observe that four events are responsible for mobilization of around 55-70% de total eroded soil.
Six years after its implementation, RT had increased the SOC, relative to that in CT, in both crops. However, increments in the soil N content due to RT were only observed in the almond field, while the soil P concentration was increased in RT, compared to CT, only in the wheat field (Table 1).
En cuanto al OC movilizado es interesante recalcar que a pesar de que las prácticas sostenibles revirtieron tambien en una mejora de OC y nutrientes en el suelo estos no se vieron reflejados enel sedimento como podemos ver por las razones de enriquecimiento….Así, concentraciones de OC mayores en el suelo conllevan menores enriquecimientos. Esto es así claramente para el almendro, mientras en el cereal simplemente no existen diferencias entre tratamientos…
Even at seemingly low rates, eroded sediments are rich in OM and nutrients (Marques et al., 2008). The loss is, therefore, qualitatively important and may have a considerable impact on almond
sustainability (Quiquerez et al., 2008).
This selective transport by erosion is highlighted by our estimates of the enrichment ratios of nutrients in the sediments.
These findings are similar to those of other authors and may be attributed to the greater amount of clay occurring in the sediment than in the soil where the nutrients originated (Xingchang et al., 2004). They are more easily transported by erosion, especially by interrill erosion (Schiettecatte et al., 2008), which is the erosion type that the system of plots used in this study is capable of measuring.
The events were classified in three classes according to their RE values (KE*I30): Class I: RE≤ 25, Class II: 25< RE ≤ 90, and Class III: RE >90, representing low, medium, and high erosive events, respectively, according to the rainfall characteristics of this area (Martinez-Mena et al., 2001).
In the wheat field the greatest reduction in runoff (50%) was found for the least erosive rainfall events (class I), while the reduction in erosion was not dependent on the rainfall erosivity. By contrast, in the almond field the greatest reduction in runoff and erosion was found for the most erosive events (classes II and III) (Figure 6).
The correlations between erosion and rainfall erosivity were stronger in conventional tillage than in reduced tillage. For RTG in the almond field there was no significant correlation between the rainfall intensity and erosion rates
With the RTG management, where the average reduction in erosion for the less erosive events (class I) was about 40%, the reduction in class III was almost double (70%)