Practicing Agroforestry
1. Presentation
Characterization of the technique
Description of the technique:
| Julien Halska | INRA | julien.halska(at)grignon.inra.fr | Dijon (21) |
|---|---|---|---|
Agroforestry consists of growing trees and crops in rotation on the same plots. Trees are generally planted in rows with spacing depending on the working width of tools and optimizing competition between trees and crops. The goal is to limit competition between the two crops and maximize facilitation, i.e., the increase of resources to share (water, nutrients). The association of crops in winter with trees developing in summer reduces competition, especially for light.
Details on the technique:
The case of leasing is specific; arrangements between tenant and owner are possible (compensation for tree maintenance by the owner, possible acceptance of the tenant's will to plant trees, etc.).
Implementation period On established crop
In general, and depending on the growth rate of trees, the time scale of this technique corresponds to several crop rotations.
Spatial scale of implementation Plot
Application of the technique to...
All crops: Sometimes difficult to generalize
All soil types: Easily generalizable
Species choice must be adapted to the pedo-climatic context.
All climatic contexts: Easily generalizable
Species choice must be adapted to the pedo-climatic context.
Regulation
POSITIVE influence
Since 2006, the CAP recognizes agroforestry. Any plot with a tree density below 50/ha is eligible for all aids on the entire surface (DPU). The European rural development plan and the plant-environment plan provide planting aids. Specific aids may be granted by local authorities.
Common Agricultural Policy, numerous texts (rural law, etc.) notably article 44 of the European rural development plan
Plant-Environment Plan
2. Services provided by the technique
3. Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality: Increasing
Phytosanitary emissions: DECREASE
GHG emissions: DECREASE
Effect on water quality: Increasing
N.P.: DECREASE
Pesticides: DECREASE
Other: No effect (neutral)
Auxiliaries being favored, a reduction in pesticide use can be expected. Pollutant transfers are limited by reduced leaching and assimilation by trees of part of the nitrogen and phosphorus that escaped the crop. Trees also limit drift by their windbreak effect and increase the size of phytosanitary intervention windows.
GHG emissions are limited especially because trees store carbon in their wood and in the organic matter of the soil. One can also account for the reduction of deforestation in tropical areas linked to local production of quality wood, which strengthens this positive aspect of agroforestry.
Flood risks : link=|alt=green face size 10
There is a slowing of water progression, soil retention by tree roots and by earth berms and/or grass strips located at planting lines.
"Agronomic" criteria
Productivity: Increasing
Here, yield means the sum of productions of successive crops and trees. Agroforestry plots are generally more productive than plots of the same species separated. Indeed, the surface needed when separating trees and crops to obtain the same production as one agroforestry hectare varies between 1.2 and 1.6 hectares. The yield of intercropped crops may decrease slightly, depending on the distance between tree rows and their development.
Production quality: No effect (neutral)
Soil fertility: Increasing
Via the supply of organic matter from leaves and annual tree roots. Via mechanical action of roots, and low mineral exports. Mycorrhizae developing at tree roots can also benefit crops. Finally, trees access nutrients from the decomposition of bedrock not directly accessible to crops but accessible through litter decomposition. These effects depend on tree species and are visible long term (no short-term fertilizer savings).
Water stress: Decreasing
Presence of trees reduces wind speed, thus crop transpiration. Water infiltration is also better and storage capacity increased medium term via organic matter accumulation. Water stress risk is thus reduced in agroforestry.
Functional Biodiversity: Increasing
Trees and the cover at their base shelter many plant and animal species that find refuge and food there.
Other agronomic criteria: Decreasing
Risks linked to climatic hazards: link=|alt=green face size 10
Spatial and temporal distribution of crops provides some security against climatic hazards.
Mulch production: link=|alt=green face size 10
Pruning residues can be chipped and used as mulch.
"Economic" criteria
Operational costs: No knowledge on impact
Costs allocated to crops decrease as their surface decreases. New costs linked to tree maintenance appear.
Mechanization costs: No knowledge on impact
Costs allocated to crops decrease as their surface decreases. Mechanization costs for trees relate to soil preparation for planting, row maintenance, and harvesting.
Margin: Increasing
Profitability depends on wood and crop prices. According to INRA simulations, agroforestry is always more profitable than reforestation of agricultural land (plus 20 to 30%). However, the choice between agroforestry and sole crops depends on prices. Trees also constitute a form of savings. Gross margin of intercrops varies from 65 to 90% of pure crops, depending on tree row spacing and development.
Other economic criteria: Variable
Risks linked to economic hazards: link=|alt=green face size 10
Spatial and temporal distribution of crops provides some security against economic hazards (price fluctuations).
Necessary investment:
An initial investment is necessary since trees are not valorized at the end of the annual campaign. Aids exist for this and investment can be spread over time.
"Social" criteria
Working time: No knowledge on impact
This time depends on the sum of work on the (reduced) surface of intercropped crops and maintenance of the row at the base of trees.
Managing agroforestry trees does not require much additional work (annual pruning during the first 10 to 15 years, i.e., 1/3 of tree life). This work is estimated at 1/2 day per hectare during the first 5 years then one day during the next 5 to 10 years (for 50 trees per hectare).
4. Organisms favored or disfavored
Favored Bioagressors
| Organism | Impact of the technique | Type | Details |
|---|
Disfavored Bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| pest, predator or parasite | pest, predator or parasite | Concerns all bioagressors targeted by one or more auxiliaries favored by agroforestry. |
Favored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Disfavored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Favored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
Disfavored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
5. To learn more
- Agroforestry or how to associate trees and crops on the same plot for more benefits!
- -Agroperspectives, Technical brochure, 2011
- The words of agronomy
- -Torquebiau E.
Website, 2012
6. Keywords
Bioagressor control method:
Mode of action: Action on initial stock
Type of strategy regarding pesticide use: Redesign
Annexes
S'applique aux cultures suivantes
Défavorise les bioagresseurs suivants
