Similar names: Alley farming (Nalaad tribe, The Philippines), intercropping, farming with shading trees
Alley cropping is an agroforestry technique that involves planting crops between hedgerows of trees and shrubs. Tree-crop combinations are used to solve soil erosion problems by slowing water runoff and increasing its infiltration rate. Trees also provide very effective protection for crops against strong winds, can serve as wildlife habitat, and attract pollinators. Hedgerows can be tailored to the farmer’s needs and serve as crop facilitators or as a source of fodder, food, firewood, mulching material, or as an additional source of income.
This technique can be applied on a large scale, increasing the distance between the alleys and allowing for the use of big machinery, but can also be applied on a small scale, where a hedgerow surrounding the field or farm area may be all that is possible, instead of complete alleys.
NOTE: This method works particularly well in humid and semi-humid regions but should be well planned in dry areas, as hedgerows can compete with crops for soil moisture.
- Climate: Alley cropping is most successful in tropical or subtropical climates with warm temperatures and abundant rainfall. However, it can also be adapted to other climatic conditions, such as arid or semi-arid regions, but must be well planned in dry areas as hedgerows can compete with crops for soil moisture.
- Soil conditions: This intervention requires soils that are well-drained and not too compacted. Soils should be deep enough to accommodate the root systems of both crops and trees and/or shrubs, with a good balance of nutrients and organic matter. The ideal soil depth is at least 1.5 metres.
- Topography: The topography of the land can affect the effectiveness of alley cropping. Steep slopes or uneven terrain can make it more difficult to establish and maintain the system - flat or gently sloping land is generally more suitable.
- Farmer goals: The objectives of the farming system should be considered when implementing alley cropping. For example, if the goal is to increase soil fertility and reduce erosion, certain tree and crop species may be more appropriate than others.
- Tree availability: If no seed nursery available, establishing an alley cropping system can be expensive as seeds will need to be acquired and transported (depending on the species to be planted). The availability of good quality seeds, or access to a tree nursery, is important.
- Crop choice: Leguminous trees and other nitrogen fixing species should be planted to increase the amount of nitrogen fixed in the soil. Additionally, certain tree, shrub, and plant species release chemical substances that have negative impacts on other crops and plants which can inhibit growth. Careful consideration of hedgerow species should be made in relation to the planted crops to reduce chemical leaching.
- Land rights and ownership: If you are renting the land you are farming, make sure the owner agrees with the establishment of trees.
If you are not sure the above conditions apply to your land or would like additional help in growing trees in an agroforestry system such as alley cropping, get in contact an extension officer or NGO in your region.
- Choose the right location: Select a location with suitable soil, adequate sunlight, and access to water.
- Select appropriate species: Determining which species to plant in the hedgerows and which crops are compatible with these trees or shrubs. There are different possible combinations, but it is important to keep in mind the desired function of the hedgerows and the suitability of environmental conditions (see next section). Crops that grow well in shade, such as leafy greens or some root vegetables, are good choices. The most common crops grown tend to be maize, soybean, wheat, groundnut, coffee and cacao.
- Prepare the land: Clear the area where you want to plant your crops and trees. Make sure to remove any debris, rocks, or weeds that could interfere with growth.
- Plant the trees or shrubs: On flatlands to gentle slopes, hedgerows are usually put 2 to 6 m apart. On steeper slopes, the hedgerows should be about 2 m apart and placed along the contour of the land (at right angles to the slope). The distance between each tree should be 5 to 10 m apart to be able to capture eroded material. On such steep slopes it is possible to plant temporary stakes in the ground near the seedlings to form barriers that control soil erosion whilst waiting for the trees to grow.
- Plant the crops: Plant your chosen crops in the space between the rows of trees or shrubs. Be sure to leave enough space for the crops to grow and for you to walk through the rows.
- Maintain the crops and trees: Water, fertilize, and weed your crops and trees as necessary. Monitor their growth and health regularly to ensure they are thriving until harvesting.
Additional considerations for implementation:
- Weeding: in the initial stages of tree growth, weeding must be done to maintain the intervention and ensure continued healthy growth as the trees mature.
- Tree placement: Trees should be arranged perpendicular to the wind direction so as to reduce wind speed, thereby acting as windbreaks that reduced wind-induced soil erosion.
For a more detailed description of the method of application, please read this document.
The Homaray Project, Madagascar
The Inga Foundation has been working in Madagascar with two local Malagasy men to develop and implement sustainable farming techniques and introduce the alley cropping method to other local farmers. The Inga foundation specializes in using Inga trees in alley cropping systems, however, as this tree is not native to Madagascar, more suitable species are being researched for this project. Working with the Ministry of Forestry and Kew Gardens, the Inga Foundation and local farmers compiled a list of suitable native tree species for this area. Currently, three different species are being trialled over 3.5 ha of land in alley cropping systems. You can follow updates on the Homaray Project through the Inga Foundation's website.
The Chaillu Massif, Congo
Another project run by the Inga Foundation, this time located in the Congo Basin, aims to introduction an alley cropping-based system. This project involved identifying suitable native tree species which can be used instead of Inga trees. The Inga Foundation aims to identify a suitable species which can then be used in future projects across Central Africa. Currently, 9 candidate species have been identified and tree nurseries are being constructed in order to establish a strong supply of seedlings for trialling these different candidate species in alley cropping systems. The first candidate species have been planted, and trials have begun to found the most suitable species for the future of the project. You can follow the progress of this project via the Inga Foundation.
- The US Department of Agriculture (USDA) have a database of webinars that are free to use. These webinars provide trainings and insights into different agroforestry practices, including alley cropping. You can access the Agroforestry Webinar Library here.
Resources used for this intervention:
- Aihou, K., Sanginga, N., Vanlauwe, B., Lyasse, O. & Merckx, R. (1998). Alley cropping in the moist savanna of West-Africa: Restoration and maintenance of soil fertility on 'terre de barre' soils in Bénin Republic. Agroforestry Systems 42, pp. 213-227. Springer.
- Radbourne, A. (2019). Alley cropping - Agroforestry [France]. WOCAT.
- Spence, B. & Semple, H. (1999). The Hedgerow/Alley Cropping System of Vegetative Soil Conservation: A Strategy for Sustainable Soil Conservation on Hillside Farms in Jamaica. 10th Annual Meeting of the Caribbean Academy of Science.
- Tripathi, B. R. & Psychas, P. J. (1992). The AFNETA alley farming training manual. Volume 1: Core course in alley farming. IITA, ILCA & ICRAF.
- USDA (n.d.). Alley Cropping. USDA Forest Service.
- USDA (2017). Can alley cropping support soil health? USDA.
- Xu, H., Bi, H., Gao, L & Yen, L. (2019). Alley Cropping Increases Land Use Efficiency and Economic Profitability Across the Combination Cultivation Period. Agronomy 9 (1). MDPI.