• This intervention requires seeds, so a nearby seed bank is opportune.
• Pest management: it is important to understand which pests affect what species to not place those species in a close rotational succession. 
• Water management: if not planned correctly, fallow species can cause competition for water and nutrients with the fast-growing traditional crop.
• Although some fallow species are very good at keeping away pests, they can sometimes attract pests that affect particular types of crops (e.g. root-knot nematodes in the Sesbania sesban and beans plants), therefore, it is recommended not to plant beans in the first season after these fallows.

Steps of implementation

1. Fallow plants are usually planted halfway through the dry season, especially when using species with deep roots. They should be left to grow in the soil for a prolonged period (ideally from 6 to 12 months depending on the species used). 
2. A traditional fast-growing crop is then planted during the wet season in between the fallow species to provide the traditional crop with partial shade and to keep the soil fresh. 
3. Once too big, fallow plants are trimmed or cut and used as mulch or green manure to replenish the soil. Sometimes, the fallow species produce high amounts of biomass which can be used as firewood (when trees are used) and fodder, or sold on the market (when beans and fruit trees have been planted). Trees used in an improved fallow intervention can be planted via direct seeding or by transplanting seedlings.

More information about the establishment of an improved fallow can be found here.

Considerations for application

If fallow species are not an option, it is still important to highlight the benefits of a rotational crop system instead of planting the same crop each year in the same place as a monoculture. Alternating crops such as maize or wheat with leguminous species such as beans (nitrogen-fixing species with long roots) will benefit the soil in terms of water retention and nutrients.

This intervention contributes to:

Estimation of costs & benefits of intervention

Source: based on a case study in Western Kenya, 1991

1. Mixed Improved Fallows to Keep Jumbos Away in Segalla Hills, Kenya

Description
In Kenya, farmers in Sagalla, near Tsavo East National Park, face annual challenges from drought and elephant invasions that damage crops and lead to food insecurity. To address this, the Integrated Livelihood Drought Preparedness Project (ILDPP), launched in 2019 by the National Drought Management Authority (NDMA) with support from the European Union (EU) and Save the Elephant (STE), promotes the cultivation of drought-tolerant crops that elephants avoid, such as sunflowers, Africa Bird’s Eye Chili, Moringa, and Custard Apple trees. Sunflowers have proven particularly effective as elephants avoid them, and they also support beekeeping, providing an alternative income for farmers. Approximately 131 farmers have adopted sunflower farming, covering over 300 acres, and the project plans to include oil press machines for value addition, creating sunflower oil and nutritious poultry feed from the byproducts. However, farmers face challenges such as lack of funds for seeds and irrigation systems, and inadequate rainfall affects sunflower germination and oil content, hindering commercial success. Despite these challenges, there are plans to extend the project to other regions like Mgeno and Kishushe, which also experience significant human-wildlife conflicts, offering a sustainable solution by leveraging crops that deter elephants while providing additional economic benefits through related activities like beekeeping and poultry farming.

2. Ngitili system for improved fallows in Shinyanga, Tanzania 

Description

In the traditional Tanzanian following system, certain individual and communally-owned lands are excluded from grazing during the wet season, assuring regeneration and making forage available during the dry season. In recent decades, deforestation, bush clearing, and chronic overgrazing have degraded the original woodland ecosystem, negatively impacting human welfare. Through the efforts of the Shinyanga Soil Conservation Programme (HASHI), the ngitili system was reinstated on more than 350,000 hectares of degraded woodlands to jumpstart an ecosystem restoration process while also meeting the subsistence needs of locals. Now, the region provides a wide range of woodland services enhancing livelihoods and creating a vital safety net during dry seasons and droughts. The total monthly value of benefits from restoring this ngitili is estimated at USD14 per person, considerably more than the national average consumption level of USD 8.50 in rural areas.

External Sources

• Visit this database as an indication of which species to use in improved fallows in tropical landscapes, and click here to have a description and characteristics of each suitable species and their English common name.
• For a better indication of species and sowing times (specifically for Kenya), and income see this article. 

Guides

• If you aim at using tree species in your improved fallows intervention, here is a good step-by-step guide to planting nitrogen-fixing trees.