Using microcatchment irrigation

Constructing low-cost microcatchments for planting area that can be designed to harvest limited rainfall and store water in the ground right where the plants are growing. Microcatchments provide small seedlings with shelter from sun, heat, and desiccating winds. The technique is especially useful on sloping lands, where rapid run-off and erosion make plant establishment very challenging. Such systems can rapidly revegetate parched lands without large earthworks or irrigation systems.

In nature, new vegetation often first takes hold in pits, cracks, crevasses, and at the base of large rocks. These special areas act as small catchments, collecting rainfall and allowing it to soak into the ground. These are natural "microcatchments." Small amounts of rainfall which otherwise would not soak deeply enough into the ground to help plants, trickle to the bottom of microcatchments and can contribute significantly to soil moisture.

There are many examples such as the "net and pan" (Kenya), Zai holes (Burkina Faso), and mulch pits (Pacific islands) all of which use the same basic concepts: 1) A physical structure made of soil or rocks such as furrows, ditches, pits or a combination of these, occupying an area of 0.25-3 square meters. This structure acts as a microcatchment, collecting water and sediments. 2) A small collection area where the microcatchment funnels rainfall, soil particles and organic matter to one plant.