Similar names: Chololo pits (Tanzania), Zaï pits (Burkina Faso), tassa (Niger), agun pits (Sudan), kofyarpits (Nigeria), yamka (Kyrgyzstan), planting pits.
The name Zai pits refers to small basins in which seed of annual or perennial crops are planted. They are beneficial for soil conditions because they increase termite activity which leads to a higher water infiltration when it rains. This intervention is most suitable for flat or gently sloped terrains (0-5%) with a precipitation range of 350-600 mm/y.
The name Zai pits refers to small basins in which the seeds of annual or perennial crops are planted. The pits are then filled with mulch, manure or good soil to increase soil fertility and the capacity of the soils to capture water. Zai pits can be beneficial for soil conditions and they are a very successful method which can allow for the growth of vegetation in dry areas. They are also very efficient in protecting seeds and soil organic matter from being washed away from water runoff. This intervention is most suitable for flat or gently sloped terrains (0-5%) with a precipitation range of 350-600 mm/y.
- Rain higher than 800mm annual can cause waterlogging of pits. Avoid loose sandy soils and steep slopes or the pits will be very unstable.
- Because of labor times (especially because pits are created during dry and warm season), it is most effective if the measure is undertaken by groups of farmers together, instead of individuals.
- The construction of planting pits can be done with machines.
- Zai pits are even more efficient when combined with other interventions such as organic and inorganic soil inputs such as mulching.
- A Chaka hoe
- Digging stick
- Wheelbarrow to transport manure, mulch and/or good quality soil to fill the pits
- Manure, mulch or good quality soil to fill the pits
- Seedlings or seeds
Steps of Implementation:
There are currently new ways of mechanizing the construction of pits, click here to know more about it.
Pits usually are 20-30 cm both wide and deep, placed 60 cm – 1 m apart from each other and dug by hand. The excavated soil is placed downslope on the border of the pit to form a small ridge that further improve rainfall and runoff capture. When available, crop residue, mulch or manure is added to every pit to help vegetation grow in the first phases. In order to optimize the efficiency of Zai pits intervention, pits can be constructed in combination with stone lines, especially on degraded and crusted lands because the synergy of these two interventions helps land to be suitable again for agricultural purposes. In this case, when planting pits are used in combination with stones lines, growing grass between the stones is recommended because it helps to further increase infiltration and improve the accumulation of fertile sediment.
- Dig holes with diameter of 15-20 cm and depth of 10-15 cm or more, distance between each other from 70 to 80 cm apart, resulting in about 10,000 pits per hectare.
- Make sure they are dug perpendicularly to the slope and put the soil from the hole on the direction of the downslope (so as to create a small soil wall/bund to keep the water in the hole).
- Fill them with manure, mulch, organic material or better-quality soil.
- Row crops are then planted in the pits.
For trees: dig deeper holes and increase the distance from the pits so the tree will have the space to grow.
Estimation of costs and benefits of intervention:
|Establishment cost||US $160/ha + manure (2.5t for US $5)
(Sorghum plantations combined with Tithonia diversifolia: US $2561.43/ha)
|Labor time p/ha||100 person days (US $150) (about 10,000 pits/ha) *|
|Maintenance cost||20 person days (US $30) to remove sand from pits + apply compost/manure 1.25t (3.5) every second year = US $33.5/ha/year|
|Material required||Hoe, digging stick (US $5)|
|Products example||Maize, pearl millet grain, sorghum, pigeon peas, lablab (black beans), fruit trees such as mango|
*more time needs to be calculated if the soil contains a lot of stones
Source: Case study based in in Niger, 2011
Click here for a good example of planting pits in Kenya, where sorghum is grown in very dry conditions.
An example of the mechanisation of Zai pits in Burkina Faso can be found here (French only).
Here is an example of a smallholder cultivating maize, pigeon peas and sunflowers on 2.2 hectares of land.
Implementation of Zai pits in combination with stone lines to achieve the rehabilitation of 40km2 of degraded land. Click here to know more about it.