Water management
Water management in a banana plantation aims at finding a balance between the soil’s water content and the needs of the plant. The two main components are drainage, to eliminate excess water, and irrigation to make up for water deficits due to lack of rain or high evapotranspiration.
Drainage
Drainage is the natural or assisted elimination of excess water that could reduce the development of banana plants. Indeed, since too much water deprives roots of oxygen, even temporary asphyxiation can cause irreversible damage. Drainage is used to ensure that the soil’s oxygen levels and biological activity are optimal. Moreover, too much humidity can facilitate the development of pathogens and weeds. For example, a plot with poor drainage will be more affected by black leaf streak because of the high relative humidity but also because the plants are stressed. Drainage can also control soil salinity by eliminating excess salt.
There are two types of drainage systems: open and underground. The choice will depend on the type of soil (porosity, permeability, texture and structure), rainfall, topography, hydrological profile and available resources. For example, open drains should be well maintained to ensure their good functioning. An underground system requires a higher initial investment, but less maintenance.
To verify whether a plot is well drained, monitoring wells can be dug. If the time required for the water table to go back to its normal level after a period of saturation is long, the drainage should be improved.
Irrigation
Irrigation is a water management tool when rainfall is not enough to meet the plant’s needs, which also depends on evapotranspiration. These parameters must be taken into account to ensure adequate irrigation or avoid water wastage.
A good irrigation will ensure a uniform and homogenous distribution of water in small and regular doses. It also aims at maintaining the relative humidity in a plot at a stable level, to limit the development of weeds and pathogens. Irrigation is also used to avoid the transmission of phytosanitary problems or the leaching of pesticides.
The volumes of water to apply depend on the climatic conditions, the fractioning of the applications, the soil type and the irrigation method. There are many irrigation systems. The choice must take into account the efficiency of each system, the water availability, the installation and running costs, the maintenance needs, the spatial requirements and whether it’s possible to work while the field is irrigated. The irrigation system can also increase or reduce the impact of black leaf streak. The systems that create the least favourable conditions for the fungus are drip irrigation and micro-aspersion.
Surface irrigation
Surface irrigation is the distribution of water using open canals in which water flows by gravity. This type of irrigation, which includes flood irrigation, requires relatively flat fields and deep soils.
Advantages
|
Overhead irrigation
The technology reproduces rain by distributing water using overhead high-pressure sprinklers.
Advantages
|
Micro-aspersion
Water-saving technology that is similar to overhead irrigation except that the application of water is localized to the base of the plant.
- Requires less water.
- High fractioning of water.
- Good use of water and fertilizers.
- Very uniform application.
- Limits weed development.
- Compatible with fertigation.
- Possible to work during irrigation.
- Requires little labour.
- Requires qualified labour.
- Requires many sprinklers.
- Water needs to be filtered.
- Requires surveillance to insure that the sprinklers are functioning correctly.
- High initial investment.
Drip irrigation
Irrigation method that saves water and reduces runoff by allowing water to drip slowly to the roots of plants.
|
Advantages
Disadvantages
|
|