For more productive farmland effective irrigation and drainage systems are essential |27 January 2017

The northern monsoon comes with high levels of precipitation and seasonal runoff that can cause saturation of agricultural soils.  Saturation result in flooding and water logging leading to a loss of agricultural crops. Flooding limits the range of crops that can be grown and also increase disease incidence. Good irrigation practices and drainage systems will help to prevent flooding and over irrigation which will allows farmers a wider selection of crops and a longer growing season.

Maintaining the water supply is of great importance as excess debris and particles can block the flow of water.  This includes frequent cleaning of the reservoirs, pipelines and filters to allow free flow of water.  Installing filters at different point of entry can help prevent the entry of particles that can cause blockage in the drip lines. Weekly flushing of the drip lines will allow continuous flow of water.

Irrigation timing and frequency is also important to control waterlogging, therefore always give the plant what is required.   High frequency of irrigation can cause high evaporation loss the repeatedly wetted soil surface and from the plant canopy and in the event of high rainfall waterlogging will occur. Low frequency of irrigation may cause soil desiccation, salinity increase and plant stress during period of high temperatures between rainy days.  Drip irrigation should be used instead of sprinklers as the drippers wet only a small fraction of the surface near the root zone.

Good drainage systems will allow the removal of excess water that may cause flooding and reduced crop production particularly in flat areas. Proper drainage can be achieved by surface and subsurface drainage techniques. Surface drainage is simply inbuilt inter connected channels that allow easy flow of water to a river or a constructed ditch. Subsurface drainage consists of subsurface piping used to remove excess water from the soil profile. This can also be used to control erosion and salinity in prone areas. Cleaning the marshes around the farm will also allow quick flow of water hence reducing flooding.

As the soil can become heavily compacted after period of rainfall and period of high heat it is important to hand tilled the soil so as to improve infiltration of water and fertilizer use and reduce runoff.