This archive report was first published on 2 August 2019.
As the dry spell bites, many farmers are turning to irrigation systems to ensure their crops receive sufficient water. However, few farmers know how to use these systems efficiently to maximize yields.
During a recent visit to Machakos, I met with farmer Mary, who had just harvested her bulb onions. While she was proud of her 7-tonne-per-acre harvest, it fell short of the expected 16-20 tonnes per acre.
One of the key factors contributing to the low yields was Mary's irrigation scheduling. She was watering her crops every day using the drip irrigation system for 20 minutes, whereas the recommended duration is two hours, three times a week, depending on weather conditions.
Proper irrigation scheduling is crucial for efficient water use. Ideally, watering should occur early in the morning or late in the evening to minimize water loss due to evaporation.
Before watering, farmers should conduct a simple water test by feeling and observing the appearance of the soil and crops. This can be done by squeezing soil into a ball and creating a ribbon between the thumb and forefingers. Sticky soil indicates adequate watering, while loose soil suggests the need for irrigation.
Visible crop appearance, such as leaf colour and curling, also serves as a guide for determining the amount of water required. The number of watering sessions per week depends on the crop's growing stage, with onions requiring more water during early growth and bulb formation stages.
Overwatering can lead to wastage, increased pests and diseases, and higher production costs. When selecting drip lines, consider quality, durability, and flow rate. Regularly test water flow rates and clean blocked emitters to ensure optimal water distribution.
A well-designed irrigation system layout is essential for efficient water use. Farmers should also consider investing in solar panels to reduce pumping costs and environmental impact.
Finally, ensure that the water used for irrigation is safe and free from contamination. Testing its chemical composition is recommended.
