The delivery of dissolved mineral fertilizers to the roots of crops in the field using irrigation water is known as ‘fertigation’. The use of fertigation is gaining popularity because of its efficiencies in nutrient management, time and labor and potentially a greater control over crop performance.
Benefits of Fertigation Include…
- Better uniformity of application.
- Reduced delivery costs (no need to broadcast fertilizers, leading to less soil compaction in the inter-row areas, less fuel usage and lower labor requirements).
- Greater control over where and when nutrients are delivered, leading to greater fertilizer use efficiency.
- Less dependence on weather for timing of applications. For example, you can apply fertilizer at a high rate through the irrigation system with a minimum of water — just enough to carry the fertilizer to the field — even when fields are too wet for vehicles
- Ability to apply fertilizer only as needed by the crop, throughout the growing season (“spoon-feeding”)
- Reduced fertilizer usage resulting from greater control of application rate
- More flexibility to deal with abrupt weather changes — you can adjust application rates in a way not possible even with timed-release ground-spread fertilizers.
- More control over crop behavior through targeted application of specific nutrients during particular stages of crop development.
- Potential for reduced fertilizer losses (due to immobilization within or leaching below the root zone) by supplying small amounts often.
- Greater capital costs associated with the equipment needed to dissolve and inject the fertilizer into the irrigation water.
- Higher operating costs associated with using technical grade fertilizers as opposed to agricultural grade fertilizers.
- Chemical reactions between some types of fertilizers when mixed, potentially causing significant equipment blockages.
Before You Fertigate…
- Calculate from how many Liters of fertilizer liquid need to be applied per irrigation run.
- If you will be buying liquid fertilizer, use its N-P-K-trace content to calculate how many liters are needed to provide the weight you calculated above.
- If you will be dissolving solid fertilizer in water in a mix tank, plan on using a liter of water to dissolve about three Kg of fertilizer (this varies depending on the fertilizer composition – do a “bucket test” first to be sure).
- Calculate how many liters of fertilizer liquid need to be injected per hour to get the right quantity onto the field in one irrigation run. This is the maximum injection rate you need, in liters per hour