Irrigation Scheduling: How to Advise on When and How Much to Water

Irrigation Scheduling: How to Advise on When and How Much to WaterWater is often the most limiting input, and both too little and too much hurt the crop. Over-irrigation wastes water, power and nutrients, and can invite root disease. Under-irrigation at critical stages can cost yield that no later fix recovers.Scheduling is about matching water to what the crop needs, given soil, weather and stage. This guide gives a framework for advising on it.Start with soil and crop stageSandy soils drain fast and hold little, so they need lighter and more frequent irrigation. Clay soils hold more water and drain slowly, so they need less frequent but deeper watering and are more prone to waterlogging. Know the soil in each field before advising.Crops also have critical stages when water stress hurts most, such as flowering and grain or fruit filling for many crops. Prioritise water there if supply is limited.Use simple field checks

Feel the soil at root depth: it should hold together when squeezed, not drip or crumble to dust

Dig a small pit to check how deep the last irrigation actually wetted the soil

Watch the crop in the morning: wilting then is a sign of real stress

Check weather: rainfall, temperature and wind change demand quickly

Match the method to the fieldDrip and micro-sprinklers apply water close to the roots in small, frequent amounts and allow fertigation, which delivers nutrients with the water. Flood and furrow irrigation need levelling and attention to uniformity. Whatever the method, check that all parts of the field get water evenly, since uneven distribution is a common hidden loss.Common mistakes to flag

Irrigating on a fixed calendar regardless of rain or temperature

With surface irrigation, light and frequent watering that wets only the top soil and encourages shallow roots

Ignoring leaks, clogged emitters and low pressure in drip systems

Irrigating late in the day in humid conditions where leaf wetness drives disease

Record every irrigationLog date, field, duration or volume and any weather notes for each irrigation. Over a season, these records show which fields get too much or too little, link water use to yield, and give you evidence when advising changes. Daily field logging in a tool like AgroTrack makes this easy for supervisors to do from the field.Key takeaways

Know the soil type and the crop's critical water stages.

Check soil moisture at root depth rather than relying on a fixed calendar.

Check distribution uniformity and system faults before adding more water.

Record every irrigation so you can link water use to yield.

Frequently asked questionsHow do I know if a crop needs irrigation?Check soil moisture at root depth by feel or a small pit, watch the crop for morning wilting, and consider recent rain and temperature. Combine this with the crop's growth stage.What is fertigation?Fertigation is applying fertiliser through the irrigation system, usually drip. It delivers nutrients to the root zone in small doses when the crop needs them, which can reduce losses compared with broadcasting.