By Gary Kruger PAg, Irrigation Agrologist, Outlook, and Joel Peru PAg, Irrigation Agrologist, Outlook
Good water management provides many benefits, including higher yields, better-quality crops, conservation of water and efficient uptake of nutrients. The goal is to apply adequate amounts of water at the proper time to meet crop needs without flushing soil moisture and nutrients below the rooting zone. The water must be applied at a rate that allows the soil to absorb the water without it ponding on the surface. Ponding leads to runoff of water into depressions, which has agronomic and environmental consequences.
Soil texture is the critical factor when determining the rate and quantity of irrigation applications. Texture determines how quickly water will soak into the soil profile and how much water the soil will hold. Irrigation scheduling seeks to maintain the reservoir of water in the crop rooting zone above 50 to 60 per cent of the maximum storage capacity of the root zone. Keeping moisture levels at this level will prevent a crop from losing yield from drought stress.
The 2018 rainfall patterns have been inconsistent enough to demonstrate the importance of irrigation for our dryland and irrigated crops. Numerous techniques have been developed to assess the soil moisture status in a field. A recent survey found that soil moisture sensors are not reliable enough to be an improvement. Producers in Saskatchewan preferred the traditional hand feel method to determine the soil moisture status. The hand feel method is a relatively accurate way to determine soil’s moisture, and any producer can practice it after the proper technique is learned.
Remote techniques that transmit reliable data from the moisture measuring instrument in the field to hand-held electronic devices are currently available. Irrigators support their on-site field moisture measurement with rainfall data and use a check-book approach or a computer modeling program to predict crop water use. A significant number of new tools have been developed to automate the process and improve remote communication between in-field monitoring devices and the irrigator. Remote moisture sensing will become more common as the technology improves and becomes more cost effective, as it can save a producer time and money be reducing the need to check fields as frequently.
The Irrigation Scheduling Manual has been recently updated by the Ministry of Agriculture, and the Irrigation Crop Diversification Corporation (ICDC) provides weekly crop water use updates throughout the growing season on Twitter. The Ministry of Agriculture has also published a series of videos about Irrigation Scheduling (“What is irrigation scheduling?”, “Methods of monitoring soil moisture” and “The hand feel method of monitoring moisture”).
For more information, please contact Joel Peru at 306-867-5528 or Gary Kruger at 306-867-5524.