Irrigation Monitoring and Scheduling
Irrigation water is the life-blood of Central Washington Agriculture. Under watering or over-watering is one of the main concerns of growers throughout Central Washington. With the limited amount of water available and the increased pressure for water to be diverted for growing populations, hydro-power, and salmon restoration, water is becoming a precious commodity. Agrimanagement understands this balance and provides reliable sampling and evaluation of the amount of water available for your crop. Whether you use rill irrigation, trickle / drip systems, center pivot, or sprinklers, we can help you maintain the proper level of water for your crops.
Agrimanagement uses the following methods to monitor soil moisture levels, as appropriate for the situation:
The Gravimetric Approach utilizes multiple core composites to various depths to describe the soil moisture profile throughout the rooting zone. This method provides for ultimate flexibility. Each week or every other week, we will visit the field equipped with air-tight canisters and soil probes. These probes are capable of coring up to 4' or 5' depth, depending on the crop or location of the hard pan. Rather than coring at a single location, we walk the field in a pre-defined "representative sample strip". The soil collected will be a composite over a geographic area for a given foot depth. For many situations, this provides advantages and flexibility over single point sampling.
Once the soil has been collected, it is mixed and transferred to metal cans. The metal cans are then weighed, baked in an oven and weighed again. This "percent water by weight" (gravimetric approach) is reported to the grower in terms relative to the field capacity (water holding capacity of the soil) as percent available water and inches of profile depletion. We also include general scouting information and project the next weeks crop water use (ETP x crop coefficient). The crop coefficient helps both to further assess the crop's water requirements and to formulate a probable irrigation schedule.
Each report charts the changes in available soil moisture at various depths. These trend lines reveal where the soil moisture levels have been and they provide a guide toward making any needed adjustments to the schedule.
The ECH2O System uses Decagon ECH2O sensors, a real-time moisture sensing system provides another option for those who are concerned with precision management. installed capacitance sensors are left in the field year round, unless removal for crop rotation is necessary. The sensors are attached to ECH2O data loggers that record continuous realtime moisture readings in volumetric water percentages. The capability exists for us to bring this data into a home office computer or smartphone via radio transmission for easy access and convenient viewing. See the iMetos page for more information.
Irrometer Watermarks sensors are used in some situations where field variation is a concern as multiple stations can be installed and monitored at a reasonable cost. This approach involves the measurement of soil water tension using Watermark sensors in representative locations. Readings are taken on a weekly or every other week schedule. The data is presented graphically to show trends and a detailed recommendation is included.
All types of reports can be emailed, faxed, mailed, or posted up on our grower website, typically a day after sampling.