Soil Field Capacity
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Irrigation Interval Factor
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Irrigation Interval Factor
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Soil Field Capacity and Irrigation Interval Factor |
we look at a soil's ability to hold Moisture The percent of water a soil will HOLD before reaching saturation (see below). regardless of The soil's ability to release moisture. This measure & [HCR] are key to how long the INTERVAL between irrigations needs to be. Risk Low HCR with High Field Capacity Means the soil will stay wet or moist for a longer time. Short Intervals here can be fatal to a plant! The plants may not have the chance to respire (or breathe) Whereas Benefit HCR over 0.35 with High Field Capacity will enable air to regain access to the soil quickly while still staying availably moist for a longer period. This allows for less frequent irrigations, which reduces evaporative loss! Creating Balance Field Capacity & Wilting Point As moisture drops from Field Capacity towards Wilting, this mid-way point is known as "Available Moisture" 
This chart illustrates how higher percentage of clay affects both Field Capacity AND Wilting Point Finding BALANCE requires sufficently amending most soils in the Desert Southwest. The wrong amendments or even too little of the correct amendments will mean plant stress and Water Waste Saving $15 on Installation versus Saving 20% to 30% off your Water Bill The right amendments in the needed proportion will improve field capacity while keeping the Wilting point low. This means Money in Your Pocket At the same time as healthier more beautiful shrubs |