Over the past week, I have been on several farms experiencing water infiltration issues. Basically, water applied doesn’t move into the soil at a quick enough rate to avoid run-off and saturated soils. A few different situations may occur that cause this, and are outlined below.
Soil layering/hardpans: Layers within the soil can prevent the movement of water through the soil. In coarser soils with clay lenses, water will collect on top of the layer until it is able to break through the clay lens into the coarser soil below. Generally speaking, water doesn’t have much of a problem moving from coarse to finer soils, but does get held up when soils go from coarse to fine to coarse. Soil modification will reduce soil layering, and if discovering these problems post-plant, shorter duration, more frequent irrigations should be considered.
Water run-off, soil chemistry: Some soils have chemical properties that dont provide the ability for water to infiltrate. These soils are often prone to saturated conditions in the top 8-12 inches and run-off of applied water. It may not just be an issue with the soil as the chemistry of the water often plays a large factor in infiltration rates. Therefore, a soil and water analysis must be conducted in order to determine a proper management strategy. Common management practices to solve these types of problems often include acidifying the water or the use of gypsum. If having these types of issues, contact your local advisor/PCA/consultant with the proper analysis in order to determine the correct strategy. Just FYI – none of the strategies are an quick fix.
Too fast of an application rate: Although all run-off issues can be related to water being applied too fast, in some cases this may be the only tool for management. In orchards on hilly ground or with heavy soils, water should be applied at a rate equal to the infiltration rate. These issues are often prevented by proper irrigation system design, but if they are occurring in your orchard, sizing down the nozzle or increasing the wetting pattern may be a reasonable solution.
These are just a few of the issues that may cause water infiltration issues. If you are experiencing any of these issues, please see the “Water Penetration Problems” chapter in the Almond Production Manual or Walnut Production Manual as well as contact your local farm advisor for assistance.