Plant Available Water is the soil solution that is accessible to plant root uptake.

Plants only absorb the soil solution loosely held to pore walls once free drainage has ceased, but before the soil dries out. When irrigation or rain fully saturates the soil, water drains freely through soil pores, moving too quickly to allow roots to absorb the moisture. Excessive soil water also limits plant growth by slowing diffusion of oxygen into the soil, thereby creating anaerobic conditions. Plant roots require oxygen for survival, so maintaining adequate soil aeration is critical to crop production. When the soil becomes too dry, any remaining water molecules cling too tightly to mineral surfaces, preventing root uptake.
The amount of plant available water varies with soil texture, structure, mineralogy, and percent organic matter. Soils with a loamy texture and well formed structure have the most plant available water, while sandy and high clay soils have less. Sandy soils drain water too quickly and hold very little water in storage. High clay soils hold lots of water, but it is more tightly bound to mineral surfaces, decreasing its availability to roots. Regardless of texture, increasing the soil’s organic matter content will improve plant available water by increasing porosity, mediating soil compaction, and adsorbing water to its surfaces. Tri-Tech Ag advisors help growers maximize plant available water by recommending soil amendments and irrigation strategies customized to the unique soils on each ranch.

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Plant Available Water & Irrigation Efficiency

Increase the Water Stored in Your Soil  California’s drought conditions have improved, yet irrigation allocations will remain tightly regulated due to continued groundwater depletion and erratic weather. In order to cope with limited water rations, […] more