Can Gypsum Improve Water Penetration?
Bill Peacock* Can gypsum improve water penetration? The answer is probably yes if you are irrigating with low-salt water (canal water) on loam or fine sandy loam soils. The answer is definitely yes if your soil is impermeable because of excess exchangeable sodium (alkali). The answer is probably no if compaction has slowed water infiltration or your soil is inherently impermeable because of fine texture. Low Salt Water: Irrigating with water that is very pure (less than 250 ppm soluble salts) can slow infiltration into sandy loam or finer-textured soils. This is commonly a problem on the east side of the valley where growers rely heavily on canal water originating from snow melt. The application of 1 to 2 tons per acre of gypsum (CaS04 . 2H20) in late spring or early summer can increase infiltration as much as threefold. Gypsum is spread on the soil surface or placed in furrow bottoms without incorporation. With low volume irrigation systems, gypsum is spread on about a six foot strip
