Soil salts reduce hydration of polymeric: Gels and affect moisture characteristics of soil

Hydration of a hydrophilic crosslinked polystyrene (gel) in deionized water at 65 g of gel per g of soil was studied. Four different soil types were s elected, three were light-textured soils (loamy sand and sandy clay loam) a nd the other a clay. Container capacity, field capacity, permanent wilting point, and available water for these soils were measured for gel contents e qual to 0, 0.1, 0.2, and 0.3%. Absorption capacity of the gels when incorpo rated into the soil decreased considerably compared to its absorption in pu re water. This was attributed to the increased ionic strength of soil moist ure and the formation of additional ionic crosslinks in the gel network due to the presence of multivalent ions in the soils. It was found also that c ontainer capacity, field capacity, and available water capacity increased w ith the gel content in soil, whereas the permanent wilting point was not si gnificantly affected.