NEGATIVELY CHARGED PAM EFFICACY AS A SOIL CONDITIONER AS AFFECTED BY THE PRESENCE OF ROOTS

Daily and accumulative water consumption of sandy, loamy, arid clayey soils that had been amended by two negatively-charged organic polymers (Polyacryl-amide-PAM) applied at rates of 25, 50, and 75 mg/kg of soi l were studied in a growth chamber experiment. Water retention due to PAM application was either impaired or enhanced in sandy and loamy soi ls, respectively; clayey soil was significantly less affected. Plant r oot presence in the amended soils always had a corrective influence on soil structure and water retention over unamended soils.