Cross?linked polymers increase nutrient sorption in degraded soils

Cross-linked polymer hydrogels, polyacrylamide co-polymer (XPAM) or polyacrylate (XPAA) offer potential solutions for soil degradation, declines in resilience, and poor productivity marginal soils. However, little is known about their long-term effect on nutrient availability. This 9-yr, irrigated, outdoor, cropped pot study evaluated a single, one-time addition of XPAM XPAA at 0.25 0.5% dry wt. (5.6 11.2 Mg ha–1) degraded (artificially eroded) soil. Controls included an unamended unamended, non-degraded (i.e., topsoil). We measured nutrients leachate water each year, the first 5 yr, crop yields uptake. Both hydrogels increased average pH electrical conductivity (EC), extractable K, Na, total organic carbon (TOC), decreased relative to control. Unlike XPAM, produced greater increase Fe, Zn, Mn, Cu, Olsen P, inorganic (TIC). Neither hydrogel affected but K Zn Na uptake crops compared controls. Relative control, both cumulative Ca, Mg, S leaching mass losses mean EC leachate. NO3–N, NH4–N The hydrogels’ effects persisted ?7 differing as function quantity counterions stability gel structure after placement.