Exploring the Effects of Biodegradable and Commercial Soil Conditioners on Soil Properties, Plant Health, and Microbial Dynamics in a Pilot Study

Climate change is disrupting forests through longer summers with less rainfall and shorter winters, weakening trees and making them more vulnerable to pests, fungi, and extreme weather events like storms and wet snow. This leads to widespread forest damage, creating large clear-cut areas that require reforestation under difficult conditions, including drought, intense sunlight, and competition from other vegetation. Hydrogels can support young plants by storing and gradually releasing water, but conventional polyacrylate-based hydrogels raise environmental concerns due to their classification as microplastics and uncertain effects on soil organisms.To investigate sustainable options for enhancing plant survival and water retention, a study was performed at Heldburg, Thuringia, Germany, utilizing European Spruce (Picea abies). The research sought to assess the efficacy of various soil conditioners, with samples collected following a growing season of six months. Seven treatments were evaluated: (GZ) a control without a soil conditioner; (GTC) TerraCottem Arbor (40 g/tree), a commercial product applied beneath and around the root zone; (GBG) BeGrow Boost M Taps (1 tap/tree), another commercial product situated below the roots; (GX75) a bio-based dry hydrogel (xanthan gum + wood fibers) in chip/flake format (75 g/tree); (GX150) the same hydrogel in a larger amount (150 g/tree); (GGW) a gelatin-based hydrogel (gelatin 8.5%, sheep wool 16.5%, 75% water) in tap format (150 g/tree); and (GG) a hydrogel composed of powdered gelatin and 5% cellulose fiber in tap format (150 g/tree). These treatments were used close to the roots to evaluate their effect on successful reforestation in regions susceptible to drought.