Remediation of degraded soils with hydrogels from domestic animal wastes

Introduction This study reports on water management in the fields found in arid areas by the improvement of the soil’s waterretention capacity. This was done using hydrogels from animal wastes to mitigate the effects of climate change that lead torapid evaporation of water hence increased desertification rates.Method The modification of the cow dung to hydrogels involves the oxidation of urea or uric acid from chicken dung toform compounds that can undergo a condensation reaction with cellulose in the cow dung. This formed a product with highwater retention capacity.Results The materials were characterized using Fourier transform infra-red spectroscopy and thermo-gravimetric analysiswhich confirmed the derivatization of some functional groups. The thermo-stability was improved, as the degradation temperaturesfor urea, glycerol, and chicken dung derivatives were 245, 220, and 228 °C, respectively, while the unmodifiedform was 198 °C. The UV–Vis analysis showed no evidence of starch in the modified material which was also confirmed byLugol’s test. It was found out that modification had influence on the swelling ability giving it superabsorbent properties withswelling capacities (300 g g−1) within 5 min of moisture exposure plus a high water retention capacity of 90%.Conclusions The application of the modified materials in the growing of some selected plants showed that the moisturecontent could be sustained for a period of 6 weeks before the plants wilted. This confirms that the modified form of manurehas potential application for hydration of plants in arid areas.