Increasing Water Retention in Arid Soils through Biological Amendments: Adaptive Rotational Grazing, Cyanobacteria Inoculation, and Compost Extract

Abstract

If drought conditions continue, as expected, how can land managers prepare their fields to endure ongoing water rationing? Often adding biodiversity to land is seen as a liability to water resources, but perhaps biodiverse soil treatments can be a cost-effective tool for land managers. This research and literature review will synthesize experiments using compost extract and cyanobacteria inoculations as soil amendments to improve water retention and compare those results with experiments using adaptive rotational grazing (ARG) of livestock as a biological soil amendment positively impacting water retention. The experiment will also compare one year of ARG to three years of ARG. Data show that neither microbial inoculation helped to create more soil organic carbon, lower soil bulk density, or increase soil water infiltration. However, ARG did significantly increase soil organic carbon and marginally significantly decrease soil bulk density in the short term. Longer term increases were smaller. Based on these results, we suggest ARG is a more effective treatment for affecting soil hydrology compared to microbial treatments in hot arid systems.