Abstract
Recent interest in natural climate solutions has emphasized the role of urban soils in sequestering carbon (C) and improving soil health. Mulching can increase soil C sequestration, protect the soil from erosion, minimize soil temperature fluctuations, and maintain soil moisture levels. However, the effects of various mulching materials on soil C, nutrients, and soil health have rarely been reported from arid urban areas. This study evaluated soil C and nitrogen (N) fractions along with other soil health parameters after the application of organic and inorganic mulch at depths of 0–15 cm and 15–30 cm in an arid landscape of the southwestern USA. Two mulches tested include organic (woodchips) and inorganic (landscape rocks). Results showed that mulching increased the SOC by up to 31%, while decreasing potentially mineralizable carbon (PMC) content by 34% and microbial biomass carbon (MBC) by 55% compared to the bare-ground control. The gravimetric water content (GWC) was 75–94% greater under mulches than in bare ground. Soil microbial analysis revealed a decrease in total PLFA abundance under rock mulch than no mulching. These results suggest that soil C sequestration could be enhanced by adopting mulching practices in arid, alkaline urban soil. Specifically, woodchips should be used to enhance soil C storage and improve soil health in depleted arid urban landscapes.