The Effect of Compost Enriched with Cellulolytic Bacteria on Plant Residue Decomposition and Nutrient Release Rates in Sandy Soil

Abstract

Sandy soils are characterized by low fertility, poor water retention, and rapid leaching of nutrients. Enhancing their quality through organic amendments like compost is a key sustainable strategy. This study investigated the efficacy of compost inoculated with a consortium of cellulolytic bacteria to accelerate the decomposition of plant residues and improve nutrient release dynamics in sandy soil. A 60-day incubation experiment was conducted with four treatments: (1) control sandy soil (S), (2) soil with wheat straw (S+WS), (3) soil with conventional compost (S+C), and (4) soil with bacterially-enriched compost (S+BC). Decomposition was monitored by measuring mass loss of the straw and CO2 respiration. Soil samples were analyzed weekly for available nitrogen (N), phosphorus (P), potassium (K), and microbial biomass carbon (MBC). The results showed that the S+BC treatment exhibited the highest cumulative respiration (signifying microbial activity) and the fastest rate of straw decomposition (68% mass loss vs. 45% in S+WS and 55% in S+C). Consequently, the S+BC treatment consistently released higher levels of available N (NO₃⁻ and NH₄⁺), P, and K throughout the incubation period compared to other treatments. Microbial biomass carbon was also significantly higher in the S+BC treatment, indicating a robust and active microbial community. This study concludes that enriching compost with cellulolytic bacteria significantly enhances its effectiveness in degrading organic matter and synchronizing nutrient mineralization with plant demand, making it a superior amendment for rapidly improving the fertility and health of sandy soils.