Abstract Leguminous crop Tephrosia candida has high biomass production and contains a substantial quantity of nutrients within its biomass. Starting in 2019, a long-term study was done to find the best Tephrosia candida dose for mulching in guava orchards. The study had four treatments: T 1 = 3.0 kg dry biomass m −2 of the plant basin, T 2 = 2.0 kg, T 3 = 1.0 kg, and T 4 = control (no mulch). Every year, the treatments imposed in the month of August. The third year (2021–2022) results indicated that mulching with 3 kg of biomass m −2 increased trunk diameter, fruit yield, fruit weight, specific leaf area, total leaf chlorophyll, and leaf macro- and micro-nutrients. At 3.0 kg m −2 , mulching improved soil properties such as EC, available nitrogen, available phosphorus, exchangeable potassium, DTPA extractable micronutrients (Fe, Zn, Cu, and Mn), total organic carbon (C toc ), soil organic carbon (C soc ), organic carbon fractions, and microbial biomass carbon between 0–0.15 m and 0.15–0.30 m. There was an increasing trend in dehydrogenase activity (DHA) and fluorescein diacetate (FDA). The Tephrosia leaf litter exhibited decay constants of 1.27 year −1 , and the carbon content was 40.11%. Therefore, applying Tephrosia biomass mulching at a rate of 3.0 kg m −2 is a viable long-term solution for enhancing soil fertility and sequestering carbon.