Turning Waste into Fertilizer: Aloe vera Leaf Shavings Improve Plant Growth and Support Soil Fertility in Organic Systems

The Aloe vera industry discards large amounts of outer leaf tissue (“shavings”), creating an opportunity to repurpose this byproduct as a sustainable fertilizer. This study evaluated whether aloe shavings can serve as a plant-based alternative to compost in organic Aloe vera production. A field trial in the Lower Rio Grande Valley of Texas tested three treatments: aloe shavings (applied to supply 39 kg N ha−1), organic compost (39 kg N ha−1), and a non-fertilized control. Laboratory incubations further assessed nitrogen mineralization and microbial respiration. Aloe shavings significantly enhanced vegetative growth: leaf number increased from 5.7 to 12.3 leaves per plant (+115% over the season), and leaf length rose from 20 to 32 cm, with the greatest gains in September and March (p < 0.05). At harvest, plants receiving aloe shavings produced 456 g total leaf weight and 151 g gel weight per plant, compared to 375 g and 108 g in the control. Incubations showed initial nitrogen immobilization (negative mineralization) but subsequent slow release, while microbial respiration was higher in compost (2.3 mg CO2-C kg−1 day−1) than aloe shavings (1.4 mg CO2-C kg−1 day−1). These results highlight aloe shavings as a low-cost, slow-release organic amendment that reduces waste, supports circular economy practices, and enhances Aloe vera growth without mineral nitrogen addition.