Impacts of woody residue amendments and compost on ‘Beauregard’ orange fleshed sweet potato

Abstract

This study investigated the short-term effects of woody residues and compost on Orange-fleshed sweet potatoes (OFSP) focusing on plant growth, storage root production, and bioactive compounds. Conducted in a commercial orchard, the experiment compared different organic fertilization treatments with a control. Four treatments were established: Treatment 1 (T1) received compost fertilization; Treatment 2, control, (T2) had no fertilization; and Treatments 3 (T3) and 4 (T4) were fertilized with high (150 t ha⁻1) and low (75 t ha⁻1) doses of woody plant residues, respectively. Although woody residue application initially hampered plant growth, it ultimately enhanced biological nitrogen fixation, phosphorus availability, and reduced stress and senescence. Agronomic production did not differ between the compost and woody residue treatments but was increased at the high woody residue dose compared to control. At late growth stages, ascorbic acid decreased in all treatments. At this time, the total phenolic content in storage roots remained high in the woody residue treatments. Conversely, compost reduced the bioactive compounds, without affecting growth, potentially due to oxidative stress in late growth stages. The lower crop senescence index and comparable agronomic production to the compost treatment suggest that woody residues were beneficial for OFSP growth and bioactive composition. The superior quality of the crop produced with woody residues indicates that this is an effective organic fertilization method for sweet potato production that can contribute to its resilience to environmental variations.