Short‐term surface soil responses to compost rate during peach orchard establishment on sandy Ultisols

Abstract Compost amendment can improve soil health, but rate‐dependent responses in sandy orchard soils remain insufficiently characterized. This study evaluated the short‐term effects of compost application on soil physical, chemical, and biological properties during the first 2 years of peach ( Prunus persica (L.) Batsch) orchard establishment on a sandy Ultisol at Clemson University's Musser Fruit Research Center in South Carolina. Compost was incorporated into soils before planting at rates of 25.6 (1x treatment) and 51.2 Mg ha −1 (2x treatment) in 2019, followed by annual spring surface applications at rates of 8.5 and 17.0 Mg ha −1 for the 1x and 2x treatments, respectively. A no‐compost control (CT) was included for comparison. Surface soil (0–15 cm) was sampled in spring and fall of 2020 and 2021. Compost increased soil moisture, pH, permanganate oxidizable carbon (C), potentially mineralizable nitrogen (N), extracellular enzyme activities associated with C, N, and phosphorus (P) cycling, and total C and N by the end of the study. In contrast, compost did not increase extractable inorganic N and P. Across most short‐term biological indicators, the increase from CT to 1x was more consistent than the increase from 1x to 2x, indicating limited additional functional gains at the higher compost rate. Overall, compost enhanced surface soil moisture, organic matter accumulation, and biologically mediated nutrient cycling more than short‐term inorganic nutrient pools under this fertilized orchard establishment system. These results suggest that moderate compost input may capture much of the near‐term surface soil functional benefit during peach orchard establishment on sandy Ultisols, although long‐term studies with deeper sampling, tree performance measurements, and economic analysis are needed to identify optimal compost rates for sustainable orchard production.