Optimizing revegetation success through hydroseeder performance evaluation: Effects of nozzle type and agitation system on seed distribution and slurry homogeneity

Effective revegetation of degraded landscapes depends not only on seed composition and site conditions, but also on the performance of hydroseeding equipment. However, standard methods for evaluating hydroseeder performance are lacking. This study proposes a reproducible assessment framework to quantify three critical variables: spray footprint and range, in-tank slurry homogeneity, and ground-level seed distribution. Two types of machines were tested using conical and flat-fan nozzles: with mechanical agitation and with hydraulic recirculation.Results show that conical nozzles maximize spray distance (up to 37.3 m downhill), especially on slopes, while flat-fan nozzles provide better area coverage (up to 55 m2). Mechanical agitation consistently maintained uniform seed mixture (CV < 5%), preserving the intended ratio across different tank levels and operational durations. In contrast, hydraulic recirculation led to progressive stratification (CV: 16.6–21.3%), reducing deposition and potentially compromising revegetation function. Ground-level distribution analysis confirmed that only mechanical agitation achieved uniform coverage exceeding 3000 seeds m−2, critical for ecological establishment. This imbalance compromises ecological functions, as Leguminosae enhance nitrogen fixation and promote soil cover, which improve slope stability by reducing runoff.This study provides a quantitative basis for selecting hydroseeder components to optimize ecological outcomes in slope stabilization, erosion control, and habitat restoration. The framework supports environmental managers in aligning equipment operation with revegetation success, contributing to improved management of disturbed or at-risk landscapes.