Invasion at a Cost: Socioeconomic and Agronomic Effects of Parthenium Weed ( <i>Parthenium hysterophorus</i> ) on Farming Communities in Southern Oman

Abstract Parthenium weed ( Parthenium hysterophorus L.) is rapidly invading southern Oman, posing growing challenges to agricultural productivity and rural livelihoods in Dhofar’s crop–livestock systems. This study assesses its agronomic and socioeconomic impacts using field surveys and a stratified household survey of 40 farms conducted between June and August 2022. Data was analysed using Partial Least Squares Structural Equation Modelling (PLS-SEM) to examine the relationships between farmer characteristics, infestation levels, weed management practices, and farm revenue. Results indicate that while most farmers are aware of P. hysterophorus , limited recognition at early growth stages delays control and increases management costs. Education (β = 1.009, p = 0.06), cultivated area (β = 1.033, p = 0.003), and chemical control expenditures (β = 0.295, p = 0.05) were positively associated with gross revenue, whereas age had a negative effect (β = −0.762, p = 0.08). Infestation significantly increased labour-intensive weeding costs (β = 2.072, p = 0.07) but reduced chemical use (β = −1.303, p = 0.032), indicating substitution toward manual control. Although time spent uprooting reduced infestation levels (β = −0.128, p = 0.001), it also increased weeding and chemical control costs, highlighting the financial burden of relying on manual methods. Crop-specific analysis showed heterogeneous vulnerability, with peas more affected than wheat and tomato. Overall, the findings demonstrate that P. hysterophorus imposes measurable income and welfare risks on farming households. These impacts can be mitigated through farmer education, early detection, and judicious chemical use within an integrated weed management framework. Strengthening extension services and promoting crop-specific interventions are essential for protecting rural livelihoods and food security in arid, invasion-prone farming systems.