Farmer Perception, Environmental Awareness, and Overuse of Fertilizer in Kalpitiya: A Preliminary Investigation using Bayesian Econometrics
De Silva, L. H. N., Edirisinghe, J. C., Udayanga, N. W. B. A. L. and Gimhani, D. R.
Overuse of fertilizer has long been identified as a major issue in many parts of the world, including Sri Lanka. Sandy regosol soil and the shallow groundwater table in Kalpitiya, has aggravated the impacts of extensive fertigation, raising doubts on the long-term socioeconomic and environmental sustainability of intensive agricultural systems of the region. In this background, this study attempts to determine the driving factors influencing the overuse of fertilizer within the farming community in Kalpitiya. Primary data collected from face-toface interviews with 107 farmers from Kalpitya area using a pre-tested questionnaire was used to estimate a Bayesian probit model with sufficiently diffuse normally distributed priors. The model was estimated using a Random Walk Metropolis-Hastings sampling method, which iterated 125,000 times and 25,000 were discarded as burn-in. Results reveal that farmers who perceive that fertilizer has no effect on soil and groundwater tend to move away from fertilizer recommendations and are overusing. Farmers who are aware and believe that ground water is contaminated in the area tend to apply the recommended amount of fertilizer. In addition, larger farmers seem to apply recommended dosages than smaller farmers. Raising awareness through proper extension services and creating economic disutility by increased fertilizer costs coupled with the introduction of organic fertilizer could be recommended to circumvent the ill effects of overuse of fertilizer.
KEYWORDS: Awareness and perception, Bayesian econometrics, Fertilizer application, Kalpitiya
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