A Critical Review of Crop-Yield Data for Rice (Oryza Sativa L.) On Using Sri Lankan Biofilm Biofertilizers

Abstract

M. W. C. Dharma-wardana, D. Sumith de Z . Abeysiriwardena and Parakrama Waidyanatha

The challenge of sustainable agriculture has generated a global interest in microbial fertilizers. A Biofilm-biofertilizer introduced in Sri Lanka is claimed to reduce the usage of chemical fertilizers (CF) by ~50% while boosting harvests of rice (Oryza sativa L.) and other crops by 20-30%. In contrast, biofilm biofertilizers tested elsewhere have usually given inconsistent results. Just prior to Sri Lanka launching “100% organic farming”, the country had officially approved a nation-wide use of the commercialized biofilm-biofertilizer. Here we examine the available data on rice yields for the Sri Lankan biofertilizer and show in detail that the improved yields claimed fall within the usual uncertainties (error bars) of rice harvests. Theoretical models that produce a seemingly reduced CF usage with a misleading “increase” in harvests, as well as field data from several laboratories of the government department of agriculture are used to assess these claims. We find that Sri Lankan biofilm biofertilizers in current use have no discernable positive impact on rice yields or in reducing the need for mineral fertilizers. The field data suggest an estimated loss of at least 16 million kg in the rice harvest for 2017-18 due to BFLk use.

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