A critical examination of crop-yield data for vegetables, maize and Tea for commercialized Sri Lankan biofilm biofertilizers

TL;DR

This paper critically reviews the claimed benefits of a Sri Lankan biofilm biofertilizer, finding that its impact on crop yields is negligible within measurement uncertainties, despite some soil quality improvements.

Contribution

It provides a detailed analysis showing that the claimed yield increases from the biofilm biofertilizer are within experimental uncertainties, challenging its purported effectiveness.

Findings

Yield improvements are within measurement error margins.

Theoretical models overstate the benefits of biofertilizers.

Limited impact on crop yields despite some soil quality benefits.

Abstract

With increasing global interest in microbial methods for agriculture, the commercialization of biofertilizers in Sri Lanka is of general interest. The use of a biofilm-biofertilizer (BFBF) commercialized in Sri Lanka is claimed to reduce chemical fertilizer (CF) usage by ~50 per cent while boosting harvest by 20-30 per cent. Many countries have explored the potential of biofilm biofertilizers, but have so far found mixed results. Here we review this BFBF commercialized in Sri Lanka and approved for nation-wide use there. We show in detail that the improved yields claimed for this BFBF fall within the uncertainties (error bars) of the harvest. Theoretical models that produce a seemingly reduced CF scenario with an "increase" in harvests, although this is in fact not so, are presented. While BFBF usage seems to improve soil quality in certain respects, the currently available BFBF promoted in Sri Lanka has negligible impact on crop yields. We also briefly consider the potential negative effects of large-scale adoption of microbial methods.