Improving Crop Yield and Nutrient Use Efficiency via Biofertilization—A Global Meta-analysis

TLDR

Microbial inoculants (biofertilizers) are a promising technology for sustainable farming, addressing declining phosphorus stocks and the need for more efficient nitrogen use, and are employed in various taxa that access nutrients, fix nitrogen, improve water uptake, or act as biocontrol agents. This study aims to provide a comprehensive quantitative assessment of biofertilizer performance across crops and traits such as phosphorus solubilization and nitrogen fixation on a global scale. A meta‑analysis of 171 peer‑reviewed publications quantified yield, nitrogen, and phosphorus use‑efficiency benefits of biofertilizers. Biofertilizers yield responses were greatest in dry climates (+20 %) and increased with higher soil phosphorus, with arbuscular mycorrhizal fungi outperforming P solubilizers and nitrogen fixers, and AMF success being higher at low organic matter and neutral pH, offering guidance for selecting and applying biofertilizers.

Abstract

The application of microbial inoculants (biofertilizers) is a promising technology for future sustainable farming systems in view of rapidly decreasing phosphorus stocks and the need to more efficiently use available nitrogen (N). Various microbial taxa are currently used as biofertilizers, based on their capacity to access nutrients from fertilizers and soil stocks, to fix atmospheric nitrogen, to improve water uptake or to act as biocontrol agents. Despite the existence of a considerable knowledge on effects of specific taxa of biofertilizers, a comprehensive quantitative assessment of the performance of biofertilizers with different traits such as phosphorus solubilization and N fixation applied to various crops at a global scale is missing. We conducted a meta-analysis to quantify benefits of biofertilizers in terms of yield increase, nitrogen and phosphorus use efficiency, based on 171 peer reviewed publications that met eligibility criteria. Major findings are: (i) the superiority of biofertilizer performance in dry climates over other climatic regions (yield response: dry climate +20.0 ± 1.7%, tropical climate +14.9 ± 1.2%, oceanic climate +10.0 ± 3.7%, continental climate +8.5 ± 2.4%); (ii) meta-regression analyses revealed that yield response due to biofertilizer application was generally small at low soil P levels; efficacy increased along higher soil P levels in the order arbuscular mycorrhizal fungi (AMF), P solubilizers, and N fixers; (iii) meta-regressions showed that the success of inoculation with AMF was greater at low organic matter content and at neutral pH. Our comprehensive analysis provides a basis and guidance for proper choice and application of biofertilizers.