Biofertilizers Boost Crop Yields and Soil Health, Major Meta-Analysis Finds

A sweeping new meta-analysis of Indian agriculture has delivered some of the strongest quantitative evidence yet that living microbial inputs can raise crop yields while simultaneously improving the health of the soils that underpin them. Drawing on 2,031 paired observations from 135 peer-reviewed field studies, researchers found that biofertilizer application increased crop yields by an average of 14.43 percent, with measurable gains in soil nutrient availability of more than 16 percent and a 5.76 percent rise in soil organic carbon. The study, published in Clean Technologies and Environmental Policy, goes beyond most previous assessments by pairing these agronomic results with an economic valuation of the ecosystem services that biofertilized fields provide, arriving at figures that could reshape how policymakers weigh the true returns on sustainable farming investments.

Biofertilizers are formulations of living microorganisms, including nitrogen-fixing bacteria, phosphate-solubilizing microbes, and mycorrhizal fungi, that colonize the rhizosphere and help plants acquire nutrients that would otherwise remain locked in soil minerals or the atmosphere. Unlike synthetic fertilizers, which deliver nutrients in chemically available form but can contribute to greenhouse gas emissions, water pollution, and long-term soil degradation, biofertilizers work by augmenting the soil’s own biological machinery. Their appeal has grown as India, like much of the world, confronts the twin pressures of feeding a rising population and reducing the environmental footprint of agriculture, a sector that is a major driver of several planetary boundaries being exceeded.

To quantify the joint effects of these microbial inputs, the research team, led by Dinesh Chand Meena of ICAR-National Institute of Agricultural Economics and Policy Research in New Delhi, applied the rigorous statistical machinery of modern meta-analysis. Effect sizes were calculated using the natural logarithm of the response ratio, a standard metric in experimental ecology that expresses the proportional change between treated and untreated plots. Mixed-effects models were then used to estimate overall and subgroup responses across biofertilizer types, crop categories, soil types, and agro-climatic zones, while heterogeneity among studies was assessed with the I-squared statistic and the Q-test at a significance threshold of p less than 0.05. This framework allowed the researchers to distinguish consistent, generalizable patterns from the noise inherent in hundreds of individually small field trials.

The headline finding was a robust average yield gain of 14.43 percent, but the subgroup analysis revealed a more nuanced picture. Mixed inoculants, products combining several microbial strains, outperformed single-strain formulations, suggesting that complementary microbial functions, such as simultaneous nitrogen fixation and phosphorus solubilization, deliver synergistic benefits. Among single inoculants, Azospirillum, a genus of plant-associated bacteria best known for biological nitrogen fixation but increasingly recognized for hormone production and root growth promotion, showed the strongest yield response at 16.8 percent. The result aligns with a growing body of work indicating that Azospirillum’s benefits extend well beyond simply adding nitrogen to the plant-soil system.

Crop type mattered considerably. Horticultural crops responded more strongly than field crops, with fruits showing an average yield increase of 18.93 percent and vegetables 16.61 percent. This pattern is consistent with the biology of high-value, intensively managed systems, where root-zone conditions and nutrient demand favor microbial activity. Soil texture also emerged as a decisive variable: loamy soils, with their balanced mixture of sand, silt, and clay, showed the largest positive response at 17.65 percent, likely because their structure supports both moisture retention and the aeration that beneficial microbes require. The findings imply that blanket recommendations for biofertilizer use may be less effective than targeted strategies matched to crop and soil context.

Beyond yields, the analysis documented substantial improvements in the soil itself. Biofertilizer use increased soil nutrient availability by more than 16 percent, reflecting enhanced mobilization of nitrogen, phosphorus, and potassium, and raised soil organic carbon by 5.76 percent. That carbon figure is particularly significant in the context of climate policy, because soil organic carbon is both a key indicator of soil fertility and a reservoir for carbon sequestration. Previous meta-analyses have similarly found that biofertilization raises soil organic carbon concentrations, and long-term field studies in India and China have linked sustained microbial inoculation with improved aggregate stability and carbon storage. The new analysis consolidates this evidence for Indian conditions, where land degradation affects a substantial share of the cultivated area.

Perhaps the most distinctive contribution of the study is its economic dimension. The researchers estimated the total economic value of the ecosystem services associated with biofertilizer use, reaching USD 133.15 per hectare in field crops and USD 239.81 per hectare in horticultural crops. Strikingly, non-market ecosystem services, benefits such as soil formation, nutrient cycling, and carbon storage that do not pass through any market and therefore go unpriced in conventional farm accounting, contributed up to 43 percent of the total value in field cropping systems. This means that nearly half of what biofertilizers deliver to society is invisible in standard yield-and-price calculations, a blind spot that has historically led to the underprovision of practices with large public benefits.

The valuation approach reflects a broader shift in agricultural economics toward recognizing farms as providers of ecosystem services rather than commodities alone. Frameworks for integrating ecosystem service values into landscape planning and decision-making have matured over the past decade, and national bodies in India have begun exploring payments for ecosystem services in agriculture. By attaching concrete dollar figures to the soil health and carbon benefits of biofertilizers, the new analysis gives policymakers a defensible basis for subsidy design, incentive schemes, and climate finance proposals that reward farmers for outcomes beyond raw production. It also helps explain why adoption of biofertilizers has lagged despite their low cost: farmers capture only the market-priced fraction of the benefits, while the rest accrues to society at large.

The study’s authors frame biofertilizers as a scalable pathway toward climate-resilient, Sustainable Development Goal-aligned agricultural development, provided that appropriate policy support is in place. That caveat matters. Meta-analyses of other sustainable intensification practices, from conservation agriculture to integrated nutrient management, have shown that average benefits can mask substantial variability and that adoption barriers, including input quality, farmer knowledge, and supply chains, often determine real-world outcomes. The inherent difficulties of developing soil microbial inoculants, including strain selection and consistency across environments, remain active research challenges. Still, the sheer weight of evidence assembled here, more than two thousand paired observations spanning crops, soils, and agro-climatic zones, makes a compelling case that microbial inputs can deliver productivity and environmental gains together rather than as a trade-off.

For a world grappling with slowing agricultural productivity growth under climate change, rising fertilizer costs, and mounting pressure to cut emissions, the message is timely. Biofertilizers will not replace synthetic fertilizers outright, and their performance is context-dependent, strongest in loamy soils and horticultural systems, and enhanced when multiple strains are combined. But the analysis suggests that integrating them intelligently into nutrient management could raise yields by double digits, rebuild soil carbon, and generate hundreds of dollars per hectare in societal value, much of it currently uncounted. As governments search for win-win interventions in the race to make food systems sustainable, the smallest players in the field, the microbes in the soil, are proving to be among the most consequential.

Subject of Research: The effects of biofertilizers on crop productivity, soil ecosystem services, and their economic valuation in Indian agriculture

Article Title: Effects of biofertilizers on crop productivity and soil ecosystem services: a meta-analysis

Article References: Meena, D. C., Meena, V. S., Kumari, M., & Sharma, I. (2026). Effects of biofertilizers on crop productivity and soil ecosystem services: a meta-analysis. Clean Technologies and Environmental Policy, 28(10), Article 247. https://doi.org/10.1007/s10098-026-03597-3

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03597-3

Keywords: biofertilizers, crop productivity, soil health, ecosystem services, meta-analysis, soil organic carbon, sustainable agriculture, Azospirillum, economic valuation, carbon sequestration, Indian agriculture, soil fertility