Regenerative Soil Management: Restoring Soil Health, Biodiversity and Ecosystem Functions for Sustainable Agriculture

Climate-Smart Agriculture in Developing Countries: Scaling Science, Innovation and Policy Integration

Pavan Nitharwal, Mahendra Junjariya, Kusum Choudhary, Deeraj Sain — Fri, 16 Oct 2026 00:00:00 +0000

Climate-smart agriculture (CSA) has become a prominent framework for linking agricultural development with climate adaptation and, where feasible, mitigation. Yet its expansion in developing countries has often been treated as a technology-diffusion problem, even though persistent gaps in uptake, durability and distributional benefit point to deeper constraints in research systems, institutions, finance and policy coordination. This critical narrative review synthesises evidence published from 2010 to 18 July 2026 on how CSA science, innovation and policy can be integrated for responsible scaling in low- and middle-income settings. The literature indicates that many CSA practices can improve productivity, income, food security or resilience under particular conditions, but effects are heterogeneous and causal evidence remains uneven. Mitigation outcomes are less consistently measured than productivity and adaptation, while long-term resilience, dis-adoption, spillovers and equity are rarely evaluated. Adoption studies repeatedly identify extension, training, climate information, farmer organisations, tenure security and access to finance as enabling factors, yet their effects depend on the resource intensity and compatibility of specific practices. Evidence from scaling initiatives shows that reach is greatest when technical options are embedded in service delivery, value chains, climate information systems and public policy, but broad reach can weaken local fit and exclude resource-constrained groups. Science-policy platforms, participatory targeting and flexible financing can improve alignment, although institutional fragmentation and project dependence remain common. The synthesis therefore reframes CSA scaling as a portfolio-and-system alignment challenge rather than the replication of a standard package. Effective scale requires locally valid science, innovation systems that reduce risk and transaction costs, and policy architectures that coordinate incentives, public goods, safeguards and accountability across farm, landscape and national levels. Future research should prioritise longitudinal and experimental or quasi-experimental designs, comparable multi-pillar metrics, distributional analysis and evaluation of policy mixes rather than isolated technologies.

Root Exudates as Drivers of Soil Nutrient Cycling: Molecular Mechanisms, Rhizosphere Processes and Agronomic Opportunities

P. Raja Sekhar — Fri, 16 Oct 2026 00:00:00 +0000

Root exudates are a chemically diverse and highly regulated interface through which plants modify nutrient availability, microbial activity and soil organic matter turnover in the rhizosphere. This critical narrative review evaluates how molecular control of exudation is coupled to phosphorus, nitrogen, iron, zinc and potassium cycling, and assesses how securely these mechanisms can be translated into agronomic practice. Evidence was integrated across molecular genetics, plant physiology, soil biogeochemistry, microbial ecology and agricultural studies. The strongest mechanistic chains occur where specific metabolites, transport processes and nutrient outcomes have been connected by mutants, transporter studies, isotope tracing or soil-based validation. Examples include carboxylate and proton release by phosphorus-starved cluster roots, coumarin-mediated iron mobilisation in dicots, phytosiderophore-mediated metal acquisition in grasses, legume signalling to rhizobia, and biological nitrification inhibition by grass and sorghum root compounds. By contrast, broad claims that higher total exudation necessarily improves nutrient acquisition are poorly supported because exudates are rapidly sorbed, transformed or mineralised, and can intensify microbial immobilisation or soil organic matter priming as well as nutrient release. Exudate composition, flux, timing and spatial deployment are therefore more informative than total carbon release. Major uncertainty arises from hydroponic sampling artefacts, limited in situ metabolite recovery, weak comparability among analytical workflows, and a shortage of field experiments that link exudate traits to nutrient-use efficiency across contrasting soils. Agronomic opportunities are credible but conditional: breeding or managing crops for inducible, nutrient-specific exudation; exploiting interspecific facilitation and biological nitrification inhibition; and matching crop genotypes with responsive microbiomes are more defensible than attempts to maximise exudation indiscriminately. Progress will depend on soil-realistic phenotyping, isotope-enabled causal experiments, spatially resolved metabolomics, and multi-environment field validation that quantifies both nutrient gains and carbon, greenhouse-gas and ecological trade-offs.

The Rhizosphere as an Agronomic Frontier: Engineering Root-Soil-Microbiome Interactions for Sustainable Crop Production

Parthiv Rhythm Das, Pintu Kumar, Imtiyaz T. Nazki, R. Jayasankaramoorthy — Fri, 16 Oct 2026 00:00:00 +0000

The rhizosphere offers opportunities to improve crop resource acquisition and stress management, but successful manipulation of root-associated microorganisms remains less predictable than the mechanisms proposed to explain their benefits. This critical narrative review evaluates how host traits, soil physical and chemical conditions, resident communities and management jointly determine the performance of rhizosphere interventions. Literature covering 2012 to 27 July 2026 was selected through targeted scholarly searches, bibliographic verification and qualitative appraisal of causal inference, experimental realism and agronomic relevance. The synthesis distinguishes mechanisms demonstrated in simplified systems from microbial establishment, functional activity, harvestable yield and independently verified environmental benefits. Genetic and chemical studies provide convincing examples of host-mediated recruitment, microbial regulation of root development and community-dependent disease suppression. Recent field studies also demonstrate conditional benefits from mycorrhizal inoculation, bacterial consortia and altered nitrogen cycling. Nevertheless, colonisation does not consistently translate into crop response, positive biomass effects cannot automatically be interpreted as grain-yield gains, and molecular indicators do not establish nutrient transfer or carbon persistence. Apparent disagreements frequently arise from differences in inoculant quality, soil resource limitation, resident-community competition, crop developmental stage and the chosen comparator. A staged evaluation framework is developed around diagnosis, mechanism, ecological compatibility, field benefit and sustainability accounting. It favours host and habitat management where useful functions are already present, and targeted inoculation where a defined functional deficit and a compatible establishment niche can be demonstrated. Priority research should combine strain-resolved tracking and direct process measurements with factorial, multi-environment field trials, independent prediction tests and transparent economic assessment. Rhizosphere engineering is therefore best understood as context-dependent agronomic design rather than the addition of universally beneficial microorganisms. Its contribution to sustainable production will depend on identifying where interventions work, explaining where they fail and demonstrating that resource savings persist without transferring costs to soil fertility, environmental quality or farmers.