Next-Generation Agricultural Soil Science: From Rhizosphere Ecology and Soil Microbiomes to Climate-Resilient Farming

Artificial Intelligence in Agronomic Decision-Making: From Crop Monitoring to Prescriptive Field Management

2026-10-13T05:56:02+00:00

Artificial intelligence (AI) is increasingly embedded in agronomic sensing, crop diagnosis, yield forecasting, irrigation scheduling, nutrient management, crop protection and field robotics. Yet the literature often treats high predictive accuracy as evidence of decision value, even though agronomic decisions require reliable inference under variable field conditions, explicit objectives and constraints, and a credible link from prediction to intervention. This critical narrative review examines the transition from crop monitoring to prescriptive field management and asks where AI has demonstrated operational agronomic value rather than task-specific technical performance. Literature published principally from 1 January 2010 to 20 July 2026 was examined, with earlier seminal work retained where necessary. Evidence was synthesised across remote and proximal sensing, computer vision, multimodal data fusion, yield prediction, irrigation, nitrogen management, site-specific crop management, selective spraying, robotics and agricultural decision support. The strongest evidence supports AI for perception and state estimation, especially where labelled data are abundant and sensing conditions are controlled. Performance becomes less consistent under domain shift across fields, seasons, cultivars, sensors and management regimes. Predictive models can improve forecasting, but prediction alone does not identify the management action that will improve an outcome. More decision-relevant evidence is emerging from hybrid crop-model-machine-learning systems, in-season nitrogen recommendation, irrigation decision support and perception-to-actuation weed management, although multisite and multi-season intervention validation remains limited. A central conclusion is that agronomic AI should be evaluated as a decision system rather than only as a model. Trustworthy prescriptive field management requires external validation, uncertainty calibration, causal or response-aware reasoning, economically and environmentally meaningful objectives, machinery interoperability, human oversight and feedback from intervention outcomes. Future progress depends on shifting research benchmarks from model accuracy to decision quality, robustness and realised field benefit.

Nanofertilisers in Crop Production: Agronomic Potential, Nutrient-Use Efficiency and Environmental Safety

2026-10-13T06:00:03+00:00

Nanofertilisers are being developed to improve the synchrony between nutrient supply and crop demand, reduce nutrient losses, and enable lower-dose foliar or soil applications. Yet the term encompasses chemically and functionally dissimilar products, from nanoscale nutrient oxides and apatites to nutrient-loaded nanocarriers, nanohybrids and commercial liquid formulations. This heterogeneity has encouraged broad claims that are not always supported by nutritionally equivalent controls or field-scale evidence. This critical narrative review evaluates the agronomic potential, nutrient-use efficiency and environmental safety of nanofertilisers, with emphasis on the distinction between material properties, nutrient delivery mechanisms and demonstrable farm-level benefit. Evidence was selected from peer-reviewed literature indexed in major open scholarly sources and assessed for formulation characterisation, comparator validity, nutrient-dose equivalence, study scale, nutrient recovery, environmental relevance and independent replication. The evidence supports a conditional rather than universal advantage. Nanoscale zinc, iron and phosphate systems can improve nutrient availability or biofortification in specific crop–soil combinations, while slow-release nanohybrids can alter nutrient-release kinetics. Recent multi-location and multi-season field studies of nano-urea and nano-diammonium phosphate indicate that moderate reductions in conventional nutrient inputs can sometimes maintain yield when nanoformulations are used at appropriate crop stages. Conversely, aggressive substitution, poorly matched controls and efficiency metrics that increase automatically as fertiliser dose declines can overstate performance. Nanoparticle uptake also cannot be inferred solely from plant response because dissolution, transformation and ionic uptake may dominate. Environmental advantages are plausible when total nutrient loading and losses decline, but nano-specific fate, soil microbial effects, long-term accumulation, residue speciation and food-chain exposure remain incompletely resolved. Progress therefore depends on nutrient-equivalent field comparisons, rigorous particle characterisation, isotope or speciation methods, full nutrient budgets, realistic ecotoxicology and independent multi-environment validation. Nanofertilisers should be evaluated as formulation-specific nutrient-management technologies rather than as a single superior class of fertilisers.

Microbial Nutrient Mining in the Rhizosphere: Unlocking Native Soil Fertility for Low-Input Agriculture

2026-10-13T06:04:37+00:00

Low-input agriculture depends not only on reducing fertiliser use but on improving the capacity of crops to acquire nutrients already present in soil. This critical narrative review evaluates microbial nutrient mining in the rhizosphere as an operational concept encompassing microbial processes that mobilise, mineralise, weather, redistribute or recycle sparingly available native and legacy nutrient pools. The evidence shows that the strongest mechanistic basis exists for phosphorus mobilisation through organic-acid-mediated dissolution, phosphatase-driven mineralisation, microbial turnover and mycorrhizal transport. Potassium release from minerals, iron acquisition through ligand-mediated chemistry, zinc solubilisation and microbial sulfur transformations extend the concept beyond phosphorus, although their agronomic evidence bases are less mature. Root exudates are central because they supply carbon, alter pH and ligand chemistry, and select microbial partners, but this creates an intrinsic trade-off: the same carbon subsidies that stimulate nutrient acquisition can intensify microbial competition and rhizosphere priming of soil organic matter. Meta-analyses and field syntheses indicate that microbial inoculants and arbuscular mycorrhizal fungi can improve nutrient acquisition and yield, yet effect sizes are strongly context dependent and are generally smaller in field than in controlled experiments. A recurring weakness is the assumption that in vitro solubilisation predicts net nutrient transfer to crops; in soil, released nutrients may be sorbed, reprecipitated, immobilised by microbes or lost before root capture. For low-input systems, the most defensible strategy is therefore not indiscriminate inoculation but ecological management of plant-microbiome-soil interactions, combined with targeted inoculants where colonisation and function are demonstrated. Microbial mining should be treated as a means of increasing access and synchrony rather than creating nutrients. Its long-term value depends on replenishing exported nutrient stocks, protecting soil organic matter and matching mobilisation to crop demand. Future progress requires isotope-resolved field experiments, trait-based microbiome design, spatially explicit measurements and multi-season nutrient budgets that distinguish gross mobilisation from net plant acquisition.

Plant Growth Promoters and Biostimulants in Modern Agronomy: A Critical Synthesis of Mechanisms, Field Performance and Crop Nutrition

2026-10-13T06:07:14+00:00

Plant biostimulants and related growth-promoting inputs are increasingly used to improve crop productivity, nutrient use efficiency and stress resilience while reducing dependence on intensive fertilisation. Their agronomic value is difficult to generalise because function-defined biostimulants, nutrient-mobilising microbial inoculants and other growth-promoting inputs differ in composition, mechanism and dependence on crop genotype, soil, climate, nutrient supply and application practice. This critical narrative review evaluates functional boundaries, mechanistic evidence, field performance and integration with crop nutrition. Literature was identified through live scholarly searching and citation tracing, with priority given to verified peer-reviewed studies, field experiments, meta-analyses and mechanistic work. The evidence supports recurring pathways involving root-system architecture, membrane transport and nutrient assimilation, microbial nutrient mobilisation or fixation, phytohormone and redox signalling, and abiotic-stress acclimation. Mechanistic plausibility, however, does not ensure field reliability. Quantitative syntheses generally show positive average responses, but effects are smaller and more variable under field conditions, and crop identity, soil properties, formulation, dose, application method, native microbiota and baseline fertility can materially alter outcomes. Statistically significant mean responses also should not be equated automatically with economically meaningful farm benefits. The strongest case for crop-nutrition integration is therefore context-dependent improvement in nutrient capture, utilisation and yield stability, not universal fertiliser replacement. Reliable translation requires product-resolved characterisation, multi-site and multi-season testing, explicit nutrient-response gradients, clearly defined nutrient use efficiency metrics, and economic assessment alongside biological efficacy. Biostimulants can contribute to nutrient-efficient agronomy when treated as evidence-defined management components rather than interchangeable growth-promoting products.