The approach at the heart of the study is known as the soil test crop response integrated plant nutrition system, or STCR-IPNS. Rather than applying a blanket fertilizer recommendation to every field, the STCR method translates the measured fertility status of a specific soil into a precise fertilizer dose calculated to achieve a chosen yield target. In this experiment, the researchers paired that prescription with the integrated plant nutrition system concept: nutrients supplied by farmyard manure were credited against the calculated inorganic fertilizer requirement, so that manure and mineral fertilizer worked together rather than in parallel. The team compared this manure-adjusted prescription against fertilizer-only STCR prescriptions, organic-only inputs, the recommended dose of fertilizer, the recommended dose plus farmyard manure, and local farmer practice, across yield targets of 0.8, 1.0, and 1.2 tonnes per hectare.

The field trial was conducted at Poolampatty in the Vagarai block of Dindigul district, on a red, non-calcareous sandy loam of the Palaviduthi series, classified as a Typic Rhodustalf. The soil was mildly alkaline with a pH of 8.02, low in organic carbon at 0.35 percent, and contained available nitrogen, phosphorus, and potassium at 230, 25, and 370 kilograms per hectare respectively. Greengram cultivar CO 8 was grown at 30 by 10 centimeter spacing in a randomized block design with three replications, under a warm semi-arid monsoonal climate with only 26.6 millimeters of rain during the cropping period. Because the study covered a single season, the authors are careful to frame it as short-term validation evidence rather than a final recommendation.

The results were striking. The manure-adjusted STCR-IPNS treatment at the highest yield target of 1.2 tonnes per hectare achieved 105.8 percent of its target, meaning the prescription slightly over-delivered. That treatment produced plants 56.63 centimeters tall, with a leaf area index of 3.98 and SPAD chlorophyll readings of 50.76, the strongest canopy response in the experiment. Yield components followed suit, with more pods per plant, more seeds per pod, and heavier test weights than in fertilizer-only prescriptions at matched targets. Importantly, the yield advantage came from greater total biomass production rather than a shift in harvest index, indicating that better nutrient supply fueled overall growth rather than simply reallocating assimilates to grain.

Nutrient acquisition told a similar stoichiometric story. At harvest, the top treatment recorded peak uptake of 56.01 kilograms of nitrogen, 16.96 kilograms of phosphorus, and 41.43 kilograms of potassium per hectare across grain and haulm. The researchers mapped the relative balance of the three nutrients and found that manure-adjusted prescriptions moved the crop closest to balanced uptake, while control and organic-only plots sat far from that ideal. At equivalent yield targets, the integrated system recovered more of the applied nutrients than the fertilizer-only prescription, suggesting that the organic component improved the synchrony between nutrient release and crop demand, a long-standing goal of precision nutrient management.

Grain quality also responded. Crude protein, calculated from grain nitrogen using a conversion factor of 6.25, and true protein, measured by the Folin phenol method, both peaked under the manure-adjusted integrated treatment, along with crude protein yield per hectare. Fibre and sugar fractions shifted as well, indicating that the treatment altered carbohydrate partitioning in the grain alongside its protein enrichment. For a pulse crop whose value rests on protein density, this matters: the study suggests that yield gains need not come at the expense of nutritional quality, and may in fact reinforce it when nitrogen supply is well synchronized with crop demand.

But the most novel part of the study lies underground. The researchers measured a battery of rhizosphere indicators across the vegetative, flowering, and harvest stages: the activities of urease, alkaline phosphatase, beta-glucosidase, nitrate reductase, and dehydrogenase, which together represent nitrogen, phosphorus, carbon, and redox-linked biochemical processes; microbial biomass carbon and nitrogen; potentially mineralizable nitrogen; populations of bacteria, fungi, and actinomycetes; basal respiration; and the metabolic quotient, which expresses respiration per unit of microbial biomass. The integrated treatment lifted microbial biomass, most enzyme activities, and microbial populations above both fertilizer-only prescriptions and non-prescription benchmarks, pointing to a more functionally active rhizosphere community.

The authors are notably careful about what they claim. Soil organic carbon, labile carbon, and water-soluble carbon showed treatment-related trends but did not separate statistically across all stages, so they interpret the carbon response as short-term substrate support from manure rather than a confirmed improvement in carbon pools. Beta-glucosidase, likewise, was not consistently distinguishable from the next-best treatment and is treated as part of an overall enzyme pattern rather than standalone proof of enhanced carbon turnover. The metabolic quotient did not decline uniformly across stages, so it is discussed as a stage-dependent indicator rather than conclusive evidence of improved microbial carbon-use efficiency. This restraint strengthens the credibility of the findings that do hold up.

To integrate all these signals, the team built a soil quality index using principal component analysis. Indicators were standardized, components with eigenvalues above one were retained, and variables with absolute loadings of at least 0.70 formed a minimum data set, which was scored and weighted to produce a single index value. The index clearly separated the manure-adjusted integrated treatment, especially at the highest yield target, from fertilizer-only prescriptions, organic-only inputs, blanket recommendations, farmer practice, and the unfertilized control. Enzyme activity, microbial biomass, respiration balance, and nutrient availability emerged as the dominant drivers of the index, confirming that the treatment’s superiority rested on coordinated changes across multiple soil functions rather than any single variable.

The broader significance is a validation framework. Target-yield fertilizer prescriptions have historically been judged almost exclusively on whether the crop hits its yield goal, with little attention to whether the prescription sustains the enzyme-mediated nutrient cycling and microbial regulation on which long-term soil fertility depends. By coupling yield achievement, nutrient uptake, grain quality, enzyme activity, microbial functional response, and a multivariate soil quality index in one evaluation, this study shows that a prescription can be designed to do both jobs at once. The authors caution that the reliability of the approach depends on site-specific soil test calibration, accurate assessment of manure nutrient composition, and realistic consideration of input availability and economics, and they call for multi-season, multi-location trials across contrasting Alfisols and other pulse systems. If those trials confirm the pattern, manure-adjusted, soil-test-based prescriptions could become a practical template for pulse production that treats soil health not as a constraint on yield, but as part of the yield equation itself.

Subject of Research: Target-yield based integrated nutrient management for greengram productivity and soil biological quality in an Alfisol

Article Title: Target yield based integrated nutrient management improves greengram productivity nutrient uptake and soil biological quality in an Alfisol

Article References: Abhirami, P., Venkateswarlu, M., Maragatham, S., Rajeswari, R., & Balachandar, D. (2026). Target yield based integrated nutrient management improves greengram productivity nutrient uptake and soil biological quality in an Alfisol. Discover Soil, 3(1), Article 169. https://doi.org/10.1007/s44378-026-00328-4

Image Credits: AI Generated

DOI: 10.1007/s44378-026-00328-4

Keywords: greengram, STCR-IPNS, target yield prescription, farmyard manure, integrated nutrient management, Alfisol, soil quality index, soil enzymes, microbial biomass, nutrient uptake, rhizosphere, Tamil Nadu

The findings, published in the Journal of Agriculture and Food Research, carry serious implications for how growers interpret soil tests, not just in Florida but anywhere crops are grown on phosphorus-enriched soils. Florida’s potato industry is substantial, with roughly 6,800 hectares harvested in 2023 producing 190,500 megagrams of tubers valued at 105.4 million dollars. Because potato plants have shallow root systems, limited root hairs, and a notoriously weak ability to scavenge phosphorus from soil, the crop is heavily dependent on fertilizer inputs. Decades of repeated applications have left many fields with elevated soil-test phosphorus values, well above the thresholds where guidelines say no additional fertilizer is needed.

Yet growers in the region have repeatedly reported yield losses when they withheld phosphorus in high-testing soils. To investigate, the research team ran a factorial experiment over three growing seasons at the UF/IFAS Hastings Agricultural Extension Center. Two adjacent 0.3-hectare sites were planted with the chipping cultivar Atlantic each spring from 2023 to 2025. The sites shared a soil type, a sandy Alfisol of the Ellzey series, but differed sharply in their starting phosphorus status. Site 1 averaged 50.6 milligrams per kilogram of Mehlich-1 extractable phosphorus in the surface 15 centimeters, while site 2 averaged 110.9 milligrams per kilogram. Under the historical interpretation system, both values fall into the high or very high categories, which normally trigger no phosphorus recommendation at all.

Each site received ten treatment combinations: five phosphorus pentoxide rates, from zero up to 269 kilograms per hectare, crossed with two nitrogen rates of 168 and 280 kilograms per hectare. The team tracked soil phosphorus and mineral nitrogen through the profile, measured plant biomass and nutrient uptake at 50, 70, and 90 days after planting, and mechanically harvested and graded tubers according to USDA size classes. A total of 240 plot-level observations across six site-years fed into the analysis.

The results were striking. At site 1, the field with the lower starting phosphorus, fertilization raised total yield from 21.6 megagrams per hectare in the unfertilized control to an average of 30.6 megagrams across rates of 135 to 269 kilograms of phosphorus pentoxide per hectare, a gain of roughly 42 percent. Marketable yield climbed even more dramatically, from 16.4 to about 25.1 megagrams per hectare, an increase of 53 percent. Most of the gain came from intermediate-sized tubers, the A23 fraction, which jumped from 9.1 to 17.4 megagrams per hectare. Tuber specific gravity, a key quality measure for chipping potatoes, also improved. At site 2, by contrast, phosphorus rate had no significant effect on total yield, marketable yield, tuber size distribution, or specific gravity, and the yield gap between the two sites vanished once phosphorus was applied at 135 kilograms per hectare or more.

The physiological story behind those numbers is revealing. At site 1, phosphorus fertilization increased whole-plant dry biomass from 5.48 to 7.96 megagrams per hectare and nitrogen uptake from 89.5 to 132.2 kilograms per hectare, while nitrogen uptake efficiency rose from 26.8 to 42.3 percent. In other words, when phosphorus is limiting, the constraint ripples outward: restricted root and shoot growth lower the plant’s demand for nitrogen and its capacity to acquire it. Adequate phosphorus supply therefore unlocks the crop’s ability to use nitrogen efficiently. At site 2, the higher-phosphorus field, the only response to added fertilizer was a modest increase in nitrogen uptake efficiency, with biomass and productivity per unit of nitrogen unchanged. Notably, whole-plant phosphorus uptake at site 2 pulled ahead of site 1 after 50 days after planting and stayed ahead through harvest, showing that the richer soil sustained phosphorus delivery during the critical tuber-bulking period.

Nitrogen management, meanwhile, turned out to be a non-player in the phosphorus story. The two nitrogen rates produced clearly different soil mineral nitrogen levels, but phosphorus rate by nitrogen rate interactions were limited to efficiency indices, and the crop’s principal responses to phosphorus were identical under both nitrogen regimes. Raising nitrogen from 168 to 280 kilograms per hectare never increased yield and consistently reduced both nitrogen uptake efficiency and partial factor productivity, the tubers produced per kilogram of nitrogen applied. In the difficult 2024 season, when seed-piece decay cut plant stands by 57 percent, the higher nitrogen rate actually lowered total and marketable yields by about 4.4 megagrams per hectare. The team stresses this does not establish 168 kilograms as a regional optimum, only that extra nitrogen neither overcame phosphorus deficiency nor added yield when phosphorus was sufficient.

The soil itself told a story of accumulation and movement. Over the experiment, surface Mehlich-1 phosphorus in fertilized plots rose by roughly 63 to 67 milligrams per kilogram, while unfertilized controls declined by 7 to 27. Concentrations peaked near crop emergence after pre-plant fertilization and then shifted, with measurable increases detectable down to the 30 to 45 centimeter layer, particularly at site 2 in 2024. Because most potato roots in these seepage-irrigated soils sit within the top 30 centimeters, phosphorus moving below that depth is effectively out of reach for the crop and represents a potential pathway for transport off-site, although drainage losses were not directly measured in this study.

To translate the yield responses into a usable threshold, the researchers modeled relative yield against Mehlich-1 phosphorus measured at harvest using four normalization methods and several calibration models. The best-performing combination, the MAXRATE normalization paired with a modified arcsine-log model, explained 41 percent of the variation in relative yield. It estimated critical phosphorus levels of 63.6 milligrams per kilogram for 80 percent relative yield, 81.4 for 90 percent, and 96.2 for 95 percent, with the response curve flattening above roughly 100 milligrams per kilogram. Those numbers are far above the historical sufficiency threshold of about 30 milligrams per kilogram of Mehlich-1 phosphorus, and they even exceed the high category boundaries of both the Mehlich-1 and Mehlich-3 systems currently used in Florida. The moderate fit and the overlap of high- and low-yielding observations across the range reinforce a point echoed in decades of Ohio fertilizer trials: a soil test is a probabilistic index of potentially available phosphorus, not a deterministic boundary between deficiency and sufficiency.

The practical message is nuanced. A high soil-test classification does not guarantee a field will ignore added phosphorus, and skipping fertilizer in a responsive high-testing soil can be costly; conversely, blanket phosphorus applications to nonresponsive soils simply inflate soil phosphorus reserves and environmental risk. The authors caution that their critical level of 96.2 milligrams per kilogram derives from a specific soil, cultivar, sampling protocol, and set of conditions, and that each initial phosphorus status was represented by a single site with different irrigation infrastructure, so broader calibration and independent validation are needed before any new threshold enters recommendations. Still, the study makes a compelling case that Florida’s provisional allowance of up to 134 kilograms of phosphorus pentoxide per hectare, applied regardless of soil test, is a blunt instrument. A validated critical level could enable a tiered strategy: full fertilization below the threshold, crop-removal-based maintenance near it, and deliberate drawdown above it, protecting both potato yields and the waterways downstream of phosphorus-enriched sands.

Subject of Research: Potato yield and nutrient uptake responses to phosphorus fertilization in phosphorus-enriched sandy soils

Article Title: Initial soil phosphorus status governs potato yield and nutrient uptake responses to fertilization in P-enriched sandy soils

Article References: Oliveira, J. D. M., de Castro, G. F., da Silva, B. A., Clark, M. W., Nunez, G. H., Guzmán, S., & Zotarelli, L. (2026). Initial soil phosphorus status governs potato yield and nutrient uptake responses to fertilization in P-enriched sandy soils. Journal of Agriculture and Food Research, 31, Article 103296. https://doi.org/10.1016/j.jafr.2026.103296

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103296

Keywords: phosphorus, potato, soil testing, Mehlich-1, fertilizer recommendations, sandy soils, nitrogen use efficiency, critical phosphorus level, Florida agriculture, nutrient uptake, soil fertility, alfisols

The new study, published in the journal Blue Biotechnology, put five native red seaweed species to the test: Sarconema filiforme, Gracilaria corticata, Scinaia carnosa, Gracilaria dura, and Acanthophora sp. All were collected from the intertidal rocky shore at Veraval on Gujarat’s coast, while the effluent came from a shrimp farm at Mithi Virdi in Bhavnagar. The researchers cultivated the seaweeds in controlled laboratory tanks at 24 degrees Celsius with a 12:12 light-dark cycle and constant aeration, then transferred precisely weighed two-gram samples into flasks containing 400 milliliters of effluent water. Over the following days, they sampled the water at intervals ranging from fifteen minutes to 96 hours, measuring how quickly each species stripped nutrients from the polluted medium.

The analytical approach was rigorous. Phosphate concentrations were determined using the ascorbic acid method, with the resulting blue complex measured at 880 nanometers on a UV-Vis spectrophotometer. Nitrate was quantified through the vanadium chloride method, detected as a pink complex at 543 nanometers, while ammonium was estimated via the phenate method, which produces indophenol blue measured at 640 nanometers. Calibration curves with R-squared values above 0.99 were required for valid quantification, and all analyses were run in duplicate alongside blanks and standards to guard against contamination and instrument drift. This colorimetric toolkit allowed the team to track the disappearance of each nutrient with high precision across the entire time course.

The results were striking. Sarconema filiforme emerged as the overall champion, achieving the highest removal efficiencies across the board: roughly 85.77 percent of phosphate, 100 percent of nitrate, and 73.80 percent of ammonium within the experimental window. When uptake was normalized to biomass, S. filiforme again led the pack, absorbing nitrate at 1.18 micromoles per gram of wet weight per hour and ammonium at 2.16 micromoles per gram of wet weight per hour. Phosphate removal was also strong across all species, with Scinaia carnosa, Gracilaria corticata, and Gracilaria dura each removing more than 81 percent, while Acanthophora sp. trailed at about 63 percent but with high variability.

Nitrate proved to be the nutrient the seaweeds craved most. All five species achieved near-complete nitrate removal, and Acanthophora sp. accomplished something remarkable: complete nitrate uptake in just 48 hours, the fastest assimilation pattern recorded in the study. The overall preference followed a clear sequence of nitrate greater than phosphate greater than ammonium, a pattern the researchers attribute to red algae’s protein-rich pigments and high nitrogen quotas, which make them especially effective at assimilating nitrogen compounds. Ammonium, by contrast, was taken up more slowly, likely because high concentrations are toxic and most seaweeds preferentially use nitrate as their nitrogen source when both are available.

The physiological mechanisms behind this cleanup are well understood. Seaweeds absorb dissolved inorganic nutrients through a combination of passive diffusion, facilitated diffusion, and active transport via carrier proteins embedded in their cell membranes. Ammonium is the energetically cheapest nitrogen source, requiring no chemical reduction before incorporation into amino acids, while nitrate must be converted to nitrite and then ammonium inside the cell before it can be used to build proteins. Phosphate enters through dedicated transporters and fuels energy transfer via ATP, nucleic acid synthesis, and membrane formation. This dual passive-and-active uptake machinery allows seaweeds to keep functioning even when ambient nutrient concentrations are low, and to surge when nutrients are abundant, exactly the conditions found in aquaculture effluent.

But the study also delivered a sobering caveat: the best removers are not necessarily the best survivors. Despite its stellar uptake numbers, Sarconema filiforme showed signs of physiological stress under prolonged exposure and eventually died in the high-ammonium effluent. Acanthophora sp., the nitrate sprinter, likewise suffered high mortality after its rapid initial performance. High ammonium is known to suppress the light-saturated photosynthetic electron transport rate and maximum quantum yield in other seaweed species, inhibiting photosynthesis to the point of death, and the researchers believe a similar mechanism may have doomed their top performer. Only Gracilaria corticata remained viable after extended exposure, staying healthy even after 20 days in effluent water, by which point the water’s color had visibly faded, a sign that the seaweed had absorbed most of the dissolved nutrients.

This survival difference carries a crucial lesson for designing real-world treatment systems: nutrient removal efficiency alone is not enough. Longevity and tolerance under high nutrient loads matter just as much. The effluent itself was punishingly concentrated, containing 14.56 milligrams per liter of phosphate, 18.34 milligrams per liter of nitrate, 57.38 milligrams per liter of ammonium, and a salinity of 18.56 grams per liter. The authors therefore propose a sequential bioremediation strategy that deploys multiple species in stages, matching each seaweed’s uptake profile and environmental tolerance to the conditions it will face. Fast but fragile species like Acanthophora sp. could handle the initial nitrate pulse, while hardy generalists like Gracilaria corticata provide sustained, long-term polishing.

The broader context makes this work especially timely. The concept of Integrated Multi-Trophic Aquaculture, or IMTA, pairs fed species like shrimp with extractive species like seaweeds and filter-feeding invertebrates, so that the waste of one becomes the resource of another. Seaweeds in such systems do more than clean the water; they also yield valuable biomass that can be harvested for food, agar and carrageenan production, fertilizers, medicines, and biofuels, turning a pollution problem into a secondary crop. Gujarat’s coastline alone hosts around 285 seaweed species, and the researchers emphasize that using indigenous, locally adapted species avoids the ecological risks of introducing invasive aliens while ensuring compatibility with local temperature and salinity regimes.

For a coastal industry that generates both export income and employment across India, the prospect of a low-cost, nature-based solution to effluent pollution is compelling. The study demonstrates that five common intertidal red seaweeds can strip the three principal eutrophying nutrients from shrimp farm wastewater within 96 hours, with one species achieving complete nitrate removal in half that time. The challenge now is scaling from laboratory flasks to farm-scale treatment channels, where light, temperature, and nutrient loads fluctuate far more than they did under controlled conditions. If the sequential approach holds up in the field, shrimp farms of the future may grow their own cleanup crews, harvesting both protein and clean water from the same system.

Subject of Research: Nutrient uptake efficiency of intertidal red seaweeds for bioremediation of shrimp farm effluent

Article Title: Time-course nutrient uptake efficiency of intertidal red seaweeds in shrimp farm effluent: a sustainable bioremediation approach

Article References: Jaiswar, S., Raval, D., Patel, P., & Bhagiya, B. K. (2025). Time-course nutrient uptake efficiency of intertidal red seaweeds in shrimp farm effluent: a sustainable bioremediation approach. Blue Biotechnology, 2(1), Article 23. https://doi.org/10.1186/s44315-025-00044-8

Image Credits: AI Generated

DOI: 10.1186/s44315-025-00044-8

Keywords: bioremediation, seaweed, shrimp aquaculture, nutrient uptake, eutrophication, red algae, Gracilaria corticata, Sarconema filiforme, IMTA, coastal pollution, sustainable aquaculture, wastewater treatment

The team searched the SCOPUS database using a deliberately stringent four-domain strategy, requiring studies to simultaneously address seaweed or marine algae, specific crop types, yield and productivity parameters, and nutrient uptake or soil fertility. From more than 55,000 seaweed-related records and over a million crop-focused publications in the database, the intersection yielded just 156 non-redundant English-language journal articles. That narrow funnel was intentional, the authors explain, because it captured only research sitting squarely at the soil–crop–nutrient nexus rather than the broader universe of algal science. A parallel search in Web of Science returned 139 articles with roughly 89 percent overlap, lending confidence that the core literature was well captured.

Geographically, the field is dominated by Asia, which produced 84 of the 156 papers, with India alone contributing 41. Europe followed with 41 publications, led by Italy, Greece, and Portugal, while North America added 12. The authors attribute Asia’s leadership to abundant coastal biodiversity, long-standing cultural use of marine biomass in farming, and national programs encouraging bio-input adoption. Europe’s output, they note, has been stimulated by the EU Fertilising Products Regulation, which formally recognized biostimulants as a product category in 2019. Africa and South America remain strikingly underrepresented, a gap the researchers link to limited marine access, infrastructure, and research funding rather than any lack of agronomic potential.

What exactly makes seaweed so valuable to crops? The answer lies in a dense cocktail of bioactive compounds. Brown seaweeds such as Ascophyllum nodosum contain alginates, laminarin, and fucoidan; red species like Kappaphycus alvarezii and Gracilaria supply carrageenan and agar; green algae such as Ulva contribute their own sulfated polysaccharides. Layered on top are phytohormones including auxins, cytokinins, and gibberellins, along with betaines, phenolic antioxidants, amino acids, and micronutrients. Together, these molecules modulate plant physiology at multiple levels, from photosynthetic efficiency to the expression of nutrient transporter genes in root membranes.

The molecular evidence is particularly compelling. Transcriptomic analyses show that seaweed extracts reprogram key metabolic pathways, including phenylpropanoid and flavonoid biosynthesis, and upregulate genes tied to photosynthesis, hormone signaling, and carbon, nitrogen, and sulfur metabolism. In rapeseed, Ascophyllum nodosum extract improved nitrogen and sulfur acquisition by boosting the transcription of root membrane transporters for those nutrients. Betaines in the extracts appear to inhibit chlorophyll degradation, preserving photosynthetic capacity, while enhanced activity of enzymes like Rubisco and carbonic anhydrase supports greater carbon assimilation and starch biosynthesis.

Field results back the laboratory findings. Seaweed sap applied as a foliar spray or soil drench has boosted yields in rice, wheat, maize, green gram, tomato, kiwifruit, and citrus across multiple studies. One trial reported a nearly 19 percent grain yield increase in boro rice with Ascophyllum-derived biostimulants compared to untreated controls. Nutrient uptake enhancements ranged from modest 7 to 11 percent gains in potato tubers to extraordinary responses exceeding 200 to 400 percent in sesame, though the authors caution that this variability reflects species-specific and application-dependent differences. Notably, most experimental evidence comes from India, where Kappaphycus alvarezii and Gracilaria edulis dominate the literature, raising generalisability concerns that the review flags explicitly.

Beyond the plant itself, seaweed amendments reshape the soil. Polysaccharides like alginate form gel-like matrices that improve soil aggregation, aeration, and moisture retention, while humic and fulvic acids in seaweed sap buffer soil pH. The amendments also feed rhizosphere microbial communities, including nitrogen-fixing bacteria and phosphorus-solubilizing fungi, accelerating organic matter decomposition and nutrient mineralization. Seaweeds even act as chelating agents, adsorbing heavy metals from contaminated soils and shielding crops from toxicity. Under stress conditions, seaweed extracts help plants maintain favorable potassium-to-sodium balances under salinity, preserve leaf turgor during drought, and activate salicylic acid and jasmonic acid signaling pathways that prime defenses against pathogens.

The thematic mapping revealed four dominant research clusters: algal physiology and bioactive mechanisms, seaweed-based inputs for yield and nutrition, soil health and organic amendments, and biofertilizers combined with stress adaptation strategies. Temporal clustering showed the field’s evolution from taxonomic and foundational algal studies in the early 2000s toward applied agronomic research after 2010, and finally toward integrated soil health and climate-smart agriculture in recent years. The post-2018 surge in soil health and biofertilizer research coincides with the EU regulation and the launch of the UN Decade of Ecosystem Restoration, suggesting policy is actively steering the science.

Economically, the picture is promising but incomplete. Commercial products such as Stimplex, Kelpak, Maxicrop, and Sagarika have achieved market penetration, and studies on rice and maize in India reported net returns exceeding 15 to 25 percent above conventional fertilizer-only treatments. Yet comprehensive techno-economic assessments for smallholder contexts in South Asia and sub-Saharan Africa remain scarce, and production costs hinge heavily on harvesting methods, extraction technology, and formulation type. Integrating seaweed processing into coastal biorefineries, where co-products like agar and carrageenan offset costs, offers one pathway to economic sustainability within a circular bioeconomy.

The review’s authors are candid about remaining gaps: standardized application protocols, multi-location field trials across diverse agroclimatic zones, multi-omics elucidation of molecular mechanisms, life-cycle assessments, and systematic screening of underutilized red and green seaweed species all demand attention. Still, the trajectory is unmistakable. As agriculture grapples with soil degradation, nutrient leaching, and climate volatility, seaweed-based amendments offer a rare combination of benefits, feeding crops, restoring soils, and supporting microbial life, all from a renewable marine resource. The evidence base is now consolidated; the challenge ahead is translating it into reproducible, affordable practice at farm scale.

Subject of Research: Bibliometric analysis of global research trends on seaweed-based soil amendments and biostimulants for crop productivity and soil health from 2000 to 2024

Article Title: Global research trends on seaweed-based amendments for soil health and crop productivity

Article References: Sarkar, S., Dutta, S., Dey, S., Dhar, A., Garai, S., Ghosh, S., Brahmachari, K., & Ghosh, A. (2026). Global research trends on seaweed-based amendments for soil health and crop productivity. Discover Agriculture, 4(1), Article 289. https://doi.org/10.1007/s44279-026-00741-x

Image Credits: AI Generated

DOI: 10.1007/s44279-026-00741-x

Keywords: seaweed, biostimulants, soil health, crop yield, sustainable agriculture, macroalgae, biofertilizers, nutrient uptake, bibliometric analysis, Ascophyllum nodosum, Kappaphycus alvarezii, climate-smart agriculture

The stakes could hardly be higher. Global food systems face the challenge of feeding a projected 10 billion people by 2050, yet current fertilizer practice is astonishingly wasteful. Between 40 and 80 percent of the millions of tons of fertilizer applied each year are lost to volatilization, leaching, and runoff, driving eutrophication, soil degradation, and groundwater contamination. Nutrient use efficiency remains dangerously low, typically 30 to 50 percent for nitrogen, 20 to 50 percent for phosphorus, and 35 to 50 percent for potassium. Farmers compensate by applying more, which amplifies both costs and environmental externalities. Any material that could lock nutrients into a slow-release scaffold tuned to plant demand would represent a genuine revolution.

Metal-organic frameworks are, in chemical terms, lattices of metal nodes—iron, zinc, zirconium, or copper—connected by organic linker molecules into three-dimensional networks with extraordinary internal surface area and programmable porosity. That architecture allows them to adsorb, carry, and release guest molecules on cue. In agriculture, researchers have loaded MOFs with nitrogen, phosphorus, potassium, and micronutrients, or with agrochemicals such as fungicides and the plant hormone abscisic acid, so that release is triggered by environmental stimuli like pH, moisture, or enzyme activity. Examples cited in the review include iron-based MOFs that boosted biomass in hydroponic beans by roughly 9.6 percent with lower fertilizer inputs, biodegradable oxalate-phosphate-amine MOFs that break down naturally in soil, and beta-cyclodextrin-derived MOF carbon that slowly delivers potassium to rice while simultaneously adsorbing herbicides.

To move beyond scattered anecdotal claims, the research team—led by Shelly Singh of the Patanjali Research Foundation and Banasthali Vidyapith, with Sourav Ghosh of the Centre for Human Genetics among the co-authors—registered a protocol with PROSPERO and followed PRISMA 2020 reporting standards. They searched PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar for controlled experiments published between 2015 and October 2025 that tested MOF formulations on cultivated plants and reported extractable data on yield, nutrient uptake, or toxicity. From 67 initial records, only six studies survived screening; five provided sufficient statistics for meta-analysis. Inter-reviewer agreement at full-text screening was high, with a Cohen’s kappa of 0.87, and study quality was rated with a modified Newcastle-Ottawa Scale, with four studies judged good and two fair.

The pooled results were striking, though uneven. Across five estimates, MOF treatments produced a standardized mean difference of 24.04 for nutrient uptake, encompassing ammonium and nitrate nitrogen, available phosphorus, and iron accumulation. Yield indices, drawn from rice experiments with Fe-based MOFs and polymer-MOF hybrids, showed a pooled effect of 3.65, while kernel-related attributes improved with a pooled effect of 1.99. Perhaps most eye-catching was pathogen inhibition: functionalized MOFs, including abscisic-acid-loaded MIL-100(Fe) that protects cotton against drought and azoxystrobin-loaded iron MOFs that suppress Phytophthora infestans, yielded a pooled effect of 13.34 with zero heterogeneity. Notably, no phytotoxicity, chlorosis, or growth suppression was reported at the doses tested, which ranged from 20 to 150 milligrams per liter in liquid applications to 2 to 3 grams per pot or soil unit.

Yet the authors are emphatic that these numbers demand caution. The nutrient uptake estimate was dominated by two nitrogen-specific results from a single 2019 study, each with standardized effects exceeding 50, and heterogeneity across studies was extreme—an I-squared of 93.1 percent and a between-study variance of 287.60. Leave-one-out sensitivity analysis showed that removing either of those two observations dramatically shrank both the pooled effect and the heterogeneity. In plain terms, the headline figure reflects context-specific responses to particular MOF chemistries, crops, and exposure durations rather than a stable, generalizable agronomic gain. For yield and kernel outcomes, only two studies contributed to each pooled estimate, making formal sensitivity analysis impossible and marking the findings as low-certainty, exploratory evidence.

The environmental picture is even thinner. None of the included studies measured how MOFs persist, degrade, or transform in soil—processes such as linker hydrolysis, metal-node transitions, complexation with organic matter, or secondary mineral formation. No study profiled soil microbial communities, measured enzyme activity, or tracked leaching, runoff, or vertical transport of MOF particles or their breakdown products toward groundwater. Because experiments lasted less than six months, chronic toxicity, bioaccumulation, and trophic transfer could not be assessed at all. The review also flags that conventional MOF synthesis relies on organic solvents, metal salts, and energy-intensive steps, and that no life-cycle or techno-economic analysis exists to support claims of large-scale sustainability.

Geographic concentration compounds the problem. Nearly all the studies came from China, with one from India, and crops tested were limited to wheat, rice, tomato, and cotton. The formulations examined—ZIF-8, MIL-100(Fe), UiO-66-family materials, MOF-biochar composites, and polymer hybrids—represent only a sliver of the vast MOF design space, and inconsistent characterization of particle size, crystallinity, and dissolution behavior hampers cross-study comparison. Extrapolating from iron- and zinc-based frameworks to the entire class of MOF fertilizers, the authors warn, is not scientifically justified at this stage.

What the review does establish is a roadmap. The authors call for multi-season field trials that capture realistic soil-plant-environment interactions, long-term monitoring of MOF persistence and metal-ligand release, soil-column leaching studies to trace exposure pathways to groundwater, and systematic assessment of soil microbiome responses. They also urge life-cycle assessment, green synthesis development, and techno-economic analysis to determine whether MOF fertilizers can be produced affordably and cleanly at agricultural scale. Until those gaps are filled, the verdict is a carefully hedged one: MOF-based nanofertilizers clearly deliver measurable agronomic benefits in the greenhouse and the laboratory, and their controlled-release chemistry aligns elegantly with sustainable development goals on hunger and responsible production—but their safety, scalability, and real-world performance remain, for now, an open question that only rigorous field ecology can answer.

Subject of Research: Agronomic efficacy and environmental safety of metal-organic framework-based nanofertilizers in agriculture

Article Title: Evaluating metal-organic framework-based fertilizers in agriculture: evidence from a systematic review and meta-analysis

Article References: Singh, S., Ghosh, S., Arya, V. P., Chakraborty, D., & Balkrishna, A. (2026). Evaluating metal-organic framework-based fertilizers in agriculture: evidence from a systematic review and meta-analysis. BMC Agriculture, 2(1), Article 23. https://doi.org/10.1186/s44399-026-00047-9

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DOI: 10.1186/s44399-026-00047-9

Keywords: metal-organic frameworks, nanofertilizers, controlled nutrient release, crop yield, nutrient uptake, systematic review, meta-analysis, agricultural nanotechnology, environmental safety, soil health, sustainable agriculture, pathogen inhibition