Crops

Climate change may soon impact popcorn productivity. The aim was to assess physiological and growth traits in two popcorn genotypes with different water use efficiency under water-deficit stress. The plants were grown in a greenhouse under either water stress (WS) or non-water stress (WW) conditions. Gas exchange, chlorophyll fluorescence, and leaf temperature were assessed every three days, for a total of nine measurements. At the end of the assessment period, growth traits and the SPAD index were evaluated. Our hypotheses were as follows: (a) plants of the P7 genotype (water-efficient agronomic genotype) would take longer than L65 plants (water-inefficient agronomic genotype) to reduce photosynthetic rates under water stress conditions; (b) after re-irrigation, P7 plants would recover photosynthetic capacity with values similar to the period without water stress; and (c) P7 plants would recover photosynthetic capacity faster than L65 plants when subjected to the same period of water stress. The P7 genotype (agronomic water-efficient genotype) absorbed water more quickly due to higher root biomass, root length, and root volume. Yet, at 14 days after suspending irrigation (DASI), the P7 genotype had the lowest net CO₂ assimilation rate (A_net), stomatal conductance (g_s), and transpiration rates (E) values. However, L65 (agronomic water-inefficient genotype) had the lowest A_net, g_s, and E values only at 17 DASI. As a consequence of stomatal closure in both genotypes, the E rates were reduced, and there was an increase in leaf temperature for WS plants, while L65 had higher leaf temperature at maximum water stress. No photochemical damage was detected, indicating that the reduced A_net in WS was likely due to stomatal limitations and biochemical disturbances in both genotypes. Photosynthetic recovery occurred gradually, with full restoration of rates in both genotypes at the end of the experiment. Although our initial hypothesis expected the P7 genotype to maintain photosynthesis longer under water stress, our findings showed an earlier decline in A_net compared to L65. This result is likely due to the large root system of P7 exhausting the limited soil water more rapidly in pot conditions, accelerating the onset of stress. Full article

To meet global food demand, agricultural systems must enhance crop performance, productivity, and sustainability. Biostimulants have emerged as a promising strategy, particularly in vegetable production, due to their ability to enhance plant growth and resilience. This study characterized milk-derived protein hydrolysates (MPH) produced from expired milk and evaluated their potential as biostimulants for hydroponic cos lettuce. Hydrolysis of expired milk with hydrochloric acid achieved 94.55% hydrolysis and yielded 80.77% free amino acids. MPH was applied at volumes of 0, 1, 3, and 5 mL L⁻¹ in combination with Hoagland and Arnon nutrient solution. The 1 mL L⁻¹ (MPH1) treatment significantly increased shoot and root biomass and canopy size while reducing nitrate accumulation and enhancing total flavonoid and ascorbic acid content, as well as antioxidant capacity. HPLC analysis showed that MPH1 treatment promoted the accumulation of key metabolites, including vanillic acid, para-coumaric acid, salicylic acid, ferulic acid, gallic acid, syringic acid, quercetin, myricetin, and naringenin. MPH1 improved uptake of phosphorus, potassium, calcium, magnesium, and iron, contributing to mineral biofortification and nutritional quality. These results demonstrate that MPH at 1 mL L⁻¹ is an effective biostimulant, improving yield and quality while reducing nitrate levels in hydroponically grown cos lettuce, offering a sustainable solution for food waste valorization. Full article

Accurate prediction of soil phosphorus (P) adsorption capacity is essential for efficient fertilizer management and environmental protection. Traditional isotherm models, such as the Langmuir equation, have been widely used to quantify P sorption, but they do not adequately capture the nonlinear and multivariate nature of soil systems. This study evaluates the performance of a multi-output XGBoost regression model trained on laboratory-measured P adsorption data from 147 soils, representing a wide range of textures, pH levels, and CaCO₃ contents. The model was developed to simultaneously predict P adsorption at five different equilibrium concentrations (1, 2, 4, 6, and 10 mg/L). SHAP analysis and causal discovery via DirectLiNGAM revealed that initial Olsen P concentration and sand content are the primary factors reducing P adsorption. The multi-output XGBoost model was compared against classical Langmuir isotherms using an extended dataset of 10,389 soil samples. The extended dataset was binned into four groups based on Olsen P concentrations and four groups based on sand content. This binning was based on the identification of these variables as highly influential by the XGBoost model, and on their demonstrated causal relationship with soil P sorption capacity through causal inference analysis. The XGBoost model outperformed the Langmuir model in capturing the effect of Olsen P and sand content, as it predicted a 12.6% drop in P adsorption in the very high Olsen P group and a 19.2% drop in the very high sand content groups, which are substantially higher than the reductions estimated by Langmuir isotherms. These results demonstrate that machine learning models, trained on well-designed experimental data, offer a superior alternative to classical isotherms for modeling P sorption dynamics. Full article

Water-use efficiency (WUE) plays a crucial role in sustainable crop production, particularly in water-limited environments where maximizing natural resource use is essential. This study evaluated the physiological and agronomic performance of two Piper nigrum cultivars, Clonada and Uthirankotta, grown under different soil water potential conditions. The trial was conducted in a 1930 m² field using a randomized block design and drip irrigation system, calibrated to 3.55 L h⁻¹ with a uniformity of 97%. Soil water availability was managed based on daily tensiometer readings at 20 and 30 cm depths, triggering irrigation at defined tensions (10–55 kPa). Clonada exhibited higher net CO₂ assimilation rates (A) and stomatal conductance (g_s), but these responses did not lead to higher yields. In contrast, Uthirankotta consistently maintained superior water-use efficiency and yield across all soil moisture conditions by favoring water conservation and targeted biomass allocation over maximized gas exchange. Both cultivars performed optimally at a soil water potential range of 25–35 kPa, with declines in yield and gas exchange parameters at higher tensions (45–55 kPa). Under such conditions, Uthirankotta was 51.3% more water-use efficient and 40.8% more productive than Clonada. Based on this, a Principal Component Analysis (PCA) further demonstrated distinct physiological profiles, underscoring trade-offs between yield and water-use strategies. These results highlight the significance of cultivar selection for optimizing WUE and provide valuable insights into irrigation management and breeding programs aimed at boosting black pepper performance under water-limited conditions. Full article

Hazelnut is an important crop worldwide, and the characteristics of the fruits are quite variable according to a number of factors, including variety and cultivation conditions, which in turn can vary according to harvest year. This study aimed to investigate some physical and chemical characteristics of three hazelnut varieties grown in Portugal (Grada de Viseu, Tonda di Giffoni and Butler) along two different harvesting years (2021 and 2022). Also, the microbial quality was investigated for its relevance to the conservation of the fruits. The physical properties evaluated were biometric characteristics and colour, the chemical components analysed were moisture, lipids, protein, ash and fibre, and the microbial properties investigated were the microorganisms, moulds and yeasts. The results showed that, generically, statistically significant differences were found between the three varieties under study on several properties investigated. The kernel was confirmed as the lighter part of all hazelnuts, and when comparing between varieties, Tonda di Giffoni presented the lighter fruits in both harvesting years. With respect to weight, the Tonda di Giffoni variety was the lightest in both harvest years. Moisture content was observed to be higher than the recommended limits for two of the samples (Grada de Viseu in 2021: 6.01 ± 0.26 g/100 g and Butler in 2022: 6.02 ± 0.37 g/100 g), although the difference was marginal given that the recommended limit is 6%. Not surprisingly, lipids were the major chemical component, ranging from 66.46 ± 1.67 to 70.14 ± 1.75 g/100 g in 2021 and from 64.38 ± 1.67 to 77.77 g/100 g in 2022. It was further observed that the three varieties presented a satisfactory microbiological quality. Finally, applying factor analysis with principal components and Varimax rotation, a solution that explains 92.8% of the variance was obtained. This study provided information that is relevant for the characterisation and evaluation of variability according to the year of hazelnuts of three varieties cultivated in Portugal. Full article

Insect pests cause severe damage and yield losses to many agricultural crops globally. The use of chemical pesticides on agricultural crops is not recommended because of their toxic effects on the environment and consumers. In addition, pesticide toxicity reduces soil fertility, poisons ground waters, and is hazardous to soil biota. Therefore, applications of entomopathogenic nematodes (EPNs) and plant growth-promoting rhizobacteria (PGPR) are an alternative, eco-friendly solution to chemical pesticides and mineral-based fertilizers to enhance plant health and promote sustainable food security. This review focuses on the biological and ecological aspects of these organisms while also highlighting the practical application of molecular communication approaches in developing a novel plant health product. This insight will support this innovative approach that combines PGPR and EPNs for sustainable crop production. Several studies have reported positive interactions between nematodes and bacteria. Although the combined presence of both organisms has been shown to promote plant growth, the molecular interactions between them are still under investigation. Integrating molecular communication studies in the development of a new product could help in understanding their relationships and, in turn, support the combination of these organisms into a single plant health product. Full article

Chemical fertilizers pose significant risks to both human health and the environment. To investigate the effect of substituting nitrogen fertilizer with vermicompost tea on wheat yield, shoot chemical constituents, and grain quality under clay-loam soil conditions, two field experiments were conducted at the Faculty of Agriculture, Cairo University, Egypt, during the winter seasons of 2021–2022 and 2022–2023. A split-plot design in randomized complete blocks with three replications was employed. Vermicompost tea was assigned to the main plots, while wheat cultivars were assigned to the subplots. The cultivars were evaluated under four treatments involving partial substitution of mineral nitrogen (recommended dose of nitrogen (RDN%, 190 kg N ha⁻¹): a control (90% of RDN + 25 kg vermicompost tea), 80% of RDN + 37.5 kg vermicompost tea, and 70% of RDN + 50 kg vermicompost tea. Nitrogen fertilizer (RDN%) was applied at rates of 190 (control), 170 (90%), 150 (80%), and 130 (70%) kg N ha⁻¹. The results indicated that partially substituting mineral nitrogen with vermicompost tea significantly increased grain weight/Ha, chlorophyll A, chlorophyll B, carotenoids, nitrogen, phosphorus (P), and potassium (K) content in shoots, as well as ash, crude protein, crude fiber, total sugar, and N, P, and K content in wheat grains. The grain weight/Ha of the Sakha-95, Giza-171, and Sads-14 cultivars increased by 38.6%, 33.5%, and 39.3%, respectively, when treated with 70% RDN + 50 kg vermicompost tea. The combination of the Sads-14 cultivar and 70% RDN + 50 kg vermicompost tea resulted in the highest values for grain weight/ha (9.43 tons ha⁻¹), chlorophyll A (1.39 mg/g), chlorophyll B (1.04 mg/g), N (5.08%), P (1.63%), and P (2.43%) content in shoots. The same combination also improved ash (2.89%), crude fiber (2.84%), and K (6.05%) content in grains. In conclusion, the application of vermicompost tea in conjunction with chemical fertilizers offers a viable alternative to using chemical fertilizers alone, promoting sustainable agricultural practices and improving wheat production. It is recommended that mineral nitrogen fertilizer be partially replaced with vermicompost tea to enhance both the productivity and grain quality of wheat while minimizing environmental pollution. Full article

Soil nematodes are essential components of the soil food web and are widely recognised as key bioindicators of soil health because of their sensitivity to environmental factors and disturbance. In agriculture, many studies have documented the effects of fertilisation on nematode communities and explored their role in nutrient cycling. Despite this, a key gap in knowledge still exists regarding how fertilisation-induced changes in nematode communities modify their role in nutrient cycling. We reviewed the literature on the mechanisms by which nematodes contribute to nutrient cycling and on how organic, inorganic, and recycling-derived fertilisers (RDFs) impact nematode communities. The literature revealed that the type of organic matter and its C:N ratio are key factors shaping nematode communities in organically fertilised soils. In contrast, soil acidification and ammonium suppression have a greater influence in inorganically fertilised soils. The key sources of variability across studies include differences in the amount of fertiliser applied, the duration of the fertiliser use, management practices, and context-specific factors, all of which led to differences in how nematode communities respond to both fertilisation regimes. The influence of RDFs on nematode communities is largely determined by the fertiliser’s origin and its chemical composition. While fertilisation-induced changes in nematode communities affect their role in nutrient cycling, oversimplifying experiments makes it difficult to understand nematodes’ functions in these processes. The challenges and knowledge gaps for further research to understand the effects of fertilisation on soil nematodes and their impact on nutrient cycling have been highlighted in this review to inform sustainable agricultural practices. Full article

Entomopathogenic fungi are among the most promising non-chemical alternatives for the control of many serious phytophagous insect pests, such as moth species. The present research investigates the use of the little-studied entomopathogenic fungus Beauveria varroae as a biocontrol agent against the notorious pests Helicoverpa armigera and Sesamia nonagrioides in laboratory conditions. Conidial suspensions of B. varroae were prepared at 10³-10⁴-10⁵-10⁶-10⁷-10⁸ conidia/mL to assess their insecticidal potential. In this study, we used 100 3rd-instar larvae for each concentration. During the lab bioassays, almost complete mortality of 35–96.6% was recorded for H. armigera larvae and 40–96.6% for S. nonagrioides larvae 10 days after exposure. The lethal effect of the entomopathogen was related to both dose and exposure time of the entomopathogen, with higher concentrations resulting in increased mortality. The survival effect of S. nonagrioides and H. armigera larvae was dependent on the hazard effect of the used dose and the exposure time. These findings indicate that B. varroae has potential as a biocontrol agent. Further research will elucidate this new isolate and optimize application methods in field conditions. Full article

Native bean genotypes (Phaseolus vulgaris L.) play a crucial role in ensuring food security in the Andean region. However, their cultivation faces challenges, such as low yields and a high dependence on nitrogen fertilizers. Addressing these issues requires the development of sustainable strategies to enhance productivity. This study evaluated the interaction between Rhizobium phaseoli inoculation and three levels of phosphorus (P) and potassium (K) fertilization on the growth, yield, and nutritional profile of the ‘Tiachos bayo’ native bean variety under Andean field conditions. Two R. phaseoli strains (UNC-1 and CIAT-2) were tested in combination with three levels of chemical fertilization (0%, 50%, and 100%) using a factorial design under field conditions. Parameters assessed included nodule number, plant height, phenology, yield, and proximal grain composition. Results indicated that inoculation and fertilization levels significantly influenced nodulation, phenological phases, and crop yield. The highest yield (2172 kg·ha⁻¹) and nodule number (78) were observed with the combined treatment of R. phaseoli CIAT-2 strain with 100% fertilization. It was concluded that R. phaseoli inoculation, when integrated with appropriate fertilization, enhances the productivity of native beans. Full article

The review summarizes the historical and current research on perennial grain breeding in Russia within the context of growing global interest in perennial crops. N.V. Tsitsin’s pioneering work in the 1930s produced the first wheat–wheatgrass amphiploids, which demonstrated the capacity to regrow after harvest and survive for 2–3 years. Subsequent research at the Main Botanical Garden in Moscow focused on characterizing Tsitsin’s material, selecting superior germplasm, and expanding genetic diversity through new cycles of hybridization and selection. This work led to the development of a new crop species, Trititrigia, and the release of cultivar ‘Pamyati Lyubimovoy’ in 2020, designed for dual-purpose production of high-quality grain and green biomass. Intermediate wheatgrass (Thinopyrum intermedium) is native to Russia, where several forage cultivars have been released and cultivated. Two large-grain cultivars (Sova and Filin) were developed from populations provided by the Land Institute and are now grown by farmers. Perennial rye was developed through interspecific crosses between Secale cereale and S. montanum, demonstrating persistence for 2–3 years with high biomass production and grain yields of 1.5–2.0 t/ha. Hybridization between Sorghum bicolor and S. halepense resulted in two released cultivars of perennial sorghum used primarily for forage production under arid conditions. Russia’s agroclimatic diversity in agricultural production systems provides significant opportunities for perennial crop development. The broader scientific and practical implications of perennial crops in Russia extend to climate-resilient, sustainable agriculture and international cooperation in this emerging field. Full article

Salvia pratensis L. is a valuable medicinal plant rich in bioactive compounds, yet its allelopathic potential remains underexplored. This study evaluated allelopathic effects and total phenolic (TPC) and flavonoid (TFC) contents of water extracts from the dry aboveground biomass of S. pratensis. To assess their selectivity and potential application in sustainable weed management, extracts at five different concentrations were tested on the germination and early growth of lettuce, radish, tomato, and carrot. The results demonstrated that the phytotoxic effects of S. pratensis extracts were both concentration- and species-dependent. Higher extract concentrations significantly inhibited germination and seedling growth, while lower concentrations of extracts stimulated shoot elongation by up to 30% compared to the control. Phytochemical analysis revealed that S. pratensis extracts contain notable TPC and TFC contents, with their concentrations increasing consistently with the extract concentration. Correlation analysis showed that higher TPC and TFC contents were strongly negatively correlated with germination and seedling growth parameters. Radish exhibited the highest sensitivity to the extracts, while lettuce was the most tolerant. Further research under field conditions is needed to assess the efficacy, selectivity, and practical potential of S. pratensis extracts in sustainable crop production systems. Full article

The emerging sesame (Sesamum indicum L.) industry in Australia faces potential threats from multiple pre-harvest diseases and pests, which will necessitate an initiative-taking approach for pest management. Here we assess the diseases and pests most likely to impede the development of a viable Australian sesame industry. Drawing on the international literature, we also consider the management approaches most likely to be viable and identify key research gaps necessary for effective and sustainable crop protection. More than sixty-seven plant pathogens have been identified worldwide that cause diseases in sesame, with some being observed to be major in Australia. Part of this review aims to provide an extensive overview of previous research on sesame and its diseases, shedding light on the evolving knowledge within sesame research, emerging trends, and the current state of understanding on the topic as it applies to Australia. Among the hundreds of pests reported to attack sesame internationally, this review identifies fifty-six pest taxa that are established in, or native to, Australia. We rank those most likely to be serious based on overseas damage levels and observations from recent trial plantings in Northern Australia. Chemical control methods have demonstrated efficacy overseas but are associated with concerns over resistance and environmental impact. Extremely limited numbers of pesticides are currently registered for pest or disease control in sesame by the Australian Pesticides and Veterinary Medicines Authority so non-chemical methods will be important. These include botanical, biological, cultural, and physical control approaches. This review underscores the need for continued research and tailored plant protection strategies to optimize sesame. Full article

Rice is one of the most important staple foods worldwide. Asia, particularly South and Southeast Asia, is a major rice producer, and rice production is also gradually increasing in Africa. However, rice cultivation poses economic and environmental challenges, which are exacerbated by climate change. Hence, diversification of rice-based production systems is highly imperative to improve soil health and thus sustain productivity while also enhancing income opportunities. Vegetables and pulses are crucial components for diversifying rice-based production systems as they have the potential to increase income and improve soil health. The World Vegetable Center has introduced mungbeans and vegetable soybeans to diversify the cereal-based production systems in Asia. About 27–93% of the mungbean area in India, Pakistan, Bangladesh, and Myanmar is planted with varieties containing improved germplasm developed by WorldVeg in collaboration with national agricultural research systems. Additionally, the introduction of vegetables and legumes is highly remunerative and improves dietary diversity, leading to better nutrition. For instance, the productivity of vegetable crops increased by 200–350% when they were combined with improved production practices. Such diversification also holds great promise for improving income and nutrition in Africa. It also enhances the resilience of farming systems, particularly in a changing climate. Hence, governments should prioritize system diversification to enhance the income and livelihood opportunities for smallholders in Asia and Africa. Full article

Forages are the primary feed source for livestock production systems due to their diversity of adapted species and lower production costs. Forage-based livestock operations are complex systems across climates, soil types, genetics, and production systems. Therefore, increasing the resilience of forage ecosystems requires a comprehensive approach to assess and understand the conditions of each system while considering its needs, goals, and resources. In the southeastern USA, favorable climatic conditions allow for the incorporation of annual forage species into perennial stands to extend the grazing season. Adopting management strategies that support forage biodiversity and nutrients, and land use efficiency are ways to improve sustainable production intensification of forage ecosystems. Additionally, providing proper access to education and knowledge transfer for current and future generations is essential to guarantee the success and longevity of the livestock industry. This review provides an overview of key issues related to the climate and economic resilience of forage–livestock ecosystems and the role of agricultural education and knowledge transfer in shaping sustainable ecosystems. Full article

The extension of genetic diversity is the basis for yield and adaptability improvements of winter wheat varieties under climate fluctuations. In the present study, an international collection consisting of 96 winter bread wheat accessions from Russia, Germany, Finland, Kazakhstan, Bulgaria, Turkey, the USA, and the international programme (Turkey–CIMMYT–ICARDA) was analysed under the conditions of Western Siberia during three growing seasons. Yield and yield-related traits were recorded following standard agronomy practices. Genotyping of the germplasm panel was conducted using 55 KASP markers at the Institute of Plant Biology and Biotechnology (Kazakhstan). The yield had a high correlation with the number of fertile tillers per unit area (0.68), which indicates significant yield reduction in wheat accessions from different origins that are not adaptive to the conditions of Western Siberia. The main stable QTLs associated with yield-related traits during two growing seasons, ippb_ta_1147 (1A), ippb_ta_107 (4A), ippb_ta_239 (5D), and ippb_ta_283 (6A), can be used in MAS for the improvement of yield and related traits. The outperforming genotypes Zhiva, Zolushka, Doneko, Line K 18918, Line 2293; CO13D1299, KS13DH0030-32, Gondvana//HBK0935-29-15/KS90W077-2-2/VBF0589-1… are recommended to be included in hybridisation programmes and represent promising sources for breeding high-yielding and climate-resilient winter wheat. Full article

Microelement deficiencies, often termed “hidden hunger”, represent a significant global health challenge. Optimal human health relies on adequate dietary intake of essential microelements, including selenium (Se), zinc (Zn), copper (Cu), boron (B), manganese (Mn), molybdenum (Mo), iron (Fe), nickel (Ni), and chlorine (Cl). In recent years, there has been a growing focus on vitality and longevity, which are closely associated with the sufficient intake of essential microelements. This review focuses on these nine elements, whose bioavailability in the food chain is critically determined by their geochemical behavior in soils. There is a necessity for an understanding of the sources, soil–plant transfer, and plant uptake mechanisms of these microelements, with particular emphasis on the influence of key soil properties, including pH, redox potential, organic matter content, and mineral composition. There is a dual challenge of microelement deficiencies in agricultural soils, leading to inadequate crop accumulation, and the potential for localized toxicities arising from anthropogenic inputs or geogenic enrichment. A promising solution to microelement deficiencies in crops is biofortification, which enhances nutrient content in food by improving soil and plant uptake. This strategy includes agronomic methods (e.g., fertilization, soil amendments) and genetic approaches (e.g., marker-assisted selection, genetic engineering) to boost microelement density in edible tissues. Moreover, emphasizing the need for advanced predictive modeling techniques, such as ensemble learning-based digital soil mapping, enhances regional soil microelement management. Integrating machine learning with digital covariates improves spatial prediction accuracy, optimizes soil fertility management, and supports sustainable agriculture. Given the rising global population and the consequent pressures on agricultural production, a comprehensive understanding of microelement dynamics in the soil–plant system is essential for developing sustainable strategies to mitigate deficiencies and ensure food and nutritional security. This review specifically focuses on the bioavailability of these nine essential microelements (Se, Zn, Cu, B, Mn, Mo, Fe, Ni, and Cl), examining the soil–plant transfer mechanisms and their ultimate implications for human health within the soil–plant–human system. The selection of these nine microelements for this review is based on their recognized dual importance: they are not only essential for various plant metabolic functions, but also play a critical role in human nutrition, with widespread deficiencies reported globally in diverse populations and agricultural systems. While other elements, such as cobalt (Co) and iodine (I), are vital for health, Co is primarily required by nitrogen-fixing microorganisms rather than directly by all plants, and the main pathway for iodine intake is often marine-based rather than soil-to-crop. Full article

Climatic changes threaten many forms of crop production as well as adversely affecting global ecosystems and human activities. There are two principal ways in which the balance of the global carbon cycle can be restored, firstly by decreasing anthropogenic CO₂ emissions and secondly by increasing the rates of carbon sequestration. Even if emissions are successfully reduced to net zero over the coming decades, it will still be essential to reduce atmospheric CO₂ concentrations to preindustrial levels. This can only be achieved by global-scale carbon sequestration of the order of gigatonnes (Gt) of CO₂ annually. Over recent decades, engineering approaches have been proposed to tackle carbon sequestration. However, their technological effectiveness has yet to be demonstrated at a global scale, with even the most optimistic current values at less than 0.1 Gt CO₂/yr, i.e., 50–100-fold less than required to meet IPCC targets for 2050. In contrast, biological carbon sequestration already operates as a proven global mechanism that also has the potential for increased effectiveness by harnessing high-yield tropical vegetation including perennial crops with sequestration values already exceeding 1 Gt CO₂/yr. This review will contrast engineering and biological approaches to carbon sequestration with a particular focus on the potential for perennial crops, especially in the tropics. The major conclusions are that (i) the 2 Gt CO₂/yr capacity of biological carbon sequestration already dwarfs that of all engineering approaches at 0.0013 Gt CO₂/yr, (ii) biological sequestration is proven to operate at global scale, and (iii) compared to engineering approaches, it will be orders of magnitude less expensive to upscale further in the coming decades. Full article