Global Crop Research Articles

Nocturnal seston: A key to explain the cadmium transfer from seawater to mussels (Mytilus chilensis)

The objective of this work was to discover a biochemical pathway to explain the transfer of cadmium, a toxic element, from seawater to cultured mussels. Understanding the intricacies of this transfer is crucial for global mussel crops, as it has the potential to mitigate risks to human health and prevent economic losses in the industry. We focused our investigation on Yal Bay, a typical area with intense mussel aquaculture activity (16,000 t y−1) in the inland sea of southern Chile. Seasonal samples of blue mussels (Mytilus chilensis) were collected and analyzed from September 2014 to December 2015 at two integrated depths (0–5 m and 5–10 m). Diurnal and nocturnal seston, seawater, benthic sediments and decanted suspensions from the water column were recorded. Our findings indicate that nocturnal seston satisfactorily explains the presence of cadmium in Mytilus chilensis aquaculture throughout its annual temporal distribution (Spearman rs = 0.63, p = 0.002).

Physisorption-Mediated Charge Transfer in TiS2 Nanodiscs: A Room Temperature Sensor for Highly Sensitive and Reversible Carbon Dioxide Detection.

Real-time and high-performance monitoring of trace carbon dioxide (CO2) has become a necessity due to its substantial impact on the global climate, human health, indoor occupancy, and crop productivity. Two-dimensional materials such as transition metal dichalcogenides (TMDs) have gained significant interest in gas sensing applications owing to their intrinsically high surface-to-volume ratio. However, the research has been limited to prominent TMDs such as WS2 and MoS2. Specifically, the chemiresistive sensing performance of titanium disulfide (TiS2) has rarely been investigated. We present an electric-field-assisted TiS2 nanodisc assembly for the fabrication of a low-cost, low-power CO2 gas sensor based on charge transfer between physisorbed CO2 analyte molecules and TiS2 nanodiscs operating at room temperature. The physiochemical properties of the synthesized TiS2 nanodiscs were investigated via scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The fabricated sensor demonstrated an ultra-high sensor response of 60%, a fast response time of 37 s toward 500 ppm CO2 gas, and the lowest detection limit of 5 ppm under ambient conditions. The low adsorption energies and vdW interaction between CO2 molecules and TiS2 resulted in easy desorption, allowing the sensor to self-recover without the need for external stimuli, which is hardly been witnessed in other 2D material analogues. Furthermore, the sensor has excellent reproducibility and stability for successive analyte exposures, as well as excellent selectivity for CO2 over other interfering gases. This reported sensor based on 2D TMDs is the first of its type to integrate such a broad range of sensor characteristics (such as high sensor response and sensitivity, rapid response and recovery times, a high signal-to-noise ratio, and excellent selectivity at room temperature) into a single, revolutionary device for CO2 detection.

Crop response pattern to several drought timescales and its possible determinants: A global-scale analysis during the last decades

Crop response characteristics to different timescales of precipitation deficit may represent crop system resilience to drought characteristics. In this study, we assess the crop yield response of major crops to meteorological drought estimated by a standardized precipitation index with multiple timescales (1-12 months) during 1981-2016 all over the globe. We estimate that about one- to two-thirds of global harvested areas of maize, rice, soybean, and wheat, were significantly affected by various drought timescales. Soybean and wheat might respond to more prolonged droughts, while rice and maize responded to short-medium drought time scales. Using multiple machine learning models, we reveal that set of determinants could explain most variations of crop response to drought timescale with average accuracies between 45.7% - 56.0% (across models and crop types). Moreover, this study suggests that crops in warmer and higher water availability (precipitation minus potential evapotranspiration) might respond significantly to more short-term drought. The other factors (i.e., socioeconomic, fertilizer, soil, topography, production, irrigation) shows a complex and weaker effect on defining crop vulnerability to the various drought characteristics. This study attempts to fill the gaps in understanding global crop resistance to different drought characteristics. The future challenge in understanding the multifaceted effect of physical and socioeconomic factors on global crop vulnerability to drought may remain and should be addressed in further studies.

Global patterns and controls of soil greenhouse gas fluxes and crop yield under biochar application

AbstractBiochar application has been proven to be a viable technique in mitigating soil greenhouse gas (GHG) emissions and improving crop yield; however, the global patterns and responses of soil GHG fluxes, global warming potential (GWP), crop yield, and greenhouse gas intensity (GHGI) to biochar application, as well as the key drivers of biochar‐induced changes, are not fully synthesized. Hence, we conducted a meta‐analysis of 3883 paired observations from 220 studies. Overall, biochar application significantly increased carbon dioxide (CO2) emissions (7.4%) and yield (9.4%) and decreased soil methane (CH4, −13.0%) and nitrous oxide (N2O, −26.8%) emissions, as well as GWP (−7.7%) and GHGI (−14.3%). CH4 uptake was, however, not observed to change. The responses of soil GHG fluxes to the biochar application were more sensitive in the incubation and pot experiments compared to the field studies. In addition, increased CO2 emissions were mainly derived from incubation and pot experiments, whereas the biochar application did not significantly change CO2 emissions in the field studies. The climate, soil, and experimental conditions also affected the responses of soil GHG fluxes to biochar application, and the biochar‐induced change in soil pH was the most essential factor associated with the variations in soil GHG fluxes. Globally, biochar application boosted the soil carbon (C) pool (38.1% in upland and 33.4% in paddy) and decreased soil GHGI (−18.7% in upland and −14.5% in paddy). Our study highlights the role of the reduced CH4 and N2O emissions in the biochar‐induced mitigation of soil GHG emissions while exploring the relative importance of the influencing factors and providing crucial insights for the development of individualized biochar management measures.

Investigating the Use of Street-Level Imagery and Deep Learning to Produce In-Situ Crop Type Information

The creation of crop type maps from satellite data has proven challenging and is often impeded by a lack of accurate in situ data. Street-level imagery represents a new potential source of in situ data that may aid crop type mapping, but it requires automated algorithms to recognize the features of interest. This paper aims to demonstrate a method for crop type (i.e., maize, wheat and others) recognition from street-level imagery based on a convolutional neural network using a bottom-up approach. We trained the model with a highly accurate dataset of crowdsourced labelled street-level imagery using the Picture Pile application. The classification results achieved an AUC of 0.87 for wheat, 0.85 for maize and 0.73 for others. Given that wheat and maize are two of the most common food crops grown globally, combined with an ever-increasing amount of available street-level imagery, this approach could help address the need for improved global crop type monitoring. Challenges remain in addressing the noise aspect of street-level imagery (i.e., buildings, hedgerows, automobiles, etc.) and uncertainties due to differences in the time of day and location. Such an approach could also be applied to developing other in situ data sets from street-level imagery, e.g., for land use mapping or socioeconomic indicators.

Building soil to reduce climate change impacts on global crop yield

Improving soil health and resilience is fundamental for sustainable food production, however the role of soil in maintaining or improving global crop productivity under climate warming is not well identified and quantified. Here, we examined the impact of soil on yield response to climate warming for four major crops (i.e., maize, wheat, rice and soybean), using global-scale datasets and random forest method. We found that each °C of warming reduced global yields of maize by 3.4%, wheat by 2.4%, rice by 0.3% and soybean by 5.0%, which were spatially heterogeneous with possible positive impacts. The random forest modeling analyses further showed that soil organic carbon (SOC), as an indicator of soil quality, dominantly explained the spatial heterogeneity of yield responses to warming and would regulate the negative warming responses. Improving SOC under the medium SOC sequestration scenario would reduce the warming-induced yield loss of maize, wheat, rice and soybean to 0.1% °C−1, 2.7% °C−1, 3.4% °C−1 and − 0.6% °C−1, respectively, avoiding an average of 3%–5% °C−1 of global yield loss. These yield benefits would occur on 53.2%, 67.8%, 51.8% and 71.6% of maize, wheat, rice and soybean planting areas, respectively, with particularly pronounced benefits in the regions with negative warming responses. With improved soil carbon, food systems are predicted to provide additional 20 to over 130 million tonnes of food that would otherwise lose due to future warming. Our findings highlight the critical role of soil in alleviating negative warming impacts on food security, especially for developing regions, given that sustainable actions on soil improvement could be taken broadly.

Transcriptomic and genetic approaches reveal that low-light-induced disease susceptibility is related to cellular oxidative stress in tomato.

The impact of low light intensities on plant disease outbreaks represents a major challenge for global crop security, as it frequently results in significant yield losses. However, the underlying mechanisms of the effect of low light on plant defense are still poorly understood. Here, using an RNA-seq approach, we found that the susceptibility of tomato to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) under low light was associated with the oxidation-reduction process. Low light conditions exacerbated Pst DC3000-induced reactive oxygen species (ROS) accumulation and protein oxidation. Analysis of gene expression and enzyme activity of ascorbate peroxidase 2 (APX2) and other antioxidant enzymes revealed that these defense responses were significantly induced by Pst DC3000 inoculation under normal light, whereas these genes and their associated enzyme activities were not responsive to pathogen inoculation under low light. Additionally, the reduced ascorbate to dehydroascorbate (AsA/DHA) ratio was lower under low light compared with normal light conditions upon Pst DC3000 inoculation. Furthermore, the apx2 mutants generated by a CRISPR-Cas9 gene-editing approach were more susceptible to Pst DC3000 under low light conditions. Notably, this increased susceptibility could be significantly reduced by exogenous AsA treatment. Collectively, our findings suggest that low-light-induced disease susceptibility is associated with increased cellular oxidative stress in tomato plants. This study sheds light on the intricate relationship between light conditions, oxidative stress, and plant defense responses, and may pave the way for improved crop protection strategies in low light environments.

Annual Field-Scale Maps of Tall and Short Crops at the Global Scale Using GEDI and Sentinel-2

Crop type maps are critical for tracking agricultural land use and estimating crop production. Remote sensing has proven an efficient and reliable tool for creating these maps in regions with abundant ground labels for model training, yet these labels remain difficult to obtain for many regions and years. NASA’s Global Ecosystem Dynamics Investigation (GEDI) spaceborne LiDAR instrument, originally designed for forest monitoring, has shown promise for distinguishing tall and short crops. In the current study, we leverage GEDI to develop wall-to-wall maps of short vs. tall crops on a global scale at 10 m resolution for 2019–2021. Specifically, we show that (i) GEDI returns can reliably be classified into tall and short crops after removing shots with extreme view angles or topographic slope, (ii) the frequency of tall crops over time can be used to identify months when tall crops are at their peak height, and (iii) GEDI shots in these months can then be used to train random forest models that use Sentinel-2 time series to accurately predict short vs. tall crops. Independent reference data from around the world are then used to evaluate these GEDI-S2 maps. We find that GEDI-S2 performed nearly as well as models trained on thousands of local reference training points, with accuracies of at least 87% and often above 90% throughout the Americas, Europe, and East Asia. A systematic underestimation of tall crop area was observed in regions where crops frequently exhibit low biomass, namely Africa and South Asia, and further work is needed in these systems. Although the GEDI-S2 approach only differentiates tall from short crops, in many landscapes this distinction is sufficient to map individual crop types (e.g., maize vs. soy, sugarcane vs. rice). The combination of GEDI and Sentinel-2 thus presents a very promising path towards global crop mapping with minimal reliance on ground data.

Differential shifts in microbiome and pathogen populations associated with suppressive soil in long-term continuous corn field compared to rotation corn field

Unraveling soil suppressiveness and the involvement of microbiome could provide the insight needed to advance development of cost-effective and eco-friendly alternatives for managing plant diseases. This could enhance global crops and subsequent food production without large-scale use of pesticides, which may cause pollution and negatively affect human health. The goal of this study was to evaluate changes in the microbiome and diversity of beneficial microbial communities in soils suppressive to soilborne pathogens under long-term continuous corn cultivation compared to rotation corn fields. Samples were collected three times during the year from four locations in Nebraska. Sequencing was conducted on the paired-end Illumina HiSeq platform with three primer sets, including 515F/806R, 1737F/2043R, and 1380F/1510R. Parameters evaluated for microbial activity showed a consistent pattern where they were significantly (p = 0.05) greater in continuous corn than rotation in one region of the state but no differences in another region. There were relatively higher operational taxonomic units (OTUs) for the potential biocontrol agents Bacillus, Paenibacillus, Massilia, Pseudomonas, and Sphingomonas in the long-term continuous corn field compared to the other three locations. This study identified certain microbial populations which appeared to drive community activities, the link between pathogens and beneficial organisms, the effect of soil nutrients, and the net feedback that played important roles in the development of soil suppressive properties. Additional research is needed to unravel the mechanisms and to fast-track the time required to attain soil suppressiveness.

The importance of wild pollinators for indigenous crop pollination: The case of Cyclopia (honeybush)

Pollination is an important ecosystem service. Animal-mediated pollination (mostly insects) increases the production of 35% of global crops. Honey bees (Apis mellifera) are considered important crop pollinators globally, but are under pressure and therefore the value of wild pollinators for crop production is receiving more attention. The importance of pollinators (including non-Apis) has been extensively studied in the agricultural sector of South Africa, however little research is available on the pollination of indigenous crops. With the considerable value of the indigenous honeybush (Cyclopia Vent.) in the tea industry, it is important to determine the pollinators since Cyclopia is widespread across the fynbos biome and the pollinators are largely unknown. Here we ask whether carpenter bees (xylocopid bees) are the only pollinators of commercially important Cyclopia species, or if honey bees contribute to pollination. Floral observations and camera trapping confirmed that six species of xylocopid bees were the only pollinators of four commercially important Cyclopia species. Honey bees were observed to be ineffective pollinators of Cyclopia owing to their inability to trip Cyclopia flowers and gain access to the floral reproductive parts. Similarly, an additional seven species including Diptera, Apidae and Lema sp. were unable to gain access to Cyclopia flowers, although were observed visiting. Nectar measurements revealed the highest nectar volume in C. genistoides, while C. intermedia had the highest nectar sugar concentration (above 35% for all species). The value of native non-Apis insects for crop pollination in a changing world is highlighted in Cyclopia, an indigenous legume gaining traction in the global tea market and therefore in cultivation.

The marksman: Bioactivated nematicides selectively kill plant-parasitic nematodes.

Plant-parasitic nematodes (PPNs) are destructive pathogens that cause great damage to crops and severely limit food production, hindering our ability to meet the growing demand for food worldwide (Topalovic and Vestergård, 2021). The global crop losses caused by PPNs are estimated to be about 8.8%-14.6% of total crop production and 100-157 billion USD annually (Singh et al., 2013). Due to their small size and fast propagation speed, PPNs are difficult to see with naked eye, hence difficult to control. Farmers employ different ways to reduce or prevent the damage caused by nematodes This article is protected by copyright. All rights reserved.

Maize and heat stress: Physiological, genetic, and molecular insights.

Global mean temperature is increasing at a rapid pace due to the rapid emission of greenhouse gases majorly from anthropogenic practices and predicted to rise up to 1.5°C above the pre-industrial level by the year 2050. The warming climate is affecting global crop production by altering biochemical, physiological, and metabolic processes resulting in poor growth, development, and reduced yield. Maize is susceptible to heat stress, particularly at the reproductive and early grain filling stages. Interestingly, heat stress impact on crops is closely regulated by associated environmental covariables such as humidity, vapor pressure deficit, soil moisture content, and solar radiation. Therefore, heat stress tolerance is considered as a complex trait, which requires multiple levels of regulations in plants. Exploring genetic diversity from landraces and wild accessions of maize is a promising approach to identify novel donors, traits, quantitative trait loci (QTLs), and genes, which can be introgressed into the elite cultivars. Indeed, genome wide association studies (GWAS) for mining of potential QTL(s) and dominant gene(s) is a major route of crop improvement. Conversely, mutation breeding is being utilized for generating variation in existing populations with narrow genetic background. Besides breeding approaches, augmented production of heat shock factors (HSFs) and heat shock proteins (HSPs) have been reported in transgenic maize to provide heat stress tolerance. Recent advancements in molecular techniques including clustered regularly interspaced short palindromic repeats (CRISPR) would expedite the process for developing thermotolerant maize genotypes.

Chromosome-scale genome sequence of Suaeda glauca sheds light on salt stress tolerance in halophytes.

Soil salinity is a growing concern for global crop production and the sustainable development of humanity. Therefore, it is crucial to comprehend salt tolerance mechanisms and identify salt-tolerance genes to enhance crop tolerance to salt stress. Suaeda glauca, a halophyte species well adapted to the seawater environment, possesses a unique ability to absorb and retain high salt concentrations within its cells, particularly in its leaves, suggesting the presence of a distinct mechanism for salt tolerance. In this study, we performed de novo sequencing of the S. glauca genome. The genome has a size of 1.02Gb (consisting of two sets of haplotypes) and contains 54 761 annotated genes, including alleles and repeats. Comparative genomic analysis revealed a strong synteny between the genomes of S. glauca and Beta vulgaris. Of the S. glauca genome, 70.56% comprises repeat sequences, with retroelements being the most abundant. Leveraging the allele-aware assembly of the S. glauca genome, we investigated genome-wide allele-specific expression in the analyzed samples. The results indicated that the diversity in promoter sequences might contribute to consistent allele-specific expression. Moreover, a systematic analysis of the ABCE gene families shed light on the formation of S. glauca's flower morphology, suggesting that dysfunction of A-class genes is responsible for the absence of petals in S. glauca. Gene family expansion analysis demonstrated significant enrichment of Gene Ontology (GO) terms associated with DNA repair, chromosome stability, DNA demethylation, cation binding, and red/far-red light signaling pathways in the co-expanded gene families of S. glauca and S. aralocaspica, in comparison with glycophytic species within the chenopodium family. Time-course transcriptome analysis under salt treatments revealed detailed responses of S. glauca to salt tolerance, and the enrichment of the transition-upregulated genes in the leaves associated with DNA repair and chromosome stability, lipid biosynthetic process, and isoprenoid metabolic process. Additionally, genome-wide analysis of transcription factors indicated a significant expansion of FAR1 gene family. However, further investigation is needed to determine the exact role of the FAR1 gene family in salt tolerance in S. glauca.

The Great Game between Plants and Viruses: A Focus on Protein Homeostasis.

Plant viruses are tiny pathogenic obligate parasites that cause significant damage to global crop production. They exploit and manipulate the cellular components of host plants to ensure their own survival. In response, plants activate multiple defense signaling pathways, such as gene silencing and plant hormone signaling, to hinder virus propagation. Growing evidence suggests that the regulation of protein homeostasis plays a vital role in the ongoing battle between plants and viruses. The ubiquitin-proteasome-degradation system (UPS) and autophagy, as two major protein-degradation pathways, are widely utilized by plants and viruses in their arms race. One the one hand, these pathways act as essential components of plant's antiviral defense system by facilitating the degradation of viral proteins; on the other hand, viruses exploit the UPS and autophagy to create a favorable intracellular environment for viral infection. This review aims to provide a comprehensive summary of the events involved in protein homeostasis regulation during viral infection in plants. Gaining knowledge in this area will enhance our understanding of the complex interplay between plants and viruses.

Genebanks at Risk: Hazard Assessment and Risk Management of National and International Genebanks.

Genebanks are crucial for safeguarding global crop diversity but are themselves exposed to several risks. However, a scientific basis for identifying, assessing, and managing risks is still lacking. Addressing these research gaps, this study provides risk analysis for three key risk groups: natural hazards, political risks, and financial risks, carried out on a sample of 80 important national and international genebanks, comprising at least 4.78 million accessions or roughly 65% of the reported total of ex situ conserved accessions worldwide. The assessment tool of Munich Re "Natural Hazards Edition" allowed a location-specific comparison of the natural hazard exposure. Results showed that genebanks in the Asia-Pacific region are most exposed to natural hazards, while institutions in African and some Asian countries are rather vulnerable to political risks. Financing is a major problem for national genebanks in developing countries, whereas the Global Crop Diversity Trust achieved considerable financial security for international genebanks. Large differences in the risk exposure of genebanks exist, making a location- and institution-specific risk assessment indispensable. Moreover, there is significant room for improvement with respect to quality and risk management at genebanks. Transferring risks of genebanks to third parties is underdeveloped and should be used more widely.

The Current Status of Weed Resistance to Herbicides and The Discovery of New Herbicides With Novel Modes of Action Necessary to Combat Them

In 2016 and after retiring from a fulltime career in Herbicide Research and Development, I wrote an article for Outlooks addressing the question ‘Can we expect new herbicides with novel modes of action in the foreseeable future?’ and I would like to use this editorial to investigate if we are any closer to answering this question which is important because of the increasing problems of weeds evolving resistance to existing herbicides. Weed management is still essential to maximise crop yields in agriculture. Yield losses of up to 40% across the major global food crops can occur without effective weed control, due to competition between the weeds and crops for nutrients and light, as well as interfering with crop harvest and quality. Herbicides are essential tools in integrated weed management (IWM) but their effectiveness is being eroded due to widespread weed resistance, in part due to overuse of the limited number of herbicide products currently available to the grower. Cultural methods for control of weeds such as, changing rotations, use of cover crops; deep ploughing; manual removal of weeds and chemical mulching are clearly part of the IWM toolbox. However, deep ploughing (and any type of physical disturbance of soil) and chemical mulching, whilst potentially effective, are not applicable throughout global crop production and also are not sustainable environmentally friendly options. Similarly, other non-chemical methods, such as electro-physical and heat treatments including high energy light, boiling water, steam, fire, flame weeding and hot foam have been sold as having potential to replace herbicides, but I question their suitability in main stream row-crop agriculture and also the environmental impact of their use, particularly if they would be regulated as herbicides and needed the extensive catalogue of ecotoxicology studies to investigate adverse effects on non-target organisms and environmental fate studies. Biological approaches are receiving increasing interest in pest management for control of diseases and insects, but these appear not to be an option for weed control.

Toxin removal during protein extraction from tomato leaves

Protein production from agricultural side streams aids in global crop valorisation. This study aimed to isolate protein from tomato leaves (Solanum lycopersicum) with simultaneous toxin removal for use as a food ingredient. Protein was isolated through three methods; pH precipitation, ethanol precipitation, and a combination of heat coagulation and filtration. Protein yield and purity were determined and protein isolates were tested for presence of the toxins, tomatine and dehydrotomatine. Protein recovery was 6–10% of the original total protein content. The pH precipitation method yielded a powder with the highest purity of 76%, but was least effective at removing toxins. Ethanol precipitation removed toxins most effectively, but gave a low protein purity of 40%. The combination of heat coagulation and filtration gave the optimal result, yielding a high purity protein powder of 71% with 99.7% of toxins removed. However, absolute toxin levels might still be too high and safety assessment of toxin removal will be necessary. Industrial relevanceLeaves can be a good source of protein and Rubisco product from sugar beet leaves is now undergoing EFSA approval. Water lentil (Lemna) protein concentrate has recently been approved. The generally low yield of protein product from 1 kg of (wet) leaves is most challenging in these processes compared to more efficiently obtained isolates from (dry) pulses. The better functionality of Rubisco should compensate for that. Rubisco protein from tomato leaves (Solanum lycopersicum) can also be recovered, although toxins need to be removed to allow for human consumption. This additional hurdle will make industrial implementation more difficult.

Short-term extreme heat at flowering amplifies the impacts of climate change on maize production

Extreme weather poses a threat to global crop production, food security and farmer livelihoods. High temperatures have been identified as detrimental to crop yields; however, how heat stress during the critical flowering stage will influence future maize (Zea mays L.) yields remains unclear. Here, we combined statistical and process-based models to assess impacts of short-term extreme heat at flowering on Chinese maize yield under climate change. We showed that heat around flowering has a stronger impact on yields than heat at other times in the growing season, especially for temperatures >30 °C. Heat stress during flowering was responsible for 23% of total yield loss from extreme degree days (EDDs) in 1990–2012. An improved process-based model (Agricultural Production Systems sIMulator (APSIM)-maize) incorporating a grain-temperature function was then applied and indicated that extreme heat at flowering amplified the impacts of climate change on maize production compared to the original model. The improved APSIM-maize predicted an 8.7% yield reduction across the Chinese Maize Belt as EDDs increased more than quadrupled at the end of the century (2070–2099) under a high emissions pathway (SSP585) in comparison with the baseline period (1990–2019). Our study highlights the importance of extreme heat at flowering on maize yield and can inform farmers and policy makers on adaptive measures as well as providing a reference for other crop areas facing similar challenges.

Changes in crop failures and their predictions with agroclimatic conditions: Analysis based on earth observations and machine learning over global croplands

In this study, we aim to characterize synchronized global crop failures using remote sensing-based products, analyze their predictability and relationships with agroclimatic conditions using machine learning, and identify trends of the most influential agroclimatic indices revealed by machine learning over global croplands. We found that global synchronous crop failures showed strong interannual variability during 1982 to 2016. The most extreme global synchronous crop failure events occurred over 40% of global croplands in the years 2002 (rice and wheat) and 2012 (maize and soy), which had drier and warmer conditions compared to the normal years. Crop failure events can be accurately predicted using machine learning with agroclimatic indices. Of the four crops for both temperate and tropic regions, soy crop failure is most accurately predicted, with an Area Under the Curve (AUC) score of 0.8991 for the temperate region and 0.7892 for the tropics. The AUC score of maize failure in the temperate region is 0.8760, followed by wheat failure (0.8627) and rice failure (0.8025). In the tropics, the remaining crops performed similarly, with AUC scores of 0.7298 (maize), 0.7313 (rice), and 0.7337 (wheat). The machine learning model revealed that growing degree days, last spring frost, first fall frost, growing season precipitation, and optimal field conditions (represented by soil moisture) are the most influential agroclimatic indices, showing various nonlinear relationships with crop failure probabilities. The most influential agroclimatic indices present significant trends on more than 25% of global croplands, showing increasing growing degree days, earlier last spring frost, later first fall frost, while growing season precipitation and optimal field conditions are increasing. Our findings may inform food security predictions, selections of weather index for crop insurance, and climate adaptations.

Can macroplastics affect riparian vegetation blooming and pollination? First observations from a temperate South-European river

Since plastics are a global growing concern that persists in nature, they threaten ecosystem conservation and human health. Particularly, pollination is one of the most important ecological services being pivotal to the ecosystem’s long-term functioning and human welfare. However, pollination is threatened by pesticides, urbanisation, habitat loss, and contaminants. As interactions between plastics and biota or ecosystem service remain neglected, the major challenge would be to research it. Our achievement was a first attempt to assess the effects of macroplastics on riparian vegetation and the ecosystem service of pollination. Here, (i) while investigating macroplastics entrapped by riparian vegetation, (ii) we propose the new field observation of the flower’s coverage by macroplastics. Then, (iii) we indirectly assessed the possible interaction between macroplastic litter and the ecosystem service of pollination. Finally, (iv) we performed a meta-analysis search to understand better how many studies were carried out on this topic. To achieve our aim, surveys of riverine macroplastic litter entrapped in riparian vegetation were carried out in the urban tract of the Aniene River. To assess if pollination was possibly reduced by macroplastics covering flowers, we observed the visitation of pollinators on flowers. Overall, we observed that flowers of riparian vegetation were covered by macroplastics, preventing them from being pollinated by insects, and pollination success (i.e., successful pollination) was potentially reduced to 81.4% by a factor of 18.6%. Our research highlights that macroplastics on vegetation indicate a new stress to plant reproduction, reducing blooming (i.e., flowering or flower production) and pollination. These recent observations urge new studies to evaluate how macroplastic litter accumulates and might affect ecosystem services in long-term research. Our findings could be of particular concern as pollination in agricultural crops and riverine habitats is central to human welfare as an ecosystem service. Considering that most global food crops depend on pollination by insects, crops and fruits (e.g., coffee, cocoa, apples) would not be present without the essential ecosystem service of pollination. Our findings highlight for the first time a new threat (i.e., macroplastic litter) to the blooming with possible implications for the pollination process.