Search

9 páginas.- 5 figuras.- 51 referencias.- Supplementary information The online version contains supplementary material available at https://doi.org/10.1038/s41561-023-01170-x, Soil mosses are among the most widely distributed organisms on land. Experiments and observations suggest that they contribute to terrestrial soil biodiversity and function, yet their ecological contribution to soil has never been assessed globally under natural conditions. Here we conducted the most comprehensive global standardized field study to quantify how soil mosses influence 8 ecosystem services associated with 24 soil biodiversity and functional attributes across wide environmental gradients from all continents. We found that soil mosses are associated with greater carbon sequestration, pool sizes for key nutrients and organic matter decomposition rates but a lower proportion of soil-borne plant pathogens than unvegetated soils. Mosses are especially important for supporting multiple ecosystem services where vascular-plant cover is low. Globally, soil mosses potentially support 6.43 Gt more carbon in the soil layer than do bare soils. The amount of soil carbon associated with mosses is up to six times the annual global carbon emissions from any altered land use globally. The largest positive contribution of mosses to soils occurs under a high cover of mat and turf mosses, in less-productive ecosystems and on sandy and salty soils. Our results highlight the contribution of mosses to soil life and functions and the need to conserve these important organisms to support healthy soils., The study work associated with this paper was funded by a Large Research Grant from the British Ecological Society (no. LRB17\1019; MUSGONET). D.J.E. is supported by the Hermon Slade Foundation. M.D.-B. was supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I), a project from the Spanish Ministry of Science and Innovation for the I + D + i (PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033a) and a project PAIDI 2020 from the Junta de Andalucía (P20_00879). E.G. is supported by the European Research Council grant agreement 647038 (BIODESERT). M.B. is supported by a Ramón y Cajal grant from Spanish Ministry of Science (RYC2021-031797-I). A.d.l.R is supported by the AEI project PID2019-105469RB-C22. L.W. and Jianyong Wang are supported by the Program for Introducing Talents to Universities (B16011) and the Ministry of Education Innovation Team Development Plan (2013-373). The contributions of T.G. and T.U.N. were supported by the Research Program in Forest Biology, Ecology and Technology (P4-0107) and the research projects J4-3098 and J4-4547 of the Slovenian Research Agency. The contribution of P.B.R. was supported by the NSF Biological Integration Institutes grant DBI-2021898. J. Durán and A. Rodríguez acknowledge support from the FCT (2020.03670.CEECIND and SFRH/BDP/108913/2015, respectively), as well as from the MCTES, FSE, UE and the CFE (UIDB/04004/2021) research unit financed by FCT/MCTES through national funds (PIDDAC).

Among the numerous archaeological remains that recent LiDAR flights revealed in Guatemala and Mexico, agrarian features are the most abundant. Archaeologists today are compelled to revise their paradigms in terms of methodology and assessment of environmental appropriation for agriculture. The Malpaís de Zacapu in west Mexico is one example. Besides the discovery of a substantial Epiclassic occupation near the well-documented Postclassic urban centers of the area, LiDAR imagery brought to light a deeply modified agrarian landscape and thereby dramatically changed our understanding of human settlement in this lava flows complex. Focusing on the northern part of the Malpaís, this study uses archaeogeographical and soil science methods to assess ancient farming systems and their evolution. We updated the archaeological and soil maps of the area, combining traditional field survey techniques and LiDAR-derived data interpretation. This allowed us to identify residential zones and a wide range of associated agrarian features adapted to the variety and agronomic challenges of volcanic soils. We further implemented a production-consumption model to reconstruct agricultural strategies from the Epiclassic to the Middle Postclassic period, from self-reliance to the necessity of supra-local agricultural inputs, possibly foreshadowing the Tarascan state tribute system.

12 páginas.- 4 figuras.- 49 referencia.- Supplementary information The online version contains supplementary material available at https://doi.org/10.1038/s41558-023-01646-z .- Full-text access to a view-only version (Acceso a texto completo de sólo lectura en este enlace) https://rdcu.be/c8vZi, Urban greenspaces support multiple nature-based services, many of which depend on the amount of soil carbon (C). Yet, the environmental drivers of soil C and its sensitivity to warming are still poorly understood globally. Here we use soil samples from 56 paired urban greenspaces and natural ecosystems worldwide and combine soil C concentration and size fractionation measures with metagenomics and warming incubations. We show that surface soils in urban and natural ecosystems sustain similar C concentrations that follow comparable negative relationships with temperature. Plant productivity’s contribution to explaining soil C was higher in natural ecosystems, while in urban ecosystems, the soil microbial biomass had the greatest explanatory power. Moreover, the soil microbiome supported a faster C mineralization rate with experimental warming in urban greenspaces compared with natural ecosystems. Consequently, urban management strategies should consider the soil microbiome to maintain soil C and related ecosystem services., This study was supported by a 2019 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation (URBANFUN), and by BES Grant Agreement No. LRB17\1019 (MUSGONET). M.D-B., P.G-P., J.D. and A.R. acknowledge support from TED2021-130908B-C41/AEI/10.13039/501100011033/ Unión Europea NextGenerationEU/PRTR. M.D.-B. also acknowledges support from the Spanish Ministry of Science and Innovation for the I + D + i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. was also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático ‘01 - Refuerzo de la investigación, el desarrollo tecnológico y la innovación’) associated with the research project P20_00879 (ANDABIOMA). D.J.E. was supported by the Hermon Slade Foundation. J.P.V. thanks the Science and Engineering Research Board (SERB) (EEQ/2021/001083, SIR/2022/000626) and the Department of Science and Technology (DST), India (DST/INT/SL/P-31/2021) and Banaras Hindu Univeristy-IoE (6031)-incentive grant for financial assistance for research in plant-microbe interaction and soil microbiome. J.D. and A. Rodríguez acknowledge support from the FCT (2020.03670.CEECIND and SFRH/BDP/108913/2015, respectively), as well as from the MCTES, FSE, UE and the CFE (UIDB/04004/2021) research unit financed by FCT/MCTES through national funds (PIDDAC).

22 páginas.-. 5 figuras.- 64 referencias.- Supplementary Information This pdf file includes: Supplementary Figs. 1–5, Tables 1–11 and references. https://static-content.springer.com/esm/art%3A10.1038%2Fs41559-022-01935-4/MediaObjects/41559_2022_1935_MOESM1_ESM.pdf, While the contribution of biodiversity to supporting multiple ecosystem functions is well established in natural ecosystems, the relationship of the above- and below-ground diversity with ecosystem multifunctionality remains virtually unknown in urban greenspaces. Here we conducted a standardized survey of urban greenspaces from 56 municipalities across six continents, aiming to investigate the relationships of plant and soil biodiversity (diversity of bacteria, fungi, protists and invertebrates, and metagenomics-based functional diversity) with 18 surrogates of ecosystem functions from nine ecosystem services. We found that soil biodiversity across biomes was significantly and positively correlated with multiple dimensions of ecosystem functions, and contributed to key ecosystem services such as microbially driven carbon pools, organic matter decomposition, plant productivity, nutrient cycling, water regulation, plant–soil mutualism, plant pathogen control and antibiotic resistance regulation. Plant diversity only indirectly influenced multifunctionality in urban greenspaces via changes in soil conditions that were associated with soil biodiversity. These findings were maintained after controlling for climate, spatial context, soil properties, vegetation and management practices. This study provides solid evidence that conserving soil biodiversity in urban greenspaces is key to supporting multiple dimensions of ecosystem functioning, which is critical for the sustainability of urban ecosystems and human wellbeing., This study was supported by a 2019 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation (URBANFUN), and by the BES grant agreement number LRB17\1019 (MUSGONET). M.D.-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I+D+i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. is also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático ‘01-Refuerzo de la investigación, el desarrollo tecnológico y la innovación’) associated with the research project P20_00879 (ANDABIOMA). H.C. was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDA28020202), National Key R&D Program of China (2022YFD1500202) and the National Natural Science Foundation of China (91951109, 42230511, 92251305). K.F. was supported by Young Elite Scientist Sponsorship Program by CAST (2021QNRC001) and China Postdoctoral Science Foundation (2021M703302). F.D.A. and S.A. were supported by ANID FONDECYT 11180538 and 1170995. J.P.V. was supported by SERB (SIR/2022/000626, EEQ/2021/001083), DST (DST/INT/SL/P-31/2021) and Banaras Hindu University, IoE (6031) incentives grant for plant-microbe interaction and soil microbiome research. T.G. and T.U.N were supported by the Slovenian Research Agency grants P4-0107, J4-3098 and J4-4547.

Bison are considered an ecologically keystone species of the North American grasslands because their activities influence ecosystem dynamics and interactions, particularly their wallowing behavior. In 2009, 23 bison were reintroduced within a 1,500 ha private native semi-arid grassland in Janos, Chihuahua. Our objective was to evaluate the effect of bison wallows on the composition and structure of the vegetation, on species composition of annual grasses, and soil properties. Soil and vegetation samples were taken from inside the wallows and were compared against the samples obtained outside the wallows from late August to early September. The percentage of plant cover and the height of the foliage were measured inside and outside the wallow. Soil cores were taken, and the presence of soluble salts, moisture retention capacity, percentage of clay, and concentration of nutrients was determined. The three associations preferred by bison for wallowing were toboso grassland, vine mesquite and annual grassland. Of the 27 species of grasses and forbs recorded in the three plant associations mostly used for wallowing, we found that 17 species were present inside and outside wallows. Five different species were found only inside wallows and another five, only outside of wallows. The annual grassland plants had a greater height outside the wallows. The toboso grassland association presented higher soil moisture, likely related to the higher percentage of clay, and the annual grassland presented the highest bulk density (BD) inside the wallows, which limited plant growth in this association. Soils in other associations did not show significant differences in BD among them, mainly due to their finer texture. No significant effect of the wallows on nutrient concentrations was recorded. The lack of significant differences related to bison activities could be related to the brief period since the herd was reintroduced to the site. These differences might become apparent over time with a larger herd. For this reason, we conclude that the current differences in the soil properties are mainly due to geomorphological processes. That is, at this stage after the reintroduction, the grasslands are responding to soil characteristics, and not to the activity of the bison.

Purpose Long-term agricultural irrigation with untreated wastewater has resulted in metals and metalloids accumulation in soil. Little information is available on the consequences of a change to irrigation with treated water on the mobility of these potentially toxic elements (PTEs). Materials and methods The potential mobility of PTEs was assessed using sequential extractions performed on soil irrigated with untreated wastewater for a century in Mexico. The possible effects of change in irrigation practices on PTEs mobility was evaluated through batch experiments, simulating a decrease in pH, an increase in salinity, and in chlorine of the irrigation water. Geochemical modeling allowed predicting the speciation of mobilized PTEs. Results and discussion Soils irrigated with untreated water were mainly enriched with PTEs in surface horizons. Only Cd and As were found in the soluble or exchangeable fractions ( Conclusion A change in irrigation practices could increase the mobility of PTEs if water treatment is not adapted to the soil type. The mobilization of PTEs, especially As and Cd, could affect both crops and groundwater quality. It is essential to monitor this mobility to avoid future risks to human health.

While monitoring the presence of antibiotic resistance in municipal wastewater bacteria from Mexico City, five Escherichia coli isolates were found to be resistant to carbapenems, antibiotics of “last resort” used mostly in hospitals. Further analysis revealed that these carbapenem-resistant isolates carried the gene encoding a metallo-beta-lactamase, NDM-5. The gene was found to be beared by a large, ∼145 kb conjugative plasmid, which also carries putative genes encoding resistance to sulfonamides, trimethoprim, tetracycline, ciprofloxacin, and chloramphenicol (although no phenotypic chloramphenicol resistance was detected) and quaternary-ammonium compounds. The plasmid also carried gene mobility determinants, such as integron integrase and two transposases. In addition to the direct public health threat posed by the presence of such multi-resistant organisms in wastewater released into the environment and used for crop irrigation; it is particularly concerning that carbapenem-resistant E. coli is rather rare in Mexican hospitals (

A healthy development is denied to millions of children worldwide as harsh life conditions manifest themselves in an altered inflammation-prone microbiome crosstalk environment. Keynote of this tragedy is that insufficient nutritious amino acid blocks lipids-intake to sustain diverse microbiota, and promotes the generalist strategy followed by Escherichia coli -besides other proteobacteria- of shifting gut metabolism, subverting the site specificity of first immune reaction. Furthermore, it could be hypothesized that selective success lies in their ability to induce inflammation, since this phenomenon also fuels horizontal gene transfer (HGT). In this review, we dilucidate how immune mechanisms of environmental enteric dysfunction affect overgrowth restriction, infectious morbidity rate, and acquired lifelong risks among severe acute malnourished children. Also, despite acknowledging complexities of antimicrobial resistant enrichment, we explore and speculate over the links between virulence regulation and HGT as an indissociable part in the quest for new inflammatory niches by open genome bacteria, particularly when both collide in the most vulnerable.

An alternative for sustainable urban development is to revegetate cities with the construction of planters as well as to recover degraded sites. The objective of this work was to characterize urban waste materials produced in Mexico City and to evaluate their potential for constructing Technosols for plant growth, as an alternative to use in revegetating the city without affecting natural landscapes. Construction and demolition waste materials amended with different application rates of compost made out of gardening wastes from Mexico City green areas were tested. Nine mixtures were prepared; three based on concrete, three based on demolition waste and three based on excavation waste. Changes on physical, chemical and physicochemical properties of these mixtures, namely nutrient contents, water retention and aeration capacity, were monitored in a twelve-month experiment. The mineralogy and the risk regarding the release of heavy metals and trace elements were also evaluated in the soluble fraction. The constructed Technosols were appropriate, to a greater or lesser extent, for tomato plant growth. Soil pH and soil electrical conductivity (EC) were the main factors defining their suitability; both parameters changed over time due to the washing of salts. The particle size of the mineral materials as well as the application rates of compost used in the construction of the Technosols resulted in adequate water holding capacity and soil aeration for plant growth. The type of parental materials defined the majority of the Technosol characteristics as well as their ability to function as a plant support. The concentrations of readily available heavy and trace metals were not a limitation for plant growth. However, potential co-transport of these elements with soluble organic matter should be considered in further research.

Forest regrowth is key to achieve restoration commitments, but a general lack of understanding when it occurs and how long secondary forests persist, hampers effective upscaling. We quantified spatiotemporal forest dynamics in a recently colonized agricultural frontier in southern Mexico, and tested how temporal variation in climate, and cross-community variation in land ownership, land quality and accessibility affect forest disturbance, regrowth and secondary forest persistence.We consistently found more forest loss than regrowth, resulting in a net decrease of 45% forest cover (1991-2016) in the study region. Secondary forest cover remained relatively constant while secondary forest persistence increased, suggesting that farmers are moving away from shifting cultivation. Temporal variation in disturbance was explained by annual variation in climatic variables and key policy and market interventions.We found large differences in forest characteristics across communities, and these were explained by differences in land ownership and soil quality. Forests were better conserved on communal land, while secondary forest was more persistent when farms were larger and soil quality is better. At the pixel-level both old forest and secondary forests were better represented on low-quality lands indicating agricultural concentration on productive land. Both old forest and secondary forest were less common close to the main road, where secondary forests were also less persistent.We demonstrate the suitability of timeseries analyses to quantify forest disturbance and regrowth and we analyse drivers across time and space. Communities differ in forest dynamics, indicating different possibilities, needs and interests. We warrant that stimulating private land ownership may cause remaining forest patches to be lost and that conservation initiatives should benefit the whole community. Forest regrowth competes with agricultural production and ensuring farmers have access to restoration benefits is key to restoration success.

While monitoring the presence of antibiotic resistance in municipal wastewater bacteria from Mexico City, five

The structure and function of the soil microbiome of urban greenspaces remain largely undetermined. We conducted a global field survey in urban greenspaces and neighboring natural ecosystems across 56 cities from six continents, and found that urban soils are important hotspots for soil bacterial, protist and functional gene diversity, but support highly homogenized microbial communities worldwide. Urban greenspaces had a greater proportion of fast-growing bacteria, algae, amoebae, and fungal pathogens, but a lower proportion of ectomycorrhizal fungi than natural ecosystems. These urban ecosystems also showed higher proportions of genes associated with human pathogens, greenhouse gas emissions, faster nutrient cycling, and more intense abiotic stress than natural environments. City affluence, management practices, and climate were fundamental drivers of urban soil communities. Our work paves the way toward a more comprehensive global-scale perspective on urban greenspaces, which is integral to managing the health of these ecosystems and the well-being of human populations., M.D.-B. and this project were supported by a 2019 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation (URBANFUN) and by the BES grant agreement no. LRB17\1019 (MUSGONET). M.D.-B. is also supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I). N.F. was supported by grants from the U.S. National Science Foundation (DEB1556090 and DEB1542653). L.T. acknowledges support from Norway-Baltic collaboration grant EMP442 and Estonian Science Foundation grant PRG632. B.K.S. acknowledges a research award by the Humboldt Foundation and funding from the Australian Research Council (DP190103714). F.A. is supported by ANID FONDECYT 11180538 and 1170995. S.A. is funded by ANID FONDECYT 1170995 and ANID ANILLO ACT192027. F.B. and J.L.M. acknowledge support from the Spanish Ministry and FEDER funds for the project AGL2017-85755-R, the i-LINK+ 2018 (LINKA20069) from CSIC, as well as funds from “Fundación Séneca” from Murcia Province (19896/GERM/15). C.P. acknowledges support from the Spanish State Plan for Scientific and Technical Research and Innovation (2013–2016), award reference AGL2016-75762-R (AEI/FEDER, UE). M.B. acknowledges support from a Juan de la Cierva Formación grant from the Spanish Ministry of Economy and Competitiveness (FJCI-2018-036520-I). T.P.M. would like to acknowledge contributions from the National Research Foundation of South Africa and cities involved in the South African survey. Slovenian coauthors were supported by the research project J4-1766 “Methodology approaches in genome-based diversity and ecological plasticity study of truffles from their natural distribution areas” and the Research Program in Forest Biology, Ecology, and Technology (P4-0107) of the Slovenian Research Agency. J.D. and A. Rey acknowledge support from the FCT (IF/00950/2014 and SFRH/BDP/108913/2015, respectively), as well as from the MCTES, FSE, UE, and the CFE (UIDB/04004/2020) research unit financed by FCT/MCTES through national funds (PIDDAC). J.P.V. acknowledges financial support from SERB (Science and Engineering Research Board) (EEQ/2017/000775) India. J.-Z.H. and H.-W.H. are financially supported by Australian Research Council (DP170101628).

The application of biochar and compost is a promising alternative to recover salt-degraded soils. However, in areas where the main source of salinity comes from the groundwater, it is also necessary to restrict the capillary rise of salts by means of a barrier. In this study, we show results of a field experiment, in which we tested the effect of a rubble barrier and the addition of biochar and compost on the establishment of a salt-tolerant grass (Distichlis spicata) in a highly saline-sodic soil. Our results showed that the capillary barrier: i) diminished the electrical conductivity and the CO2 fluxes by about one third to one half the values without barrier for both variables, ii) decreased the topsoil moisture (without barrier ca. 25–35%; barrier-zone ca. 15–25%), and iii) promoted the plant growth. Organic amendments did not show any effect. However, high-dose treatments had lower moisture content than the unamended ones (ca. 3–6% less water). Arrival of new plant species occurred preferably in the barrier-zone. We conclude that the barrier is an effective tool to decrease the soil salinity, but irrigation is needed to overcome smaller soil moisture during the dry season. Pyrochar was the most recommendable amendment to be used. However, biochar and compost doses were insufficient for the rehabilitation of this highly saline-sodic soil. The natural emergence of plant species (Suaeda torreyana, Kochia scoparia and Sonchus oleraceus) can improve the rehabilitation activities in an effective and inexpensive way. Urban residues can effectively be used to establish a plant cover in saline-sodic soils.

Belowground organisms play critical roles in maintaining multiple ecosystem processes, including plant productivity, decomposition, and nutrient cycling. Despite their importance, however, we have a limited understanding of how and why belowground biodiversity (bacteria, fungi, protists, and invertebrates) may change as soils develop over centuries to millennia (pedogenesis). Moreover, it is unclear whether belowground biodiversity changes during pedogenesis are similar to the patterns observed for aboveground plant diversity. Here we evaluated the roles of resource availability, nutrient stoichiometry, and soil abiotic factors in driving belowground biodiversity across 16 soil chronosequences (from centuries to millennia) spanning a wide range of globally distributed ecosystem types. Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower-productivity ecosystems (i.e., drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (i.e., wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity shares similar ecological drivers as soils and ecosystems develop. In general, temporal changes in aboveground plant diversity and belowground biodiversity were not correlated, challenging the common perception that belowground biodiversity should follow similar patterns to those of plant diversity during ecosystem development. Taken together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally distributed ecosystem types and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia. European Union's Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant [702057]; US National Science FoundationNational Science Foundation (NSF) [EAR1331828, DEB 1556090] This project received funding from the European Union's Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant Agreement 702057. N.F. was supported through grants from the US National Science Foundation (EAR1331828, DEB 1556090). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government. An extended version of the acknowledgments is provided in SI Appendix. Public domain – authored by a U.S. government employee

Municipal solid waste management is a challenge for local authorities since mismanagement leads to environmental damage and social discontent. The objective of this study was to assess in an integrated manner the socio-environmental situation of a municipal landfill from Mexico, using a design of mixed methods, which considered a quantitative evaluation of physicochemical and microbiological variables measured in leachates, surface and groundwater samples, soil and air, and a qualitative evaluation by in-depth interviews with the near-by inhabitants about their perception of the impacts of the landfill. The results show that leachates polluted the soil and surface water in a radius of up to 500 m from the landfill, but did not reach the groundwater, while the mean concentrations of PM10, Mn, and Ni measured in air samples at the landfill of 146 µg m−3, 0.12 µg m−3, 0.10 µg m−3, respectively, in the dry season and of Mn and Ni of 0.13 µg m−3 and 0.11 µg m−3, respectively, in the rainy season, surpassed permissible limits. From the residents perspective the landfill pollutes soil, water and air and it contributes to vehicle traffic and noise, promotes harmful fauna and disturbs the esthetic view. Air measurements coincide with social perception and in general, the applied mixed study design helped to assess in an integrated manner the socio-environmental concerns and to give advice to improve the current management of the landfill.

A reforestation trial was carried out with ten native tree species under four different doses of mineral fertilizer in the lowland tropics in Tabasco, Mexico. In six one-hectare plots, 2415 seedlings of Brosimum alicastrum, Calophyllum brasiliense, Ceiba pentandra, Colubrina arborescens, Diphysa americana, Enterolobium cyclocarpum, Handroanthus chrysanthus, Pimenta dioica, Pouteria sapota, and Tabebuia rosea were planted in a randomized design. The mineral fertilizer consisted of a single initial dose of 0 g, 150 g, 375 g or 750 g nitrogen-phosphorus-potassium (NPK), as well as micronutrients (Ca, Cu, Fe, Mg, Mn, Zn, S). First-year survival and median height increment of transplanted seedlings were analyzed with statistical confidence intervals. Whereas overall first-year survival for Ceiba pentandra for all fertilization doses combined was 66%, it was only 12% for Brosimum alicastrum. On the other hand, median height increment was 102 cm for Enterolobium cyclocarpum, whereas it was only 7 cm for Pimenta dioica. The survival of six of the planted species was apparently affected by the salinity effect caused by mineral fertilization. The only species that benefited from mineral fertilization in a statistically significant way was C. pentandra. In conclusion, mineral fertilization in tropical reforestation is not recommended in general. Appropriate species selection is far more important for favorable survivorship and height increment.

Background: Reusing wastewater for irrigation is a longstanding practice that enhances crop yields and improves climate resilience. Without treatment, however, wastewater contains harmful pathogens and chemicals. Reuse of untreated wastewater has been shown to be harmful to the health of nearby communities, but the routes of exposure are unknown and do not appear to be occupational. Some routes occur throughout entire communities, such as food contamination. Other routes may be spatially dependent, such as spread by domestic animals or through aerosolization. Objectives: To examine whether those wastewater exposure routes with a spatial dependency affect health, we estimated the risks of diarrheal disease in children under age 5 associated with living near wastewater canals, while adjusting for potential individual- and household-level confounders. Methods: We conducted three surveys over 1 y in the Mezquital Valley, Mexico, to measure diarrhea in children. The distance between each participating household and a wastewater canal was measured using GPS coordinates. The association between proximity and diarrhea was estimated with a multilevel logistic regression model accounting for spatial autocorrelation. Results: A total of 564 households completed one to three surveys, resulting in 1,856 survey observations of 646 children. Children living 100m from a canal had 45% lower odds of diarrhea than those living within 10m of a canal, and children living 1000m away had 70% lower odds of diarrhea [100m vs. 10m adjusted odds ratio (OR)=0.55, 95% credible interval (CI): 0.33, 0.91; 1000m vs. 10m adjusted OR=0.30, 95% CI: 0.11, 0.82]. Discussion: The estimated decline in diarrheal prevalence with household distance from a canal persisted after controlling for occupational exposure. Identifying the specific routes of exposure that drive this relationship will help identify which interventions, such as upstream treatment, can reduce health risks for entire communities where wastewater exposure occurs. https://doi.org/10.1289/EHP6443

Biochar production is a waste management option for agro-businesses and it is widely used to sequester carbon and to improve soil fertility. The preferred feedstock to produce biochar has been lignin and cellulose rich materials, or a mixture of industrial or animal residues. However, residues rich in soluble sugars, pectin and polysaccharides, such as fruit wastes, have been rarely used and are widely available. Furthermore, the release of toxic compounds has been reported when untreated biochars are used as soil amendments. Here we test if composting is able to eliminate toxicants and to improve biochar characteristics. We produced biochar out of orange and pineapple peels by pyrolysis, and characterized the physical and chemical properties of untreated and composted biochars. The analyses show that the untreated biochar has a high soluble salt and C content, an alkaline nature and high porosity. The composting process increased the pH, micronutrients, exchangeable cations, oxygen-based functional groups and the labile carbon, and reduced the PAHs and dioxins. Our results reveal that orange and pineapple peels are suitable raw materials for producing biochar but should be composted before using them as soil amendments.

Groundwater-N pollution derives from agricultural and urban activities, and compromises water quality in shallow aquifers, putting human and environmental health at risk. Nonetheless, subsurface microbiota can transform dissolved inorganic nitrogen into N2. In this study, we surveyed the microbial community of a shallow aquifer by sampling one well, one piezometer and a spring within an agricultural area that receives N-inputs of more than 700 kg/ha per year through irrigation with wastewater. The survey was conducted during a year with a 16S rRNA next-gen approach. In parallel, we quantified the number of gene copies and transcripts related to anaerobic ammonium oxidation (anammox, hzo), nitrite-dependent anaerobic methane oxidation (n-damo, nod and pmoA) and nitrous oxide reduction (last step of denitrification, nosZ), during the dry and rainy seasons. Our results showed that the groundwater samples had 17.7 to 22.5 mg/L of NO3−-N. The bacterial and archaeal community structure was distinctive at each site, and it remained relatively stable over time. We verified the co-occurrence of N-transforming bacteria, which was correlated with the concentration of NO2−/NO3− and ORP/DO values (DO: ~3.0 mg/L). Our analyses suggest that these conditions may allow the presence of nitrifying microorganisms which can couple with anammox, n-damo and denitrifying bacteria in interrelated biogeochemical pathways. Gene density (as the number of gene copies per litre) was lower in the rainy season than in the dry season, possibly due to dilution by rainwater infiltration. Yet, the numbers of hzo gene copies here found were similar to those reported in oceanic oxygen minimum zones and in a carbonate-rock aquifer. The transcript sequences showed that Candidatus Brocadia spp. (anammox), Candidatus Methylomirabilis spp. (n-damo) and autotrophic denitrifying Betaproteobacteria coexist in the groundwater environment, with the potential to attenuate the concentration of dissolved inorganic nitrogen by reducing it to N2 rather than N2O; delivering thus, an important ecosystem service to remove contaminants.

The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver; however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes., This project received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 702057 (CLIMIFUN). M.D.-B. is supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I), and by the BES Grant Agreement No. LRB17\1019 (MUSGONET). F.B. is grateful to the Spanish Ministry and FEDER funds for the project AGL2017–85755-R, the i-LINK+2018 (LINKA20069) from CSIC, and received funds from “Fundación Séneca” from Murcia Province (19896/GERM/15). S.R. was supported by the US Geological Survey Ecosystems Mission Area. C.P. acknowledges support from the Spanish State Plan for Scientific and Technical Research and Innovation (2013–2016), award ref. AGL201675762-R (AEI/FEDER, UE). A.G. acknowledges support from the Spanish Ministry of Science (CGL2017-88124-R). F.A. is supported by FONDECYT 11180538 and S.A. by FONDECYT 1170995. We would like to thank Peter Vitousek for his comments on a previous draft of this paper. Moreover, we thank Matt Gebert, Jessica Henley, Fernando T. Maestre, Victoria Ochoa, and Beatriz Gozalo for their help with lab analyses, and Emilio Guirado for his advice with topographic analyses. We also want to thank Osvaldo Sala, Matthew A. Bowker, Peter Vitousek, Courtney Currier, Martin Kirchmair, Victor M. Peña-Ramírez, Lynn Riedel, Julie Larson, Katy Waechter, David Buckner, and Brian Anacker for their help with soil sampling, and to the City of Boulder Open Space and Mountain Parks for allowing us to conduct these samplings. We are also grateful to the Division of Forestry and Wildlife of the State of Hawai’i and Koke’e State Park for their logistical assistance and for allowing us access to the HA sites. The Arizona research sites were established with the support of an EPA‐STAR Graduate Fellowship (U‐916251), a Merriam‐Powell Center for Environmental Research Graduate Fellowship, an Achievement Rewards for College Scientists (ARCS) Foundation of Arizona Scholarship, and McIntire‐Stennis appropriations to Northern Arizona University and the State of Arizona. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

A priority in restoration research is to seek methods that reach high levels of plant establishment at the lowest possible cost. Here, we test how direct seeding works with and without a plastic protector that covers seeds and seedlings in an early‐successional rainforest in Veracruz (Mexico). Two native species, Calophyllum brasiliense (bari) and Vochysia guatemalensis (corpo), at three topographic positions, were used. Germination rates with and without the protector were 84 versus 79% for C. brasiliense, and 98 versus 89% for V. guatemalensis, respectively. The protector significantly improved the germination only of V. guatemalensis. Plant survivorship of V. guatemalensis 27 months after seeding was significantly higher with the protector (78%) than without it (46%). For C. brasiliense, there were no differences in survivorship after 22 months with (61%) and without (54%) protector. In both species, the protector had no effect on height growth, which was significantly larger for seedlings located at the toeslope position. We developed a cost–benefit model that provides a threshold value at which the investment for protectors is justified by a resulting higher survivorship: If 27 months after seeding a treelet of V. guatemalensis is worth at least 0.83 USD on our sites, then the effect of the protector is worth the cost of its implementation (for C. brasiliense, survivorship was statistically undistinguishable with and without protector). We suggest that direct seeding with a plastic protector could be a promising alternative for forest restoration with suitable tree species.

Economic incentives to offset carbon dioxide (CO2) emissions associated with deforestation and other human activities affecting forest ecosystems depend on robust estimates of changes in forest carbon (C) stocks. Such stocks are difficult to assess in heterogeneous landscapes where the soil properties and the forest structure and functionality vary in space and time. Here we show that geopedological mapping is useful to quantify the above- and belowground C stocks in the different land units of the Lacandon tropical rainforest, southeast Mexico. We used an ordination method to recognize major gradients in the soil and we applied regression analyses to identify relationships between soil properties and AGB. Total forest C stocks differed among land units (287 to 478 Mg C ha− 1 in limestone mountains and fluvial terraces, respectively). Soil constrains like rooting depth (ranging from 0.13 to 1.34 m), available water storage capacity (ranging from 32.3 to 161.4 L m− 2) and Al saturation in the ion exchange complex (0 to 22.6% Alsat) were correlated with the aboveground biomass (AGB) C stock by affecting the stem size and density of trees. Soil organic carbon (SOC) in the solum represented 22 to 46% of the total forest C stock in the different landscape units, of which 28 to 45% was stored below 30 cm depth. Therefore, an accurate assessment of forest C stocks must consider not only the variation between land units with contrasting soil properties, but also the solum depth. Our results indicate that stratified sampling based on geopedologic mapping is useful to allocate incentives assessment of C storage at relatively low costs and with reasonable effort.

Antibiotic resistance genes in soil pose a potential risk for human health. They can enter the soil by irrigation with untreated or insufficiently treated waste water. We hypothesized that water flow paths trigger the formation of antibiotic resistance, since they transport antibiotics, multi-resistant bacteria and free resistance genes through the soil. To test this, we irrigated soil cores once or twice with waste water only, or with waste water added with sulfamethoxazole (SMX) and ciprofloxacin (CIP). The treatments also contained a dye to stain the water flow paths and allowed to sample these separately from unstained bulk soil. The fate of SMX and CIP was assessed by sorption experiments, leachate analyses and the quantification of total and extractable SMX and CIP in soil. The abundance of resistance genes to SMX (sul1 and sul2) and to CIP (qnrB and qnrS) was quantified by qPCR. The sorption of CIP was larger than the dye and SMX. Ciprofloxacin accumulated exclusively in the water flow paths but the resistance genes qnrB and qnrS were not detectable. The SMX concentration in the water flow paths doubled the concentration of the bulk soil, as did the abundance of sul genes, particularly sul1 gene. These results suggest that flow paths do function as hotspots for the accumulation of antibiotics and trigger the formation of resistance genes in soil. Their dissemination also depends on the mobility of the antibiotic, which was much larger for SMX than for CIP.

Dryland agriculture nourishes one third of global population, although crop irrigation is often mandatory. As freshwater sources are scarce, treated and untreated wastewater is increasingly used for irrigation. Here, we investigated how the transformation of semiarid shrubland into rainfed farming or irrigated agriculture with freshwater, dam-stored or untreated wastewater affects the total (DNA-based) and active (RNA-based) soil bacterial community composition, diversity, and functionality. To do this we collected soil samples during the dry and rainy seasons and isolated DNA and RNA. Soil moisture, sodium content and pH were the strongest drivers of the bacterial community composition. We found lineage-specific adaptations to drought and sodium content in specific land use systems. Predicted functionality profiles revealed gene abundances involved in nitrogen, carbon and phosphorous cycles differed among land use systems and season. Freshwater irrigated bacterial community is taxonomically and functionally susceptible to seasonal environmental changes, while wastewater irrigated ones are taxonomically susceptible but functionally resistant to them. Additionally, we identified potentially harmful human and phytopathogens. The analyses of 16 S rRNA genes, its transcripts and deduced functional profiles provided extensive understanding of the short-term and long-term responses of bacterial communities associated to land use, seasonality, and water quality used for irrigation in drylands.

Tropical rainforests harbor a high diversity of tree species, offering a potentially rich array of timber (TFP) and non-timber (NTFP) forest products. The supply of such products has been commonly evaluated at the local (plot) scale; however, little is known about how their availability and diversity change at the landscape scale, particularly in heterogeneous environments. This information is critical in designing landscape forest management programs. Here, we assess the extent to which the frequency, abundance, diversity, composition and productivity (aboveground biomass) of tree assemblages with potential forest products (PFPs) change across three landscape units (LUs) that differ in soil and topographic conditions. The study was carried out in a well-conserved old-growth tropical rainforest in southeastern Mexico. Three plots (0.5 ha each) were established per LU, in which all trees ≥ 10 cm were inventoried, taxonomically identified and assigned to eight forest product categories. General linear models, multiple regression and ordination analysis (CCA) were used to assess structural and compositional changes in the tree assemblages supplying different PFPs among LUs and along soil physicochemical gradients. More than half (94 species, 57%) of the total number of identified species (165) had one or more PFPs, mostly related to timber products. Ordination analysis showed that the abundance of species with different PFPs has a heterogeneous distribution among LUs, mostly related to changes in soil nitrogen, pH and aluminum saturation. Variation among LUs in terms of tree biomass was strongly driven by soil available phosphorus and soil physiological depth. Each LU had a different potential to provide forest products, producing a diverse mosaic of PFPs within the landscape. Decisions concerning sustainable forest management should consider such variability in the availability and diversity of forest products across landscapes, as well as the environmental factors that govern this spatial variation.

Land use changes often diminish soil carbon stocks and alter soil organic matter (SOM) quality affecting soil productivity. Therefore, intensively managed agricultural systems are intended to maintain and even increase SOM stocks. Here we compared soil organic carbon (SOC) stocks and their quality in fields under natural vegetation (mesquite forest and xerophytic shrubs), converted first to rain fed maize cultivation and then to irrigated alfalfa-maize rotation systems in a semiarid region of Central Mexico. Fields under the alfalfa-maize rotation have been irrigated for different lengths of time (15, 35, 51, 85 and 100 years) with untreated wastewater from Mexico City. We tested if the SOC stocks of the irrigated land use system were similar or even larger than those found under natural vegetation, and investigated if the quality of the SOM changed under the different covers. We collected composite soil surface samples and soil profile samples from fields under the different land uses and irrigation lengths and determined their organic carbon concentrations; we also quantified root residues and analyzed their bromatological composition. Mid infrared spectra of the soil samples were recorded and analyzed by multivariate procedures to determine changes in SOM quality. We found the smallest SOC stocks in soils under rain fed maize (mean: 45 Mg ha −1 in 30 cm depth). In the alfalfa-maize rotation SOC stocks increased 1.5 fold during the first 40 years under wastewater irrigation, thereafter reaching an apparent new steady state, with similar C stocks to soils under xerophytic shrub cover (65 Mg ha −1 ). SOM in rain fed soils was more hydrophobic and more metabolized by microorganisms, while the SOM in irrigated soils had a more hydrophilic character. Lignin in surface horizons of long term irrigated soils has a lesser degree of condensation than in deeper soil horizons or in soils irrigated for shorter periods of time, indicating a less intensive microbial degradation. We conclude that wastewater irrigation increases SOM stocks due to the greater lignin rich root biomass produced by alfalfa in this land use system, which helps to recover the SOC loss of 17–34% of the rain fed agriculture system.

Irrigation with untreated sewage water adds fresh organic matter to the soil. When it is applied by flooding, as in the Mezquital Valley of Mexico, many of the pores in the soil become temporarily waterlogged and depleted of oxygen, and reduction generates nitrous oxide (N2O) and methane (CH4). We monitored the redox potential, Eh, in the soil at two sites in the Mezquital Valley to discover whether the short-term gaseous emissions matched the changes in Eh. One site is irrigated periodically by flooding with waste water and has alfalfa, rye grass and maize grown in succession; the other site grows maize with water from summer rain only. Each electrode buried in the soil for the purpose produced sequences of measurements that were correlated in time. We modelled the correlation and took it into account to analyse the effects of the irrigation by residual maximum likelihood (reml). After each flooding, the redox potential under alfalfa and rye grass decreased by 150–200 mV from a norm of about 450 mV for 2 days, after which it returned to its norm. The short-term response to flooding under maize was similar, but the redox potential did not recover completely; instead there was a decrease from one irrigation event to another, in particular as a result of heavy rain in September that saturated the soil. The soil under rain-fed maize was slower to respond, partly, we believe, because infiltration into the less aggregated clay soil and drainage from it were also slow. Irrigation with untreated sewage water caused a sharp decrease in Eh lasting 1–2 days. It seems to have depleted the soil of oxygen, causing reduction in microhabitats rich in carbon and nitrogen and generation of N2O, which was captured in the closed chambers that we had installed. Highlights Land in the Mezquital Valley of Mexico emits much greenhouse gas when irrigated with sewage water. The soil's redox potential was monitored in situ as crops were irrigated or depended solely on rain. Each irrigation caused a decrease in the soil's redox potential of 150–200 mV for 2 days. The decrease in redox potential corresponded in time with emission of nitrous oxide.

Wastewater reuse for agriculture is common worldwide; wastewater treatment, however, is rare in many countries, leading to high potential for exposure to harmful pathogens. Mexico City, one of the largest producers of untreated wastewater for agricultural use worldwide, was the site of key epidemiologic studies conducted in the 1990s. We both reviewed the literature on and conducted a cross-sectional study of diarrheal risk and wastewater contamination to provide an updated assessment of health risks and to inform an upcoming update of the 2006 WHO guidelines on wastewater reuse. We surveyed communities in the Mezquital Valley that use wastewater for irrigation and communities that use well water to compare the prevalence of self-reported diarrheal disease in children under five years old. Wastewater, well water, household environmental samples, and stool samples were collected and analyzed. Communities exposed to wastewater had a higher one-week prevalence of diarrhea (10%) compared to unexposed communities (5%). This association remained in an adjusted modified Poisson regression model (PR = 2.31, 95% CI 1.00, 5.31), but not when limited to households engaged in agriculture. Water quality indicators document differences between irrigation water from the two community groups. These results are in agreement with 25 population studies identified by our review that were conducted since or not included in the 2006 WHO guidelines and show consistent negative impacts of wastewater exposure on health. While overall diarrheal prevalence has declined when compared to studies conducted over 25 years ago in the same region, the association of diarrheal disease and wastewater exposure has remained and possibly increased. With rising urbanization worldwide, attention to these risks and wastewater treatment is becoming increasingly important.

Irrigation with wastewater is an increasing practice around the world triggered by the large needs of water for agriculture. Many times this source of water is added by flooding to the fields, creating short temporal oxygen-depleted environments, where nitrous oxide (N