Evidence of eared doves consumption and the potential toxic exposure during the Regional Development period in Quito-Ecuador.

Throughout history, food has played a fundamental role in the development of societies. An understanding of the diets of different cultures and their impact on health can provide valuable insights into their lifestyle. The identification of the animal remains found within two vessels is reported and, in addition, an assessment of whether the diet and soil composition of the period may be associated with toxic elements was carried out. The animal bones retrieved from the settlement, which dated from 25 to 203 cal AD, were identified as belonging to Zenaida cf. auriculata, commonly known as eared dove. Ancient starch was discovered in the sediments inside the vessels. These sediments, along with the pre-Hispanic soil collected in the study zone, showed moderate pollution, suggesting potential environmental contamination. For the first time, evidence that eared doves were part of the diet of the ancient inhabitants of Quito is presented, as shown by the occurrence of their bones within food processing utensils. Furthermore, the study highlights the possibility of environmental contamination due to volcanic eruptions that occurred during the Regional Development period from 500 BC to AD 500. These results can contribute to a better understanding of the living conditions of the early inhabitants of Quito and similar regions.

Mathematical modelling approach to understanding the effect of Mg-rich synthetic gypsum used as fertilizer on growth of Hevea brasiliensis in acid soils.

Knowledge of plant growth dynamics is essential where constraints such as COVID-19 lockdown restrictions have limited its field establishment. Thus, modeling can be used to predict plant performance where field planting/monitoring cannot be achieved. This study was conducted on the growth dynamics of rubber planted on two acid soils treated with either dolomitic limestone (GML), kieserite or Mg-rich synthetic gypsum (MRSG) to supply the Mg required by rubber seedlings. To understand the effect of applied treatments on the changes in rubber growth, data on plant height, stem diameter and biomass were regressed against months after transplanting (MAT) using the equation y = A/ (1+be-ct), and its derivative [Formula: see text] was utilized for estimating the growth rate of the parameters. The dynamics in plant height, stem girth and plant biomass were modelled using an exponential function of y = Aebt and their rate of change was derived using dx/dy = Abebt. The experiment indicated that the logistic growth curve model expressed as y = A/ (1+be-ct), closely described the growth in terms of each parameter against months after transplanting. A high probability level (a = 0.0001) was recorded in the model for all the treatments in the study. The growth of rubber seedlings in the glasshouse was improved by MRSG treatment in the two studied soils (Ultisol and Oxisol), giving comparable results to other Mg fertilizer treatments. The plant performed better on the Ultisol compared to the Oxisol. The results indicate the potential of using MRSG to replace conventional Mg-fertilizers to sustain rubber seedling growth.

Revisiting Citrus Rootstocks Polyploidy as a Means to Improve Drought Resilience: Sometimes Less Is More.

Polyploid varieties have been suggested as an alternative approach to promote drought tolerance in citrus crops. In this study, we compared the responses of diploid and tetraploid Sunki 'Tropical' rootstocks to water deficit when grafted onto 'Valencia' sweet orange trees and subjected to water withholding in isolation or competition experiments under potted conditions. Our results revealed that, when grown in isolation, tetraploid rootstocks took longer to show drought symptoms, but this advantage disappeared when grown in competition under the same soil moisture conditions. The differences in drought responses were mainly associated with variations in endogenous leaf levels of abscisic acid (ABA), hydrogen peroxide (H2O2) and carbohydrates among treatments. Overall, tetraploids were more affected by drought in individual experiments, showing higher H2O2 production, and in competition experiments, rapidly increasing ABA production to regulate stomatal closure and reduce water loss through transpiration. Therefore, our results highlight the crucial importance of evaluating diploid and tetraploid rootstocks under the same soil moisture conditions to better simulate field conditions, providing important insights to improve selection strategies for more resilient citrus rootstocks.

Fertilized soils enhance the efficiency of phytoremediation by tropical grasses in cadmium-contaminated soils.

The effectiveness of phytoremediation in Cd-contaminated soils is crucial for enhancing nutrient availability and plant tolerance to Cd. We simulated soil contamination with varying textures and fertilization conditions. Two experiments were conducted: one without liming and fertilization and another with soil fertilization for grasses. The soil types used were Oxisol and Entisol, and the grasses tested were Megathyrsus maximus and Urochloa brizantha at three Cd levels: 0 mg kg-1 (Control), 2 mg kg-1 (Low), and 12 mg kg-1 (High). Soil amendments and fertilization did not significantly change Cd availability. Soil chemical attributes were unaffected by Cd contamination but were influenced by fertilization, which kept the pH below optimal levels. Cd availability was higher in more contaminated soils, with Entisol showing greater concentrations than Oxisol. Dry matter production of the grasses decreased with higher contamination, with U. brizantha being more productive than M. maximus in fertilized soils. Cd accumulation was higher in highly contaminated soils, particularly for U. brizantha. The bioconcentration factor was higher in Entisol, while the translocation factor exceeded 1.0 only for M. maximus in low-contamination Oxisol. Fertilization can mitigate Cd contamination effects, with U. brizantha showing greater tolerance and accumulation capacity in fertilized soils.

Grasses, often seen just as cover crops or forages, can play a vital role in mitigating heavy metal pollution, especially Cd. By comparing the growth, Cd accumulation, and tolerance of different grass species in fertilized versus unfertilized soils, we identify optimal strategies to maximize the effectiveness of phytoremediation without compromising soil health and ecological balance. The findings of the study reveal that the response of grasses to fertilization in contaminated soils varies significantly, directly influencing their capacity to phytoremediate Cd. This discovery suggests that customizing fertilizer use, based on the grass species and specific soil conditions, could be crucial for optimizing the removal of Cd from the environment.

Factors that influence the migration of sorbed pesticides in polyethylene and biodegradable mesoplastics.

Trifluralin, Chlorpyrifos, and Procymidone migration performance from polyethylene (PE) and biodegradable (Mater-Bi: M-B) mulching films was examined. Desorption of pesticides from PE and M-B was studied using soil-plastic microcosms, considering temperature, soil humidity, and mulching film type as experimental variables. Trifluralin and Chlorpyrifos desorption was higher for PE than for M-B under all experimental conditions. In both cases, as the temperature increased from 25 °C to 40 °C, pesticide migration also increased, whereas as the soil humidity raised from 30% to 60%, pesticide desorption decreased. In the case of Procymidone, migration from PE and M-B at 25 °C was similar under both soil moisture conditions. Migration percentages were similar for both mulch films at 40 °C and 30% soil humidity. However, at higher soil moisture (60%), migration from M-B was greater than from PE. A linear relationship was observed between the percentage of migration and the vapor pressure of the pesticides. In all cases, migration increased with higher vapor pressure, indicating a possible migration mechanism in the vapor phase. Pesticide migration increased at high temperatures (40 °C). The effect of soil humidity in reducing pesticide migration was more significant at lower levels (30%). In addition, the mesoplastic sorption of pesticides in soil columns was studied using PE and M-B films. While the recoveries for Trifluralin, Chlorpyrifos, and Procymidone in the PE films were 0.05% ± 0.01%, 0.13% ± 0.03%, and non-detectable, the recoveries for M-B were: 0.49% ± 0.07%, 0.31% ± 0.09%, and 0.17% ± 0.10%, respectively, indicating that M-B was a better adsorbent than PE in all cases. This behavior should be considered in combination with the lower migration percentages observed for this type of mulching film in the microcosm experiments. These results could indicate a potential carrier effect of pesticide on biomesoplastic in the environment.

GIS-based G × E modeling of maize hybrids through enviromic markers engineering.

Through enviromics, precision breeding leverages innovative geotechnologies to customize crop varieties to specific environments, potentially improving both crop yield and genetic selection gains. In Brazil's four southernmost states, data from 183 distinct geographic field trials (also accounting for 2017-2021) covered information on 164 genotypes: 79 phenotyped maize hybrid genotypes for grain yield and their 85 nonphenotyped parents. Additionally, 1342 envirotypic covariates from weather, soil, sensor-based, and satellite sources were collected to engineer 10 K synthetic enviromic markers via machine learning. Soil, radiation light, and surface temperature variations remarkably affect differential genotype yield, hinting at ecophysiological adjustments including evapotranspiration and photosynthesis. The enviromic ensemble-based random regression model showcases superior predictive performance and efficiency compared to the baseline and kernel models, matching the best genotypes to specific geographic coordinates. Clustering analysis has identified regions that minimize genotype-environment (G × E) interactions. These findings underscore the potential of enviromics in crafting specific parental combinations to breed new, higher-yielding hybrid crops. The adequate use of envirotypic information can enhance the precision and efficiency of maize breeding by providing important inputs about the environmental factors that affect the average crop performance. Generating enviromic markers associated with grain yield can enable a better selection of hybrids for specific environments.

The use of phosphate rock and plant growth promoting microorganisms for the management of Urochloa decumbens (Stapf.) R.D. Webster in acidic soils.

Background: Forage production in tropical soils is primarily limited by nutrient deficiencies, especially nitrogen (N) and phosphorus (P). The use of phosphate rock by plants is limited by its low and slow P availability and microbial phosphate solubilization is the main mechanism for P bioavailability in the soil-root system. The objectives of this study were (i) select a nitrogen-fixing bacteria which could be used as a co-inoculant with the Penicillium rugulosum IR94MF1 phosphate-solubilizing fungus and (ii) evaluate under field conditions the effect of inoculation combined with phosphate rock (PR) application on yield and nutrient absorption of a Urochloa decumbens pasture which was previously established in a low-fertility, acidic soil. Methods: Various laboratory and greenhouse tests allowed for the selection of Enterobacter cloacae C17 as the co-inoculant bacteria with the IR94MF1 fungus. Later, under field conditions, a factorial, completely randomized block design was used to evaluate the inoculation with the IR94MF1 fungus, the IR94MF1+C17 co-inoculation, and a non-inoculated control. Two levels of fertilization with PR treatment (0 kg/ha and 200 kg/ha P2O5) were applied to each. Results: During five consecutive harvests it was observed that the addition of biofertilizers significantly increased (p < 0.05) the herbage mass and N and P assimilation compared to the non-inoculated control. However, no statistically significant differences were observed for the PR application as P source. Conclusion: P. rugulosum IR94MF1 is capable of solubilizing and accumulating P from the phosphate rock, making it available for plants growing in acid soils with low N content. These inoculants represent a good option as biofertilizers for tropical grasses already established in acidic soils with low N content.

Fluvial erosion in a catchment cultivated with no-tillage at the edge of the southern Brazilian plateau.

The dynamics of fluvial erosion responds to soil erosion and surface runoff on hillslopes due to land use and environmental fragility, conditioned by the soil, geology, relief, and rainfall rate. Despite the increasing problems associated with fluvial erosion in Brazil, little information is available on bedload transport in headwater catchments under intense agricultural activity. Therefore, this study sought to characterize the fluvial erosion processes and bedload dynamics in an experimental catchment in southern Brazil located at the edge of the Brazilian Meridional plateau, which is representative of a large area of high environmental fragility and intense agricultural activity in Southern Brazil. The Guarda Mor River drains a headwater catchment (18.5 km2) with undulating and hilly terrain with fragile soils and intense agricultural activity controlling fine and coarse sediment supply downstream. During 11 major rainfall-runoff events, monitoring was conducted to measure streamflow, bedload transport rates, sediment size, and hydraulic parameters, such as Manning's n values and viscous layer thicknesses. A rating curve was established based on 40 streamflow and bedload discharge measurements taken at different water levels and stages along the hydrograph. In addition, a river portion (gravel bed) was characterized as well as the granulometric characteristics of its surface and subsurface layers. The results showed that the transport pattern is influenced by factors other than hydraulic parameters alone, including the interdependence between successive events, armoring effects, and hysteresis. These factors are strongly related to the surface runoff and erosion observed on the hillslopes, which define the streamflow energy and the supply of sand fraction, respectively. A discussion is held on the bedload transport dynamics under non-equilibrium conditions in the modeling of fluvial erosion processes.

Soil attributes and leaf litter composition in forest communities of the Brazilian Pantanal.

Leaf litter is an important component related to nutrient cycling and conservation of soil biodiversity. In this context, the objective of our study was to investigate the relationship between soil and leaf litter in different forest communities in sub-regions of the Pantanal (Nhecolândia and Abobral/Miranda). To this end, we collected soil and leaf litter samples from 152 sample plots divided in physiognomies regionally called as Cordilheira, Capão, Murundu, Corixo and Cambará/Canjiqueira forest. In the laboratory, analytical determinations were conducted for 22 soil attributes and 11 elements of the chemical composition of the leaf litter. The forest communities showed a great well-defined edaphic gradient encompassing environments with high natural fertility soils (Capão and Cordilheira Abobral/Miranda), acidic soils with a high proportion of soluble Al3+ (Cambará/Canjiqueira, and Corixo), and poorly developed soils with a predominantly sandy texture (Nhecolândia region, Cordilheira and Murundu). Soil attributes are significantly related to the chemical composition of litter, as indicated by correlations between N, P, Ca, Mg, Mn and the C/N ratio with physical, chemical and soil organic matter attributes. This study revealed the interaction of soils with the chemical composition of litter, constituting an ecosystem service, in forest communities in the Brazilian Pantanal.

May Antarctic plants grow on Martian and Lunar soil simulants under terrestrial conditions?

Extremophile organisms have been largely studied in Astrobiology. Among them, two antarctic plants emerge as good candidates to become colonizers of other celestial bodies, such as Mars and the Moon. The present research aimed to evaluate survival and growing capacity of Sanionia uncinata and Colobanthus quitensis on Martian (MGS-1) and Lunar (LMS-1) regolith simulants, under terrestrial conditions. The survival responses of both species on the simulators and the original sampling site of Antarctic soil were observed during 15 days, in laboratory conditions at 'Comandante Ferraz' Station. Based on physiological parameters changes under the three soil conditions tested, our results suggest that Martian soil can be too harsh for plant growth, showing expressive decay, especially for C. quitensis. While lunar soil might provide more favorable conditions, with less observed changes, similarly to how they would in Antarctic soil from their natural habitat. This preliminary study provides resources and fosters knowledge about the possibility of these Antarctic species to survive in extraterrestrial environments, starting with soil parameters; and discusses the importance and use of Antarctic plants in astrobiology.

Salt-affected soils in the Lopez de Bertodano Formation, polar semi-desert of Seymour Island, Antarctica: topographic or lithological controls?

Salinization is one of the main pedogenetic processes occurring on the semiarid zone of the Weddel sea, like in Seymour Island, where salt-affected soils are widespread. This study aimed to investigate whether topography controls the distribution of salt-affected soils on Seymour Island, particularly with reference to the Lopez de Bertodano Formation. Chemical and physical results from 45 soil profiles were used, where morphometric variables were extracted. Descriptive statistical analysis, extraction of morphometric variables, cluster analysis and principal component analysis were carried out in this database. The separation of soils associated with the López de Bertodano Formation into two groups is explained by topographic atributes, and not by soil properties. Hence, the salts in soils have a geogenic origin, and despite differences in geological units, the uniform mineralogical composition of all Lopez de Bertodano Formation results in the widespread accumulation of salts in soils, influenced by the saline parent material and the semi-desert climate. Despite the lack of topographic control in the distribution of saline soils as a whole, geomorphology play a distinct role in the formation of secondary saline features, such as crusts, efflorescences, and columnar structures, or in salt composition of salts present in the soils.

Sawdust-based compost for production of Pycnoporus sanguineus basidiocarps.

This work aimed to get compost with cellulose-rich residues for Pycnoporus sanguineus basidiocarp production. Two isolates of P. sanguineus (Ps08 and Ps14) were grown in polypropylene bags containing sawdust of Eucalyptus sp. and rice bran in rates of zero, 5% and 20%, and humidity of 75%. We used two granulometries of sawdust, less than 500 µm and between 500 and 841 µm, compress to get a density of 0.5 g mL-1. Basidiocarps were harvested at 90 and 180 days of incubation, evaluating quantity, diameter, fresh and dry masses and production of the pigment cinnabarin. For the variable granulometry, there was an effect only for the isolate Ps14, which produced basidiocarps with diameters 14.65 mm in granulometry less than 500 µm and 8.56 in granulometry 500-841 µm, however, comparing the isolates, Ps08 produced larger basidiocarps, with an average diameter of 36.99 mm while 11.60 mm for Ps14. Only the isolate Ps08 responded in a dose-dependent manner to rice bran concentrations. As for the fresh mass of basidiocarps, in both harvests the isolate Ps08 presented higher values than the isolate Ps14 in the first and second harvests, in the granulometry less than 500 µm. The cinnabarin content of Ps14 isolate was higher than Ps08, with values of 0.67 e 0.43 mg mL-1, respectively, in the granulometry 500-841 µm, with a tendency to increase in cinnabarin content with higher additions of rice bran. Thus, it was possible to produce basidiocarps of P. sanguineus in an axenic way using cellulosic residues supplemented with rice bran.

Arsenic(V) and vanadium(V) fractionation after its incorporation into a sandy loam soil from Pampas region, Argentina.

Arsenic is a well-known toxic substance, widely distributed, whereas vanadium is a pollutant of emerging interest. Both have been found to correlate positively in groundwaters, thus concern arises on the effect of these pollutants on crops, if such waters are used for irrigation. We conducted a study on the effect of aging with a typical crop soil mimicking soils initially irrigated with water containing As and V. Afterwards, the soil was subjected to wet/dry cycles. The fractionation of both elements at different times from the addition (onset of the experiment) was determined by a modified European Community Bureau of Reference (BCR) method. It is found that the greater part of V is located in the most stable fraction from the onset of the experiment. This is attributed to interaction with amorphous and clay minerals and the precipitation of Ca(VO3)2, which is predicted by speciation modeling. The remaining fractions show the expected behavior: the most labile fraction decreases over time, that associated to oxidizable increases with time, whereas the fraction associated to reducible components stays approximately constant. Arsenic shows a lower proportion in the most stable fraction compared with V, and a higher proportion in the most labile, but otherwise shows similar tendencies. The results suggest a low availability of V and a higher one of As. No competence was observed between As and V in the experimental conditions.

Rhizobacteria and silicon modulate defense, oxidative stress, and suppress blast disease in upland rice plants in low phosphorus soils under field conditions.

MAIN CONCLUSION: Rhizobacteria and silicon fertilization synergism suppress leaf and panicle Blast, and mitigates biotic stress in rice plants. Association of bioagents and silicon is synergistic for mitigating leaf and panicle blast and low phosphorus (P) levels in upland rice, under greenhouse conditions. This study aimed to evaluate the potential of the bioagents and silicon interaction on blast disease severity suppression in upland rice plants, under field low P conditions. The experiment was conducted during two growing seasons (E1 and E2), in randomized block design with four replications, and consisted of five treatments, combining a mix of three rhizobacteria, BRM 32114 and BRM62523 (Serratia marcescens), and BRM32110 (Bacillus toyonensis), and three application methods (seed treatment, drenching, spraying). Calcium and magnesium silicate (2 t/ha) was applied over a low soil P, 30 days before sowing. Leaf blast (LBS) and panicle blast (PBS), area under the disease progress curve (AUDPC), activity of enzymes related to oxidative stress, pathogenesis-related (PR), biochemical indicators such as hydrogen peroxide, chlorophyll a and b, carotenoids, and grain yield (GY), were assessed. Bioagents and silicon suppressed LBS by 77.93 and PBS by 62.37%, reduced AUDPC by 77.3 (LBS) and 60.6% (PBS). The yield in E1 was 25% higher than in E2. The treatments statistically differ only in E2, the yield with bioagents and silicon (2435.72 kg ha-1) was 71.95% higher compared to the absolute control. All enzymatic activities related to oxidative stress and PR proteins were modulated by bioagents and silicon association. The association of rhizobacteria and silicon exhibited a synergistic effect, and represents a bioprotective combination to reduce the effects of different stresses and indirectly reduces the use of chemical inputs.

Mitigating salinity stress on tomato growth, water regime, gas exchange, and yield with the application of QuitoMax.

This study assessed the intensity of salt stress in the two tomato varieties by measuring variables associated with the water regime, chlorophyll content, normalized difference vegetation index, gas exchange, and yield. The cultivars Amalia and Claudia, which represent tolerance and susceptibility to salinity, were evaluated. Three treatments were established in plastic pots, using a completely randomized design: T1, saline soil (ECse = 6.9 dS m-1 without QuitoMax application); T2, nonsaline soil (ECse = 0.95 dS m -1 with QuitoMax application); and T3, saline soil (ECse = 6.9 dS m-1) with QuitoMax application. The QuitoMax was applied at a rate of 300 mg L-1, during the flowering phenophase. QuitoMax caused an increase in the variables evaluated in both varieties (tolerant and susceptible) of tomato, with a lower contribution of QuitoMax to the variables related to water regime and the greatest contributions to chlorophyll content and photosynthetic activity. QuitoMax contributed positively to all variables and was superior to stress intensity for most of the variables evaluated in the tolerant variety (Amalia), except for stem thickness and the number of flowers per bunch. In the susceptible variety (Claudia), the five variables of stress intensity exceeded the contribution of QuitoMax, with the strongest effects on osmotic potential, fruit mass, and yield per plant. The present work demonstrates the feasibility of using this biostimulant to increase the tolerance of tolerant varieties and maintain tolerance in tomato varieties susceptible to salinity, reducing the intensity of saline stress and increasing plant performance under salinity conditions.

Wild Andean camelids promote rapid ecosystem development after glacier retreat.

Knowing mechanisms that facilitate the emergence of post-glacial ecosystems is urgently required given rapid recent glacial retreat in high latitude and high elevation regions. We examined the effect of nutrient hotspots created via communal dung deposition by wild, native Andean camelids on soil abiotic and biotic properties and plant cover in the rapidly deglaciating Cordillera Vilcanota, southeastern Peru. Animal-modified proglacial soils were significantly enriched in all measured edaphic properties compared to reference glacial-till soils of the same age adjacent to animal-modified soil patches. Organic matter composition, soil moisture, available inorganic nitrogen, and plant cover were nearly zero in glacial-moraine reference soils, but were at least one order of magnitude greater in animal-modified soils. Likewise, DNA concentrations were almost two orders of magnitude higher in modified soils (23 ± 9 µg DNA g soil-1) compared to reference soils (0.6 ± 0.3 µg DNA g soil-1). Animal-modified soil microbial community composition differed significantly from reference soils for both prokaryotes and eukaryotes, and eukaryote ASV richness was significantly higher in camelid latrines than in controls. Nutrient transfer into glacier forefields by native camelids shortcuts a 100+ year lag between glacier retreat and primary succession. Our results suggest that nutrient transfer into glacier forefields by wild, native animals may be an important, natural mechanism by which tropical Andean species can expand upslope at a pace relevant to climate change.

Exploring soil bacterial and fungal communities in Colombian terrestrial ecosystems modulated by altitude-influenced factors.

A bacterial (16S rRNA) and fungal (ITS rRNA) taxonomic characterization was carried out using metabarcoding along an altitudinal gradient in the western range of the Valle del Cauca, Colombia. This study encompassed Tropical Dry Forests, Andean, and Páramo ecosystems in Laguna de Sonso (900 m.a.s.l), Yotoco (1,800 m.a.s.l), Bosque del Duende (2,400 m.a.s.l), and Páramo del Duende (3,200 m.a.s.l). The physicochemical analyses revealed soils with high organic matter (>10%), non-compacted, extremely acidic pH levels (4.4) at higher altitudes, and slightly to moderately acidic pH in lower areas (5.5-6.1). 59 plant families were identified, with Araceae, Lauraceae, and Fabaceae being the most abundant. The most abundant bacterial taxonomic assignments were Acidobacteriota and Proteobacteria phyla, while for fungi, it was Ascomycota and Basidiomycota. Alpha diversity analysis showed high community diversity, whereas beta diversity reflected composition differences among locations and their heterogeneity. The most abundant functional predictions for bacteria were chemoheterotrophic activity and nitrogen cycle involvement. At the same time, for fungi, it was ecological guilds related to pathogenic activity in both animals and plants, endophytes, and epiphytic saprotrophs. The PLS-PM analysis revealed an indirect influence of altitude on microbial abundance and diversity.

The pesticides carbofuran and picloram alter the diversity and abundance of soil microbial communities.

Many countries widely use pesticides to increase crop productivity in agriculture. However, their excessive and indiscriminate use contaminates soil and other environments and affects edaphic microbial communities. We aimed to examine how the pesticides carbofuran and picloram affect the structure and functionality of soil microbiota using cultivation-independent methods. Total DNA was extracted from microcosms (treated or not with pesticides) for amplification and metabarcoding sequencing for bacteria (16S gene) and fungi (28S gene) using Illumina-MiSeq platform. Data analysis resulted in 6,772,547 valid reads from the sequencing, including 3,450,815 amplicon sequences from the V3-V4 regions of the 16S gene and 3,321,732 sequences from the 28S gene. A total of 118 archaea, 6,931 bacteria, and 1,673 fungi taxonomic operating units were annotated with 97% identity in 24 soil samples. The most abundant phyla were Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Chloroflexi, Euryarchaeaota, and Ascomycota. The pesticides reduced the diversity and richness and altered the composition of soil microbial communities and the ecological interactions among them. Picloram exerted the strongest influence. Metabarcoding data analysis from soil microorganisms identified metabolic functions involved in resistance and degradation of contaminants, such as glutathione S-transferase. The results provided evidence that carbofuran and picloram shaped the soil microbial community. Future investigations are required to unravel the mechanisms by which soil microorganisms degrade pesticides.

Nutrient availability and growth of bell pepper plants under fertilization management with humic substances and cattle manure.

Humic substances associated with cattle manure can enhance and reduce the costs of organic fertilization. In this sense, the objective was to evaluate the application of humic substances in association with cattle manure on soil fertility, growth and root nutrition in pepper plants. The experimental design used was randomized blocks, arranged in a factorial scheme with 4 doses of cattle manure (8, 18, 28 and 38 Mg ha-1), 3 doses of humic substances (0, 8 and 12 kg ha-1), with 4 replicates. The variables analyzed were plant height, stem diameter, leaf area, root growth, fresh and root dry weight, root macronutrient contents and soil fertility. Increases in plant height, leaf area and root dry matter (21.2, 58.21 and 8% respectively) were obtained by associating the application of humic substances with manure. Humic substances (12 kg ha-1) in association with manure (8 Mg ha-1) provided an increase in nitrogen content in the roots (36.05%) compared to the application of manure alone, and the application of humic substances (12 kg ha-1) promoted an increase of 10.62% in potassium content in the roots. The availability of calcium in the soil regulated primary root growth. The association of humic substances with cattle manure promoted shoot growth, root dry weight and root nutritional increase in pepper plants.

Biochar enhances soil interactions and the initial development of sugarcane.

The present study evaluated the effects of biochar derived from sugarcane straw on the physicochemical and biological properties of soil and the initial development of sugarcane. Microcosm and pot experiments were conducted over 60 days to monitor variables such as pH, water retention capacity, microbial activity, initial growth, and the metabolomic profile of the plant leaves. The results indicated that biochar increased the soil water retention capacity without significantly affecting the pH. The biochar significantly promoted root length and mass and favored the growth of the soil microbiota, as reflected by an increase in the amount of microbial biomass carbon. Metabolomic analysis of sugarcane leaves revealed that soil conditioning with biochar at application rates of 3 and 5% w/w led to increased concentrations of the amino acids isoleucine and valine, accompanied by a reduction in galactose, maltose, and glucose levels. Furthermore, biochar treatment resulted in a decrease in aconitic acid and an increase in acetic and succinic acid concentrations. These findings suggest that biochar may be a promising strategy for enhancing the productivity and sustainability of sugarcane cultivation.