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ABSTRACT Pedogenetic processes or phenomena not directly related to pedogenesis can strongly influence soil formation. This study aimed to identify the origin of the abrupt textural difference and the deep, dark horizon in a soil profile located in southern Brazil by examining pedogenetic processes and sedimentology. The research was conducted in the geomorphological province of the Coastal Plain of Rio Grande do Sul, characterized by marine and eolian sedimentary deposits from the Quaternary (Pleistocene) period, formed during alternating humid and arid climates. In this region, rapid observations of soil profiles were conducted, and one soil profile was selected for detailed study. The studied soil is strongly acidic, pH(H2O) ≤4.7, with low cation exchange capacity (CEC ≤5 cmolc kg-1) and base saturation, attributed to the high quartz sand content. Micromorphological analysis revealed sub-rounded to sub-angular quartz grains, suggesting that the sediments forming the soil were transported over long to medium distances. In terms of indicators used to assess lithological discontinuity, a difference of 0.20 or greater was observed in the fine sand/total sand ratio (FS/TS), and a uniformity value (UV) greater than |0.60| was found between horizons Ap, 2E, and 3Ab1. This same trend appeared in the cumulative curve and mean sand diameter across these adjacent horizons, indicating an allochthonous origin of the soil and that sedimentary processes buried the deep dark horizon. The high aluminum oxalate/soil organic carbon ratio (Alo/SOC) in 3Btg (1.6/2.0) than in 3Ab1 (1.6/14.3) indicated another source of Alo besides complexation with SOC, which is associated with the formation of low-crystallinity aluminosilicates rather than an Al-humus complex. The significant presence of low-crystallinity kaolinites confirms this finding. Interstratified smectite-kaolinite was identified by the asymmetry of the primary and secondary reflections of kaolinite, indicating that, despite the low base saturation, drainage impediment favors an intermediate weathering condition in the soil. Sediment deposition of sandy parent material was the main factor responsible of the abrupt textural change at greater depth. Deep dark horizons 3Ab1 and 3Ab2 were not formed through the pedogenetic process of podzolization but were instead buried by depositional processes that formed the Coastal Plain of Rio Grande do Sul.

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ABSTRACT The absence of quantitative limits for the diagnostic attributes that define spodic B horizons in the Brazilian Soil Classification System (SiBCS) allows the inclusion of soils in the Espodossolos (the equivalent of Spodosols or Podzols) classes that contradict the classical concepts that define the podzolization process, by including horizons with low organic carbon (Corg) content, and with alkaline pH, high sum of bases and sodic or solodic characteristics. This study aimed to propose quantitative criteria and limits to identify spodic B horizons and to contribute to the hieraquical structure of SiBCS. Morphological, physical and chemical attributes were defined after analyzing a large set of spodic B horizons of profiles classified as Espodossolos in the SiBCS available in the literature. In total, 385 spodic B horizons were identified. From this total, they were identified as following: 93 as Bs(m), 127 as Bh(m) and 165 as Bhs(m). In terms of color, the main hues were 7.5YR and 10YR, while the value and the chroma were ≥4 in Bs(m), <4 in Bh(m) and a wide variation in Bhs(m). The means and medians of the Corg contents are 7.5 and 6.7 g kg-1 for Bs(m), 19.8 and 15.1 g kg-1 for Bh(m), and 19.0 and 14.5 g kg-1 for Bhs(m). When the limit of Corg content is established as ≥3.0 g kg-1, 90 % of the spodic horizons are included in this group, with 85 % of the horizons for Corg ≥4.0 g kg-1 and 81 % of the horizons for Corg ≥5.0 g kg-1. The pH(H2O) had 94 % of the spodic B horizons with values ≤5.9. Around 48 % of the spodic B horizons have Alo and Feo data and, by calculating the equation Alo + 0.5 Feo, around 47 % of the horizons have a value ≥0.25 %. The evaluation highlighted the potential for adopting the minimum Corg ≥5.0 g kg-1 and pH(H2O) ≤5.9 as quantitative limits for defining the spodic B horizon in the SiBCS. It is also suggested to apply a lower requirement for the Corg content in spodic horizons with very low clay content that is sand texture classes, using the values of Corg ≥3.0 or ≥4.0 g kg-1 as limits. Otherwise, the minimum Corg value proposed is 5.0 g kg-1 and the types of spodic B horizons could be differentiated using a second limit of Corg, distinguishing the Bs with a content of Corg between 5.0 and 15.0 g kg-1 and Bsh ≥15.0 g kg-1.

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ABSTRACT Globally, soils with gypsic horizons cover approximately 1 million km², predominantly in arid climates. The formation of pedogenic gypsum in soils has been a topic of discussion in pedological studies for some time, with gypsification representing the process responsible for secondary gypsum accumulation. Even though international classification systems acknowledge the existence of gypsic horizons, there is a paucity of documented evidence concerning their occurrence in Brazilian soils. This study aimed to identify and describe a soil with secondary gypsum accumulation in the Brazilian semiarid region, employing the established criteria for in situ identification and classification. The study was conducted on a soil profile in the semiarid region of Pernambuco State, Brazil, that is undergoing salinization. Morphological descriptions of gypsum precipitates and chemical and mineralogical analysis were evaluated for their suitability for characterizing the material. Turbidimetric methods are more suitable for gypsum determination in hypersaline soils, while thermogravimetric analysis is the most accurate method for its mineralogical identification. This study establishes the first national record of gypsification in Brazilian soils and underscores the necessity of incorporating gypsum presence criteria into the Brazilian Soil Classification System (SiBCS) for effective soil management and environmental conservation.

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ABSTRACT Soil taxonomic systems seek to express pedogenic processes in their classes by choosing attributes or differential characteristics to identify classes at different categorical or hierarchical levels. Due to the advancement of knowledge, classification systems are periodically revised and/or expanded, and this may happen based on the evaluation of the database of these attributes or characteristics for a given class. In this context, the analysis of a broad set of Espodossolos (the equivalent of Spodosols or Podzols) from different pedoenvironments in Brazil is considered relevant to support the improvement of the categorization of this order in the Brazilian Soil Classification System – SiBCS. This study aimed to classify the profiles in the database and, based on their distribution, propose the restructuring of the Espodossolos classes up to the fourth categorical level in the SiBCS. Data from profiles with spodic horizons and the Espodossolos available in the literature, including surveys since 1960, were compiled in an electronic spreadsheet, displaying the morphological, physical, and chemical attributes. In the current edition of SiBCS, there are limitations in clearly separating the Espodossolos at the order and suborder levels due to the definitions adopted for the diagnostic attributes and the control section of the spodic B horizon. From the data base of compiled profiles, at the great group level, the soils are mostly identified in the Órticos class, in the subgroup as espessarênicos, arênicos and típicos, with few profiles or absence of profiles in the êutricos, êutricos arênicos and carbonáticos classes. Based on this assessment, it is proposed, for the order level, the reduction of the control section of the spodic B horizon to start within 2.00 m of depth; for the suborder, a criterion based on the organic carbon contents separating two classes: Humilúvicos and Háplicos. In the great group, based on the criterion of starting depth of spodic B horizon: Hiperespessos, Espessos and Órticos; and in the subgroup to adopt the classes of tiônicos, organossólicos, húmicos, saprolíticos, dúricos, fragipânicos, abrúpticos, hidromórficos, espessarênicos and típicos.

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ABSTRACT Knowing and defining the spatial and temporal variability of soil chemical properties becomes important for soil management. The definition of application zones in agricultural areas consists of dividing the area into homogeneous subareas, thus allowing the development of localized management. These zones can be defined by cluster methods and one of their advantages is to direct the determination of a future soil sampling, with a possible sample reduction. This study aimed to propose a methodology that integrates multivariate and space-time analyses to obtain an optimized sample configuration, using spatio-temporal data and application zones. First, three spatial multivariate clustering methods were evaluated to obtain the application zone (fuzzy C-means, K-means and Ward). Clusters were obtained by considering the analysis of spatio-temporal dependence through the empirical orthogonal function. Afterward, 50, 60 and 70 % of the sampling points of the initial sampling configuration were selected in each application zone, generating an optimized sample configuration. This choice was made by an optimization process, whose efficiency was evaluated based on spatial prediction, using the sum of the Overall Accuracy Index, of all soil properties. The results indicated the division of the agricultural area into two application zones, considering the K-means method. For most soil properties, when comparing the original and reduced sampling configurations, a similarity was observed in descriptive statistics. Regarding the estimates of the accuracy indexes, considering all the optimized sample configurations, the best estimates were observed comparing the initial sample configurations and the optimized ones in 70 % for most soil chemical properties.

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ABSTRACT Understanding methodological and environmental implications for coastal soil identification is essential for developing integrated approaches to land management that address soil physical and chemical aspects, environmental dynamics, and their importance for coastal ecosystem sustainability. In this context, a study was conducted in a natural environment, near a marine extraction reserve that was degraded by irregular urbanization and road construction in Santa Catarina Island, Florianópolis, SC, Brazil. The study focused on identifying ecological patterns and impacts associated with acid-sulfate soils. The method used consisted of: i) photointerpretation of physiographic characteristics in a historical series of aerial photos; ii) reinterpretation of historical soil data containing physical and chemical characteristics and available sulfate, and trace elements; and iii) collection, description, and analysis of the soil profile. The main pedogenetic processes affecting the area include sulfidization, paludization, gleization, salinization, and solodization. The soils were classified as Neossolos Quartzarênicos (Typic Sulfaquents and Typic Psammaquents), Gleissolos Tiomórficos (Typic Sulfaquents and Histic-Haplic Sulfaquents), and Gleissolos Háplicos (Sodic Hydraquents). The presence of materials containing reduced inorganic sulfur indicates the need to apply special procedures for the sampling, storage, and analysis of these soils to avoid misleading interpretations and conclusions about soil characteristics. The following recommendations were compiled based on the results: the inclusion of information on procedures for field analysis, sampling, and storage of soil samples in the Manual for Describing and Collecting Soil in the Field; the inclusion of analytical procedures in the Manual of Soil Analysis Methods; revisions to definitions of sulfidic materials, including hypersulfidic and hyposulfidic materials; and the inclusion of these materials as a fifth categorical level in the Brazilian Soil Classification System. Additionally, infrastructure and transport agencies should make alternatives for the total or partial replacement of soft soils in technical standards conditional on the absence of potential acid sulfate soils or on the treatment for mitigating impacts of soil disturbance. This study emphasizes the contribution of soil formation and attributes to mitigating environmental disputes. It also highlights the importance of managing acid-sulfate soils in urban planning to prevent environmental degradation and protect coastal ecosystems.

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ABSTRACT In precision agriculture, accurate delineation of management zones and understanding spatial variability of soil properties and crop yields are critical for optimizing resource allocation and improving productivity. Spatial variability of different environmental factors (soil and plants) is evident in several studies. Associations between the texture and chemical properties of the soil and cowpea yield have been tested, but a large, unexplained variance of ranges between kriged maps is usually reported. This suggests that a deeper exploration into the soil properties of these spatial interactions may help develop our understanding on how to reduce the number of soil property maps to delineate management zones and simplify interpretation. The main objective of this study was to investigate whether factorial kriging analysis can be used as an auxiliar variable to cokriging of soil properties and cowpea yield, and what is the potential of Spatial Fuzzy c-Means associated with factorial kriging analysis to delineate management zones. This study employed factor maps and spatial clustering to classify the cowpea field in management zones based on a multivariate and geostatistical analysis using soil texture and chemical properties. From Farmer, 66 soil samples were collected at a layer of 0.00-0.20 m, at points with a regular spacing of 12 m, at Agropecuária Milênio in the municipality of Tracuateua, Pará State, to make the technology applicable to the most common data available to farmers. It also used Spatial Fuzzy c-Means to generate estimated maps. Only the kriged maps of soil properties were inefficient in delineating management zones. Factor maps and Spatial Fuzzy c-Means were efficient in delineating the two management zones. Factorial kriging analysis can be used in cokriging to estimate soil properties and the cowpea field. The proposed method is a practical tool to delineate management zones, performing better and more efficiently compared with soil multiple property maps. The optimal number of management zones for cowpea cultivation was determined to be two. This encompasses soil management, yield considerations, and site-specific choices, all aimed at mitigating the impacts of precision agriculture on high productivity.

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ABSTRACT Metrics are fundamental to quantify and classify the spatial dependence of soil and agricultural attributes. This study aimed to propose and validate metrics based on two distinct approaches, one additive, which considers the arithmetic mean of the vertical and horizontal components, and the other multiplicative, which considers the geometric mean of the vertical and horizontal components of the semivariogram. Furthermore, we intend to propose the classification of spatial dependence based on the categorization of these metrics. Finally, a function in R language is presented to calculate the metrics and classify spatial dependence. The spatial dependence arithmetic index 1 (SDAI1) and spatial dependence arithmetic index 2 (SDAI2) are constructed in a dimensionless way, in the range between 0 and 100 %, considering the sum (arithmetic mean) between the vertical and horizontal components of the semivariogram. The spatial dependence geometric index 1 (SDGI1) and the spatial dependence geometric index 2 (SDGI2) are constructed in a dimensionless way, in the range between 0 and 100 %, considering the multiplication (geometric mean) between the vertical and horizontal components of the semivariogram. The SDAI1, SDAI2, SDGI1, and SDGI2 metrics are compared with other metrics existing in the literature, such as the spatial dependence degree (SPD), the integral scales J1 and J2, the mean correlation distance (MCD), the spatial dependence index (SDI), and the spatial dependence measure (SDM). For different spatial dependence scenarios, correlations are calculated between the geostatistical-based metrics and the performance measures Moran’s I, mean squared error (MSE), and kriging variance (KV). The metrics perform well in describing spatial dependence, with the exception of J1 (or MCD) and J2. However, the SDAI1, SDAI2, and SDGI1 metrics have slightly better correlations with the Moran’s I, MSE, and KV measures, when compared to the SDI, SDM, SDGI2, and SPD metrics. Furthermore, the SDAI1 and SDAI2 metrics show superior performance in capturing the vertical and horizontal effects of the semivariogram. Finally, a function in R language was developed to calculate the metrics and classify spatial dependence.

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ABSTRACT Soils preserve numerous proxies for paleoenvironmental reconstruction, including phytoliths, which are highly resistant to weathering and can be preserved over long periods. This study investigates the environmental history and soil formation processes in the highlands of southern Brazil through the analysis of organic soils and phytolith records. Our research focuses on the Serra Geral formation, where soils are deeply influenced by environmental factors such as climate, vegetation, and human activities. Four soil profiles in the states of Santa Catarina and Rio Grande do Sul were studied. We reconstructed the paleoenvironmental conditions using a multiproxy approach that includes phytolith analysis, δ13C isotopes, and C/N ratios. The combined proxies identified three phytolith zones in each profile, forming three paleoenvironmental phases related to soil formation. These phases represent distinct environmental moments: the first phase, related to a colder and drier environment with C3 vegetation dominance; the second phase, associated with higher temperatures, elevated humidity, fewer trees, and an expansion of C4 grasses; and the third phase, characterized by an overall decrease in temperature and humidity variation in the study sites, with predominant grasslands and herbaceous marsh presence in specific areas. This study aligns with previous regional research, offering information on environmental changes and their impact on soil formation. Results enhance the understanding of the soils from high-altitude grasslands, contributing valuable data on paleoenvironmental changes in southern Brazil.

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ABSTRACT Sugar and alcohol production in Brazil comes from planting hybrids from the crossing of species belonging to the Saccharum Complex. However, little is known about the growth response of these genera to inoculation using a diazotrophic bacteria Nitrospirillum viridazoti strain BR11145, currently recommended in Brazil as an inoculant for sugarcane growth promotion. This study aimed to evaluate the initial growth of 12 sugarcane genotypes inoculated or not with the strain BR11145. After 109 days, plant growth, biomass and macronutrient accumulation were evaluated. Fresh and dry mass at the end of the trial showed a positive response to inoculation for the genotypes US72-1319, CPDAU 849678, and NG77-122 of S. spontaneum and for Fiji 10 of Miscanthus. A negative response was observed for Q45416 of Saccharum sp. The growth of S. spontaneum US72-1319 is significantly improved by the inoculation with BR11145, which leads to a high accumulation of nutrients, especially N, standing out among the genotypes tested.

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ABSTRACT Atlantic Forest devastation has resulted in the search and introduction of management capable of promoting and reestablishing the quality and sustainability of the ecosystem. Agroforestry systems (AS) are recognized for many benefits due to their management. This study compares an agroforestry system macrofauna and physical and chemical soil properties to those of a secondary forest area in the Atlantic Forest biome in southeast Brazil. Agroforestry system with 8 years of establishment and the regenerating subcaducifolious tropical forest fragment with 28 years were examined. Samplings were conducted in two periods of the year (rainy and dry seasons) to evaluate physical and chemical soil fertility-associated properties, as well as soil organic matter (SOM) fractions and biological aspects (macrofauna). Higher clay content, moisture levels, basic cations, and greater values of the sorption complex, diversity indices, and uniformity in macrofauna were observed in the agroforestry plots. Agroforestry systems increased the levels of the most labile fraction of soil organic matter (SOM) compared to the forest fragment. Higher abundance, diversity indices, and evenness of fauna were observed in the agroforestry plots during both seasons. In terms of multivariate analyses, a higher correlation was observed among fauna, carbon fractions, P, K+, pH, clay, potential acidity, moisture, and temperature in the Agroforestry plots. In general, AS promoted a positive relationship between physical and chemical properties and the macrofauna community of soil invertebrates, in a similar way and sometimes superior to the forest, confirming the study hypothesis and demonstrating the efficiency of management in maintaining soil properties and, consequently, ecosystem services.

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ABSTRACT Centipedes and millipedes promote important functions in the ecosystem. However, land use intensification in agricultural areas can reduce the abundance and diversity of these organisms. To understand the effect of grazing intensification on communities of centipedes and millipedes, we sampled these organisms in an integrated crop-livestock system (ICLS) experiment, cultivated for 13 years with soybean (Glycine max) in the summer and black oat (Avena strigosa) + Italian ryegrass (Lolium multiflorum) for cattle grazing in the winter. Treatments consisted of different grazing intensities defined by sward heights of 0.10, 0.20, 0.30, and 0.40 m under continuous stocking, and control paddocks (no grazing). We used monoliths to collect centipedes and millipedes in the 0.00-0.10 and 0.10-0.20 m soil layers, and pitfall traps to collect specimens on the soil surface. Samplings were conducted for two years at two distinct moments of the ICLS: immediately after cattle removal from the pasture in 2014 and 2015 (post-grazing), and after soybean harvest in 2015 and 2016 (post-soybean). To evaluate the composition of millipede community, an extra sampling was performed with pitfall traps in 2018 (post-grazing). A total of 498 centipedes and 217 millipedes were collected during the two methods. We observed a greater abundance of centipedes and millipedes in the post-grazing environment and at lower grazing intensities in the 0.00-0.10 m soil layer. No significant effects of sward height were observed on centipede and millipede abundance in the 0.10-0.20 m soil layer or in the sampling with pitfall traps. Millipedes of genera Catharosoma, Leptodesmus, and organisms of the Pseudonannolenidae family occur in the integrated crop-livestock system, and Rhinocricus and Catharosoma in no grazing pastures. Moderate to light grazing intensities (0.30 m sward height) promote soil centipede and millipede communities with animal and soybean production in the integrated crop-livestock system, aligning sustainable intensification to food production.

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ABSTRACT Antimicrobial resistance is a global public health concern that requires an integrated approach including human, animal and environmental health. Agricultural environments, such as soil, animal waste and irrigation water, play crucial roles in the dynamics of antimicrobial resistance, as they act as reservoirs and pathways for disseminating resistance determinants. However, these agricultural environments are still often underestimated or neglected in many studies. This study aimed to address antimicrobial resistance in agricultural environments in Brazil and summarize the current state of knowledge about this issue in the country. Google Scholar, Google, ISI Web of Knowledge and Web of Science databases were searched for Portuguese, English and Spanish articles addressing antimicrobial resistance in agricultural environments in Brazil published through 2023. Different terms were used, and the findings were categorized according to the research questions posed. A total of 36 articles were found, 20 of which focused on antimicrobial resistance in animal waste from livestock production, 13 addressed antimicrobial resistance in agricultural soils, two considered both environments, and only one considered antimicrobial resistance associated with irrigation water in different agricultural environments. In all studies, diverse classes of resistant bacteria and antimicrobial resistance genes and mobile genetic elements were detected. However, the number of articles addressing this topic in Brazilian agricultural environments - in animal waste, followed by soils and, to a lesser degree, irrigation water - is still quite limited, revealing significant gaps to be filled. Therefore, it is essential to conduct more studies on antimicrobial resistance in these environments to elucidate their roles as reservoirs and sources of antimicrobial resistance and assess the risks to public health.

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ABSTRACT Sustainable agricultural systems, such as integrated crop-livestock systems under no-tillage, represent effective strategies for improving the soil microbiota, promoting nutrient cycling, and leading to gains in crop yield. Despite that, little is known about maintaining yield only through microbiological pathways for accessing nutrient reserves (without mineral fertilization) in established systems. This study aimed to evaluate whether the absence of mineral fertilization for two consecutive years and grazing activity affect soil microbial activity. An additional aim was to evaluate whether biological cycling of nutrients maintains yield without mineral fertilization. A completely randomized block design was used in a 2 × 2 factorial arrangement in split-plots, in which the factors consisted of grazing activity (integrated crop-livestock production system – ICLS and system without winter grazing – NG) and mineral fertilization (with and without). The experiment began in 2017 with a ryegrass / soybean succession, and in the integrated crop-livestock production system, there was winter grazing with sheep. In the fertilization treatment, nitrogen fertilizer was applied to the ryegrass, and phosphorus and potassium were supplied to soybean. Absence of mineral fertilization was tested by not adding fertilizers for two consecutive years (2020 to 2022). Production system phases were characterized by two soil samplings, at the end of the pasture cycle (2021) and after the soybean harvest (2022), when soil microbiological and enzymatic analyses were performed. Ryegrass and soybean yields were also evaluated. Only soybean had a 13.7 % yield reduction under the ICLS without mineral fertilization and a 16 % reduction under the NG with mineral fertilization. The lack of mineral fertilization did not affect soil microbiology. Enzymatic activity was sensitive to different phases of the production system, and it was higher in the pasture phase. Additionally, soybean yield showed a strong correlation with the enzymes β-glucosidase (r = 0.90; p = 0.01) and arylsulfatase (r = 0.88; p = 0.05) in the NG system. Grazing activity did not always affect soil microbiology; however, when it did, it had a negative effect on the NG, particularly in the cropping phase. Soil microbiology remains unchanged in the absence of mineral fertilization in established soybean systems, and grazing systems (as ICLS) are more effective in maintaining microbial activity and yield compared with systems without winter grazing (NG).

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ABSTRACT Soil saturated hydraulic conductivity (Ksat) and steady-state infiltration rate (SSIR) are essential and necessary soil properties for different geoscience applications. Values of these hydraulic properties for the Brazilian territory are difficult to access and are dispersed in research efforts carried out around the country. This study developed an easy-to-manipulate, freely accessible database of soil saturated hydraulic conductivity, comprising field and laboratory analyses, and steady-state infiltration rates for Brazilian soils. This database was named Ksat-SSIR-DB. One analysis of the Ksat-SSIR-DB aimed to evaluate its coverage in Brazilian territory and in different soil groups. Average values of these hydraulic properties were also presented for textural classes, with values compared to those reported in international literature, and for other groupings, such as soil class, land use class, and porosity class. The variability of Ksat data in these groupings and in their combinations were also analyzed. The Ksat-SSIR-DB showed broad national coverage, comprising a total of 2,579 records, corresponding to 409 sampling sites, with Ksat and/or SSIR data and other associated soil information. A significant difference was observed between Ksat values for the vast majority of Brazilian clayey and very clayey soils compared to soils from the same textural groups from temperate regions. The two groupings that presented the lowest variability in terms of Ksat standard deviation values were the combination of textural classes with soil classes at the second category level of SiBCS (Brazilian Soil Classification System), and porosity classes with soil classes at the second category level of SiBCS. The Ksat-SSIR-DB has enormous potential for developing and testing Ksat pedotransfer functions in Brazilian soils, serving as a reference source for different geoenvironmental applications and, in particular, for modeling land surface processes. It is open access and can be accessed at https://www.sgb.gov.br/ksat-ssir-dbbase-de-dados-de-condutividade-hidraulica-saturada-e-de-taxa-de-infiltracao-basica-emsolos-brasileiros, which also includes the python script for data analysis.

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ABSTRACT Santa Catarina State, in the South region of Brazil, has 713 thousand hectares of pine forests. Harvesting operations of this species can degrade the soil, especially when carried out on very wet soil. However, there is little information on the impact of pine harvesting on the physical properties of the soil in this region. This study aimed to evaluate the impact of Pinus taeda L. harvesting on the physical properties of a Nitossolo Bruno distrófico típico. Two areas were selected for the evaluations: a 17-year-old planted pine forest and a harvested forest area. Soil samples were collected from 0.40-m-depth soil pits in the 0.00-0.10, 0.10-0.20, and 0.20-0.40 m layers to evaluate soil bulk density, porosity (total, macro, and micro), aggregate stability, penetration resistance, field capacity, permanent wilting point, available water, aeration capacity, and saturated hydraulic conductivity. There was modification between the two areas in properties related to porosity, aeration, water retention, hydraulic conductivity, penetration resistance, and aggregate stability. Macroporosity and aeration capacity remained above the limit of 0.10 m3 m-3, even with intense machine traffic at harvest. In the pine harvesting area, hydraulic conductivity was higher and penetration resistance was lower in the deepest layer. Before and after forest harvesting, penetration resistance was less than 3.5 MPa in all the layers evaluated, a value considered not to be restrictive to root growth and development. The mean aggregate diameter in the harvested forest area is 7 % lower compared to the pine forest area in the 0.00-0.10 m layer and 12 % lower compared to the 0.10-0.20 m layer. Therefore, mechanized harvesting of pine in the tree-length system led to little modification of the physical properties of the Nitossolo Bruno in the Planalto Sul (Southern Plateau) region of Santa Catarina.

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ABSTRACT Grasses of the Brachiaria genus are widely used as cover crops in no-tillage areas of the Brazilian Cerrado. This study aimed to evaluate the ability of six Brachiaria cultivars to produce shoot and root biomass, and the potential of the root system to grow through a 0.01 m thick wax layer with 1.5 MPa penetration resistance. The plants were grown in PVC columns with a diameter of 0.1 m and a height of 0.7 m. The column was divided into an upper part measuring 0.25 m (top) and a lower part measuring 0.45 m (bottom). The wax layer was positioned between the two parts of the column as a physical barrier to be perforated by the roots. The columns were filled with peaty substrate. The Brachiaria cultivars used were: Brachiaria brizantha cv. BRS Piatã, Brachiaria decumbens cv. Basilisk, Brachiaria brizantha cv. BRS Paiaguás, Brachiaria ruziziensis cv. Ruziziensis, Brachiaria brizantha cv. Xaraés and Brachiaria brizantha cv. Marandu. The Ruziziensis cultivar accumulated a high root dry mass, but the Xaraés cultivar presented the highest wax layer perforation capacity (80 %). Decumbens is the species with the lowest wax layer perforation capacity (10 %). Brachiaria species and cultivars demonstrated differences in their responses to high root penetration ability, which can be used for recommended different species of Brachiaria in different proposes used changes in shoot, leaves, and root dry matter and the distribution of roots in the soil column profile. Xaraés cultivar has potential to be used as a management strategy in soil recovery for degraded lands with mechanical impedance.

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ABSTRACT Stress transfers inside the soil during the traveling process of agricultural machinery, and the bonding of soil particles during this process is the main cause of soil compaction. In this study, the discrete element method was used to simulate the different responses of stress transfer and particle bonding in the soil under different times of tire passes in the tire-soil interaction process of agricultural machinery operation. It was found that from 1 to 8 passes, the increase in the times of tire passing caused the soil stress to transfer from the depth of 0.20 to 0.70 m, with the maximum stress reaching 27.36 kPa. The number of force chains between soil particles increased gradually with the increase in the times of tire passing, and the number of force chains risen from 12,058 to 14,515. This indicated that there was an inextricable link between tire passes and the formation of cumulative compaction in soil. The results of this study verified the validity of the DEM model based on PFC3D, providing a theoretical basis for the subsequent research on soil mechanical compaction technology for mitigating soil compaction caused by agricultural machinery and equipment.

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ABSTRACT Soils of the Cerrados (Brazilian Savanna) are deep, well-structured, and well-drained, with flat to gently undulating terrain that favors mechanization for coffee cultivation. However, these soils are susceptible to compaction. This study aimed to assess the effect of mechanization on the physical characteristics of an Oxisol under irrigated coffee cultivation in the Alto Paranaíba-Minas Gerais State. We selected eight areas with different cultivars and years of Arabica coffee plantation, sampling five positions: right soil under the tree crown (RSC), right tractor lines (RTL), interrows (IR), left tractor lines (LTL), and left soil under the tree crown (LSC) at layers of 0.00-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.40 m. We conducted principal component analysis (PCA) and analysis of variance, comparing means through Tukey’s test (p<0.05). The PCA selected three principal components (PC1, PC2, and PC3) composed of 12 physico-chemical properties from a total of 27 evaluated. Total porosity (TP), mean penetration resistance (PRmean), volumetric moisture (θ) at 100 kPa (θ 100 kPa) and 300 kPa (θ 300 kPa) tensions, particle density (PD), and granulometric fractions (clay, fine sand, and coarse sand) were among the most influential attributes. Total porosity and PRmean demonstrated the existence of compaction in the tractor wheel tracks, particularly in the 0.00-0.20 m layer. The 3.5-year-old plantation did not show significant variations in these properties. The θ 100 kPa and θ 300 kPa were higher in the compacted areas, indicating increased water retention but potentially limiting aeration. Clay content increased with depth, while sand fractions decreased, influencing the soil susceptibility to compaction. The vigor of coffee plants, as identified by satellite images (NDVI), could not be fully associated with the physical constraints of the subsurface, as even areas with low vigor did not consistently correlate with poor physical properties in laboratory analyses. These findings highlight the complex interplay between soil physical properties and coffee plant performance, emphasizing the need for comprehensive management strategies in mechanized coffee cultivation.

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ABSTRACT The reduced crop diversity under no-tillage increases soil compaction and reduces soil quality. This study aimed to investigate whether intercropping corn and Urochloa has significant short-term effects on soil physical quality, as assessed by Visual Evaluation of Soil Structure (VESS), and its correlations with physical properties. Soil physical quality was assessed after corn and Urochloa intercropping and corn without Urochloa. The VESS, penetration resistance, bulk density, air-filled porosity, air permeability, pore continuity index, and water storage capacity were determined from 0.00 to 0.25 m depth in the Latossolo Vermelho Distroférrico. Intercropping of Urochloa and corn resulted in lower VESS values and favorable soil physical properties. For Urochloa and corn, the VESS score was improved (score 1 to 2.9). In the absence of the Urochloa, a moderate VESS score was observed (3 to 3.9). The results showed significant relationships between VESS scores and soil physical properties. Our findings suggest that the cultivation of Urochloa intercropped with corn improves the physical quality of Latossolo Vermelho Distroférrico, even in the short-term, 83 days after sowing, in a no-tillage system in a subtropical climate.

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ABSTRACT A double concentric ring is a widely used method for point measurement of water infiltration into the soil. These measurements are widely used to determine the impact of use and management on soil permeability to water infiltration. Two aspects of this technique that are interesting for research are the short duration of high infiltration rates observed after soil decompaction and the suspicion of lateral flow occurrence that overestimates infiltration. In this study, we evaluated the hypotheses that (i) agricultural traffic on the soil are responsible for decreasing the duration of the benefits of mechanical soil decompaction on the infiltration rate and that (ii) there is lateral flow in the infiltration measurements with a double concentric ring, overestimating the steady infiltration rate. These hypotheses were evaluated in a Typic Udorthent (Neossolo Regolítico distrófico) with differences in permeability in the profile resulting from no-tillage, chiseling, and plowing conditions. The infiltration was measured for four years and then compared with the infiltration measured under the same soil conditions subjected to agricultural traffic. We also compared infiltration measured at the same point without and with lateral flow control. Lateral flow was eliminated by shaping a soil column in the profile and coating it with a waterproofing agent. Results of the study corroborated both hypotheses. Excluding agricultural traffic where there was decompaction, the steady infiltration rate remained high over the four years (mean 392 mm h -1) but was significantly lower (mean 62 mm h -1) at decompacted sites that received machine traffic. Measurements of the steady infiltration rate in the soil column with only vertical flow (mean 115 mm h-1) revealed that the lateral flow was responsible for at least 70 % of the steady infiltration rate measured with the double concentric ring technique (mean 392 mm h-1). With respect to cumulative infiltration, the participation of lateral flow exceeded 80 %. This evidence shows that the maintenance of high infiltration rates after decompaction depends on the exclusion of agricultural traffic and indicates that the double concentric ring technique overestimates the permeability of the soil profile to vertical water flow.

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ABSTRACT One considerable concern arises from saline wastewater resulting from the production chain of the anticoagulant drug heparin. This waste contains a high concentration of sodium (Na, 2400 mg L-1), which can negatively influence soil structure. Simultaneously, it possesses a rich organic carbon content and nutrients that are beneficial to agricultural systems. This study sought to assess potential changes in physical and chemical properties, as well as soil mineralogy resulting from the application of varying proportions of industrial saline wastewater (ISW) from the heparin production industry. A field experiment was established on an Oxisol (Latossolo Bruno Distrófico) in southern Brazil in 2017, with heparin waste applied at rates of 0, 10, 20, 40, and 60 m3 ha-1 yr-1. After three years, deformed and undeformed soil samples were taken for physical, chemical, and mineralogical analyses. While other physical properties (soil texture, porosity and hydraulic conductivity) remained unaffected, the application of residue increased the fine clay to total clay ratio (mean increase of 13 % in the 0.00-0.20 m layer) and reduced soil bulk density (up to a 6 %) after three applications of ISW with the highest rate used (60 m3 ha-1 yr-1), suggesting the onset of particle dispersion. Exchangeable Na content in the soil increased (mean increase of 450 % in the 0.05-0.60 m layer) after heparin residue application, although it remained within the limits for sodicity (Na saturation 6 %). Residue acidified the soil, reduced exchangeable cation content, and increased the levels of available phosphorus, sulfur and exchangeable aluminum. Our results suggest that the application of ISW does not affect macroscopic physical parameters; however, a slow process of soil particle dispersion is occurring after three years of ISW applications. Furthermore, the high precipitation environment contributes to mitigating the impacts on soil physical quality, in addition to the fact that the soil is a highly weathered Oxisol and exhibits high physical resilience. Nevertheless, ISW alters soil chemistry by reducing the availability of essential nutrients and increasing acidity parameters.

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ABSTRACT Organic fertilization with tobacco powder compost produced via solid-state fermentation (SSF) is a recent practice that needs to be evaluated through research. This study aimed to evaluate the effect of two nitrogen sources – tobacco powder compost or mineral fertilizer (NPK) – and of compost doses on N use and loss in an immediate and residual way in a wheat/corn crop succession in a subtropical Argissolo. The wheat/corn crop succession was established after three successive fertilizer applications with different doses of the compost and of NPK. The following treatments were evaluated: control without application of the compost or mineral fertilizer (C0); mineral fertilization (NPK); and three doses of tobacco powder compost calculated to supply half (C50), the same amount (C100), and double (C200) the N applied via mineral NPK fertilization. To evaluate the residual effect of the fertilizer applications, the C50, C100, C200, and NPK treatments gave rise to additional treatments that did not receive more fertilization: rC50, rC100, rC200, and rNPK, respectively. The C0 generated an additional treatment that came to receive compost, identified as C0-C100. Yield and N accumulation in the aerial part of wheat and corn and N2O emission were evaluated throughout the two crop periods. Compost, in comparison to NPK, maintained the grain yield of wheat (3.0 vs2.5 Mg ha-1) and of corn (10.2 vs 9.5 Mg ha-1) and increased N accumulation in the wheat plants (96 vs 68 kg ha-1) and corn plants (191 vs 164 kg ha-1). Compost increased cumulative N2O emissions by up to three times compared to NPK (6.84 vs 1.93 kg N-N2O ha1 yr1). Increasing the compost dose increased cumulative N2O emissions by 52 % (9.36 vs 6.16 ha-1 yr-1); however, it did not change the emission factor (EF) of N2O, the yield-scaled emission, or N use efficiency. The compost residual effect increased wheat yield up to 93 % and corn yield up to 102 %, whereas no residual effect was observed from NPK. Compost applied on the previous crops did not affect N2O emissions in wheat or in corn; consequently, a residual effect did not impact the EF of N2O. Therefore, tobacco powder compost has the potential to replace mineral fertilization in wheat and in corn. Considering its residual effect is an important strategy to optimize its use and mitigate N2O emissions to the atmosphere.

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ABSTRACT Different cultivation methods directly affect the quality of medicinal materials, to gain insights into the effects of different type of mulching on the quality of Notopterygium franchetii root medicinal materials, farmland experiments were conducted in the Qinghai-Tibet Plateau. We subjected two-year-old Notopterygium franchetii seedling to five mulching treatments: no mulching (CK, control), coarse sand mulching (CM), grassy mulching (GM), stalk mulching (SM), and plastic mulching (PM). Following these treatments, we determined the moisture content, pH, NPK contents, and enzymeatic activity of the soil, and morphological indexes and content of the main components of root. Stalk mulching and PM increased the main root biomass by increasing its ground diameter and reduced branched root biomass by reducing the number of branched roots produced. Grassy mulching increased the root biomass by promoting main root elongation. Mulching increased the total content of the six main root components, with the most significant change obtained with GM, but the pattern of change of the different components varied among the mulch treatments. Contents of NPK were significantly higher than in the control with GM, but decreased with PM. Coarse sand mulching and PM significantly reduced the activities of urease and sucrase, and SM significantly increased the activities of urease, catalase and sucrase, but significantly decreased that of phosphatase. Furthermore, GM significantly increased phosphatase and sucrase activities, while CM significantly decreased urease and sucrase activities. Various soil enzymes and its pH promote main root bioaccumulation by increasing the root ground diameter or main root length. Sucrase activity promoted the accumulation of ferulic acid, psoralen, and notopterol content, and inhibited the accumulation of chlorogenic acid and nodakenin. Elevated soil water content promoted the accumulation of ferulic acid, notopterol and nodakenin, and inhibited isoimperatorin accumulation. Hence, NPK, pH, and various enzymes have different effects on the accumulation of major components in the root. The effect of mulching is closely linked to root growth and distribution, as well as to the soil environment. Various soil factors affect the quality of medicinal materials differently and, ultimately, can work together to form an equilibrium state that benefit the accumulation of main root biomass and main components with medicinal interest in Notopterygium franchetii.

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ABSTRACT Modern runner-type peanut cultivars have high yield potential, but little is still known about the dynamics of nutrient uptake by these cultivars and whether nutrient uptake differs between maturity groups. This study evaluated the growth, nutrient uptake, and nutrient removal of runner-type peanut cultivars with early and late maturity. The study was conducted in the field in the 2021/2022 season, in a sandy soil environment in southeastern Brazil. Treatments consisted of runner-type peanut cultivars (early and late maturity) and the phenological stage of sampling (V4/V5, R2/R3, R4, R5, R6, R7, and R8). Average pod yields were 4.0 and 5.9 Mg ha-1 for the early and late-maturity cultivars, respectively. Uptake of P, Cu, and Zn was linearly increased until stage R8. Nitrogen uptake continued until stage R7 for the early-maturity cultivars and stage R8 for the late-maturity cultivar. Potassium and B uptake did not increase after stages R5 and R6, respectively. For all other nutrients, maximum uptake occurred between stages R3 and R7. Leaf contents of all nutrients were within the sufficiency range, except Fe, which was higher than needed. Maximum macronutrient uptake (late-maturity cultivar) rates were 300, 28, 215, 76, 31, and 19 kg ha-1 for N, P, K, Ca, Mg, and S, respectively, and the maximum micronutrient uptake rates were 2350, 95, 391, 659, and 414 g ha-1 for Fe, Cu, Zn, Mn, and B, respectively. Maximum macronutrient removal rates were 210, 20, 48, 15, 7, and 12 kg ha-1 for N, P, K, Ca, Mg, and S, respectively, and the maximum micronutrient removal rates were 967, 59, 236, 153, and 136 g ha-1 for Fe, Cu, Zn, Mn, and B, respectively. Late-maturity cultivar had higher biomass production and greater uptake of all nutrients except K and Fe. The uptake of K and Fe was the same for both maturity groups.

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ABSTRACT Cashew tree (Anacardium occidentale L.) is a fruit species widely cultivated in Brazil, but the interest in evaluating this plant nutritional status is very recent, to the point there is still no defined diagnostic leaf. This study aimed to define the leaves that reflect the nutritional status of dwarf cashews. Leaf samples were collected from a productive orchard established with four dwarf cashew clones: ‘CCP 76’, ‘BRS 189’, ‘BRS 226’, and ‘BRS 265’. Leaf sampling was performed over four consecutive years, at the beginning of the flowering season and the emergence of inflorescences with floral buds. Sampling was carried out from the first to the sixth fully expanded (mature) leaf, from the inflorescence towards the base of the branch. Total leaf content of macronutrients, micronutrients, and Na were quantified. Multi-element index variables were obtained using Compositional Nutrient Diagnosis (CND) methodology, and total leaf concentrations were correlated with cashew nut yields. The pair of leaves closest to the base of the branch, 5th and 6th leaves, showed a balanced index of nutrients, including N, K, Ca, S, Mn, and Zn. These leaves were also positively correlated with cashew nut yield and exhibited lower coefficients of variation for most of the analyzed nutrients. Thereby, the 5th and 6th leaves are recommended as diagnostic leaves for evaluating the nutritional status of dwarf cashews.

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ABSTRACT Lime applications are used in acid soils to correct pH and eliminate Al3+ toxicity in crops. The lime rates are determined based on the estimated soil potential acidity (H+Al), using soil incubations with calcium carbonate (CaCO3) for 180 days, being a time-consuming and laborious process. An alternative method with calcium hydroxide [Ca(OH)2] for 96 h incubation may efficiently estimate H+Al, but it needs further studies. Also, soils from specific regions in southern Brazil have high organic matter (SOM) contents (>5 %), medium clay contents (20-40 %), and are stony, lacking research to improve liming recommendations. The study aimed to determine potential acidity and adjust lime rates for acidity correction in medium-textured soils with high SOM and stoniness in the Serra Gaúcha region (RS), Brazil, and to test the efficiency of the short incubation alternative method. For this purpose, 20 native forest soils were sampled in the 0.00-0.20 m layer. Samples were dried, sieved, and subjected to short and long incubations. The H+Al values obtained through the incubations were compared with the Manual de calagem e adubação para os Estados do Rio Grande do Sul e de Santa Catarina (CQFS-RS/SC, 2016) equation. The H+Al values estimated by CQFS-RS/SC were lower than those determined by the long incubation, indicating lime rates ranging from 2.0 to 5.1 Mg ha-1 lower than in the long incubation. The short incubation showed a positive correlation (0.93***) with the long incubation. The potential acidity for soil water pH 6.5 can be obtained by long [H+Al (cmolc dm-3) = 1354.9e-0.855TSM] and short [H+Al (cmolc dm-3) = 3763.8e-1.086TSM] incubations, in which TSM is the Tampão Santa Maria index. On average, 34 % of the soil volume was composed of rock fragments (>2 mm). We recommend adjusting the limestone rates for soils with stoniness, considering only the percentage of soil in the diagnostic layer (SDL%).

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ABSTRACT The influence of organic inputs, such as manure and compost, on the 15N values of growing plants suggests it may be possible to use of 15N natural abundance (NA) as a nitrogen (N) tracer. This study aimed to verify the feasibility of using the TM15N values to estimate compost-N recovery by plants. A field experiment was carried out by growing head lettuce, carrots and broccoli in sequence under increasing levels of compost (randomized complete blocks, six doses, four replicates). The compost was produced on-farm using horse bedding manure and vegetable waste. We found a positive and significant correlation between vegetables yield × TM15N-plant as well as between N-harvested × TM15N-plant, alongside the response to the increasing levels of compost. Positive and significant (α = 0.05) correlations were found for carrots (R = 0.91 and 0.95) meanwhile, no significant correlations were found for broccoli (R = 0.60 and 0.66). Lettuce did not respond to compost levels. We applied an equation to estimate compost-N recovery by carrots based on the variation pattern that was found in TM15N-plant. A positive and significant correlation between TM15N-plant and plant yield (or N harvested) is the first condition to obtain valid estimates. The estimated compost-N recovery for carrots was from 4.7 to 9.1 %, respectively, at 0.5 and 2.0 kg m-2 of compost (dry basis). Sources of uncertainty are also discussed, and include intra-plant 15N fractionation, which might require further studies of sampling strategies. This study shows the theoretical and experimental basis of using compost (dry basis). Sources of uncertainty are also discussed, and include intra-plantN to estimate organic fertilizer-N recovery by crops.

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ABSTRACT Forest seedlings production generally uses polypropylene plastic tubes due to their advantages, as root protection and easy operation. However, these tubes have limitations, as small substrate accommodates capacity, there is a possibility of root deformation, and there is a composition of pollutant and non–renewable material. It is necessary to find environmentally correct alternatives. This study aimed to evaluate the morphological and nutritional aspects of Eucalyptus urophylla seedlings produced in biodegradable containers, compared to plastic polypropylene tubes. For this, seedlings were produced in different containers/treatments (plastic tube, pig and poultry litter, and coconut fiber) in a greenhouse for 75 days. The analysis included height, collar diameter, length, and number of principal root ramification, leaves, stem and roots dry matter, number of leaves, leaf area, chlorophyll a and b, and N, P, K, Ca, and Mg concentration in leaves. Experiment design was conducted completely randomized with 24 replications, with each plant a sampling unit. Dickson quality index (DQI) and relationships between dry matter fractions and height and diameter were calculated. E. urophylla seedlings production in biodegradable containers, especially coconut fiber, promoted greater growth compared to plastic tubes, especially larger leaves and stem dry mass, and shoot and roots dry mass ratio. This favored root development and leaf area, increasing nutrient absorption and photosynthetic efficiency. Despite seedlings in plastic tubes having greater chlorophyll, N, and Mg concentrations, the biodegradable containers provided adequate P, K, and Ca concentrations, which are essential for development. A positive correlation between collar diameter, dry mass, and leaf area with DQI confirms that biodegradable containers are an effective alternative for producing Eucalyptus spp. seedlings.

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ABSTRACT Sudan grass (Sorghum sudanense (Piper) Stapf.) shows potential as a cover crop under the no-tillage system in soybean growing under the conditions of the Brazilian Cerrado region, due to high biomass production under water deficit. The large amount of biomass produced can improve soil microbiological activity, but may also negatively affect subsequent soybean yield due to nutrient competition, particularly if termination of the cover crop is delayed. To improves the use of Sudan grass as a cover crop, this study aimed to evaluate the most suitable time for terminating Sudan grass to balance the maintenance of soil biological quality and increased soybean yield. Experiment was conducted in a randomized block design, with four replications, evaluating six cutting times for Sudan grass: 150, 120, 90, 60, 30, and 7 days before soybean sowing (DBSS). Early cutting of Sudan grass did not negatively affect soil biological properties; cutting at 150 DBSS led to a significant (p≤0.05) increase in microbial biomass carbon (111 mg kg-1) and the microbial quotient (41 mg kg-1). In addition, early cutting at 150 DBSS increased the concentration of S-SO42- in the soil (13 mg dm-3). Early cutting at 150, 98, and 67 DBSS led to increases in soybean foliar concentrations of Cu (12 mg kg-1), P (4.11 g kg-1), and K (24 g kg-1), respectively. However, these increases in soybean foliar concentrations did not result in higher grain yield, 1000-seed weight, or grain protein content. Therefore, Sudan grass can be incorporated as a cover crop in a no-tillage system in the soybean off-season in the northeastern Cerrado region of Brazil. It is possible to cut the Sudan grass up to 7 days before sowing soybean without harmful effects on soybean yield. However, early cutting of Sudan grass is recommended to increase the efficiency of carbon incorporation into the microbial biomass.

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ABSTRACT Subtropical soils can have medium to high soil organic matter levels, which directly affects cation exchange capacity (CEC) and potassium (K) availability to plants. This generates the need to define K buffer capacity (KBC) values and K corrective rates to improve the fertilization recommendation system for these soils, ensuring high yields and reducing the likelihood of K losses in the environment. This study aimed to define KBC values and the K rates to be applied in corrective fertilization of acidic soils with high SOM and CECpH7.0 in a subtropical climate, and evaluate K corrective rates in vineyard soils in relation to the regional fertilization recommendation. Thirty-one native forest soils from the subtropical climate of Serra Gaúcha (RS), Southern Brazil, were collected. The samples were incubated with ten rates of K2O for 30 days, with three replicates. After the incubation period, available K (K_M1) contents were obtained by the Mehlich-1 extractor. The K_M1 contents of the 0.00-0.20 m layer of 209 vineyards in the region were evaluated in the 2021/22 and 2022/23 crop seasons. Natural K_M1 contents in 97 % of the forest soils evaluated were classified as "high" and "very high" availability. Average KBC value obtained was 3.1 kg ha-1 K2O, indicating the nutrient rate required to increase the K_M1 content by 1.0 mg dm-3. Correction rates for the low and medium K availability classes were, respectively, 170 % higher and 78 % lower than the current regional fertilization recommendation for fruit trees. The K_M1 contents in 38 % of the vineyard soils in the study region were classified as "very high" availability, indicating the possibility of reducing the use of K fertilization. We recommend adjusting the K2O rates based on KBC values, aiming to maintain K_M1 contents in the "high" availability class, reducing production costs and unnecessary K nutrient applications.

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ABSTRACT Although the hydrological importance of water infiltration into the soil and surface runoff is well known, manual measurement of these processes, especially at the plot and hillslope scales, is laborious and requires a trained team. This study aimed to develop prototypes with the tipping bucket principle for the automatic monitoring of surface runoff at a plot scale (14.5 × 3 m). In total, 18 prototypes were built and installed in an experiment with different soil covers. Aspects of the construction, calibration, operation and maintenance of the prototypes were reported in this study. Prototypes showed a satisfactory ability to monitor surface runoff with flow rates up to ~80 L min-1. The devices have an adjustable resolution of up to 5 L pulse-1, and they are inexpensive, easy to construct and simple to maintain. Although designed for a specific plot size (43.5 m2), the equipment can be adapted to smaller or larger plots by adjusting the volume of the tipping chambers. The proposed systems allow greater practicality in conducting experiments to monitor water loss through surface runoff at the plot scale and provide more detailed recordings of information.

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ABSTRACT Soil erosion in tropical environments causes environmental, social and economic damage. Canephora coffee crops are impacted by soil erosion and testing alternatives to mitigate this damage is a current need. This study aimed to evaluate the losses of sediment, organic carbon, nutrients and surface runoff caused by water erosion in between-rows spacing of Coffea canephora Pierre ex A. Froehner plants in management with and without cover crops, and the effect of the intensity of rains on sediment loss and the surface runoff. The management practices tested in between-rows spacing of coffee plants were: ES - exposed soil after manual weeding with a hoe; CC1- soil covered by palisadegrass [Urochloa brizantha (Hochst. ex A.Rich.) R.D.Webster] and nutsedge grass (Cyperus rotundus L.); and CC2- soil covered with purslane plant (Portulaca oleracea L.). Nine experimental plots were installed to measure losses of sediment, organic carbon, nutrients and surface runoff in the periods from September/2021 to March/2022 and from September to December/2022. The CC1 and CC2 reduced losses of sediment, organic carbon, nutrients and the volume of surface runoff from 37 to 86 % compared to ES. The increase in volume and rainfall intensities increased sediment loss and the surface runoff linearly, being more intense in ES management. The maintenance of the cover crops in between-rows spacing of coffee plants proved to be advantageous for mitigating losses of sediment, organic carbon, nutrients and surface runoff caused by water erosion, contributing to soil conservation and the sustainability of canephora coffee production.

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ABSTRACT Wetlands provide important ecosystem services, including climate regulation through carbon sequestration and water storage. Identifying and protecting wetlands is a potentially significant opportunity for current global mitigation efforts. Cerrado wetlands commonly contain carbon-rich soils (peat); however, these environments have been neglected due to lack of knowledge on their characteristics and behaviors. Obtaining data in remote regions using a detailed sampling approach to characterize the organic carbon accumulation in these environments is extremely necessary. In this study, soil samples from 40 points of a peat-wetland (173.16 ha) in the Urucuia River watershed (Minas Gerais, Brazil) were analyzed every 0.20 m up to 1.20 m of depth. Their chemical and physico-hydraulic properties were studied to quantify organic carbon storage under different land covers. In addition, the influence of organic carbon accumulation on soil water storage in a dry period was also investigated. Considering the contribution of each vegetation type, the (weighted) average for the wetland stocks was 321.91 Mg ha-1 of carbon at full depth, whereby vereda (462.59 Mg ha-1) and gallery forest (447.63 Mg ha-1) were the biggest stockers compared to wet grassland (267.22 Mg ha-1), pasture (123.46 Mg ha-1), and Cerrado stricto sensu (57.77 Mg ha-1). Also, the study area holds 677.38 mm of water, with the following water depths: 831.32 mm for gallery forest, 780.42 mm for vereda, 693.63 mm for wet grassland, 297.59 mm for pasture, and 220.33 mm for Cerrado stricto sensu. The total organic carbon mass and stored water volume were respectively 55,741.94 Mg and 1,155,635.21 m3, respectively. A significant correlation between organic carbon and water stored was found (0.73), highlighting the role organic matter plays in water storage, whereby the latter is under greater influence and can be explained by layer depth rather than vegetation type. However, surface layers show evidence of a degradation process that may be linked to the lowering of the water level due to subsurface lateral flow, either through the indirect use of their soils and/or through the input of mineral material (erosion process). The study data highlight that riparian zones of the Cerrado biome must be protected to maintain their ecosystem services.

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ABSTRACT Extreme weather events, such as heavy rains and droughts, necessitate the rapid adaptation of production systems to prevent the degradation of natural resources and to maximize production potential. Defining adaptive practices requires an in-depth understanding of the factors that control the formation and propagation of surface runoff and the identification of specific practices tailored to each location. No-till system, coupled with complementary storm runoff management practices, is effective in controlling surface runoff and related processes. However, the planning of the capacity and allocation of these practices, considering the specific interaction of controlling factors in each catchment, is not well understood. Planning conservation practices at the catchment scale through hydrological modeling and monitoring presents an efficient alternative, as it integrates the controlling factors that govern storm runoff dynamics. This study sought to understand the influence of different levels of conservation intervention (surface runoff control practices) on the hydrological behavior of the experimental catchment of the Guarda Mor River (southern Brazil). The method relied on monitoring hydrological variables (rainfall and streamflow) at the catchment outlet and on the physiographic characterization of the catchment, including the spatial variability of soils, topography, land use, and soil management. After analyzing a significant set of rainfall-runoff events, the generation and propagation of surface runoff were modeled (calibration and validation) using the Limburg Soil Erosion Model. The impacts of two conservation intervention scenarios were tested: buffer strips plus well-managed no-till (Scenario 1) and retention broad-based terraces plus well-managed no-till (Scenario 2). Conservation practices were assessed by evaluating the following hydrologic parameters: surface runoff volume, peak flow, and time to peak. Simulation results indicate that both intervention levels effectively controlled surface runoff. Scenario 1 resulted in an average reduction in surface runoff volume and peak flow attenuation of 7 and 6 %, respectively. Scenario 2 achieved an average decrease in surface runoff volume and peak flow attenuation of 30 and 28 %, respectively. These results quantitatively demonstrate the positive impact of soil and water conservation practices on the drainage network. The impacts of the two scenarios in the time to peak were not significantly altered, except for one event. Catchment-scale conservation planning is an efficient and promising strategy for improving conservation agriculture, underscoring its importance in water resource management and promoting environmental services.

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ABSTRACT Agricultural yield depends on a series of ecosystem services provided by soil biota, among other factors. Soil management systems that are more sustainable than conventional tillage mitigate harmful effects to soil, improving the structure and function of the soil biota and facilitating ecosystem services. This study aimed to evaluate the effect of soil management practices on epigeic soil fauna and soil physical, chemical and microbiological properties. The experimental design was completely randomized, with the following treatments: NT - no-tillage; RT - rotation tillage; MT - minimum tillage; BS - bare soil; CT - conventional tillage; NG - native grassland, in Inceptisol. The BS treatment produced the lowest soil fauna abundance and richness, indicating that the lack of cultivation combined with intense soil disturbance creates a critical environment for soil fauna. The greatest abundance and richness were observed under RT, and the highest diversity was in the NG treatment. Different soil management practices and their intensity influenced epigeic soil fauna diversity. Differences between groups of organisms were related to soil physical and chemical properties (organic carbon; macropores; aeration pores; hydrogen potential (pHSMP); exchangeable aluminum) resulting from different management practices. The present study demonstrated the contribution of soil fauna as a bioindicator of soil quality.

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ABSTRACT Available phosphorus (P) content on bare soil surface and in runoff varies with the variation in the dose and form of P application and soil management. Phosphorus applied to recently cultivated, bare soil with minimal roughness remains on the surface, increasing the element content in the runoff. This study was carried out under simulated rainfall in a recently cultivated, bare, and minimally rough Cambissolo Húmico Alumínico, or Aluminum Humic Distrudept. Efect of phosphorus dosage on the element content in both the soil surface and runoff was determined. Treatments consisted of 0 (zero), 37, 73, and 147 kg ha-1 of P that was applied manually, uniformly, and not incorporated into the soil. Four rainfalls were performed with a predicted intensity of 85 mm h-1 and a duration of 45 minutes. Phosphorus content was higher in sediments with a smaller diameter than in larger ones, being significantly high in those with diameter ≤0.038 mm. Available P content in the sediments was equivalent to 86 % of that found on the soil surface. In the runoff water, the soluble P content was equivalent to 5 % of the available P content in the sediments, and, in relation to the available P content in the soil, this equivalence was 3 %. Soluble P content in the water decreased with the increase in the time between the application of P to the soil and the occurrence of rainfall. In the research conditions, it can be concluded that the available P on the soil surface was easily transported by erosion and that transport increased with the increase in the P dose. In sediments, the increase in P loss was 2.6 times; in runoff water, it was 1.5 times for a four-fold increase in the dose of P applied to the soil. Phosphorus transport was selective according to the diameter of the sediments, having been greater in sediments with a diameter ≤0.038 mm, and greater at the beginning than at the end of the runoff.

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ABSTRACT Soil organic carbon (SOC) sequestration in croplands represents a significant opportunity to mitigate climate change by removing carbon dioxide from the atmosphere. Simulation tools are increasingly used to assess the impact of climate change and soil management on soil organic carbon stock dynamics. Although Andean soils typically store large amounts of organic carbon, agricultural practices, especially plowing, may deplete these stocks, creating a need to understand these dynamics better. Here, we show the soil organic carbon sequestration potential in croplands in the Peruvian Andean region over 50 years. Soil organic carbon content and bulk density were spatially predicted across the study area using 100 georeferenced soil samples to quantify organic carbon stocks. Spatial interpolation was performed using Ordinary Kriging with exponential and spherical variogram models, which provided the best fit to the data. The RothC model was used to simulate changes in soil organic carbon stocks under two contrasting agricultural management scenarios: one without manure application and another with annual application of one ton of manure per hectare. We found that manure application can substantially increase soil organic carbon sequestration in croplands with increases ranging from 105.22 to 214.94 Mg ha-¹ over 50 years. The potential for increased carbon sequestration through manure application could help compensate for losses in other areas of the watershed, particularly grasslands (74.4 % of the area). This study contributes valuable information for developing sustainable land management strategies in Andean agroecosystems.

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ABSTRACT Pineapple is a nutrient-demanding plant and information regarding the amounts accumulated in its organs is essential in decision-making for management practices and fertilization recommendations. This study aimed to determine the macronutrient absorption during the plant cycle of pineapple cv. BRS Imperial that was cultivated in sandy loam soil with and without plastic mulch cover. Plants were grown at a spacing of 0.9 × 0.4 × 0.4 m, 38,460 plants per hectare, irrigated by drip and fertilized according to soil analysis, with fertigation on a weekly basis. Experimental design was in randomized blocks, with three replications and treatments arranged in a split-plot scheme, with two soil covers (with and without plastic mulch) in the plots, and five time periods in the subplots (90, 180, 270, 360, and 450 days after planting). Soil cover with plastic mulch promoted higher leaf, stem, and root dry mass in pineapple cv. BRS Imperial throughout the plant cycle. Mulch soil cover determined higher accumulation of all macronutrients in the decreasing order of K, N, Ca, P and Mg. Potassium was the most accumulated in the leaves, whereas N in the stem and roots. Potassium showed higher accumulation rates until 270 days and lower ones up to 450 days after planting; the other macronutrients increased the rates from 270 days after planting. Both dry mass and macronutrient accumulation were much higher in the leaves than in the stem and the roots throughout the plant cycle.

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ABSTRACT To optimize land use and achieve carbon peaking and carbon neutrality targets, in this study, we investigated the spatial and temporal patterns of land use and land cover change (LUCC) and carbon storage (CS) in the Jinan Metropolitan Area from 2010 to 2030. Using land use data from 2010 to 2020, the PLUS model was employed to simulate land use patterns for 2030 under four development scenarios: Natural Development Scenario (NDS), Ecological Protection Scenario (EPS), Cropland Protection Scenario (CPS) and Urban Development Scenario (UDS). The InVEST model was then used to calculate CS under these scenarios. Between 2010 and 2020, the most significant reduction was in cropland, with a decrease of 3.34 %, while the most significant increase was in construction land, with an increase of 3.13 %. Total CS showed a decreasing trend. By 2030, CS is projected to increase exclusively under the EPS, with an increase of 873015.30 Mg, while other scenarios demonstrate varying degrees of decrease. Crucially, the expansion of construction land is identified as the dominant factor driving CS depletion in the Jinan Metropolitan Area. Mount Tai and the Yimeng Mountains are significant carbon sinks in this region. In contrast, the urban area of Jinan, as well as the Zhangqiu district and Zichuan district of Zibo, are the primary areas of CS loss. Strengthening the protection of ecological land in the Jinan Metropolitan Area, along with implementing carbon reduction and sequestration measures in construction land and cropland is crucial for enhancing regional CS capacity, optimizing future land management decisions, and ultimately achieving carbon peaking and carbon neutrality targets.

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ABSTRACT Soils polluted by potentially toxic elements (PTEs) pose a high risk to human health and must be remediated. Applying biochar to such soils can reduce metal bioavailability and phytotoxicity, improving phytoremediation techniques. This study aimed to assess the effects of rice straw biochar (RSB) on mitigating metal stress and accumulation of Si, Cd, Pb, and Zn in corn plants grown in soil contaminated by metallurgy slag. Soil in pots was amended with RSB rates equivalent to 0, 5, 10, 20, and 30 Mg ha-1 and grown with corn for 45 days. Chlorophyll fluorescence, photosynthetic pigment contents, and gas exchange parameters were evaluated as PTEs toxicity indicators. The RSB rates significantly increased Si uptake while reducing Cd, Pb, and Zn accumulation in corn shoots. The addition of 30 Mg ha-1 RSB promoted 18, 34, and 37 % reductions for Zn, Cd, and Pb in the plants, respectively. Photosynthetic rate, transpiration, and stomatal conductance increased by 68, 67, and 55 %, while chlorophyll a, b, and carotenoid contents increased by 77, 57, and 42 %, correspondingly. Chlorophyll fluorescence measurements showed a linear and positive relationship between photosystem II energy consumption efficiency (Fv/Fm) and RSB rates. The combined use of RSB and corn can effectively phytoattenuate Cd, Pb, and Zn contamination by enhancing biomass and improving maize tolerance to PTE stress. This sustainable and cost-effective strategy offers environmental and health benefits while generating income for stakeholders in resource-limited areas.

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ABSTRACT The use of native and exotic species in the reforestation of degraded areas has been considered an important strategy to improve soil quality. However, there is still scarce information about which species are more efficient for soil organic matter (SOM) formation. This study aimed to evaluate the decomposition of leguminous and non-leguminous tree litter, its impact on light organic matter (LOM), particulate organic matter (POM), and mineral-associated organic matter (MAOM) dynamics, and consequently, SOM formation efficiency. Leaf litter from 16 native trees to the Atlantic Forest and a clonal Eucalyptus were added to the soil (incubation experiment) to evaluate the decomposition and contribution to the formation/degradation of SOM for 888 hours. The relative contents of δ13C, N, P and C were assessed; the cumulative emission of C-CO2, potentially mineralizable C (C0), decomposition rate constant (k) and half-life time; calculation of the priming effect and physical fractionation, obtaining the LOM, POM and MAOM fractions. Cumulative emission of C-CO2 increased, especially in the first 204 hours. Non-leguminous species C. speciosa, S. saponaria and Trichilia sp. showed faster decomposition and greater mineralization potential. Lecythis sp. showed the lowest k (0.0058), suggesting better degradability. A. peregrina was the only species with a negative priming effect and a greater contribution to the LOM fraction. C. speciosa made a greater contribution to the POM fraction. The highest efficiency of SOM formation was observed in eucalyptus residues. The leguminous species A. peregrina, I. edulis, H. courbaril and P. gonoacantha also showed high SOM formation efficiency, higher contribution in the MAOM fraction, slower mineralization and lower respiration rates. I. edulis showed the lowest respiration and decomposition rates and the greatest contribution to SOM formation efficiency. Litter quality has a significantt influence on decomposition dynamics and SOM formation. In this way, the data can help in the selection of tree species with suitable functional characteristics aimed at optimizing ecosystem services, especially in relation to soil quality and the carbon cycle in reforestation and recovery programs for degraded areas in the Atlantic Forest.

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ABSTRACT A unified theoretical framework that comprehensively explains soil conservation behavior remains elusive. This underscores the significance and novelty of research exploring the psychological factors influencing farmers’ decisions. The concept of “connection to soil” captures the emotional bond that farmers develop with the land. We hypothesized that connection to soil acts as a mediator, strengthening the relationship between farmers’ pro-environmental propensity (broad commitment to environmental protection) and their adoption of soil conservation practices. This study involved 150 farmers, equally distributed across three culturally and geographically diverse regions in Chile. Our target population consisted of farmers who independently manage soil practices on their farms. Data collection utilized surveys incorporating three validated scales: pro-environmental propensity, connection to soil, and soil conservation behavior. While pro-environmental propensity directly predicted the adoption of specific soil conservation practices, this study highlights the crucial role of connection to soil in translating this general environmental motivation into concrete actions. Notably, we identified a significant indirect effect of pro-environmental propensity on soil conservation behavior mediated by connection to soil (ab = 0.15, 95 % CI [0.05, 0.26], p<0.001). This finding is particularly relevant because traditional soil science education has primarily focused on psychomotor and cognitive learning, neglecting the affective domain (emotions and feelings). Consequently, the potential of fostering connection to soil as a response to global soil degradation has been under-emphasized. Our contribution lies in highlighting the importance of connection to soil as a factor influencing farmers’ soil conservation behavior.