ABSTRACT Adopting conservationist soil use and management practices, such as the no-tillage system and cover crops associated with organic agriculture, can improve the quality of fragile soils. This study aimed to evaluate changes in soil fertility and the accumulation of soil organic matter and its fractions in sandy-textured soils under a 3-year no-tillage system in Seropédica, Rio de Janeiro. The experimental design was in randomized blocks, with three replications, in a 2 × 6 split plot scheme, with two planting systems distributed in the plots (no-tillage and conventional-tillage) and six cover plants distributed in isolated and intercropped subplots (Millet - Pennisetum glaucum; Crotalaria - Crotalaria juncea and Jack beans - Canavalia ensiformis; cocktailsformed by mixing 100 % of the seeds of the recommended cover crops; consortium formed by combining 50 % of the plant seeds recommended coverage and spontaneous plants maintained in the fallow area). The contents and stocks of total soil organic carbon, particulate organic carbon, mineral-associated organic carbon, soil organic carbon free light fraction, and soil fertility properties were measured in layers 0.00-0.05, 0.05-0.10, and 0.10-0.20 m in 2019 and 2022. Our findings suggest that cover crop incorporation in the conventional-tillage favored greater nutrient availability compared to the no-tillage. Conversely, the no-tillage system demonstrated promising potential for soil carbon sequestration, especially within the more stable fractions (mineral-associated organic carbon), in organic vegetable production. The three-year period was insufficient to promote an increase in labile soil organic carbon, particularly particulate organic carbon (POC) and the free light fraction (FLL). Notably, POC decreased in the 0.05-0.10 and 0.10-0.20 m layers under both no-tillage (-37 % and -48 %) and conventional tillage (-5 % and -38 %) systems.

Os solos com textura arenosa na camada superficial, possuem limitações a agricultura. O manejo conservacionista pode melhorar a qualidade desses solos. Entretanto, para identificar essas modificações são necessárias análises laboratoriais. Logo, este estudo visou avaliar a qualidade do solo em áreas de produção orgânica, identificando atributos de campo associados a dados laboratoriais para propor indicadores de fácil observação e interpretação. O estudo foi realizado na Baixada Fluminense - RJ, em 14 unidades de produção orgânica, selecionando glebas uniformes, coletando amostras indeformadas e deformadas na profundidade de 0,00-0,20 m. Nas amostras foi determinada a cor, textura, estrutura, densidade do solo, densidade de partículas, volume total de poros, diâmetro médio ponderado, carbono orgânico total (COT) e estoque de carbono orgânico. A cor úmida do solo predominante foi vermelho escuro-acinzentado (39%). A classe textural predominante foi argiloarenosa (27%). A estrutura predominante foi a em blocos subangulares (63%). Os maiores teores de COT ocorrem nas áreas com texturas mais argilosas, cultivo intensivo, e cores mais escuras. A classe textural direcionou a cultura conduzida. De acordo com os resultados obtidos, os atributos cor, estrutura e textura podem ser utilizados como parâmetros de avaliação de qualidade do solo de forma inicial e de fácil acesso.

Agricultural expansion, combined with poor soil management, can result in soil degradation, erosion, and nutrient depletion. Agroforestry systems (AFS) are sustainable alternatives that promote soil health, conserve biodiversity, and increase productive resilience. This study aimed to evaluate the physical, chemical, and biological attributes of soils under AFS and forests (FOR) in Paraty, Rio de Janeiro, located in the Atlantic Forest biome. In each area, mini-trenches were opened to collect five composite samples at 0–10 cm, with four replicates for chemical, physical, and biological analyses. Ecological similarities were observed between the AFS and FOR systems. While AFS was associated with fertility-related attributes and FOR with organic matter content, the biological components showed comparable patterns. Macrofaunal composition, β-glucosidase activity, abundance of arbuscular mycorrhizal fungi, and glomalin-related soil protein did not markedly differ between the systems. Only arylsulfatase levels were increased in the AFS group. The AFS maintained soil biological integrity, with fungal and bacterial communities exhibiting structures and diversities similar to those observed in the FOR. The fungal class Eurotiomycetes stood out in the AFS due to its higher abundance, while the families and genera Melanommataceae, Hygrophoraceae, Memnoniella, Hygrocybe, Myxarium, and Byssosphaeria were also enriched in this system. In bacterial communities, the class Acidobacteriae was more abundant in FOR, reflecting the influence of soil pH on bacterial composition. Overall, the evaluated AFS demonstrated potential as a strategy for ecological intensification and environmental conservation by maintaining soil and biological attributes comparable to those observed in the forest area while simultaneously enhancing soil fertility.

This study evaluated the effects of seasonality, soil management (no-till and conventional tillage), and different cover crop combinations on (i) aboveground dry biomass production, nutrient content, and accumulation; (ii) residue decomposition; and (iii) nutrient release (N, P, K). The experiment was conducted in summer and winter at the certified organic farm Sítio do Sol, Seropédica, Rio de Janeiro, Brazil. A randomized complete block design with three replicates was used in a 2 × 6 split-plot scheme. Main plots were two soil management systems: no-till (NT) and conventional tillage (CT). Subplots included six cover crop treatments: millet (M) (Pennisetum glaucum), sunn hemp (CJ) (Crotalaria juncea), jack bean (JB) (Canavalia ensiformis), two mixtures of these three cover crops (C1 = 100

Objective: This study aimed to evaluate the influence of soil physical-hydraulic attributes in a toposequence at the Federal Rural University of Rio de Janeiro campus, identifying their relationship with erosion susceptibility. Theoretical framework: The research is based on studies on erosive dynamics and soil conservation, considering the influence of relief and physical-hydraulic characteristics on soil formation and degradation. Method: Three soil profiles were analyzed at different slope positions (upper, middle, and lower thirds). Undisturbed and disturbed samples were collected for chemical and physical analyses, including bulk density, gravimetric moisture, penetration resistance, and porosity. Descriptive statistics, correlation coefficients, and principal component analysis (PCA) were applied. Results and Discussion: Soil physical-hydraulic attributes varied even over short distances in the toposequence, influencing erosion susceptibility. The middle-third profile showed the highest erosion risk due to its slope position and physical-hydraulic characteristics. Research implications: The findings contribute to soil management and conservation practices, supporting erosion mitigation and the adoption of sustainable agricultural strategies in vulnerable areas. Originality/value: This study provides a detailed analysis of physical-hydraulic attribute variation in a specific toposequence, expanding knowledge on erosion processes and sustainable soil management in tropical soils.

Agricultural sustainability is the ability of a system to produce food properly without damaging environmental conditions. Assessing the quality of the soil and its attributes informs its proper use without compromising ecosystems. This study analyzes the chemical and physical properties of soil at sites under different management in the mountainous region of the state of Rio de Janeiro, Brazil. Two cultivation areas were selected: tomato (Solanum lycopersicum L.) and corn (Zea mays L.) production and; secondary forest. Four samples were taken at a depth of 0-10 cm to assess pH in water, Al+3, Ca+2, Mg+2, P, K+, Na+, H+Al, carbon (C), particulate organic carbon (COP), organic carbon associated with minerals (COMA), total nitrogen content, carbon stock (SCS), carbon in the free light fraction (FLFC) and intra-aggregate light fraction (ILFC). The apparent density (AD), particle density (PD) and weighted average diameter (WAD) of the aggregates were characterized. High P contents were observed in the tomato area (125.78 to 502.03 mg kg-1) and in the corn area (127.80 to 253.14 mg kg-1), indicating excessive fertilization. As for BD, values of 1.25 Mg m-3 and 1.60 Mg m-3 were observed in the tomato and corn areas, respectively, which were higher than those observed in the forest area. It was noted that the management carried out in the cultivated areas is not promoting the accumulation of organic matter in the soil. Monitoring soil properties can help identify changes that impact on productivity and environmental quality. Keywords: agricultural sustainability, environmental fragility, soil conservation.

ABSTRACT The effects of water deficit and fertilization are fundamentals for productivity and quality of ornamental plants. This study evaluated the production, quality, and longevity of zinnia flower stems under irrigation levels and silicon doses. In a greenhouse, irrigation levels corresponding to crop water requirement (V4 - 100%) and three deficits (V3 - 85%; V2 - 73%; V1 - 61%), and Si doses of 0 (S1), 75 (S2), 150 (S3) and 300 (S4) mg per plant, in five weekly applications, were evaluated. The irrigation system was composed of emitters with different flow rates and it was automatically activated in response to the soil water tension. The total volume applied in treatment V4 was 5.2 L per plant. The results showed that higher water levels increased stem length and total fresh mass, and the supplementation with S3 provided greater dry mass in leaves and flowers. Plants in V1S3 exhibited higher fresh mass and leaf area. Water absorption and fresh mass of the stems followed a similar post-harvest pattern, with stability for five to six days, and a subsequent gradual loss of mass. The commercial longevity of stems was 6.4 days, but the total longevity ranged from 9.7 to 12.7 days, being greater in V4S2. Application of 150 mg of Si and full water replacement are recommended to increase the growth and longevity of zinnia stem flower.

Light-textured soils are widely distributed globally and, despite their limitations, have been integrated into agricultural production systems. This study aimed to assess how management systems-conventional tillage (CT) and no-till (NT)-affect aggregate formation pathways (physicogenic and biogenic) and bacterial communities. Two management systems (NT and CT) and three cover crops were evaluated: CJ: Crotala-ria (Crotalaria juncea (40 kg ha(-1)); M: Millet (Pennisetum glaucum - 60 kg ha(-1)); and C: Cocktail (Crotala-ria - Crotalaria juncea - 10 kg ha(-1), Jack bean - Canavalia ensiformis - 75 kg ha(-1), and Millet - Pennisetum glaucum -30 kg ha(-1)). Undisturbed soil samples were collected from the crop row at a depth of 0.00-0.10 m. Aggregates with diameters between 9.7 and 8.0 mm were classified as biogenic or physicogenic. In addition to the chemical attributes of the aggregates, total organic carbon (TOC) and its fractions (mineral-associated organic carbon, MAOC; particulate organic carbon, POC; and free light fraction carbon, FLFC) were quantified. The structure and bacterial composition of the aggregates were also characterized. A higher proportion of biogenic aggregates (53-64%) was observed compared to physicogenic aggregates (36-47%). Cover crops exhibited significant differences in pH, calcium (Ca2+), base saturation, phosphorous (P), and percentage of base saturation. The management systems differed significantly for Ca2+ and P, with CT showing higher values than NT. The management system influenced organic matter accumulation and stabilization in the aggregates, with MAOC content being significantly lower in CT. POC and TOC were also significantly lower in physicogenic aggregates under CT. Bacterial community richness, diversity, and structure were significantly influenced by the management system, with greater richness and diversity in NT compared to CT. Network analysis revealed NT had more nodes and edges (65 and 406, respectively) than CT (52 and 357, respectively. Phyla abundance differed between the systems, with Firmicutes and Entotheonellaeota more abundant in CT, while WPS_2, GAL15, Bdellovibrionota, and Myxococcota were more abundant in NT. Despite the relatively short period of NT implementation (5 years), it had a positive effect on the bacterial community, which may subsequently influence nutrient and carbon content and their fractions in the aggregates.

Na Baixada Fluminense, o relevo é um dos principais fatores de formação responsáveis pela variabilidade de solos. Adicionalmente, a geologia, em sua grande parte, composta principalmente por rochas ácidas influência nos atributos do solo. O objetivo deste estudo foi avaliar a gênese e os atributos dos solos de uma topossequência sujeita a diferentes intensidades de uso agrícola na Baixada Norte Fluminense na região sudeste do Brasil. Foi selecionada uma topossequência e abertas trincheiras nas posições de terço superior (P1), terço médio (P2) e terço inferior (P3). Foi realizada a descrição morfológica, as análises dos atributos físicos e químicos e a classificação dos perfis de solo. Em relação aos atributos morfológicos, foi observada cores mais escuras no horizonte superficial de todos os perfis. Quanto à classe textural, houve predominância da textura argilosa para o P1, textura argiloarenosa para o P2, e textura arenosa para o P3. Os perfis foram classificados como PLINTOSSOLO ARGILÚVICO Eutrófico típico (P1), ARGISSOLO AMARELO Distrófico abrúptico (P2), e PLANOSSOLO HÁPLICO Distrófico espessarênico (P3). Os teores de Ca+2 + Mg+2 foram superiores a 3 cmolc dm−3 em todos os perfis, com algumas variações em profundidade. Os maiores valores de K+ foram observados nos horizontes superficiais, com diminuição em profundidade. Os menores teores de fósforo (P) disponível em P2, quando comparado a P1 e P3, podem estar associados a uma maior adsorção de P nos coloides e a formação de complexos com a matéria orgânica (MO). Os maiores teores de COT e COam foram observados em P2, em função menor revolvimento e maior adição de MO pelas gramíneas. Os maiores teores de COp em P1, quando comparado a P2, ocorre em função do revolvimento e uso mais intenso do solo. Os processos pedogenéticos de plintização, ferrólise, gleização e eluviação/iluviação de argila foram observados. Destaca-se que os atributos químicos e físicos dos perfis são resultantes da interação entre relevo, clima e material de origem. Adicionalmente, o uso agrícola pode impactar significativamente os atributos do solo, especialmente os químicos.

Mountain ecosystems in tropical regions are increasingly vulnerable to human activities, with changes in soil management significantly impacting the structure and activity of edaphic communities. This study adopts an integrative approach to assess soil quality by combining classical biological indicators with high-resolution molecular tools in areas under intensive agricultural management within a mountainous region of the Brazilian Atlantic Forest. Three sites were selected: two agricultural areas cultivated with tomato (Solanum lycopersicum L.) and maize (Zea mays L.), and a secondary forest with minimal anthropogenic disturbance. Soil macrofauna, the activity of (3-glucosidase and arylsulfatase, and the abundance of arbuscular mycorrhizal fungi (AMF) were evaluated. Bacterial and fungal communities were characterized through high-throughput sequencing of the 16S rDNA and ITS regions. Macrofauna richness was highest in the forest and maize areas, while the tomato area exhibited the lowest species richness and density. Enzymatic activity varied across areas: (3-glucosidase activity peaked in maize cultivation, while arylsulfatase proved to be a more sensitive indicator of soil degradation, decreasing with increased soil management intensity. Bacterial networks revealed more competitive interactions in cultivated areas, whereas cooperative associations dominated in the forest area. Fungal networks were more connected and structurally stable in the forest area, indicating higher ecological integrity. Overall, biological attributes effectively distinguished intensively managed agricultural soils from forest soils. The combined use of functional biological indicators and high-resolution molecular tools provides a sensitive, detailed assessment of soil biological responses to intensive agriculture in fragile mountain ecosystems, underscoring its detrimental effects on soil functional biodiversity.

ABSTRACT Phosphorus (P) is an essential macronutrient for plant growth, and its availability is often influenced by management systems adopted over time. Adopting management systems, such as no-tillage, combined with cover crops, can influence soil P availability through factors including soil organic matter accumulation. This study aimed to evaluate how management systems and cover crops influence different P fractions and organic matter. Furthermore, the effect of the time since the implementation of management systems on phosphorus (P) availability and soil organic matter accumulation was assessed. The study was conducted at an organic farm in Seropédica, Rio de Janeiro, Brazil. The soil was classified as Argissolo Amarelo with a sandy texture in the surface layer, corresponding to Ultisols. The experimental design was a randomized complete block design with three replications in a 2 × 6 factorial scheme, with two main plots representing the management systems (no-tillage and conventional tillage) and six subplots within each main plot: monocultures of pearl millet Pennisetum glaucum, sunn hemp (Crotalaria juncea), and jack bean (Canavalia ensiformis), two cover crop mixtures (100 and 50 % seed ratios of the aforementioned species), and a control subplot with spontaneous vegetation. Soil organic matter (SOM) particle size fractionation and P fractionation were analyzed at two-time points: the beginning of the experiment, in 2019, and four years later, in 2023. Four years later, the management systems increased the soluble phosphorus fraction (114-161 % across the evaluated layers) and decreased the occluded fraction (-23 to -43 %). However, within the management systems, higher values were observed for the occluded fraction and organic phosphorus, which may be correlated with the increase in soil organic matter fractions over time. Cover crops did not affect SOM accumulation and P availability. Soil management systems and time since adoption influenced phosphorus availability and soil organic matter accumulation. However, the timeframe was too short to observe the effects of cover crops.

Rainfall simulators (RS) have been used, above all, to evaluate hydrological processes related to soil water infiltration, surface runoff and soil erosion. They allow repeatability of rain application with different precipitation intensities in field and/or laboratory conditions and should produce events with physical characteristics similar to natural rain. In this manuscript, we carried out a bibliometric and scientometric analysis of studies with simulated rainfall in Brazil to assess the temporal evolution of publications, the main topics addressed and the degree of technological development of the equipment. We searched for the terms “rainfall simulator” OR “simulated rainfall” AND “Brazil” in the Scopus, Web of Science, SciELO and Google Scholar databases. We found 143 articles published in the last 37 years (1985–2022). Our findings indicate that the main research areas covered in papers are soil erosion (57.34%), soil water infiltration (24.47%), nutrient losses (9.8%) and RS development and calibration/assessment (8.39%). In recent years, the number of published papers in international high-impact factor journals has increased. Most of the papers (49.65%) refer to studies carried out by institutions located in the south and southeast regions of Brazil. Moreover, there is a large gap of studies on simulated rainfall in other regions of Brazil, where important biomes such as the Cerrado, Amazon, Caatinga, and their transitions are located. This study informs research priorities on soil erosion under simulated rainfall and provides a bibliographic database that can assist in more detailed future analyses.

Regenerative agriculture practices, including crop rotation, cover crops, reduced tillage, and no-tillage, have gained recognition for mitigating soil erosion and enhancing soil quality. This study focuses on organic vegetable production in the Baixada Fluminense region of Rio de Janeiro, Brazil, where soils are sandy and nutrient-poor. The research aims to evaluate the impact of no-tillage systems combined with various cover crops on soil quality, particularly physical–chemical properties, soil fertility, and carbon sequestration. The experimental design included conventional tillage (CT) and no-tillage (NT) systems, with six types of cover crops. Soil samples were collected over three years at multiple time points: before cover crop implementation, after cabbage harvest, and after scarlet eggplant harvest. Chemical analyses measured soil pH, cation exchange capacity (CEC), soil organic carbon (SOC), and nutrient levels. Results indicated that in the short term, CT had higher averages for calcium (Ca), potassium (K), base saturation (BS), and pH, while NT showed higher values for potential acidity (H + Al) and CEC. Over time, pH, H + Al, and SOC increased significantly, suggesting improved soil conditions. Principal Component Analysis (PCA) revealed distinct separation between CT and NT systems, with CT associated with higher pH, K, magnesium (Mg), and BS, and NT showing stronger associations with H + Al and CEC. The PCA also highlighted a positive gradient in SOC and K from year one to year three. The study underscores the benefits of no-tillage systems in enhancing soil quality and promoting sustainable agricultural practices. Despite short-term advantages in CT due to cover crop incorporation, long-term sustainability of soil quality, particularly SOC, may be better maintained in NT systems due to less soil disturbance. This research highlights the potential of no-tillage systems combined with cover crops to improve soil fertility, enhance carbon sequestration, and support sustainable agriculture.

No-tillage (NT) has been adopted in organic agriculture as an alternative to conventional tillage (CT) for improving soil conservation. Cover crops (CC) play a vital role in this process by providing straw and releasing nutrients into the soil. Therefore, in this study, we aimed to evaluate the effects of NT and CT management on the chemical properties and bacterial diversity of soil following the cultivation of diverse CC in an organic system. The experiment was conducted using a randomized block design with subdivided plots, wherein the plots represented CT and NT, and the subplots represented the diverse CC tested, including pearl millet, sunn hemp, jack bean, seed mixes 1 and 2 (containing 100% and 50% of the recommended seeding rates for each crop), and spontaneous plants. The evaluations were conducted one year after the experiment was conducted. The results demonstrated that NT promoted increases in soil magnesium, phosphorus, and organic carbon contents, including increased bacterial richness. Moreover, NT resulted in a higher abundance of Bacteroidetes, GAL15, and Myxococcota. Conversely, CT favored a greater relative abundance of Actinobacteria, in addition to the members of Bacteroidetes. Regarding the influence of CC, no significant differences were observed in the diversity and structure of the bacterial communities, except for subgroup 17, which was more abundant in spontaneously grown plants. NT proved to be more effective than CT in improving soil chemical properties and bacterial diversity, implying its potential to contribute to sustainable agricultural systems.