This study evaluated the agronomic and bromatological characteristics of green maize grown under different cover crops and developmental stages of the no-till system (NTS) in the Brazilian Cerrado. A randomized block design with a 6 × 3 factorial arrangement and four replications was used. Six cover crops were evaluated: Brachiaria (B), Pearl millet (PM), Sunn hemp (SH), and mixtures B + SH, B + PM, and PM + SH. Three NTS stages were assessed: initial (1 year, NTS1), transition (8 years, NTS8), and consolidation (20 years, NTS20). Evaluated variables included cover crop dry matter (DM), green maize ear yield with husk (EYH), shucked ear yield (SEY), straw yield (SY), grain yield per ear (GYE), and grain bromatological characteristics: pH, moisture (HU), ash (AS), lipids (LIP), protein (PTN), carbohydrates (CHE), total titratable acidity (TTA), total soluble solids (TSS), and ascorbic acid (AA). SH and the PM + SH mixture produced the highest DM across the NTS stages. Cover crop residues did not affect green maize yield attributes, whereas progression through NTS stages increased SEY, EYH, and GYE. Bromatological quality was mostly unaffected by cover crops, except for moisture and TSS, while NTS stages influenced pH, moisture, LIP, PTN, TTA, TSS, and AA. The integrated use of cover crops, either as sole crops or intercropping systems, associated with long-term no-till adoption, contributes to increased biomass production and improved grain quality attributes of green maize under Cerrado conditions.

This study evaluated the temporal dynamics of soil physical quality and soil organic carbon (SOC) stocks in Hevea brasiliensis plantations of different ages established on degraded sandy Oxisols in the Brazilian Cerrado under low-input management, focusing on the relationships between seasonal litter inputs, soil structural development, and SOC accumulation over time. Three rubber plantations established in 2006 (S2006), 2007 (S2007), and 2009 (S2009), together with a reference native forest stand (NF), were evaluated at soil depths of 0.00–0.40 m. After the first two years following establishment, no additional fertilization or herbicide applications were performed. Soil physical attributes, aggregation indices, total organic carbon (TOC), and SOC stocks were determined. Older plantations exhibited lower penetration resistance, higher porosity, and improved soil aggregation, indicating progressive structural recovery over time. The aggregation index (AGRI) was more sensitive than the aggregate stability index (ASI) in detecting structural changes. The oldest plantation (S2006) presented higher TOC and SOC stocks than the adjacent native forest reference stand evaluated in this chronosequence, indicating substantial carbon accumulation under long-term low-input management. Low-input rubber plantations promoted significant improvements in soil physical quality and SOC accumulation in sandy Oxisols of the Brazilian Cerrado. These findings highlight the importance of seasonal litter deposition and natural nutrient cycling in supporting long-term soil structural development. Under the conditions evaluated in this chronosequence, the oldest plantation accumulated SOC stocks higher than those observed in the reference native forest stand, demonstrating the potential of low-input perennial rubber plantations to contribute to soil restoration and carbon accumulation in degraded tropical soils.

Use of biochars as a nutrient source and inoculation of plants with plant growth-promoting bacteria (PGPB) have been studied, but the interaction between different biochars and these bacteria remains poorly explored, especially in subtropical soils with low natural fertility. This study evaluates whether swine digestate biochar (BD) and poultry litter biochar (BC), alone or combined with A. brasilense inoculation, can partially substitute liming and soluble NPK fertilization under short-term greenhouse conditions in maize cultivation in a low-fertility Ultisol. The study was conducted in 8 L pots, in a greenhouse, using samples of a Ultisol, in a randomized block design with a 4 × 2 factorial scheme. Treatments consisted of nutrient sources: 1-BD; 2-BC; 3-liming and NPK; and 4-control; and the presence or absence of A. brasilense inoculation on the heirloom maize seeds. Biomass, accumulation of C, N, and S in biomass, SPAD index, stem diameter, chlorophyll, and carotenoids were evaluated in maize plants. After cultivation, the soil was evaluated for pH, P, K, Al, Ca, Mg, N, C, and S. Biochars produced responses comparable to the liming + NPK treatment for most of the variables analyzed in this pot expriment. Synergistic responses were observed when inoculation was combined with biochars, although inoculation effects were treatment-dependent; for stem diameter, responses varied with nutrient source and sampling date, with the clearest endpoint increase observed in BC. In the BC and BD treatments, inoculation was associated with marked reductions in exchangeable Al and increases in cation exchange capacity and base saturation. Additionally, inoculation increased the availability of K in BC and P in BD, indicating treatment-specific shifts in nutrient availability associated with inoculation. In contrast, in the NPK and Control treatments, the predominant effect of inoculation was the mobilization of Al, raising exchangeable Al and Al saturation to potentially toxic levels (above 34%). Overall, our results suggest that inoculation with A. brasilense in acidic soils may benefit from the concurrent use of an amendment that mitigates Al toxicity (e.g., biochar), thereby reducing the risk of Al mobilization observed in unamended treatments. We conclude that these manure-derived biochars—especially when combined with A. brasilense inoculation—represent a promising strategy to reduce reliance on liming and highly soluble fertilizers in the short term under controlled conditions, warranting field-scale and longer-term validation before agronomic recommendations can be made.

Fungicides applied to grapevines can increase the levels of copper (Cu), zinc (Zn), and manganese (Mn) in soils and cause phytotoxicity to plants. However, plants native to the Pampa biome might have the potential to phytostabilize these metals. The study aimed to (a) verify whether higher levels of Cu, Zn, and Mn in the soil increase the concentrations of these elements in different organs of the native species; (b) determine which variable is most directly associated with biomass variation in the evaluated species; and (c) identify the tolerance mechanisms used by these species to tolerate high levels of Cu, Zn, and Mn in the soil, as well as their phytostabilization potential. To this end, three native species, Axonopus compressus, Paspalum notatum, and Paspalum plicatulum, were grown in vineyard soil and native field soil. The cell wall and vacuole played an important role in detoxifying the metals. The concentrations of photosynthetic pigments were lower in the A. compressus and P. notatum species grown in the vineyard soil. Metals caused oxidative stress in roots, and the activities of the antioxidant enzymes SOD and POD increased in leaves and roots. The three species showed the lowest dry mass yields in the aerial part. The species P. notatum and P. plicatulum are the most suitable to be used for the phytostabilization of Cu, Zn, and Mn in vineyards in the Pampa biome.

O objetivo deste estudo foi avaliar o efeito de doses e métodos de aplicação de um solubilizador de fósforo sobre a disponibilidade de P no solo, o estado nutricional das plantas e a produtividade de grãos de milho de segunda safra cultivado em Latossolo Vermelho Distrófico do Cerrado brasileiro. O experimento foi conduzido em delineamento de blocos ao acaso com parcelas subdivididas, avaliando sete tratamentos com doses do solubilizador (0 a 300 mL ha?¹), aplicadas em área total ou no sulco de plantio, com quatro repetições. O bioinsumo, associado à adubação fosfatada, elevou o P disponível no solo em até 313% e aumentou linearmente o P remanescente nas três profundidades avaliadas. O incremento das doses em área total promoveu resposta linear positiva na produtividade de grãos. A aplicação de 150 mL ha?¹ no sulco proporcionou melhor estado nutricional das plantas, maior teor de P disponível no solo (33,02 mg dm?³) e maior rendimento de grãos (2,12 Mg ha?¹), com incrementos de 26% em relação à testemunha e de 9% em comparação à adubação fosfatada sem o bioinsumo. O bioinsumo mostrou potencial para otimizar o aproveitamento de fertilizantes fosfatados e aumentar a produtividade do milho safrinha no Cerrado.

Context The no-tillage vegetable system (NTVS) is a form of regenerative agriculture. However, which cover crops (CCs) are most effective in improving soil physical properties in this system remains unclear. Aims This study evaluates whether improvements in water infiltration and soil penetration resistance (PR) in NTVS are influenced by CC diversification. Methods The experiment consisted of seven treatments with different levels of temporal and spatial diversification of CCs in no-tillage, plus a treatment under conventional tillage and low vegetation cover: NT-Ma, succession of onion and maize in vegetable no-tillage (NT); NT-Comt, commercial rotation and winter coverage and triennial onion in NT; NT-Gb, maize/winter grasses and biennial onion in NT; NT-La, legume in summer and annual onion in NT; NT-Ga, grass summer/winter and annual onion in NT; NT-LGa, legume summer/winter grass and annual onion in NT; CT-Ma, succession of onion and maize, in conventional tillage; and NT-Mixa, consortium (mix) of summer CCs and annual onion in NT. Soil assessments included PR (0–50 cm) and the water infiltration rate (double-ring infiltrometer method); the latter was also measured in an adjacent secondary forest area (dense ombrophilous forest), used as a reference. The biomass of the CCs and onion yield were determined. The analyses were conducted during the 2024/2025 growing season, 17 years after the trial establishment. The soil was classified as a Humic Dystrudept. Key results The greatest water infiltration occurred in the treatments with more frequent use of grasses (NT-Gb and NT-Ga) and in the treatment with single and recurrent use of velvet bean (NT-La). Infiltration in these treatments was similar to that of the secondary forest. The NT-La stood out for its reduction in PR. The system with the greatest spatial diversification of CCs (NT-Mixa) was the most efficient at increasing biomass production. However, onion yield was not affected by the amount or type of above-ground biomass. The differences in the physical properties of the soil were small compared with the good physical quality indexes observed across all treatments under NTVS. Conclusions In long-term no-till systems, the benefits of CCs on soil PR and water infiltration reached a saturation point. In this scenario, the predominant species type (e.g. legume or grass) and the approach to spatial or temporal diversification exerted minor influence on these variables. Implications The results demonstrate a high degree of flexibility in the selection of CC species in long-term no-till systems.

The adoption of conservation systems in agriculture has been increasingly explored as a strategy to improve soil quality and potentially influence greenhouse gas (GHG) emissions. This study reports the first assessment of GHG emissions within a long-term (14 years) agroecological field experiment evaluating soil management systems for onion (Allium cepa L.) production in a Humic Dystrudept (Cambissolo Húmico Distrófico, Brazilian Soil Classification System) in Southern Brazil. Three management systems based on permanent soil cover and crop diversification were evaluated in an onion–maize rotation: conventional tillage (CT) without cover crops, no-till (NT) without cover crops, and a no-till vegetable system (NTV) with a summer cover crop mixture of pearl millet (Pennisetum americanum), velvet bean (Mucuna aterrima), and sunflower (Helianthus annuus). Short-term GHG emissions were monitored during one onion growing season (106 days), while soil chemical and physical properties reflect long-term management effects. Evaluations included (i) daily and cumulative GHG (N2O, CH4, and CO2) emissions, (ii) soil carbon (C) and nitrogen (N) stocks, (iii) soil aggregation, porosity, and bulk density in different soil layers (0.00–0.05, 0.05–0.10, and 0.10–0.30 m), and (iv) onion yield and cover crop dry matter production. The NTV system improved soil physical and chemical quality and increased onion yield compared to NT and CT. However, higher cumulative N2O emissions were observed in NTV, highlighting a short-term trade-off between increased N2O emissions and long-term improvements in soil quality and crop productivity. All systems acted as methane sinks, with greater CH4 uptake under NTV. Despite higher short-term emissions, the NTV system maintained a positive C balance due to long-term C accumulation in soil. Short-term greenhouse gas emissions were assessed during a single onion growing season, whereas soil carbon stocks reflect long-term management effects; CO2 fluxes measured using static chambers represent ecosystem respiration rather than net ecosystem carbon balance. These results provide an initial baseline of GHG dynamics within a long-term agroecological system and support future multi-year assessments aimed at refining mitigation strategies in diversified vegetable production systems.

The soil microbiome is essential for ecosystem functions and food production; however, it undergoes structural and functional changes due to management practices. This study describes the microbial community associated with long-term onion systems: conventional tillage (CT), no-tillage (NT), and no-tillage vegetable system (NTVS). The long-term experiment was conducted over 17 years in Ituporanga, SC, Southern Brazil. The treatments included: CT (soil turned over before planting onions, followed by corn in summer and a fallow period in winter), NT (similar to CT but with restricted soil turnover), and NTVS (similar to NT but with greater species diversity grown in a consortium during summer, including millet + velvet-bean + sunflower). The soil microbiome (16S and ITS gene) was analyzed by next-generation sequencing - NGS of soil samples collected after the onion cycle. Soil management influenced microbiome structure, with each system exhibiting distinct compositional patterns. NTVS had a higher proportion of bacteria, fewer unclassified groups, and a greater abundance of taxa linked to nutrient cycling and beneficial plant relationships. NT showed a higher relative presence of archaea, particularly nitrifying groups such as Nitrososphaeraceae. In CT, Firmicutes and Bacillaceae were more prevalent, indicating a typical response to more disturbed environments. At all taxonomic levels, NTVS reduced the occurrence of unidentified taxa, suggesting a more stable environment with clearer ecological selection. For fungi, similar trends were observed, with higher richness in NTVS and lower in CT, favoring microorganisms adapted to stressful, fast-growing conditions and readily available nutrients. Both NT and NTVS showed increased abundance of microorganisms involved in nutrient cycling, organic matter decomposition, and symbiosis, which are vital for soil health. Therefore, conservation-oriented tillage systems, especially NTVS, foster a more diverse, functional, and potentially growth-promoting microbiome in the onion, whereas CT directs the community toward opportunistic and less functional groups.

Conventional tillage in onion cultivation degrades physical, chemical and biological properties of soil. In response, the no-tillage vegetable system (NTVS) is increasingly recognized as efficient conservationist cropping system for onion cultivation. To determine how distinct crop successions combinations optimize soil functioning, this study evaluated a long-term organic NTVS experiment comprising eight treatments of winter (black oat, oilseed radish, or fallow) and summer crops (velvet bean, soybean, millet, common bean, or maize) succession combinations for onion production. This study assessed cover crop mulch, onion yield, soil fertility, and enzyme activities (FDA hydrolysis, arylsulfatase, and β-glucosidase). Results showed that the organic NTVS improved soil fertility, increasing organic matter by 38

Crop phenology influences the relationship between remotely sensed signals and agronomic traits; however, its effect on the prediction of sugarcane yield and technological quality remains insufficiently understood under tropical production conditions. This study evaluated the influence of crop growth stage on remote sensing-based estimates of sugarcane yield and total recoverable sugar (TRS) in the Brazilian Cerrado. Field data were collected from 51 georeferenced sampling points distributed across five commercial sugarcane fields totaling 98.1 ha and cultivated with the CTC-04 variety in Campo Florido, Minas Gerais, Brazil. Vegetation indices derived from Sentinel-2 imagery, including NDVI, EVI, NDRE, GNDVI, and VARI, as well as RGB- and ALOS/PALSAR-2-derived metrics, were evaluated at vegetative and pre-harvest stages. Multiple linear regression models were developed to estimate total cane yield (TCH), net cane yield after removal of leaves and apical stalk portions (TCH-L), and total recoverable sugar (TRS). Total cane yield and TCH-L were more accurately estimated using optical vegetation indices, with the Normalized Difference Vegetation Index (NDVI) providing the most consistent performance and explaining up to 60% of TCH variability, with mean absolute percentage error (MAPE) values below 20%. In contrast, TRS showed a distinct phenological response, achieving MAPE values below 5%, with its best estimates during the pre-harvest stage when the Normalized Difference Red Edge Index (NDRE) and NDVI were combined.

ABSTRACT Phosphate fertilization is a consolidated practice in Southern Brazil vineyards and directly affects soil phosphorus P fractions, with implications for environmental sustainability due to the risk of P transfer to adjacent agroecosystems. This study aimed to (i) evaluate changes in P fractions according to cultivation time and soil depth in vineyards of Southern Brazil, and (ii) compare P accumulation patterns with other regional studies, assessing the contaminant potential of these areas. Three vineyard sites with different cultivation periods were selected in the municipalities of Bento Gonçalves (BG), Santana do Livramento (SL), and Urussanga (U), with a native forest used as a reference. Soil samples were collected in 0.00–0.05, 0.05–0.10, 0.10–0.15, and 0.15–0.20 m layers in BG, and 0.00–0.05, 0.05–0.10, 0.10–0.20, and 0.20–0.40 m layers in the vineyards of SL and U and submitted to P chemical fractionation, and the P stratification index was calculated. In addition, data on P fractions from published studies were compiled, and the environmental critical P-threshold of the 0.00–0.05 m layer was estimated for all vineyard soils. The vineyards evaluated showed significant accumulation of all P fractions, with the highest concentration in the surface layers (0.00–0.05 and 0.05–0.10 m), regardless of cultivation time. This accumulation was observed in both labile and moderately labile forms, reflecting successive fertilizer applications. Stratification was more pronounced in vineyard soils compared with native forest, consistent with surface fertilization and the low mobility of phosphate in subtropical soils. Sandy soils exhibited greater P mobility, with residual P increases in deeper layers. The relationship between total organic carbon and organic P fractions highlighted the role of soil organic matter, particularly in clay-rich Inceptisols of higher-altitude vineyards. Compared with critical environmental limits, 81 % of vineyard soils exceeded the P threshold, in some cases by up to 9.9 times, indicating a high risk of P losses through runoff and erosion. These findings demonstrate that vineyard soils in Southern Brazil accumulate across all P fractions and depths, surpassing agronomic requirements and environmental safety limits. Adjustments in fertilization practices, including suspending P fertilizer in high-P soils, adopting cover crops, and continuously monitoring soil and plant P, are urgently needed to balance vineyard productivity with the resilience and sustainability of these agroecosystems.

This study evaluated the effects of peat-based organomineral fertilizers with different compositions and Bacillus spp. inoculation on the growth and nutrient accumulation of loose-leaf lettuce grown under summer and winter conditions. Two independent greenhouse experiments were conducted using a randomized complete block design with eight treatments: no basal fertilized control (T1); conventional mineral fertilization (T2); peat-based organomineral fertilizers containing 50% (T3), 40% (T4), or 30% peat (T5); and the corresponding formulations supplemented with Bacillus subtilis, Bacillus megaterium, and Bacillus aryabhattai (T6-T8). All fertilized treatments were standardized to supply the same P rate. Multivariate analyses revealed a strong effect of fertilization strategy on plant growth and nutritional status. In both seasons, fertilized treatments significantly outperformed the control, while organomineral fertilizers performed similarly to or better than conventional mineral fertilization. The greatest shoot fresh mass and nutrient accumulation were observed in formulations containing lower peat proportions and higher mineral nutrient density, particularly when combined with Bacillus spp. inoculation. In the summer experiment, the 40% peat formulation supplemented with Bacillus spp. (T7) produced the highest shoot fresh mass (197.57 g plant-1), whereas in the winter experiment the highest value was obtained with the 30% peat formulation supplemented with Bacillus spp. (T8; 157.86 g plant-1). These treatments also exhibited greater accumulation of macronutrients and micronutrients, particularly N, P, K, Fe, Mn, and Zn. The results indicate that the performance of peat-based organomineral fertilizers was influenced by the balance between the organic matrix and mineral fraction, as well as by seasonal growing conditions. In addition, Bacillus spp. inoculation was associated with improved performance of formulations with greater mineral nutrient density but did not compensate for less favorable fertilizer compositions. Under the conditions evaluated, peat-based organomineral fertilizers containing lower peat proportions and supplemented with Bacillus spp. performed similarly to or better than conventional mineral fertilization and promoted greater lettuce growth and nutrient accumulation than the non-fertilized control. These findings are limited to a single lettuce cultivar grown in pots under greenhouse conditions across two seasonal experiments conducted at one location.

Conservation Agriculture for vegetable production, which is designated as No-Tillage Vegetable System (NTVS) in southern Brazil, sustainably improves food production through the strategic arrangement of cover crops (CCs) in crop rotation. However, the functional differentiation of CCs arrangements needs further understanding in NTVS. This study investigated the functional differentiation of CCs combinations in an NTVS in southern Brazil. The experiment was conducted on a Humic Dystrudept soil in southern Brazil. Treatments included: T1 - fallow in fall/winter (weeds, mainly Galinsoga parviflora) followed by onion (Allium cepa L.) and then corn (Zea mays) (F/Oni/C); T2 - turnip forage (Raphanus sativus L.) in fall/winter followed by onion and then millet (Pennisetum glaucum) (T/Oni/M); T3 - mix of oats (Avena strigosa) and turnip forage in fall/winter, followed by onion and then beans (Phaseolus vulgaris) (O+T/Oni/B); and T4 - oats in fall/winter followed by onion and then soybean (Glycine max) (O/Oni/S). From 2024-2025, after 16 years of long-term experiment that has been carrying out, the following traits were evaluated: soil penetration resistance (PR) (0-50 cm); aggregate stability (0-10 cm); water infiltration into the soil (using concentric double ring); carbon (C) and nitrogen (N) contents (0-10 cm); beta-glucosidase enzyme activity and glomalin fractions (0-10 cm); qualitative indices of soil structure and health; and biomass production by CCs. The onion yield data from 2019 to 2024 was also added to the database. The system with the greatest diversity of CCs (O+T/Oni/B) showed the highest water infiltration. The T/Oni/M treatment promoted greater enzymatic activity and lower PR (0-15 cm). Treatments with summer grasses (T/ Oni/M; F/Oni/C) resulted in higher biomass production and improved qualitative indexes of soil health, while those with summer legumes (O+T/Oni/B; O/Oni/S) increased onion yield. Aggregate stability, C and N content, and glomalin levels in the soil were high across treatments but had no significant differences. In conclusion, each CC system provides specific benefits to the soil. These findings demonstrate the high degree of functional differentiation of CCs in organic NTVS, allowing management to be tailored to goals (e.g., biomass production, biological activity, water infiltration, or crop yield). The diversity of species, the quantity and type of biomass, and seasonality influence the physical and biological properties of the soil and the functional differentiation between CCs in a long-term organic NTVS. Qualitative indicators of soil health complement quantitative indicators and broaden the functional differentiation of CC arrangements, guiding the regenerative management of soil health.

Apple yield can be maximized through balanced nutritional management of orchards. This can be achieved by defining nutritional standards and nutrient reference values through multivariate database analysis. The objectives of the study were: i) to set and compare apple trees' nutritional standards based on the Diagnosis and Recommendation Integrated System (DRIS) and on the Composition Nutritional Diagnosis (CND) and ii) to generate nutrients' critical levels (CL) and sufficiency ranges (SR) in relation to the productivity of apple trees. The study was carried out in commercial Gala and Fuji cultivar orchards in Fraiburgo, Lebon Regis, Santa Cecilia, and Monte Carlo municipalities - Santa Catarina State, Brazil. A database comprising information on fruit yield and leaf nutrient contents, from 10,179 observations performed from 2006 to 2021 was used in the study. According to the results, there is low association between mean nutrient balance index (NBIm) and nutritional imbalance index (CND-r2), and yield. DRIS and CND methods were effective in diagnosing apple trees' nutritional status. Apple trees' greatest nutritional requirements comprise the following macronutrients: nitrogen (N), potassium (K) and calcium (Ca), and the following micronutrients: manganese (Mn), iron (Fe) and zinc (Zn), all of them determined through the CND method. CL and SR established through the DRIS and CND methods were alike, but the best-adjusted SRs were found through CND: 22.1 - 26.4; 1.4 - 2.1; 11.5 - 15.8; 11.0 - 15.2; 2.9 - 4.0 g kg-1 and 70.2 - 116.7; 208.2 - 552.7; 5.8 - 8.6; 99.3 - 182.9; 31.4 - 41.9 mg kg-1 for N, P, K, Ca, Mg, Fe, Mn, Cu, Zn and B, respectively, for the cv. Gala; and 24.3 - 28.5; 1.6 - 2.2; 10.7 - 15.0; 12.0 - 16.01; 2.7 - 3.8 g kg-1 and 75.9 - 125.6; 107.3 - 364.1; 6.1 - 9.1; 43.4 - 124.4; 32.8 - 44.3 mg kg-1 for N, P, K, Ca, Mg, Fe, Mn, Cu, Zn and B, respectively, for the cv. Fuji. The use of the CL and SR standards established here will allow the rational use of fertilizers, but also the adequate nutritional balance of the orchards to achieve the greatest yield efficiency.

O trabalho objetivou avaliar as propriedades químicas e os estoques de carbono (C) e de nitrogênio (N) do solo sob cultivo de cebola por 16 anos, no sistema de plantio direto de hortaliças (SPDH), comparado com o sistema de preparo convencional (SPC) e o sistema de plantio direto (SPD). O delineamento experimental foi em blocos ao acaso com quatro repetições e três tratamentos: SPD - sucessão milho/cebola anual; SPC - sucessão milho/cebola anual; SPDH - consórcio mucuna+milheto+girassol e cebola anual. Amostras de solo foram coletadas nas profundidades de 0-5 cm, 5-10 cm e 10-30 cm para avaliação dos atributos químicos do solo e dos estoques de C e N. Não foram verificadas diferenças de pH e de densidade do solo entre os tratamentos. O SPDH apresentou maiores teores de potássio entre 10 e 30 cm. Para o fósforo, o SPDH e o SPD apresentaram os maiores valores nos intervalos de 0-5 e 5-10 cm. O SPDH tem maior potencial para armazenar C e N em comparação com os demais tratamentos. O consórcio de plantas de cobertura no SPDH é eficaz para aumentar os teores de potássio em profundidade, bem como promover maiores teores e estoques de C e N em comparação aos tratamentos SPD e SPC. Palavras-chave: sistema de plantio direto de hortaliças; ciclagem de nutrientes; consórcio de plantas de cobertura; acúmulo de carbono. Total carbon and nitrogen stocks and soil chemical properties in onion production ABSTRACT: The study aimed to evaluate soil chemical properties and carbon (C) and nitrogen (N) stocks after 16 years of onion cultivation in the no-till vegetable system (SPDH) compared with the conventional tillage system (SPC) and the no-till system (SPD). The experimental design was a randomized block with four replicates and three treatments: SPD (annual maize/onion rotation), SPC (annual maize/onion rotation), and SPDH (a mix of velvet bean, pearl millet, and sunflower intercropped with annual onion). Soil samples were collected at depths of 0–5 cm, 5–10 cm, and 10–30 cm to assess chemical properties and C and N stocks. No significant differences were observed for soil pH or bulk density among treatments. The SPDH showed higher potassium levels at 10–30 cm. For phosphorus, SPDH and SPD had the highest values at 0–5 cm and 5–10 cm depths. SPDH demonstrated a greater capacity for storing C and N compared to the other treatments. The plant cover mix in SPDH proved effective in increasing potassium at deeper soil layers and enhancing C and N levels and stocks relative to SPD and SPC treatments. Keywords: no-tillage vegetable system; nutrient cycling; cover crop consortium; carbon accumulation.

Coprophagous dung beetles provide important ecosystem services in improving soil quality and plant development in agricultural environments due to the availability of nutrients from dung removal. The study aimed to compare the effect of dung removal performed by two functional groups, among themselves and with mineral fertiliser, on improving soil and forage grass characteristics. An experiment in mesocosms was conducted in Southern Brazil during the summer/autumn of 2021, sowing Urochloa brizantha in the treatments: (1) telecoprid species (Canthon rutilans cyanescens), (2) paracoprid species (Dichotomius sericeus), (3) both species together, (4) mineral fertiliser and control with cattle dung. Dung removal was quantified weekly. At the end of the experiment, the soil's physical, chemical and microbiological characteristics, dry biomass and macronutrients (N, P and K) of the leaves and roots, and photosynthetic pigments of grasses were analysed. The dung beetle species studied increased total nitrogen and organic matter contents and their particulate fractions of C and N. Paracoprids decreased the soil bulk density and improved its soil aggregation, influencing the pH and Mg contents, with a reduction in Al levels. They were as efficient as mineral fertiliser in incorporating K into the soil. Treatments with beetles had values similar to mineral fertiliser in the foliar concentrations of P, and paracoprids promoted increases in the K concentration in the leaves and roots of the grass. This functional group was also more efficient in removing cattle dung, which was positively related to the amounts of N, organic matter and its particulate fractions, P, macroaggregates and the cation exchange capacity (CECpH7.0) of the soil. Thus, dung removal was associated with improvement in the soil, mainly paracoprids, reinforcing the importance of the ecosystem functions performed by these organisms in agricultural environments, where they can contribute to the increase in nutrient cycling with a consequent decrease in the use of mineral fertilisers.

The study aimed to evaluate soil chemical properties and carbon (C) and nitrogen (N) stocks after 16 years of onion cultivation in the no-till vegetable system (SPDH) compared with the conventional tillage system (SPC) and the no-till system (SPD). The experimental design was a randomized block with four replicates and three treatments: SPD (annual maize/onion rotation), SPC (annual maize/onion rotation), and SPDH (a mix of velvet bean, pearl millet, and sunflower intercropped with annual onion). Soil samples were collected at depths of 0-5 cm, 5-10 cm, and 10-30 cm to assess chemical properties and C and N stocks. No significant differences were observed for soil pH or bulk density among treatments. The SPDH showed higher potassium levels at 10-30 cm. For phosphorus, SPDH and SPD had the highest values at 0-5 cm and 5-10 cm depths. SPDH demonstrated a greater capacity for storing C and N compared to the other treatments. The plant cover mix in SPDH proved effective in increasing potassium at deeper soil layers and enhancing C and N levels and stocks relative to SPD and SPC treatments.

Vegetable production primarily relies on the conventional tillage system (CTS), which leads to soil degradation through erosion and reduced soil health. The use of no-tillage vegetable systems (NTVS) aims to mitigate these issues; however, information about the impact of this management system on soil health and greenhouse gas (GHG) emissions remains limited. Thus, the objective of this study was to conduct an on-farm evaluation of the effects of no-tillage and cover crop use on soil C and N contents and stocks, soil bulk density (SD), mean geometric diameter (MGD) of aggregates, soil temperature, volumetric soil moisture (VM), plant yield, and GHG emissions in cauliflower production under NTVS compared to CTS in a subtropical ecosystem in southeastern Brazil. Chemical and physical properties were assessed at depths of 0–5, 5–10, and 10–30 cm. GHG emissions, particularly nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) were measured using closed static chambers and gas chromatography. NTVS with cover crop mixes had higher yield than CTS without cover crops (25.1 and 18.4 Mg ha−1, respectively). NTVS exhibited increased MGD and VM and reduced SD. Soil temperature in the 0–5 cm layer was lower in NTVS than in CTS. Soil C and N stocks were higher in NTVS, but high N2O emissions offset this advantage compared to CTS. Overall, NTVS emitted more CO2 and N2O than CTS, while both systems showed soil CH4 uptake. NTVS maintained sufficient carbon equivalent reserves (0–30 cm) to offset GHG emissions, making it a viable alternative for plant yield and soil quality; however, its environmental impact on GHG emissions requires further attention.