Abstract in English:

ABSTRACT For a comprehensive and global evaluation of soils, it is essential to define common diagnostic properties among classification or interpretative systems. Specifically, in soil taxonomy, the Brazilian Soil Classification System (SiBCS) adopts analytical methods that differ from those used in international systems such as the World Reference Base for Soil Resources (WRB) and the Soil Taxonomy (ST). In the chemical properties, differences are observed in the determination of exchangeable basic cations and potential acidity (H+Al), as well as derived properties such as the sum of bases (SB), cation exchange capacity (CECpH7), and base saturation (V). This study aimed to: (i) to compare the values of H+Al, SB, CEC, and V in Brazilian soils determined by different analytical methods; (ii) to propose regression models to harmonize values of the properties obtained through different analytical procedures; and (iii) to compare the threshold values of diagnostic properties used as classification criteria in the SiBCS with those adopted by WRB and ST. A representative database of Brazilian soils published in the Brazilian Soil Data Repository (SoilData) was used, comprising 2,217 samples from surface horizons and 3,726 from subsurface horizons. Values of SB, CEC, and V for surface and subsurface horizons, obtained using the methods applied in the SiBCS, were lower than those determined by the WRB and ST methods. The difference in the estimated V values was below 5 %, which falls within the analytical error range. Thus, the SiBCS criteria of V ≥50 % for identifying eutrophic character and >65 % for defining a chernozemic A horizon were found to be high, and they tend to underestimate several Brazilian soil classes, particularly those classified as Chernossolos, as well as the misclassification of anthropic and other soils modified by agricultural practices. It is proposed that the SiBCS adopt thresholds similar to those used in WRB and ST for base saturation, or alternatively, apply regression equations to improve correspondence among the systems.

Abstract in English:

ABSTRACT The widespread deficiency of available phosphorus (P) in soils, particularly in tropical regions, necessitates the application of phosphate fertilizers due to their high adsorption. However, excessive use engenders significant economic costs and contributes to eutrophication of aquatic ecosystems and the mobilization of heavy metals. One viable alternative is the use of phosphate-solubilizing bacteria (PSB), which can solubilize phosphate through the production of acids and enzymes. This study aimed to assess the cultivable PSB community in different pedogenetic horizons of degraded and preserved Planosols and Luvisols (Planossolos and Luvissolos) in the semiarid and subhumid regions of Brazil, as these soils exhibit a high P availability, particularly in deeper layers. Furthermore, the biotechnological potential of the most promising PSB was evaluated in corn. A total of 170 PSB strains were collected, with 96 bacteria isolated from Planosol and 74 from Luvisol. The majority of the PSB exhibited a medium solubilization index and a broad morphophysiological diversity, and all solubilized calcium phosphate in liquid media. To investigate the biotechnological potential of these bacteria, eight PSB strains were selected based on their ability to solubilize calcium phosphate (>160 mg L-1) and to promote plant growth through mechanisms such as high auxin production, exopolysaccharide synthesis, zinc solubilization, and antagonism against the pathogen Fusarium sp. The PSB were identified as follows: PL1A, PL2L (Priestia sp.), PL1B (Neobacillus sp.), PL3J and LU13C (Streptomyces sp.), PL6A (Fictibacillus sp.), and PL18E and LU10E (Bacillus sp.). The PSB were inoculated into corn with the treatments based on the absence of phosphorus (-P) (control), simple superphosphate (SSP), reactive natural phosphate (RP), and the SSP + RP combination. The maximum available P value in the soil was observed in the RP treatment, where LU10E (78.70 mg dm-3) was inoculated, and in the SSP treatment, where LUC13C (69.9 mg dm-3) was inoculated. Isolates LU13C, LU10E, and PL3J exhibited the highest efficiency in phosphorus mobilization, PL1B and PL18E were moderately efficient, while PL1A, PL2L, and PL6A were the least efficient. This study assessed the diversity of phosphate-solubilizing bacteria (PSB) across soil profiles of degraded and vegetated Planosols and Luvisols in the Borborema Province, Northeastern Brazil, resulting in the establishment of the first bacterial collection comprising 170 strains with confirmed potential for phosphorus solubilization and corn growth promotion.

Abstract in English:

ABSTRACT Onion is predominantly grown under conventional management. Alternatively, the no-tillage vegetable system uses cover crops to form a residue layer, which improves soil physical, chemical, and biological quality. Aiming to understand the effect of mycorrhizal and non-mycorrhizal cover crops on arbuscular mycorrhizal fungus diversity, we used morphological characterization of spores and high-throughput sequencing in soil from a long-term experiment with no-tillage onion. Treatments were black oats (Avena strigosa Schreb.); rye (Secale cereale L.); oilseed radish (Raphanus sativus L.); rye + oilseed radish; black oats + oilseed radish before the onion crop, and the control was a fallow area. In spring, all plots had onions, followed by velvet-bean in summer. Additionally, a conventional tillage system area and a forest, both adjacent to the experiment, were evaluated. Morphological identification of spores of arbuscular mycorrhizal fungi showed dominance of the Glomeraceae and Acaulosporaceae families. The DNA sequencing of rhizospheric soil confirmed those data and estimated 75 operational taxonomic units, with a predominance of the genus Glomus. Presence of oilseed radish, a non-mycorrhizal cover crop, did not reduce the occurrence of fungal species in relation to mycorrhizal cover crops. The use of different cover crop species in a long-term succession system maintains the natural mycorrhizal community.

Abstract in English:

ABSTRACT Soil aggregates are critical for maintaining soil structure, nutrient cycling, and microbial habitats, but their dynamics under land-use change remain unclear in cold-region ecosystems. This study aimed to examine soil aggregates, physical and chemical properties, enzyme activities, and bacterial communities across three aggregate size classes (mega-, macro-, and micro-aggregates) in wetland and farmland soils in northeastern China. Wetland soils contained larger proportions of coarse aggregates, higher mean weight diameter (MWD), and greater carbon and nitrogen contents than farmland soils, indicating stronger structural stability and nutrient retention. Microbial α- and β-diversity differed by aggregate size, with larger aggregates harboring more diverse bacterial communities. Soil organic carbon, TN, and SWC were the main drivers of microbial composition, especially in larger aggregates. Bacterial taxa also shifted with land use, with Nitrospinota and Desulfobacterota enriched in wetlands, while Actinobacteriota and Gemmatimonadota were more abundant in farmland. These results highlight the role of aggregate stability in shaping microbial diversity and soil functions during wetland-to-upland transitions.

Abstract in English:

ABSTRACT Plant roots can modify the stability of soil aggregates in the rhizosphere and the surrounding bulk soil. Italian ryegrass (Lolium multiflorum) is known to improve soil aggregation through processes related to microbial activity, but these dynamics vary throughout the crop cycle. This study aims to correlate microbial activity with soil aggregate stability, determined by turbidimetry (readily-dispersible clay and mechanically-dispersible clay), in the rhizosphere and bulk soil of Italian ryegrass at 86, 113, 141, and 168 days after sowing. Results showed that the rhizosphere soil was significantly more stable, with 85–154 % lower dispersed clay than the bulk soil. Furthermore, aggregate stability increased (i.e., dispersed clay decreased) throughout the crop cycle, in tandem with a general increase in microbial parameters such as β-glucosidase, acid phosphatase, and glomalin-related soil protein. Aggregate stability was strongly correlated (R2 = 0.17–0.53; p<0.01) with these microbial parameters. In conclusion, Italian ryegrass effectively enhances soil aggregation and microbial activity, particularly in the rhizosphere, making it a valuable crop for improving soil health.

Abstract in English:

ABSTRACT In southern Bahia, Brazil, cocoa trees (Theobroma cacao L.) are grown in soils with varied physical properties. As many orchards in the region have surpassed their productive lifespan, renewal is crucial for increasing productivity. However, there is limited understanding of how soil physical properties affect the productivity of renovated cocoa orchards. This study aimed to assess the relationship between soil physical properties and cocoa productivity in no-till renovated orchards. The research was conducted across 15 field trials on cocoa farms in southern Bahia. Cocoa yield was monitored from 2019 to 2022 (4th to 7th year post-establishment), while soil physical properties—granulometry, porosity, bulk density, soil penetration resistance, and volumetric water content (at field capacity, permanent wilting point, and available water)—were measured in 2019 as baseline in three soil layers: 0.00–0.10, 0.10–0.20, and 0.20–0.40 m. Data were subjected to univariate and multivariate statistical analyses. In all layers, yield was significantly correlated (p<0.05) with silt content (r = −0.29 to −0.31), silt/clay ratio (r = −0.23 to −0.27), field capacity (r = 0.24 to 0.34), permanent wilting point (r = 0.23 to 0.26), and available water (r = 0.22 to 0.24). Principal Component Analysis showed that yield was positively associated with field capacity and permanent wilting point, and negatively related to soil resistance to penetration and bulk density in the surface layers. Hierarchical cluster analysis grouped the 90 plots into four productivity classes: G1 (74 %, 2,758 kg ha-1), G2 (58 %, 1,878 kg ha-1), G3 (37 %, 1,557 kg ha-1), and G4 (17 %, 792 kg ha-1). Tukey’s HSD test (p<0.05) revealed that the higher-yielding groups (G1 and G2) had significantly lower silt content and silt/clay ratios compared to the lowest-yielding group (G4). Overall, cocoa yield was constrained by excessive soil penetration resistance in surface layers and by high silt content and silt/clay ratios across all layers, while balanced sandy-clay textures with improved aeration and water retention favored higher productivity. These results corroborate previous studies recommending cocoa cultivation in soils with lower silt content, due to its association with compaction, drainage limitations, and reduced water retention. The findings highlight the importance of considering soil physical properties, particularly granulometry, as a criterion for selecting priority areas for orchard renewal, thereby contributing to high-yielding and climate-resilient crops.

Abstract in English:

ABSTRACT Soil nutrient availability affects economically significant crops, yet its influence on forage sorghum remains poorly understood. This study aimed to assess the impact of soil fertility on Bolivian Giant Sorghum AGRI 002E (Sorghum bicolor) across morphological, sanitary, yield, chemical, and nutritional attributes. A completely randomized experimental design was employed, comprising two treatments and ten replicates, representing two soil fertility conditions: A (fertile) and B (low fertility). The experiment was conducted in the Brazilian savanna. Soils A and B differed mainly in potassium (K), phosphorus (P), base saturation, manganese (Mn), and zinc (Zn) (0.00-0.20 m), and potassium (K), phosphorus (P), sulfur (S), and Al3+ saturation (0.00-0.40 m). Sorghum cultivated in soil A exhibited a remarkable 64.83 % increase in green forage mass compared to soil B, translating to a difference of 24.04 Mg ha-1 in dry matter. Furthermore, sorghum in soil A maintained a significantly higher number of live leaves, approximately 5.6 more than soil B, albeit experiencing a 33.59 % reduction in estimated leaf area under the lower soil fertility condition. Significantly, a conspicuous negative correlation emerged between the severity of anthracnose and morphological and yield traits. Under conditions of low soil fertility, the severity of anthracnose was six times higher, the dry forage yield was 13.04 Mg ha-1, and this hindered structural development, increased fibrous structures, diminished crude protein, and reduced digestibility.

Abstract in English:

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.

Abstract in English:

ABSTRACT Using pelletized cricket feces as a soil amendment not only enhances soil fertility but also addresses issues of convenient use, reduces dust pollution, and lowers the costs of storage and transportation. This study aimed to evaluate the effects of pelletized cricket feces on nitrogen (N) transformation and fertility of soil, and biomass of a vegetable in an acidic sandy soil. Microcosm and plant bioassay experiments were conducted in a greenhouse, with Chinese kale (Brassica oleracea var. alboglabra) used as the plant bioassay. The experiments compared unamended soil (not treated with any soil amendment) with soil amended using either unpelletized or pelletized feces at rates of 3.13, 6.25, and 12.5 Mg ha-1. Compared to unpelletized feces, pelletized feces resulted in decreased soil N mineralization, decreased concentrations of soil NH4+-N and NO3--N, and diminished availability of N, P, K, Ca, and Mg in both soil and kale tissue, which in turn led to lower biomass of Chinese kale. Despite less beneficial effects than their unpelletized counterparts, pelletized feces could still improve soil fertility and kale yield compared to unamended soil, with benefits increasing at higher application rates. The 12.5 Mg ha-1 of unpelletized feces, however, adversely affected Chinese kale biomass due to the antagonistic effect of K on Ca and phytotoxicity of NO3-.

Abstract in English:

ABSTRACT To define a suitable N fertilization management strategy to improve the productivity and economic performance of banana (Cavendish subgroup) production, technical criteria are needed to select N sources and establish dose rates. This study aimed to evaluate the effects of different forms of N, specifically amidic (urea and urea + NBPT), ammoniacal (ammonium sulfate), and nitric (calcium nitrate), on the nutritional status of banana plants, the severity of Sigatoka complex, and fruit productivity and quality. Profitability associated with the use of different N sources was also assessed. Treatments were conducted according to the factorial combination (3 × 4 × 2) + 1, considering three N sources (urea treated with NBPT, ammonium sulfate, and calcium nitrate), four N application rates (0, 75, 150, and 225 kg ha-1), two production cycles (second and third cycles), and a control treatment (plain urea applied at 150 kg ha-1). Fertilization led to soil acidification in the second cycle, with no increase in foliar N content associated with the N sources or doses, indicating that the N supply was due to the residual effect of previous fertilizations and to the mineralization of organic matter and plant remnants. Urea, urea treated with NBPT, ammonium sulfate, and calcium nitrate did not differ in banana plant nutrition, Sigatoka severity, or fruit production and quality. Higher N doses increased production in the third cycle, indicating that the recommended dose for high productivity was an underestimation. Nitrogen fertilizer that provided the best economic return was urea, followed by urea treated with urease inhibitor (NBPT), ammonium sulfate, and calcium nitrate. Fertilizer cost per unit of N was found to be a major factor determining the expense of fertilization and the profitability of banana production.

Abstract in English:

ABSTRACT The combination of farming dairy effluent (FDE) with mitigating agents’ nitrogen (N) losses to the environment, such as zeolites, dicyandiamide (DCD), and biochar, may reduce losses and improve N availability to plants. A field experiment was conducted in an Argiudol of the Pampa region, Argentina, to evaluate N use efficiency and associated losses following FDE application. On a natural grassland with a predominance of ryegrass (Lolium multiflorum) and the presence in smaller quantities of fescue (Festuca sp.), alfalfa (Medicago sativa), and white clover (Trifolium repens). The treatments included application of FDE, FDE plus zeolite (Zeo), FDE plus dicyandiamide (DCD), FDE plus biochar (BC), and a control untreated soil (C), each with three replicates. A uniform application of 11 L m-2 of effluent (eq to 250 kg of N ha-1) was performed, and nitrous oxide (N₂O) emissions, ammonia (NH₃) volatilization, soil and atmospheric temperature, and water-filled pore space were monitored up to three months. Overall, N₂O emissions were low across all treatments, reaching a maximum of 18.4 µg m2 h-1 of N-N2O. Zeo and BC significantly reduced N₂O emissions by 63.1 and 63.8 %, respectively, compared with FDE alone. Furthermore, BC reduced NH₃ volatilization by 55.5 % relative to FDE, highlighting its strong potential to mitigate total N losses. Regarding pasture performance, the highest greenness index was observed in the BC treatment, followed by intermediate values in FDE, DCD, and Zeo, and the lowest in the control. Under our study conditions, with particularly low rainfall and high temperatures, the mitigating effects of DCD and Zeo appeared to be limited. In contrast, the combination of FDE and BC emerged as the most effective strategy to reduce N losses and enhance pasture quality. Furthermore, environmental conditions play a key role in determining the efficacy of mitigation strategies to curb N losses.

Abstract in English:

ABSTRACT The critical soil test value (CSTV) of phosphorus (P) is defined by the relationship between relative crop yield (%) and soil P availability and is essential to guide fertilization decisions. However, CSTVs may vary depending on the diagnostic soil layer, crop type, and the Mathametical model used, highlighting the importance of refining their estimation. This study aimed to evaluate whether the subsurface layer (0.10–0.20 m) improves the diagnosis of P availability under different fertilization strategies and to re-estimate CSTVs for the Center-South region of Paraná, Brazil, by integrating new field trials with existing regional datasets and comparing multiple models. Relative yield and Mehlich-1 extractable P data were fitted to five models: Cate and Nelson (1965), modified ALCC, Mitscherlich, linear-plateau, and quadratic-plateau. Field trials were conducted in Oxisols (Humic Hapludox - Latossolos) with medium and high soil test P (STP) levels. Data were grouped by soil layer (0.00–0.20, 0.00–0.10, and 0.10–0.20 m) and crop season (summer and winter). In a second analysis, regional data were grouped by soil layer and crop type (summer + winter, summer, and winter), and all models were adjusted to 90 % of maximum relative yield. The field trials showed limited model fit due to high P availability in the surface layer, which was sufficient to sustain high yields even without P fertilization for four years. The Cate and Nelson model yielded CSTVs of 3.7 mg dm-3 for the 0.00–0.20 m layer and 0.9 mg dm-3 for the 0.10–0.20 m layer, both adequate for maintaining crop productivity. In the regional analysis, all models provided statistically significant fits, though numerical differences were not statistically significant due to overlapping 95 % confidence intervals. Estimated CSTVs ranged from 7.4–13.5 mg dm-3 (summer + winter), 6.6–19.0 mg dm-3 (summer), and 5.5–12.5 mg dm-3 (winter), encompassing the regional threshold of 8 mg dm-3. Plateau models tended to estimate higher CSTVs for summer crops, while ALCC and Mitscherlich were more aligned with winter crop requirements, with Mitscherlich showing the best performance for winter crops in both 0.00–0.10 and 0.00–0.20 m layers. These results support the use of the 0.10–0.20 m layer as a diagnostic depth under no-till systems and highlight the need for standardized model selection and expanded regional datasets to refine CSTV estimates and enhance the efficiency of P fertilization strategies.

Abstract in English:

ABSTRACT Brazil has the largest commercial cattle herd in the world, with 197.2 million head in 2023, representing approximately 12 % of the global herd. Cattle raising in Brazil is primarily carried out in pasture grazing systems. In this context, the adoption of well-adapted, high-yielding, and nutritious forage crops is essential for the sustainability of cattle raising, cost reduction, and increased yield efficiency. The cultivar ‘BRS Tamani’, a Megathysus maximus hybrid, stands out for its short plant height, high nutritional value, and resistance to pasture spittlebug and is recommended for well-drained soils of medium to high fertility, typical of the Brazilian Cerrado region. Despite its high potential, information is lacking regarding nutritional standards for the cultivar, which hinders precise fertilization recommendations. This study aimed to establish nutritional sufficiency ranges for BRS Tamani using the Compositional Nutrient Diagnosis (CND) and boundary line methods, aiming to improve nutrient management and promote yield gains. A database was used to compile information from 123 experimental units of BRS Tamani during the period from July to December 2017. Leaf samples were collected at various growth cycles / cuttings of the forage crop, and chemical analyses were performed to determine contents of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The CND method was used to calculate nutritional levels and identify nutrient imbalances. The boundary line method was applied to establish relationships between yield and the levels of each nutrient. The following critical levels were proposed by the CND: N = 20 g kg-1; P = 2.2 g kg-1; K = 20 g kg-1; Ca = 2.3 g kg-1; Mg = 2.8 g kg-1; and S = 1.4 g kg-1. The values obtained by the boundary line method were as follows: N = 23 g kg-1; P = 2.3 g kg-1; K = 20 g kg-1; Ca = 2.6 g kg-1; Mg = 2.8 g kg-1; and S = 1.3 g kg-1.

Abstract in English:

ABSTRACT High soil acidity and low nutrient availability in the deeper soil layers of no-tillage systems (NTS) can restrict crop yield potential. This study aimed to evaluate the impact of different soil acidity correction strategies and P and K application methods on the vertical variation of soil acidity, nutrient availability, and on corn and soybean yields. A randomized block factorial experiment was established in 2020 on a Plinthosol (Plintossolo Argilúvico Distrófico típico) under NTS since 2004. The first factor consisted of soil acidity correction strategies: (i) control, (ii) surface application of dolomitic limestone, (iii) surface application of calcium and magnesium oxide (CaO·MgO), and (iv) incorporation of dolomitic limestone to 0.20 m depth. The second factor corresponded to P and K application methods: (i) control without fertilization, (ii) in-furrow application, and (iii) surface broadcast application. The corrective amendment rates were calculated to raise the soil pH in the 0.00–0.20 m layer to 6.0. Six months after treatment application, soil samples were collected down to a depth of 0.40 m. Application of CaO·MgO increased soil pH, Ca2++Mg2++K+ saturation, and Ca2+ and Mg2+ contents, but these effects were confined to the surface soil layer (0.00–0.10 m). In contrast, limestone incorporation reduced soil pH, and Ca2++Mg2++K+ and Al3+ saturation gradients over a greatest soil depth (0.00–0.15 m), demonstrating greater effectiveness than both surface-applied limestone and CaO·MgO. Improvements in soil acidity resulting from limestone incorporation led to a 66 % increase in corn yield compared to other correction strategies. Soil chemical properties were minimally affected by P and K application methods, with higher available P observed only in the 0.00–0.05 m layer under surface broadcast application. Nevertheless, in-furrow P and K fertilization increased corn yield by 35 % compared to surface application. Soybean yield was not influenced by any of the treatments. In soils with high subsurface acidity, incorporating soil amendments is essential for effective acidity correction and yield improvement, while in-furrow P and K fertilization remains an efficient strategy to sustain high crop yields.

Abstract in English:

ABSTRACT In tropical and subtropical agricultural no-till (NT), lime and nitrogen (N) fertilizers are surface-applied. The pH increase from liming can enhance ammonia (NH3) volatilization. This study aimed to quantify NH3 losses from NT areas treated with different N fertilizers and lime rates and assess the effects on topsoil pH. Field experiments were conducted on clayey soil (Latossolo Vermelho distroférrico típico). The experimental design was a randomized complete block design with a 4 × 4 factorial split-plot arrangement and four replications. Main plots received four rates of dolomitic limestone (0, 2.6, 5.4, and 8.1 Mg ha-1) and subplots received four N fertilizers. Nitrogen fertilizers were: conventional urea (46 % N), urea coated with copper (Cu) and boron (B) (Ur-Cu+B; 0.15 % Cu, 0.4 % B, and 44 % N), NBPT-treated urea (Ur-NBPT, 46 % N and 0.53 % NBPT), and ammonium sulfate (AMS, 21 % N and 22 % sulfur). Nitrogen fertilizers were applied during two second-crop corn growing seasons, at 24 and 36 months after liming. Soil pH in the 0.00-0.05 m layer was determined at the end of the experiment. The increase in soil pH due to liming enhanced NH3-N volatilization losses, regardless of the N fertilizer used. Ammonia volatilization losses ranged from 16 to 32 % in urea plots, 12 to 31 % in Ur-Cu+B plots, 7 to 19 % in Ur-NBPT plots, and 0.2 to 5 % in AMS plots treated with lime rates of 0 to 8.1 Mg ha-1, respectively. For every 1 Mg ha-1 of applied lime, NH3-N volatilization increased by 1.7 to 2.2 % in Ur plots, 1.6 to 5.1 % in Ur-Cu+B plots, 1.3 to 1.5 % in Ur-NBPT plots, and 0.7 to 0.9 % in AMS plots. These results highlight the need to adjust N management after liming, with ammonium-based fertilizers (e.g., AMS) or stabilized urea sources (e.g., Ur-NBPT) being more effective mitigation strategies than urea or Ur-Cu+B in reducing NH3 volatilization under surface-limed no-till conditions.

Abstract in English:

ABSTRACT A recent trend in sugarcane production is to apply urea fertilizers in combination with vinasse (V) to balance nitrogen (N) and potassium (K) supply. This practice promotes a circular economy and a possible reduction in N losses through ammonia (NH3) volatilization due to the acidic nature of V. However, it is unclear whether V reduces NH3 volatilization, and whether the addition of urease inhibitors further reduces NH3 losses. Furthermore, the efficacy of formulations containing urea and urease inhibitors may decrease over time when blended with acidic fertilizers such as ammonium sulfate (AS). This study aimed to determine the efficacy of urease inhibitors N-(n-butyl) thiophosphoric triamide (NBPT) and Duromide in reducing NH3 volatilization losses from urea applied with V and from urea blended with AS and stored for 10 months in a warehouse. Two different experiments were conducted under controlled conditions. Seven days after fertilizer application, urea addition to V resulted in a 35 % NH3 loss (a reduction of only 36 % compared to urea), whereas NBPT-treated urea + V and Duromide-treated urea + V resulted in reductions of 51 and 74 %, respectively. The efficacy of NBPT-treated urea blended with AS to control volatilization decreased from 41 to 9 % after 10 months of storage. In contrast, the efficacy of Duromide-treated urea in reducing the NH3 volatilization remained relatively constant. Duromide is a more stable and effective urease inhibitor than NBPT, supporting agronomic practices that reduce NH3 volatilization and maintain inhibitory effects when blended with acidic fertilizers such as AS or combined with acidic organo-mineral fertilizers like V.

Abstract in English:

ABSTRACT Nitrogen (N) losses from soil through volatilization are influenced by multiple factors, including the amount and source of nitrogen fertilizer applied, crop type, intrinsic soil characteristics, and environmental conditions. The study aimed to quantify ammonia (N-NH3) volatilization in relation to the method of nitrogen application, either split or single-rate, on annual ryegrass (Lolium multiflorum Lam.) pasture in an integrated crop-livestock system. The trial was conducted on a Humic Cambisol in Southern Brazil during the fall and winter seasons of 2022 and 2023. The treatments were: N-0 – no nitrogen fertilization; N-split – fertilization with 200 kg ha-1 of N as urea split into four applications (50 kg ha-1 at tillering and three subsequent applications of 50 kg ha-1); and N-single – fertilization with 200 kg ha-1 of N as urea applied in a single rate at the ryegrass tillering stage. Ammonia volatilization was assessed using static semi-open collectors and quantified by colorimetry. Losses due to volatilization were monitored for 14 days after each N application and summed over 56-day period. In both years, during the first evaluation, the N-single treatment caused the greatest losses but did not differ significantly from split fertilization (N-split). However, in the subsequent three evaluations, the highest volatilization losses were observed with N-split. Regarding the total accumulated losses of N-NH3 over 56 days, the values in the first year were 375, 810, and 345 g ha-1 for N-0, N-split, and N-single, respectively. In the second year, the losses were 808, 1963, and 900 g ha-1 of N-NH3 for N-0, N-split, and N-single. Splitting nitrogen fertilization resulted in greater N losses through volatilization than a single application at tilling; however, the losses remained below 1 % of the applied N. Despite these differences in volatilization, split nitrogen fertilization produced ryegrass forage yields equivalent to those obtained with the single-rate application. Split N fertilization increased NH3 losses compared to single-dose application in ryegrass, yet yields were equivalent, and losses remained below 1 % of the applied N.

Abstract in English:

ABSTRACT Developing strategies for monitoring concentrations of rare earth elements (REEs) in soils is an urgent issue. Using near-infrared spectroscopy (NIR) as an alternative method could optimize the assessment of REEs across large areas. This study evaluated NIR performance for predicting REEs in soils from Piauí State (about 241,755 km2), one of the largest producers of agricultural commodities in Northeast Brazil. To cover the pedological variability across the entire state, 243 composite topsoil samples were collected. Samples were ground and sieved to ≤150 µm, then analyzed for REE concentrations using inductively coupled plasma optical emission spectroscopy (ICP-OES). Spectra were obtained in the NIR range (1000–2500 nm) from soil samples with particle sizes ≤2 mm using an FT-IR/NIR spectrometer. To reveal relationships between local REE characteristics and the performance of prediction models, the samples were subdivided into three distinct regions within Piauí State: (1) North, (2) Southeast, and (3) Southwest. To provide a comprehensive view of the data, the model performance across the entire state of Piauí was also evaluated. Soil spectra were preprocessed, and models were built using partial least squares (PLS) and random forest (RF) regression algorithms. Soil samples from Piauí state showed high spatial variability in terms of REE concentrations. The overall performance of prediction models was improved by reducing the scale to smaller areas. Reasonable results were found for dysprosium (Dy), erbium (Er), and ytterbium (Yb) in the Southwest and for the average concentration of heavy rare earth elements (∑HREE) in both the Southeast and Southwest. Our findings indicated that reducing the sampling scale area could lead to better modeling results and that NIR spectroscopy is a viable alternative method for assessing REEs. We suggest future similar studies in Piauí State should focus on localized areas with more homogeneous environmental settings.

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ABSTRACT In sandy soils, low organic carbon content and weak structural stability often constrain pore functionality, water availability, and gas exchange, highlighting the need for management strategies that improve soil physical quality. The aim of this study was to quantify the impact of cover crops on SOC, soil physical properties, and soil processes in a sandy loam dystrophic Ferralsol (Latossolo Vermelho-Amarelo Distrófico). The experiment followed a randomized complete block design composed of five treatments and five repetitions. The experimental treatments were: (1) Control (fallow plots subjected to weed desiccation), (2) G (single grass: Urochloa ruziziensis), (3) GG (two grasses intercropped: Pennisetum americanum + U. ruziziensis), (4) GL (one grass and one legume intercropped: P. americanum + Mucuna pruriens), and (5) MIX (two grasses and one legume intercropped: P. americanum + U. ruziziensis + M. pruriens). Undisturbed samples were collected from the layers of 0.00-0.10, 0.10-0.20, 0.20-0.40, and 0.40-0.60 m to determine physical indicators such as bulk density (Bd), total porosity (TP), field capacity (FC), permanent wilting point (PWP), plant-available water (PAW), and the soil water retention curve, pore size distribution, water storage capacity (FC/TP), saturated hydraulic conductivity (Ksat), air permeability (Kair), and pore continuity index (K1). Results demonstrated that, compared with the Control (absence of cover crops), GL (grass + legume), MIX (mixed species), and GG (grasses) improved air conductivity by 8, 3.5, and 2.9 times, and pore continuity by 5.8, 2.9, and 2.2 times, respectively. The MIX system led to a 39 % increase in SOC relative to the Control. Additionally, intercropping two grass species with one legume (MIX) and combining one grass with one legume (GL) resulted in a 19 % increase in plant-available water compared with the Control treatment. Importantly, these improvements in pore architecture occurred without significant changes in soil bulk density (Bd) or total porosity (TP), underscoring that cover crops can reorganize the pore network independently of mass–volume relationships. Combination of grasses and legumes (GL, MIX) has substantial potential to improve plant-available water and the overall soil physical quality of sandy soils.

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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.

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ABSTRACT The extreme climatic event in southern Brazil underscores the hydro-sedimentological vulnerability of agricultural headwater catchments within the Jacuí River Basin. This article describes the hydrological and erosive processes that took place between April 29 and 30, 2024, in the Guarda Mor River experimental catchment (18.5 km2), located at the interface between the Basaltic Plateau and the Central Depression regions of Rio Grande do Sul. The hydrological event was monitored based on rainfall, streamflow, and suspended sediment concentration to characterize runoff generation and sediment transport. In addition, topographic and geospatial surveys were conducted to characterize hillslope erosion processes and morphological changes in the stream channel. The study of the behavior of this event allows for a more precise understanding of local water dynamics, enabling stakeholders to anticipate flood risks, manage water resources more efficiently, and design targeted conservation strategies. Over a 31-hour period, 435 mm of rainfall were recorded, resulting in multiple streamflow peaks, with the highest reaching approximately 700 m3 s-1, and an estimated suspended sediment yield of around 12,365 Mg. Numerous diffuse and concentrated erosion processes occurred simultaneously and extensively, aggravated by local geomorphological, pedological, and land-use characteristics. The results underscore the importance of hydrological monitoring in headwater catchments and the adoption of practices to control and reduce surface runoff. These findings are particularly relevant for the Southern region of Brazil, which is characterized by intensive agricultural activity, complex topography, and a high frequency of extreme weather events, including intense rainfall and prolonged droughts. In this context, headwater catchments play a critical role in regulating water flow, sediment transport, and nutrient cycling across larger river basins.

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ABSTRACT Adopting management practices that enhance biomass production and metal accumulation in hyperaccumulator species is a key strategy to improve agromining efficiency. This study evaluated the effects of mineral (NPK) and organic (cattle manure) fertilization on the growth, nutritional status, and accumulation of Ni, Co, Cr, Cu, Mn, and Zn by Berkheya coddii cultivated in ultramafic soil. The experiment was conducted in a greenhouse using a randomized block design with three treatments: control, NPK (100:100:120 kg ha-1), and cattle manure (5 Mg ha-1). Both fertilization strategies improved plant nutritional status and significantly increased biomass, with mineral fertilization (NPK) exhibiting the most pronounced effect. Although shoot Ni content declined under fertilization, particularly in the NPK treatment, this was offset by a substantial biomass gain, resulting in the highest total Ni removal (35.1 g plant-1), nearly double that of the control. Nickel hyperaccumulation (>1,000 mg kg-1) was observed in all treatments, with the highest foliar content in unfertilized plants. The NPK also enhanced the uptake of other metals, especially Co, Cr, Mn, Zn, and Cu, confirming its broader impact on trace element accumulation. These findings underscore the key role of biomass accumulation and fertilization management in maximizing phytoextraction efficiency. Future field-based studies should explore reduced fertilization rates to balance agronomic performance, economic viability, and environmental sustainability in Ni agromining systems.

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ABSTRACT In the Moatize mine, tree species have been used for the coal minesoil restoration for more than 10 years. Nevertheless, the effects of such revegetation on chemical and physical properties of Moatize minesoils remain unknown. Here we present a pioneering 10.6-year chronosequence study aiming to monitor Moatize minesoils fertility, organic carbon stocks, and porosity, as well as interrelations of these properties. Furthermore, a natural (unmined) soil was sampled for comparison to provide insights into the reintegration of minesoils into the environment. We hypothesized that the fertility, organic carbon stocks, and physical properties of the minesoils improve with increasing restoration time but remain inferior to those of the unmined soil, likely due to the short revegetation period (10.6 years). The study was carried out in the Moatize coal mining area in Mozambique. In 2023, soil samples were collected from the 0.00−0.10 m layer in three 100 m transects, totaling 12 replicates per site, and chemical and physical properties were determined. Minesoils exhibited similar and strong acidity (pH <5.0) until 1.4 years, while from 5.3 to 10.6 years, they exhibited intermediate (5.14) and moderate (6.14) soil pH. Soil organic carbon stocks doubled in minesoils between the initial (until 1.4 years) and the final phase of evaluation (10.6 years). The positive effect of revegetation is also evident in the increase in macroporosity of the minesoils over time. The minesoil with 10.6 years of restoration presented properties very close to those of the unmined soil. However, we reinforce the need to monitor these minesoil properties in the long term to certify the successful integration of the mined land into the landscape.

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ABSTRACT Open-pit gold and platinum mining is one of the main economic activities in the tropical region of the planet. However, it disturbs the ecosystem, including soil physical and chemical properties, with negative consequences for vegetation growth and recovery; therefore, it is expected that soil fertilization will have significant effects on tree growth. To evaluate the effects of soil fertility on post-mining forest in the Biogeographic Chocó (Colombia), we established an experiment with five treatments of soil fertilizer addition: N (125 kg ha-1 yr-1), P (50 kg ha-1 yr-1), K (50 kg ha-1 yr-1), NPK, and control. Generalized Linear Models (GLM) were used to evaluate the treatment effects on the relative growth rate (RGR) of trees in two size categories (small trees, 0.05 m < diameter at breast height (DBH) <0.10 m, and large trees, DBH >0.10 m) and in three dominant species (Cosmibuena grandiflora, Cespedesia spathulata and Clidemia septuplinervia) of the ecosystem. Soil N addition increased small tree RGR across the ecosystem and in the species C. grandiflora and C. spathulata. In contrast, the P and K treatments produced no detectable change in RGR for either small or large trees. At the ecosystem level, this study demonstrated that nitrogen (N) fertilization significantly enhanced tree growth. This effect was primarily driven by the response of smaller individuals, which exhibited greater sensitivity to N amendment than larger trees. Specifically, small trees of C. grandiflora and C. spathulata growing in post-mining forests of the Chocó show enhanced responsiveness to shifts in nutrient availability.

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ABSTRACT In basic education, teachers are essential for Soil Education, a field that seeks to raise awareness about the importance of soil and its conservation. This study examined the soil knowledge of 81 Basic Education teachers in Planalto Serrano, Santa Catarina. Questionnaires and lexicometric analysis were applied, including Descending Hierarchical Classification and Factorial Correspondence Analysis, which were conducted using IRAMUTEQ software. Lexicometric analysis clusters texts, identifies patterns, and evaluates word frequency associations using chi-square statistics to assess their divergence from the central theme. The results identified 10 thematic categories, with the most significant being: (1) the role of soils in agricultural sustainability and biogeochemical cycles; (2) the need for region-specific supplementary materials; and (3) the influence of academic background and practical experience on teacher perceptions. Soil education to instill pedological awareness requires contextualized approaches and continuous training.

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ABSTRACT Achieving soil conservation requires education that not only delivers factual knowledge but also sparks the personal commitment and care essential for lasting behavioral change. However, by emphasizing cognitive domains, current soil science curricula often neglect the affective dimensions that foster a deep connection to soil. This study explores how emotions and feelings influence soil-care attitudes among university agriculture students. The study participants were undergraduate students enrolled in the introductory soil science course (n = 28). The test design involved a survey, with a pre-test administered at the beginning of the semester and a post-test administered at the end of the semester. A confidential code was used to match the two tests of each respondent. Students with rural backgrounds demonstrated a stronger emotional connection to soil compared to their urban peers (p = 0.037). However, no significant effect of place of upbringing was observed on students’ attitude toward soil care. The course significantly improved students’ attitude toward soil care (p = 0.0049). Pre-test emotional connection to soil emerged as a strong predictor of post-test attitude toward soil care (r = 0.52, p = 0.004). In contrast, the predictive power of pre-test soil science knowledge on post-test attitude toward soil care was not statistically significant. The results of this study suggest that fostering a deeper emotional connection to soil can be a crucial strategy for promoting soil conservation among students. To achieve this, soil science education should incorporate more experiential and emotionally engaging learning activities.

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ABSTRACT Cadmium (Cd) is a toxic heavy metal with no biological function in plants. This element has been found at high levels in some Andean Colombian cacao-crop soils. This study aims to assess the relations between soil physical and chemical properties, enzymatic activities, and Cd levels in rhizospheric and non-rhizospheric soils, and Cd accumulation based on soil-to-plant transfer factors. Physical and chemical properties, pseudo-total and potentially available Cd (DPTA-Cd), and soil enzymatic activities related to C, N, and P cycles were analyzed in soils at two layers. Pseudo-total Cd levels present in non-rhizospheric soils ranged from 1 to 9 mg kg-1, and were higher in rhizospheric soils with more acidic pH. Cadmium did not differ significantly with soil layer. Overall, P, pH, Zn, organic carbon, and effective cation exchange capacity were related to potentially available Cd. Urease decreased, and protease and alkaline phosphatase increased in soils with higher Cd, showing a synchronous inverse behaviour. Cadmium contents in cacao plants follow the order: leaf litter > leaves > beans. The transfer factors soil-to-leaves were >1, indicating that Cd is accumulated more efficiently in leaves (TF >1) than in beans (TF <1). This research improves knowledge of Cd dynamics relative to physicochemical and biochemical parameters in cacao-crop soils.

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ABSTRACT Amid contemporary debates on decolonial ecologies and traditional knowledge, it is essential to understand how historically marginalized communities articulate the interconnections among territory, nature, and cultural practices. This study seeks to understand the existence of a sentipensante relationship — from the Spanish sentipensar, a way of knowing in which thought and feeling flow as one — between quilombola women, the soil on which they build their lives, and their agricultural practices. It explores how three women from different generations, from the urban Adelaide Maria Trindade Batista Quilombola – one of the quilombo communities formed by enslaved, free, or freed black people, in the first half of the 19th century - located in Palmas, Paraná, Brazil, perceive and interact with the soil of their gardens and backyards. The research examines how this bond becomes evident in their perceptions, narratives, daily cultivation practices, and in the intergenerational transmission of knowledge. Rooted in ethnographic methodology and a qualitative approach, the study draws on personal communications, recorded in audio and captured in field notes and later organized and interpreted through content analysis. The findings suggest that the connections between quilombola women, the soil and its cultivation are deeply embedded in their history, culture, identity and sense of belonging. Their work with the soil and agricultural practices is an expression of intimacy with the earth, an act of cultural resistance, and a preservation of ancestrality — a relationship that is, in its essence, sentipensante.