Emmanuel Gabioud

Question: Effective environmental management depends on accurate and efficient assessments of ecological conditions. This study introduces a method that combines remote sensing with a Rapid Assessment Method (RAM) to evaluate the environmental status of land units at the ranch scale. We ask whether this integrated approach can generate spatially explicit information to support the implementation and monitoring of sustainable livestock grazing in native forests. Study area: The study was conducted in three livestock ranches in Argentina. These ranches encompass heterogeneous landscapes characterized by varying soil types, vegetation cover, and topographic features that influence ecological conditions. Methods: Remote sensing imagery was used to delineate Ecological Sites (ESi) based on bio-geomorphic attributes such as soil, topography, and vegetation. These spatial units guided field sampling, where RAM was applied to assess environmental indicators. Field data were integrated into an Environmental Health Index (EHI), summarizing the ecological status of each ESi. Ordinary kriging interpolated EHI values across the landscape, enabling spatial visualization of environmental health patterns and spatial variability. Results: Mapping of EHI values showed that most land units exhibited intermediate to high environmental health, suggesting generally favorable ecological conditions across the ranches. However, some areas had low EHI values associated with signs of disturbance or degradation, including fire, flooding, invasive species, or overgrazing. Conclusions: The integration of remote sensing with RAM provided a detailed overview of ecological conditions at the ranch scale. The results can guide more focused and efficient fieldwork in areas requiring closer monitoring due to potential environmental degradation or changes linked to livestock management. This approach supports the implementation and evaluation of sustainable grazing management in native forests, offering a robust, scalable tool for environmental assessment. Additionally, by optimizing the allocation of sampling effort, it enables more informed decision-making to maintain and enhance ecological health in these production systems. Taxonomic reference: Anton and Zuloaga (2023). Abbreviations: EHI = environmental health index; ESi = ecological site; RAM = rapid assessment methodology; MBGI = silvo pastoral or forest management with integrated livestock.

The addition of organic and inorganic amendments can improve soil structure and reduce soil compaction. In this context, this study aimed to evaluate whether the application of amendments reduces penetration resistance (PR) in the short term and describe the spatial variability of PR in the surface horizon of an Aquic Argiudoll under no-tillage in northeast Argentina. Four treatments, consisting of surface applications of 7.5 Mg ha−1 poultry litter (PL), 3.0 Mg ha−1 gypsum (G), the combination of PL+G, and untreated control (T), were arranged in a complete randomized block design with three replications. Two more treatments were added to the experiment 12 months later, consisting of PL reapplications on half of the surface of the PL+G and PL treatments (PL+G+PL and PL+PL, respectively) in a split-plot design with three replications in 4×20-m plots. PR was determined in the field with an Eijkelkamp penetrologger following a 2-m long transect perpendicular to the sowing direction at 10 different spots separated 0.2 m from each other. The spatial variability was quantified for each treatment using semivariograms. The highest PR was observed in the T treatment (1.96 MPa) and the lowest PR in PL+G+PL (0.21 MPa). All treatments showed a high spatial dependence (94.9 to 99.9%). Treatments with PL reapplication (PL+PL and PL+G+PL) showed profiles with lower PR and more homogeneous kriging maps. PL reapplication on PL treatments showed no effects on PR values. However, PL reapplication on the PL+G treatment led to positive effects in all PR ranges. Thus, the PL+G+PL treatment, which had the highest PR values, showed a decrease in PR from 54.17 to 6.65% with the reapplication 12 months later. The addition of organic and inorganic amendments reduced specific compacted soil areas on the surface horizon of an Aquic Argiudoll under no-tillage.

Land use changes have led to the degradation of multiple ecosystem services and affected the quality of aquatic ecosystems. The aims of this study were (i) to assess the expansion of the agricultural border over the native forest of an Argentinean stream basin and (ii) to characterize the surface water quality, considering physicochemical parameters, and pesticide concentrations. The agricultural frontier expansion was estimated through the analysis of satellite image coverage. Samples of surface water were taken bimonthly for 2 years. The native forest cover decreased from 72% in 1987 to 60% in 2017 due to the sustained increase in agricultural activities. In surface water, the concentrations of cations decreased: Na > Ca > K > Mg, whereas those of anions decreased: HCO₃ > > Cl > SO₄ > PO₄. The 84 surface water samples analyzed revealed 25 pesticides, including herbicides (44%), insecticides (28%), and fungicides (28%). Herbicides were detected in more than 60% of the samples. 2,4-D, atrazine, cyproconazole, diazinon, glyphosate, AMPA, and metolachlor were detected in all the study sites and sometimes, 2,4-D, atrazine, dicamba, and metolachlor concentrations exceeded the guideline levels. The high sampling frequency of this study and the two annual cycles of crops in the basin enabled sensing of pesticide molecules and concentrations that had not been previously detected, indicating diffuse contamination. These findings signal an emergent challenge on the Espinal agro-ecosystem integrity due to changes in land use.

Se estimó el carbono (C) almacenado en la biomasa aérea de bosques nativos del Espinal (Distrito del Ñandubay, provincia de Entre Ríos, Argentina) y la reducción de emisiones de CO2 por deforestación evitada. Se utilizó la información reportada en el Primer Inventario Nacional de Bosques Nativos del año 2007. Los bosques del área evaluada almacenaban a 2007 un total de 54.48 Tg C, con un promedio de 38.82 Mg.ha-1. En un escenario de deforestación cero a partir del año 2020 se lograría una reducción de emisiones del orden de 17.7 Tg CO2 para el 2030, que representa un 3.7% de la meta nacional propuesta por Argentina de no superar, al año 2030, la emisión neta de 483 Tg CO2 (Contribución Nacionalmente Determinada). La conservación de los bosques del Espinal constituye, además, un mecanismo de gran potencial para generar y comercializar créditos de C según los estándares del mecanismo REDD+.

Mollisols are a fundamental component of global agricultural production. In the Argentine Pampas region, 65% of the Mollisols belong to Argiudoll great group. These soils have an agricultural aptitude, with limitations given mainly by varying thickness of the top horizon A as a result of the severity of water erosion depending on its site in the landscape layered on an argillic B horizon. Over the last three decades, Pampean agriculture has been widespread because of a modern technological matrix characterized by transgenic crops, and increasing use of fertilizers and pesticides. Large changes have taken place in crop sequence composition, toward the disappearance of pastures and the rapid expansion of soybean monoculture due to the upward trend of the international price of this commodity. This review contributes to an alertness regarding the significance of the soil degradation problem, in terms of decline in soil fertility and structural condition, decrease in size of soil aggregates, surface and subsurface compaction, decrease in organic carbon content, soil and water contamination, reduction of infiltration rate and structure stability, causing an increase in water losses through surface runoff and water erosion and lost ecosystem services. Additionally, a set of sustainable land management practices and legal aspects is shown.

The widespread degradation of the structure of silty soils under no‐till systems ( NT ) that has been observed in recent years is characterized by the presence of a Platy structure (P) near the soil surface. Under these conditions, addition of organic and inorganic amendments could have beneficial effects on soil physical properties. We assessed structural regeneration following addition of amendments in an Argiudoll of Paraná, Argentina. Poultry litter ( PL ) and gypsum (G) were applied, providing an organic and inorganic amendment, respectively. Four treatments were tested: PL (7.5 Mg ha ⁻¹ ), G (3 Mg ha ⁻¹ ), the combination of PL +G (7.5 + 3 Mg ha ⁻¹ ), and control (T) with no amendment. Description and quantification of the structural state of the soil profile was made using a Visual Soil Evaluation method: “Le profil cultural”. Aggregate stability, bulk density, total porosity, pore size distribution and soil shear strength for each soil structure and soil organic carbon ( SOC ) were determined at two depths. Twenty months after the amendment applications, both PL and PL +G treatments led to a significant increase of SOC in the upper 5 cm of soil. The proportion of Gamma (Γ) structure increased and P declined under PL and PL +G compared with G and T inn the A horizon. Treatments G and PL +G contributed to an increase in average diameter of aggregates in Γ only. The use of PL amendment alone or in combination with G could be a promising strategy to regenerate, in the short term, the degraded soil structure under NT .