Soil organic carbon (SOC) stocks play an important role in ecosystem functioning and climate regulation. These stocks are declining in many tropical dry forests due to land-use change and degradation. Data on topsoil (0–300 mm) organic C stocks from six experiments conducted in the Dry Chaco region, the world’s largest dry tropical forest, were used to test the predictive performance of the Rothamsted Carbon Model (RothC) after its implementation in an object-oriented graphical programming language. RothC provided promising predictions (i.e., precise and accurate) of the SOC stocks under two representative land covers in the region, native forest and Rhodes grass [relative prediction error (RPE) < 10%, concordance correlation coefficient (CCC) > 0.9, modelling efficiency (MEF) > 0.7]. Comparatively, model predictions of the SOC stocks under degraded Rhodes grass swards were suboptimal. The predictions were sensitive to C inputs; under native forests and Rhodes grass, a high C input improved the predictive performance of the model by reducing the mean bias and increasing the MEF values, compared with mean and low C inputs. Larger datasets and revisiting some of the underlying assumptions in the SOC modelling will be required to improve the model’s performance, particularly under the degraded Rhodes grass land cover.

Ruminant production in the Chaco region relies on pastures and native forest foliage, whose nutritional value is poorly characterized and may be influenced by tannins. This study evaluated the in situ digestibility and in vitro ruminal fermentation of foliage from Prosopis affinis (PA), Prosopis nigra (PN), Acacia polyphylla (AP), Phyllostylon rhamnoides (PR), and Tabebuia nodosa (TN), incubated with or without polyethylene glycol (PEG) to assess the effects of tannin on gas production and nitrogen (N) compounds degradability. Foliage contained ≥17% crude protein (CP) and ≥40% fiber-bound N. Tannin concentration was >4% dry matter (DM) in PN and PA and <1% DM in PR, AP, and TN. In situ digestibility was ≤51% in all species except PR (73%; p < 0.05). Gas production was higher in PA, PR, and TN (p < 0.05), with no PEG effect. Methane production was not affected by tree species or PEG (p ≤ 0.277). Both species and PEG affected the effective N compounds degradability (END), with PEG increasing it in PN and AP (p < 0.05). Although foliage is high in CP, its digestibility is low; N is largely fiber-bound, and tannins may further limit END, factors to consider when including them in ruminant diets.

Ruminant production in the Chaco region relies mainly on pastures and naturally available foliage from native forests. However, the nutritional value of this foliage remains poorly characterized and may be affected by tannins. This study evaluated the nutritional value, and tannin effects on in vitro ruminal fermentation of foliage from tree species of the Chaco region: Prosopis affinis (PA), Prosopis nigra (PN), Acacia polyphylla (AP), Phyllostylon rhamnoides (PR), and Tabebuia nodosa (TN). Samples were incubated with or without polyethylene glycol (PEG) to assess tannin effects on gas production and nitrogen (N) degradability. All species were high in crude protein (CP; ≥17% DM). Tannin content was high in PN and PA (>4% DM), and low (<1% DM) in PR, AP, and TN. In situ digestibility was low (≤51%) in all species except PR (73%; p < 0.05). Gas production was higher in PA, PR, and TN (p < 0.05), with no PEG effect. Both species and PEG affected the effective N degradability, with PEG significantly increasing it in PN and AP (p < 0.05). Although foliages are high in CP, their digestibility is generally low, much of the N is fiber-bound, and tannins may further limit N degradability.

Pastures in the Mediterranean region are vital for sustaining local agriculture and preserving biodiversity. When well-managed, these pastures enhance soil structure and fertility, reduce erosion, and improve water retention. These functions are especially critical in a climate marked by hot, dry summers and mild, wet winters. Moreover, these systems play a key role in carbon sequestration, contributing significantly to climate change mitigation. Mediterranean pastures also support the conservation of endemic plant species and provide essential habitats for a variety of wildlife. Quinta do Freixo (Algarve, Portugal) with an area around 800 hectares, is dedicated to sustainable agriculture and promotes ecological, economic and social sustainability. In addition to organic agriculture production, the farm also produces value-added food products and offers rural tourism experiences. On this farm, a dense shrubland of rockrose (Cistus ladanifer L.) is converted into pastures using a holistic method that includes mechanical cutting of the shrubs, spreading hay and grazing with Campaniça sheep under a regenerative rotational grazing (RRG) system. As a part of the project named “Revitalgarve: Revitalization of rural areas” (PRR-C05-i03-I-000237), these restored pastures are regularly monitored. Assessments included measurements of dry matter production and floristic composition. In addition, both the pastures and Cistus ladanifer shrublands were evaluated for the nutritional value and mineral composition of their foliage material. This approach has contributed to the development of species-rich pastures, rich in legumes and grasses and characterized by high protein content, excellent digestibility, and a well-balanced mineral composition. Although Cistus ladanifer had a relatively lower nutritional value due to its lower protein content and digestibility, the analysis showed that its aerial parts can serve as a supplementary feed resource, especially in periods of forage scarcity, contributing to overall feed availability in extensive grazing systems.The control of shrublands through this practice maintains biodiversity and reduces the risk of wildfires by effectively managing fuel loads.

In the Argentinean Chaco region, deforestation continues to be the main way to achieve higher production but at the expense of carbon, biodiversity, and other losses. We evaluated potential trends of selected productive and environmental indicators of agroforestry systems in the region, specifically, a Forest management integrated with livestock system (MBGI; a combination of land-sharing and land-sparing strategies) and a Livestock management on pastures plus forest reserves system (MGP + B; forest reserve areas on 70, 50, and 30% of the farm; land-sparing strategies). Trade-offs and synergies between indicators and the influence of rainfall regimes were also explored. Using system dynamics methodology, we partially developed and integrated a beef cattle model, a soil organic carbon model and a native forest carbon dynamic model to represent typical beef cattle systems in the region. Greenhouse gas (GHG) emissions and GHG balance, organic carbon stocks, and land area required per unit of animal production varied across agroforestry systems (MBGI and MGP + B systems) and ecoregions (Dry and Wet Chaco). Under the current modelling conditions, our simulation results show that no single system simultaneously maximized all productive indicators while minimizing all environmental impacts over the long term. Nevertheless, MBGI, MGP + B70, and MGP + B50 consistently showed a more favorable balance between productive and environmental outcomes across the indicators evaluated. More specifically, the MGP + B70 and MGP + B50 systems were identified as promising alternatives for cow-calf farms and native forest. Forest management integrated with livestock and the livestock management of pastures with forest reserves in at least 50% of the farm area could be key systems and strategies to balance food production and carbon conservation in the Argentinean Chaco region.