Silvopastoral Systems Research Articles

Nutrient Characterization and Mineral Composition of Aruana in a Silvopastoral System with Nitrogen Fertilization

The objective was to characterize the nutrient and mineral composition of M. maximus cv Aruana grazed by lambs in a silvopastoral system or full sun with added nitrogen. The treatments are: (1) Aruana grazed in full sun with nitrogen fertilization, (2) Aruana grazed in full sun without nitrogen fertilization, (3) Aruana grazed in a silvopastoral system with nitrogen fertilization and (4) Aruana grazed in a silvopastoral system without nitrogen fertilization. The nutrient dynamics, urinary excretion of N and the amount returned of the nutrient were determined from four sheep in a Latin square experimental design; the analysis of the mineral composition of the leaves and stalks of the grass was carried out by collecting samples from the plots used, totaling six in each treatment evaluated. The silvopastoral system provided high levels of P and K in forage plants. Urinary N excretion and urine mineral contents were influenced by the systems evaluated and the use of N fertilizer. N did not show differences for leaves and canes.

Farmers’ preferences and willingness to incorporate silvopastoral systems in Uruguay

Farmers’ preferences and willingness to incorporate silvopastoral systems in Uruguay

Sistema de silvipastoril com alta densidade de árvores acelera a degradação de capim tropical

ABSTRACT Tree density is an important aspect in silvopastoral system (SPS) planning, since low luminosity can limit forage perenniality, especially for tropical forages of C4 metabolism. The objective with this study was to verify if an SPS with high tree density accelerates the pasture degradation process and changes the forage chemical composition. The experiment was carried out by comparison of marandu palisade grass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster] pasture in two systems: silvopastoral and open pasture. In the SPS, teak (Tectona grandis) was planted with a density of 750 trees ha-1. Evaluations were carried out over three years (2015, 2016 and 2017). SPS shading reduced herbage mass, tiller density and soil cover over the years. In the marandu palisade grass in the SPS there was a greater stem proportion, which favoured lesser potential digestible dry matter in the first year. Even with a higher amount of stem, higher crude protein concentration and minerals were observed in the SPS. Due to the high density of trees, excessive shading accelerated the process of degradation of the pasture, which demonstrates that planning of the spatial arrangement of tree species is crucial.

Occurrence and diversity of arbuscular mycorrhizal fungi in yerba mate (Ilex paraguariensis - Aquifoliaceae) cultivation environments.

Yerba mate (Ilex paraguariensis) represents a culture of economic, social, and ecological importance for the cultivation regions. Due to the chemical, physical, and biological variations that occur in the different soils where yerba mate is economically exploited, the symbiotic associations with arbuscular mycorrhizal fungi (AMF) guarantee the plant's ability to absorb nutrients. The purpose of this study was to identify and quantify the occurrence of arbuscular mycorrhizal fungi in different environments of yerba mate cultivation. The research was performed in four areas located in the rural area of the municipality of Seberi/RS: Environment with production of yerba mate in the conventional system, silvopastoral system, organic system, and native forest. The normality of residuals and homogeneity of variances assumptions were verified using the Lilliefors and Chi-square tests and the averages compared by the Tukey's test at 5% probability of error. In addition to calculations of diversity, equivalent species, and evenness indices. The presence of AMF spores showed a direct relationship with the phosphorus (P) availability in each treatment, with a count reduction in the organic system, with P content lower than 3 mg kg-1 of soil. The species with the highest predominance were the Acaulosporaceae (Acaulospora colombiana, A. delicata, and A. tuberculata), followed by the Glomaceae (Glomus ambisporum and Glomus pansihalos) in the conventional and silvopastoral systems. The silvopastoral and conventional systems showed the highest levels of Shannon-Weaver diversity (H') and Pielou's evenness, demonstrating greater diversity and consequently greater richness and uniformity.

Viabilidade econômica de um sistema silvipastoril com e sem a inclusão de crédito de carbono

ABSTRACT This study analyzes the economic viability of exotic and native caatinga forest species grown in silvopastoral systems, combined with the Guinea grass forage crop, compared to monoculture forestry systems, using carbon credits as an alternative source of extra income, aiming for an economic return on the sale of standing timber for firewood production. The experiment was conducted at the Experimental Station of the Pernambuco Agricultural Research Institute (IPA) in Belém do São Francisco, located in the semi-arid region of the state of Pernambuco, in the Itaparica micro region. Four tree crops were chosen, two of which are native to the Caatinga biome: Angico (Anadenanthera colubrina var. Cebil) and Aroeira (Myracrodruon urundeuva Allemão), and two exotic eucalyptus clones, E. urophylla x E. tereticornis. Guinea grass (Panicum maximum Jacq) was chosen as the forage. The intercropping of Guinea grass with the two eucalyptus clones proved to be economically viable in all the economic parameters analyzed, and this is the most suitable for marketing standing wood for firewood production. It is not economically advisable to sell the standing wood for firewood production in the monoculture and silvopastoral systems with the native species (Angico and Aroeira) at 96 months of age due to the system's economic unfeasibility. By adding the possibility of financial credit through the atmospheric carbon sequestered by the trees, it is possible to make all the costs of forestry crops in silvopastoral and monoculture systems economically viable.

Capim marandu sob diferimento em monocultivo e sistema silvipastoril: composição bromatológica e mineral

Abstract This study aimed to evaluate the chemical and mineral characteristics of Marandu grass under stockpiling in monoculture (MC) and a silvopastoral system (SPS) with 12- (SPS12) and 18-m (SPS18) spacing between tree rows. The experimental design consisted of randomized blocks, in which each system was allocated individually. Each treatment was formed in the center of each plot in a 3 × 4 factorial arrangement consisting of three systems (MC and SPS12 and SPS18 between the tree rows) and four stockpiling periods (60, 90, 120, and 150 days), totaling 12 treatments with three replications. No interaction effect was observed between the factors (p>0.05) for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg). The CP content decreased with increasing stockpiling days but met the suggested requirement for ruminants up to 75 days. The NDF and ADF concentrations increased, while P and K contents decreased with increasing stockpiling days. Magnesium and Ca concentrations did not differ with stockpiling days. However, a difference was observed only for Mg relative to the evaluated systems, which was higher in MC and SPS12, differing from SPS18. The spacing adopted in the SPS of 12 and 18 m does not negatively influence the nutritional value of the forage plant. The 75-day stockpiling period from March favored the concentration of macronutrients and CP content in Marandu grass in both MC and SPS.

Relações entre o espaçamento arbóreo e características do campo nativo em sistemas silvipastoris no bioma Pampa

ABSTRACT: The current study assessed the association of eucalyptus-tree spacing with forest growth and yield, as well as with the floristic composition, diversity and yield of natural grassland grown in silvopastoral systems in Pampa biome. Data were collected in six family cattle-ranching area in Bagé County (RS). The effect of two different genetic materials (seminal-origin Eucalyptus dunnii plant and one Eucalyptus grandis clone) on shading features of plants grown in 3 planting-spacing dimensions(625, 312 and 208 trees ha-1) was assessed, as well as their association with herbaceous extract (bare soil; green cover; forage dry matter; floristic composition; species richness; and grass, legumes and winter - and summer-growth species rates) and forestry (litter accumulation, diameter at breast height, total height and volume per hectare) variables. Planting carried out at the highest tree density (625 trees ha-1) has increased forest yield. However, it reduced green cover, herbaceous extract dry-matter yield and species richness, mainly in grasses and legumeswith greater forage potential. Conversely, it is possible combining forestry and animal yield to the preservation of native forage species at low tree densities (204 to 312 trees ha-1).

Marandu grass under deferment in monoculture and silvopastoral system: chemical and mineral composition

Resumo O objetivo deste trabalho foi avaliar as características bromatológicas e minerais do capim Marandu sob diferimento em monocultivo (MC) e em sistema silvipastoril (SSP) com 12 (SSP12) e 18 m (SSP18). O delineamento experimental foi em blocos ao acaso, onde cada sistema foi alocado individualmente. No centro de cada parcela formou-se cada tratamento em fatorial de 3 × 4, composto por três sistemas (MC e SSP12 e SSP18 entre as fileiras das árvores) e quatro períodos de diferimento (60, 90, 120 e 150 dias), perfazendo doze tratamentos com três repetições. Não houve efeito de interação entre os fatores (p>0,05) para proteína bruta (PB), fibra em detergente ácido (FDA), fibra em detergente neutro (FDN), fósforo (P), potássio (K), cálcio (Ca) e magnésio ( Mg). O teor de PB diminuiu com o incremento nos dias de diferimento, mas até os 75 dias atendeu a demanda sugerida para ruminantes. As concentrações de FDN e FDA aumentaram, enquanto os teores de P e K diminuíram com o incremento nos dias de diferimento. A concentração de Mg e Ca não diferiu com os dias de diferimento. No entanto, em relação aos sistemas avaliados houve diferença apenas para Mg, que foi maior em MC e SPS12, diferindo de SPS18. O espaçamento adotado no SSP de 12 e 18m não influencia negativamente o valor nutricional da planta forrageira. O período de diferimento de 75 dias a partir de março favoreceu a concentração de macronutrientes e o teor de PB no capim marandu tanto em MC quanto nos SSP.

Governance for Mediterranean Silvopastoral Systems – a new book on the Spanish dehesas and the Portuguese montados

Governance for Mediterranean Silvopastoral Systems – a new book on the Spanish dehesas and the Portuguese montados

La mercantilización de la naturaleza en áreas naturales protegidas mexicanas. Caso Sierra de Huautla, Morelos

The commodification of nature (MN) is the expression of the penetration of the capitalist model in biodiversity. This essay seeks a contextualization of the Latin American MN and in the protected natural areas (ANP) in Mexico. The analysis focused on the discourse and concept of sustainability, the conservation policy and its implementation from the environmental management units (UMA) in the ANPs. It was found that this business model was successful on private properties and was counterproductive on collective properties. The problem that the ANPs experience with respect to the business model is because they are communities that live in collective properties, the economic income, the environmental impacts and the strict implementation of the laws, affect local actors to a greater extent. It is concluded that the MN can be countered with a bottom-up approach where traditional knowledge is a factor to empower the actors and defend them before other global processes, and revalue hunting as a space for coexistence, reinforcement of cultural identity and obtaining of food and not as a commercial practice, in addition to the use of the silvopastoral system and the use of non-timber forest product

Exploring dynamics of floristic composition in Mediterranean grasslands: a case study from Sardinia, Italy

Mediterranean grasslands stand out as biodiversity hotspots due to their inclusion of diverse habitats that foster a remarkable range of biological diversity, characterized by inter-annual variability of floristic composition. This study aims to assess the inter-annual dynamics of the floristic composition in a grassland within a typical silvopastoral system in the Mediterranean basin, within the framework of rainfall variability. The study was performed on a farm representative of Mediterranean silvopastoral systems in Central-Western Sardinia (Italy). Vegetation surveys started in the spring of 2018 and concluded in the spring of 2022. They were conducted annually in the spring (S) and winter (W) seasons, using the point quadrat method along eight permanent transects. The dynamics of floristic composition were compared within and between years in terms of variability of specific percentage contribution (CSP) of each plant species. The results highlighted substantial differences in the composition of plant assemblages between the two seasons (W vs S) and between surveys within each season for all a posteriori comparisons. Anthemis arvensis, Lolium rigidum, Festuca ligustica and Medicago polymorpha were the main discriminating plant species between seasons. Considering the discriminant species between the four winter surveys, we found a positive effect of August rain on Cynodon dactylonCSP and a negative one on Trifolium subterraneumCSP. Considering the spring surveys, we found a positive effect of January rain on L. rigidum and a negative effect on Plantago lanceolata. The rain affected the inter-annual dynamics of floristic composition in the Mediterranean grasslands. Other factors, such as temperature, remain to be investigated. Moreover, a more extended data series may allow us to strengthen our results.

Agroforestry supports high bird diversity in European farmland

Intensification and homogenization of agricultural landscapes have led to a strong decline in European farmland birds. Agroforestry systems, which were widespread in the past, are regaining attention as they could return structural heterogeneity to agricultural landscapes. However, few studies focus on the effects of such systems on biodiversity and especially bird diversity. We hypothesized that agroforestry systems host a higher alpha and beta diversity of birds compared to open agriculture as well as distinct bird communities. Moreover, we expected that bird communities in temperate Europe and the Mediterranean are differently affected by agroforestry systems. In this study, we assessed breeding bird diversity via audio recordings in nineteen mature agroforestry plots, comprising both silvoarable and silvopastoral systems distributed across seven countries in temperate and Mediterranean Europe. For comparison, bird diversity was also assessed in nearby open agricultural land, forests, and orchards. Bird species richness in agroforestry was more than doubled compared to open agricultural land and similar to the diversity found in forests and orchards. Community composition and within-habitat beta diversity differed between the habitat types and between European regions. While temperate agroforestry systems hosted generalist and woody habitat species, bird communities in Mediterranean agroforestry were composed of species from both open and woody habitats. Beta diversity was significantly higher in agroforestry than in open agriculture in temperate systems but not in the Mediterranean. Our study demonstrates that agroforestry systems represent a valuable habitat for breeding birds in European agricultural landscapes. A wider adoption of these systems could thus contribute to halting and reversing the decline in bird diversity, especially in temperate agricultural landscapes.

Forage productivity and carbon storage from based Hardwickia binatasilvopasture systems in semi arid rainfed conditions

A study was conducted from 2018 to 2022 on ten year old based silvopasture system at Hardwickia binataIndian Grassland and Fodder Research Institute, Jhansi. The treatment consisted of establishment of three types of grasses and in association with viz. Cenchrus ciliaris, Chrysopogon fulvusPanicum maximumH. binataH. binataC. fulvus and three pruning intensities of 30%, 45% and 60%. Establishment of viz.in association with recorded significantly higher dry pasture yield (7.91- 8.93 t/ha) as compared to H. binata P. maximumC. ciliaris (6.19-7.08 t/ha) and it was found at par with (7.62-8.70 t/ha) during 1 to . In st4 yearsthpruning, 60% canopy pruning of recorded significantly higher pasture yield (7.99, 8.40 and 8.99 t/ha) H. binataas compared to 30% canopy pruning (7.19, 7.27 and 7.38 t/ha) and 45% canopy pruning (7.67, 7.95 and 8.33 t/ha). Organic carbon content (0.646%) was significantly increased with during respectively2 , 3 and 4 yearsndrdthC. fulvusP. maximumC. ciliaris as compared to (0.591%) and it was found at par with (0.627%) in 4 year of thstudy. Available nitrogen (260.60 kg/ha), phosphorus (9.36 kg/ha), potash (238.70 kg/ha) and organic carbon (0.663%) were also significantly increased with 30% canopy pruning as compared to 60% canopy of H. binatapruning in . recorded 79.90% higher carbon stock in 4 year of study (19.61 t/ha) as compared 4 yearthH. binatathto initial year. Total carbon stock of the system was maximum with in association with (39.29 C. fulvus H. binata and 50.73 t/ha) closely followed by (38.51 and 50.30 t/ha) and (36.20 and 46.68 t/ha) C. ciliaris P. maximum during . recorded significantly 1 Among pruning, 30% canopy pruning of stand 4 years respectivelythH. binata higher total carbon stock during of the system (50.82 t/ha) as compared to 60% canopy pruning (47.42 t/ha)4 thyear.of study

The influence of the silvopastoral system on physiological, behavior, and health responses of the Purunã breed of cattle

Os sistemas pecuários sustentáveis devem proporcionar elevados rendimentos de produção, respeitando simultaneamente o bem-estar animal. O sistema silvipastoril (SPS: silvipastoril – árvores, pasto e gado) oferece uma estratégia de gestão de gado mais holística. O SPS incorpora árvores, forragem e proteção dos animais durante o pastoreio. No entanto, a relação entre os indicadores comportamentais dos animais no SPS tem sido pouco estudada em condições subtropicais. Um estudo preliminar foi realizado para investigar o efeito do SPS nas respostas fisiológicas, comportamentais e de saúde durante um ciclo de pastejo do Purunãgado. Trinta novilhas foram distribuídas aleatoriamente em dois grupos de 15 animais, mantidos no SPS ou em sistema de monocultivo (PAS: pastoril – gado a pasto). O peso corporal e a temperatura da superfície corporal, o tempo de pastejo e o comportamento de repouso foram avaliados para ambos os sistemas durante o final do outono (40 dias) em uma região subtropical úmida do Brasil. Os dados mostraram influência estatisticamente significativa do SPS na redução da temperatura média da superfície corporal das novilhas, de 27,7oC para 30,3oC no PAS (P = 0,02). Embora tenha havido um efeito importante do SPS na diminuição do comportamento alimentar (4,77 eventos/1,5 h), em comparação com animais mantidos no PAS (6,21 eventos/1,5 h), as diferenças na disponibilidade de forragem podem ter desempenhado um papel importantenos animais mantidos no SPS. Os animais no SPS apresentaram estatisticamente significativamente menos eventos de consumo de álcool (P = 0,0001), maior declínio no escore de condição corporal (ECC) (P = 0,02) e no escore parasita (P = 0,009), do que os animais mantidos no PAS . Houve distribuição agregada de carrapatos e os animais infestados perderam significativamente mais peso (P = 0,027) do que os não infestados do mesmo grupo (SPS). Mais estudos são necessários para compreender melhor a influência de múltiplos fatores no comportamento e na saúde dos Purunã , especialmente quando se consideram sistemas agrícolas distintos, disponibilidade de forragem, condições geográficas e climáticas e o impacto dos ectoparasitas em animais individuais .

Silvopastoral management for lowering trade-offs between beef production and carbon storage in tropical dry woodlands

Tropical dry woodlands and savannas harbour high levels of biodiversity and carbon, but are also important regions for agricultural production. This generates trade-offs between agriculture and the environment, as agricultural expansion and intensification typically involve the removal of natural woody vegetation. Cattle ranching is an expanding land use in many of these regions, but how different forms of ranching mediate the production/environment trade-off remains weakly understood. Here, we focus on the Argentine Chaco, to evaluate trade-offs between beef production and carbon storage in grazing systems with different levels of woody cover (n = 27). We measured beef productivity and carbon storage during 2018/19 and used a regression framework to quantify the trade-off between both, and to analyze which agroclimatic and management variables explain the observed trade-off. Our main finding was that silvopastures had the lowest trade-off between beef production and carbon storage, as management in these systems seeks to increase herbaceous forage by removing shrubs, while maintaining most of the bigger trees that contain most above-ground carbon. The most important variable explaining the beef production/carbon storage trade-off was pasture management, specifically the number of shrub encroachment control interventions, with a lower trade-off for higher numbers of interventions. Unfortunately, more interventions can also result in woody cover degradation over time, and shrub encroachment management must therefore be improved to become sustainable. Overall, our study highlights the strong environmental trade-offs associated with beef production in dry woodlands and savanna, but also the key role of good management practices in lowering this trade-off. Specifically, silvopastoral systems can increase beef production as much as converting woodlands to tree-less pastures, but silvopastures retain much more carbon in aboveground vegetation. Silvopastoral systems thus represent a promising land-use option to lower production/environment trade-offs in the Dry Chaco and likely many other tropical dry woodlands and savannas.

Long-term relationships of beef and dairy cattle and greenhouse gas emissions: Application of co-integrated panel models for Latin America

The cattle sector plays a pivotal role in the economies of numerous Latin American and Caribbean countries. However, it also exerts a significant impact on environmental degradation, including substantial contributions to greenhouse gas emissions (accounting for 23.5 % of global livestock emissions) and deforestation (70 % attributed to livestock in South America). This article aims to investigate the complex, long-term, and short-term relationships between population growth, pastureland expansion, deforestation, and the cattle sector in 15 countries across the region, focusing on their effects on greenhouse gas emissions as well as beef and dairy production. Utilizing data from FAOSTAT spanning the period from 1990 to 2019, a cointegrated panel model was developed using the Pooled Mean Group technique, resulting in the estimation of six models. The aggregate-level results for the region reveal the presence of relatively stable long-term relationships. This implies that over time, the influence of population growth, pastureland expansion, and deforestation on greenhouse gas emissions from cattle production tends to diminish in significance. This long-term behavior may be particularly pronounced in countries with more developed cattle sectors, where efforts to mitigate the environmental impacts of cattle production, such as promoting improved forage technologies, silvo-pastoral systems, grazing management practices, and the implementation of policies, regulatory frameworks, and incentives, have gained traction. These progressive countries can serve as regional benchmarks, and the lessons they have learned hold valuable insights for the sustainable intensification of cattle production in countries with less-developed cattle sectors.

Agroforestry enhances biological activity, diversity and soil-based ecosystem functions in mountain agroecosystems of Latin America: A meta-analysis.

Mountain agroecosystems in Latin America provide multiple ecosystem functions (EFs) and products from global to local scales, particularly for the rural communities who depend on them. Agroforestry has been proposed as a climate-smart farming strategy throughout much of the region to help conserve biodiversity and enhance multiple EFs, especially in mountainous regions. However, large-scale synthesis on the potential of agroforestry across Latin America is lacking. To understand the potential impacts of agroforestry at the continental level, we conducted a meta-analysis examining the effects of agroforestry on biological activity and diversity (BIAD) and multiple EFs across mountain agroecosystems of Latin America. A total of 78 studies were selected based on a formalized literature search in the Web of Science. We analysed differences between (i) silvoarable systems versus cropland, (ii) silvopastoral systems versus pastureland, and (iii) agroforestry versus forest systems, based on response ratios. Response ratios were further used to understand how climate type, precipitation and soil properties (texture) influence key EFs (carbon sequestration, nutrient provision, erosion control, yield production) and BIAD in agroforestry systems. Results revealed that BIAD and EFs related to carbon sequestration and nutrient provisioning were generally higher in agroforestry systems (silvopastoral and silvoarable) compared to croplands and pasturelands without trees. However, the impacts of agroforestry systems on crop yields varied depending on the system considered (i.e., coffee vs. cereals), while forest systems generally provided greater levels of BIAD and EFs than agroforestry systems. Further analysis demonstrated that the impacts of agroforestry systems on BIAD and EFs depend greatly on climate type, soil, and precipitation. For example, silvoarable systems appear to generate the greatest benefits in arid or tropical climates, on sandier soils, and under lower precipitation regimes. Overall, our findings highlight the widespread potential of agroforestry systems to BIAD and multiple EFs across montane regions of Latin America.

Tree growth as an effect indicator of silvopastoral systems in the low hilly area of western Henan province, China

The low hilly area is a major landform in the west of Henan province, China, and it is suffering soil and water loss because of human activities. The silvopastoral system that combines trees and grasses has been widely used to restore this fragile area. We conducted in situ field experiments in 2011 in the low hilly area of Henan province involving pure forests of Populus simonii (PS; Salicaceae), Platycladus orientalis (PO; Cupressaceae), Quercusvariabilis (QV; Fagaceae), and Robinia pseudoacacia (RP; Fabaceae), and also with each forest tree species being combined with Medicago sativa (MS; Fabaceae) as silvopastoral systems, i.e., PS-MS, PO-MS, QV-MS, and RP-MS, respectively. We recorded tree diameter at breast height (DBH) and tree height (TH) in the years 2014–2016, 2018, 2020, and 2022 for all the different vegetation types. Tree biomass load (TBL, i.e., tree biomass per unit area) was estimated based on DBH and TH using allometric equations for each tree species. Generally, the results showed that the DBH, TH, and TBL were promoted in the silvopastoral systems PS-MS, PO-MS, and QV-MS. Specially, the DBH and TBL of PS-MS and PO-MS tended to be higher and were significantly higher than the pure forests of PS and MS, respectively, in 2014–2016; the silvopastoral systems were not significantly different from the pure forests for DBH in 2018 and 2022, and for TBL in 2018 and 2020. TH was lower in PS-MS and PO-MS than that in PS and PO in 2014–2016, while there was no difference of TH between PS-MS and PS in 2018 and 2022, and TH was higher in PO-MS than that in PO in 2018, 2020 and 2022. The DBH, TH, and TBL were all higher in QV-MS than QV. The TBL in RP-MS was non-significant or lower compared to that in RP. Moreover, TBL tended to be lower in upslope positions than downslope in the pure forests, while there was no difference in most silvopastoral systems. In summary, PS and PO may be suggested as the tree species selection in vegetation restoration processes for about five years, QV may be a better alternative for a long term, while RP is not recommended.

Soil fertility in silvopastoral systems integrating tree legumes with signalgrass (Urochloa decumbens Stapf. R. Webster)

Silvopastoral Systems (SPS) can increase overall productivity and generate continuous income in order to stimulate simultaneous growth and development of trees, forage and livestock. Moreover, the SPS with tree legumes would be important for add nutrients to the system, mainly N, and ensure the soil health and quality. Soil properties were assessed in two SPS, implanted in 2011, using tree legumes and Urochloa decumbens Stapf. R. Webster (Signalgrass). Treatments were Signalgrass + Mimosa caesalpiniifolia Benth (Sabia) and Signalgrass + Gliricidia sepium (Jacq.) Kunth ex Walp. (Gliricidia), and they were allocated in a randomized complete block design, with three replications. Soil was sampled in 2013, 2017, and 2018, at 0, 4, and 8 m along transects perpendicular to tree double rows, from 0- to 20- and 20- to 40-cm layers. Soil chemical properties included pH, P, K+, Ca2+, Mg2+, Al3+, H++Al3+, cation exchange capacity (CEC), and base saturation. In addition, light fraction of soil organic matter (LF-SOM), soil basal respiration (SBR), and natural abundance of 13C of the respired CO2 (δ13C-CO2) were analyzed. Soil pH (5.3, 5.2, 5.1), P (11.3, 7.2, 3.6 mg dm-3), and CECeffective (5.8, 5.1, 5.0 cmolc dm-3) decreased (P < 0.05) along the years 2013, 2017, and 2018, respectively. In 2018, the LF-SOM and δ13C-CO2 was greater in Sabia (1.1 g kg-1 and -16.4‰) compared to Gliricidia (0.7 g kg-1 and -18.2‰). Silvopastoral systems reduced soil fertility regardless of the tree legume species used as result of biomass nutrient stock, without maintenance fertilization. Sabia had greater deposition of LF-SOM, without increasing SBR, providing potential for microbial C use efficiency. Enriched C-CO2 isotope composition shows an efficient SOM oxidize in SPS with Gliricidia or Sabia. This information can contribute to the assessments related to CO2 balance and C retention. Both SPS contribute to C sequestration.

Crown segmentation using Airborne Laser Scanning data in a silvopastoral system with Eucalyptus grandis

Airborne Laser Scanning (ALS) remote sensing holds immense potential for characterizing and measuring forest biomass, providing a valuable inventory tool for intensive silviculture to enhance forest management and planning. Accurate estimation of total height (Ht) and crown area (CA) is crucial to model and design silvopastoral systems. The main objective of this study was to estimate Ht and CA accurately using watershed segmentation algorithm in a triple-row silvopastoral system with Eucalyptus grandis, to compare these variables based on the position of the tree in the rows. Edge trees are the most prevalent in a triple row silvopastoral system, making it important to analyze and understand their structural differences from the trees in the interior. The study was conducted in a silvopastoral system in Reboledo, Florida, Uruguay (34° 1'15.16"S, 55° 39'13.75"W). The silvopastoral system consisted of triple rows of Eucalyptus grandis N-S oriented lined with natural pastures in 14-19 m alleys. ALS data was obtained from an area of 26 ha including two silvopastoral stands planted in 2012 (10 years) and 2019 (4 years). From the canopy height model (CHM) a Watershed segmentation algorithm was conducted to obtain individual tree segmentation, yielding Ht and CA of individual trees in both stands. Individual trees were manually classified by position in the triple row as Middle (M), External West (EW) and External East (EE). Our results show data of 1,627 individual trees in the 2019 stand and 1,405 trees in the 2012 stand, EW trees showed the highest CA in the 2019 stand with a 10% difference with M trees and a 9% with EE trees. The 2019 plot showed no significant difference in Ht. In the 2012 stand, EE trees showed the highest CA with a 22% difference from M trees and an 8% with EW, and EW trees showed a 15% higher CA than M tress in the 2012 stand. The 2012 plot showed a 1% significant average difference between Externals and Middle trees and no significant difference between EE and EW trees. Correlation between field data and ALS data in Ht showed R2=0.82, n=45 and p<0.0001 in 2019 plot, and R2=0.67, n=18, and p<0.0001 in the 2012 plot. Watershed segmentation algorithm in combination with ALS remote sensing demonstrated to be an efficient method to estimate CA and Ht in triple-row silvopastoral systems.