Effect of nitrogen fertilization and shading on morphogenesis, structure and leaf anatomy of Megathyrsus maximus genotypes.

The use of exotic grasses of African origin for pastures in Brazil has been a major advancement in livestock production, but little is known about the responses of these grasses to nitrogen fertilizers associated with shading. In this study, the morphogenetic, structural, and leaf anatomical characteristics of Megathyrsus maximus cultivars' Tamani and Quênia were investigated as a function of N dose and shade. Morphogenetic and structural characteristics and leaf anatomy were studied under three shading levels (0, 30, and 50 %) and four N doses (0, 100, 200, and 300 kg N ha-1) to simulate growth in a silvopastoral system. When comparing the cultivars, Quênia was more efficient in terms of phyllochron up to fertilization with 100 kg N ha-1. The leaf senescence rate of Tamani was higher than that of Quênia at the 30 and 50 % shade levels. The total area (TA) occupied by leaf tissues decreased in Quênia as a function of the increase in N fertilization, whereas the TA of Tamani did not change. The thickness of the adaxial epidermis was greater in Quênia (0.68 µm) than in Tamani (0.50 µm) when not fertilized. The area occupied by the mesophyll was greater in both cultivars when they received fertilization equivalent to 300 kg N ha-1. Quênia grass has a smaller phyllochron than Tamani grass, due to the rapid reconstruction of its photosynthetic apparatus, especially when it receives higher levels of nitrogen fertilization. However, Tamani grass has a greater distribution of plant tissues. The mesophyll area is larger in Tamani grass due to the greater presence of chloroplasts, which facilitates digestion by animals. The Tamani modified the leaf anatomical tissues more significantly in relation to shading, whereas the Quênia modified them in relation to N fertilization, which reinforces the suggestion of a more appropriate use of Tamani in silvopastoral systems.

Strategic control of the cattle tick Rhipicephlaus microplus applied to rotational and silvopastoral grazing systems in subtropical areas.

This work evaluated if strategic control based on no more than three or four annual treatments is useful to control Rhipicephalus microplus infestations on cattle when it is applied to intensive rotational grazing and silvopastoral systems with high stocking rates in subtropical areas. In the intensive rotational grazing system, three annual treatments with chemical acaricides were applied on cattle in two different schemes: between spring and early summer and from late winter and late spring. Strategic control based on three treatments with chemical acaricides from late winter to late spring plus an additional fourth treatment in summer was tested in the silvopastoral system. In the intensive rotational grazing systems, the control schemes allow to reach a significant reduction in the tick load on cattle considering a time interval from spring to autumn. However, the efficacy levels were not high enough in some specific moments, namely, the tick counts of summer and autumn (there were not significant differences between treated and control groups). The scheme evaluated in the silvopastoral grazing system yielded better results than those tested for the intensive rotational system, because significant differences in tick load between treated and control groups were observed in all post-treatment counts and when the analysis was performed for the whole study period. However, values of efficacy in the count-by-count comparison were disparate, ranging from 64.1 to 99.7. Although the efficacy values obtained in the silvopastoral system were better than those of the rotational grazing systems, the total tick load on treated cattle in autumn was not low enough (mean abundance values 25.14 and 38.14). Ticks were more evenly distributed among hosts in late summer and autumn than in spring or early summer, where few hosts carry most of the ticks. Some management strategies as intensive rotational systems or silvopastoral structures can lead to a more efficient forage use, but they imply greater tick challenge than in extensive grazing systems. In these situations, the schemes of strategic control bases on three or four annual treatments should be complemented with additional tactical treatments in late summer or autumn.

Pine needle abortions in cattle due to consumption of Pinus ponderosa in Argentina: Case reports.

Two outbreaks of pine needle abortions in cattle are here reported for the first time in Argentina. The cases occurred in Chubut and Neuquén provinces in the Patagonia region, causing 29.6% and 9% of abortions in each herd respectively. In both outbreaks, the dams were in the last third of gestation, and, due to a period of cold, snow and lack of available forage, they gained access to Pinus ponderosa and Pinus contorta forests. No pathological lesions, serological, molecular, or microbiological evidence of infectious causes were observed in any of the six fetuses analyzed. Microhistological analysis of feces confirmed higher presence of fragments of Pinus spp. needles in the diet of affected dams than in that of non-affected ones (12.2 vs 3.0%). Moreover, toxicological analysis showed higher tetrahydroagathic acid in the sera of affected dams than in that of non-affected ones (10.05 vs 2.81 ppm). In addition, this acid was detected in different fetal fluids (3.6-8.1 ppm) of the six fetuses analyzed. Interestingly, isocupressic acid was detected only in needles of P. ponderosa, and its content was lower than that found in other areas of the world (0.31 and 0.5% in Chubut and Neuquén respectively). These results confirm that the consumption of P. ponderosa by dams could have been the cause of these abortion outbreaks, a fact that should be considered as differential diagnosis in abortions of cattle, especially in silvopastoral systems of Argentina.

Microclimate and the thermal comfort during the implementation of silvopastoral systems: the windbreak countereffect.

Little has been studied about microclimate and the thermal comfort during the implementation of silvopastoral systems. This study aimed to evaluate the microclimate and thermal comfort during the implementation of High Biodiversity Silvopastoral System with Nuclei (SPSnu). Three treatments were investigated, SPSnu with 5 and 10% of the pasture area with nuclei, (SPSnu5 and SPSnu10, respectively), and treeless pasture (TLP). Each treatment was subdivided into 4 areas: within the nuclei, around the nuclei, around the nuclei with shade and internuclei. The analyzed variables were soil surface temperature, air temperature, wind speed, relative humidity, black globe temperature and the Heat Load Index (HLI) at 20 and 120 cm height. We hypothesized that the wind speed reduction associated with insufficient shade projection typical of the first years of SPSs may interfere in microclimate and thermal comfort during the hot seasons. SPSnu5 and SPSnu10 had a reduction in wind speed of 51.58% and 68.47% respectively when compared to TLP at 20 cm. Soil surface temperature and air temperature at 120 cm were higher for SPSnu than TLP. The same effect was observed for the HLI. At 20 cm, HLI indicated better thermal comfort in TLP than in the SPSnu treatments. The lack of shade projection from young nuclei in conjunction with the decrease of wind speed between the nuclei caused a higher air temperature and HLI in the SPSnu treatments, we called this conditions, windbreak countereffect. Farmers must knowledge this effect when implementing SPSs, and when necessary, mitigate with the proper management decisions.

Implications of converting native forest areas to agricultural systems on the dynamics of CO2 emission and carbon stock in a Cerrado soil, Brazil.

The conversion of native vegetation to agricultural areas leads to a natural process of carbon loss but these systems can stabilize in terms of carbon dynamics depending on the management and conversion time, presenting potential to both store and stabilize this carbon in the soil, resulting in lower soil respiration rates. In this context, this study aimed to investigate the effect of converting native Cerrado forest areas to agricultural systems with a forest planted with Eucalyptus camaldulensis and silvopastoral systems on the dynamics of CO2 emission and carbon stock at different soil depths. The experimental sites are located in the Midwest of Brazil, in the coordinates 20°22'31″ S and 51°24'12″ W. Were evaluated soil CO2 emission (FCO2), soil organic carbon, the degree of humification of soil organic matter (HLIFS), soil temperature, soil moisture, and soil chemical and physical attributes. The soil of the area is classified as an Oxisol (Haplic Acrustox). Soil samples were collected at depths of 0.00-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.40 m. The lowest FCO2 values were found in the silvopastoral system (1.05 µmol m-2 s-1), followed by the native forest (1.65 µmol m-2 s-1) and the eucalyptus system (1.96 µmol m-2 s-1), indicating a 36% reduction in FCO2 compared to the conversion of the native forest to the silvopastoral system and an increase of 19% when converting the native forest to the eucalyptus system. The soil chemical attributes (N, K+, Ca2+, H++Al3+, CEC, and organic carbon) showed a decrease along the profile. The shallowest depths (0.00-0.10 and 0.10-0.20 m) presented no differences between systems but the subsequent depths (0.20-0.30 and 0.30-0.40 m) had a difference (95% confidence interval), relative to N, Ca2+, H++Al3, CEC, and organic carbon stock (OCS), and the soil under silvopastoral system showed a higher concentration of these attributes than the native forest. The multivariate analysis showed that the eucalyptus and silvopastoral systems did not differ from the forest in the shallowest soil layer but differed from each other. This behavior changed from the second assessed depth (0.10-0.20 m), in which the silvopastoral system stands out, differing both from the eucalyptus system and from the native forest, and this behavior is maintained at the following depths (0.20-0.30 and 0.30-0.40 m). OCS, H++Al3, CEC, and nitrogen are strongly related to land use change for silvopastoral system. Regarding the behavior/relationship of attributes as a function of depth, the silvopastoral system contributed to soil carbon accumulation and stability over consecutive years.

Key points for the thermal comfort of water buffaloes in Eastern Amazon / Pontos-chave do conforto térmico de bubalinos na Amazônia Oriental

This study presented relevant aspects about the Amazonian environment and how it impacts the thermal comfort of domestic buffaloes (Bubalus bubalis) raised in the Eastern Amazon. Furthermore, strategies for monitoring and mitigating animal heat stress are presented, based on research results with the species. Although domestic buffaloes are considered adaptable animals, exposure to intense solar radiation causes thermal discomfort. This condition is expressed in biophysical indicators, in metabolic, endocrine, behavioral responses, and in body thermographic patterns. Therefore, the biometeorological monitoring of production is crucial to support decision-making regarding environmental management strategies, genetic selection of thermotolerant individuals, and increase in animal welfare. Lastly, the use of silvopastoral systems can help to provide higher thermal comfort, which is a condition that directly impacts the productivity of milk and meat buffaloes when they are raised in tropical regions, such as in the Eastern Amazon.

Objetivou-se apresentar aspectos relevantes sobre o ambiente amazônico e como este impacta no conforto térmico de búfalos domésticos (Bubalus bubalis) criados na Amazônia Oriental. Adicionalmente, são apresentadas estratégias para monitoramento e mitigação do estresse térmico animal, a partir de resultados de pesquisa com a espécie. Apesar dos búfalos domésticos serem considerados animais adaptáveis, a exposição à intensa radiação solar provoca desconforto térmico. Essa condição é expressa em indicadores biofísicos, nas respostas metabólicas, endócrinas, comportamentais e nos padrões termográficos corporais. Assim, o monitoramento biometeorológico da produção é crucial para subsidiar tomadas de decisão em relação a estratégias de manejo ambiental, seleção genética de indivíduos termotolerantes e incremento do bem-estar animal. Por fim, o uso de sistemas silvipastoris pode auxiliar na oferta de maior conforto térmico, que é uma condição que impacta diretamente na produtividade de bubalinos de leite e carne, quando estes são criados em regiões tropicais, como na Amazônia Oriental.

Key points for the thermal comfort of water buffaloes in Eastern Amazon / Pontos-chave do conforto térmico de bubalinos na Amazônia Oriental

ABSTRACT: This study presented relevant aspects about the Amazonian environment and how it impacts the thermal comfort of domestic buffaloes (Bubalus bubalis) raised in the Eastern Amazon. Furthermore, strategies for monitoring and mitigating animal heat stress are presented, based on research results with the species. Although domestic buffaloes are considered adaptable animals, exposure to intense solar radiation causes thermal discomfort. This condition is expressed in biophysical indicators, in metabolic, endocrine, behavioral responses, and in body thermographic patterns. Therefore, the biometeorological monitoring of production is crucial to support decision-making regarding environmental management strategies, genetic selection of thermotolerant individuals, and increase in animal welfare. Lastly, the use of silvopastoral systems can help to provide higher thermal comfort, which is a condition that directly impacts the productivity of milk and meat buffaloes when they are raised in tropical regions, such as in the Eastern Amazon.

RESUMO: Objetivou-se apresentar aspectos relevantes sobre o ambiente amazônico e como este impacta no conforto térmico de búfalos domésticos (Bubalus bubalis) criados na Amazônia Oriental. Adicionalmente, são apresentadas estratégias para monitoramento e mitigação do estresse térmico animal, a partir de resultados de pesquisa com a espécie. Apesar dos búfalos domésticos serem considerados animais adaptáveis, a exposição à intensa radiação solar provoca desconforto térmico. Essa condição é expressa em indicadores biofísicos, nas respostas metabólicas, endócrinas, comportamentais e nos padrões termográficos corporais. Assim, o monitoramento biometeorológico da produção é crucial para subsidiar tomadas de decisão em relação a estratégias de manejo ambiental, seleção genética de indivíduos termotolerantes e incremento do bem-estar animal. Por fim, o uso de sistemas silvipastoris pode auxiliar na oferta de maior conforto térmico, que é uma condição que impacta diretamente na produtividade de bubalinos de leite e carne, quando estes são criados em regiões tropicais, como na Amazônia Oriental.

Effect of Tithonia diversifolia (Hemsl.) A. Gray intake on in vivo methane (CH4) emission and milk production in dual-purpose cows in the Colombian Amazonian piedmont.

The inclusion of Tithonia diversifolia in pasture-based diets is a promising alternative to increase bovine productivity, due to its chemical composition and wide adaptation, but there are few in vivo studies to determine its effect on methane yield and animal production in grazing systems. The objective of this study was to determine the effects of the T. diversifolia inclusion in a basal diet of Brachiaria humidicola on methane (CH4) emissions by enteric fermentation, and on milk yield and quality in dual-purpose cows. The polytunnel technique was used for the determination of methane yield and two diets were evaluated (Diet 1: Brachiaria humidicola 100%; Diet 2: T. diversifolia 15% + B. humidicola 85% dry matter basis) in the moderate rainy and rainy seasons using a cross-over experimental design; milk production was measured by daily milk weighing, and milk quality was determined using a LACTOSCAN analyzer. The inclusion of T. diversifolia did not increase the dry matter intake (P = 0.369), but increased the intake of crude protein and minerals, and reduced fiber intake, resulting in the increased yield of milk and its components in the moderate rainy season (P = 0.012). The inclusion of T. diversifolia reduced the absolute CH4 emissions (P = 0.016), Ym and emission intensity (per unit of fat, protein and kilogram fat and protein corrected milk yields) both in the moderate rainy and rainy seasons (P < 0.05). We conclude that the inclusion of T. diversifolia in the forage feed base in the humid tropics such as the Amazon piedmont can be used as a tool to both mitigate enteric CH4 emissions and to increase animal productivity and hence reduce emissions intensity, and thus reduce pressure on the agricultural frontier in critical areas such as the Amazon.

Analyzing influencing factors to scale up agroforestry systems in Colombia: A comparative ex-ante assessment of cacao farming and cattle ranching in two regions.

Agroforestry systems (AFS) are proved to enhance sustainable land management. Thus, there is increasing demand for effective ways to scale up AFS so that more people can benefit. Consequently, this study assesses the scaling-up potential of agroforestry systems (AFS) using cacao farming and cattle ranching in Caquetá and Cesar, Colombia, as examples. An ex-ante assessment using the ScalA tool is conducted through interviews with AFS experts from institutions promoting AFS. Using a comparative approach, results reveal that AFS have different scaling-up potential depending on the type of farming system and location characteristics. In our case, it is slightly higher for cacao farming than for cattle ranching in both regions and it is higher in Caquetá than in Cesar for both systems. Factors hindering the scaling-up potential for both regions are economic conditions at the local and regional levels since there is a lack of stable and differentiated markets to absorb AFS products. In contrast, the scaling-up potential in both regions is increased by the factors related to the capacity of the organizations that promote AFS and the attitudes of local communities toward them. The study generates information about factors that may hinder or foster AFS scaling-up, including not just the capacities and mechanisms to promote them but also the enabling conditions. This contributes to prioritizing AFS interventions and better allocating their resources to increase their chances of successful scaling-up. Supplementary Information: The online version contains supplementary material available at 10.1007/s10457-022-00730-1.

A classification of cultivated pastures in the Brazilian Cerrado for sustainable intensification and savanna restoration.

The Brazilian Cerrado, with over 200 million hectares, has approximately 28% of its area occupied by cultivated pasturelands and 39% of them are degraded. In this study, we propose a new classification of the Cerrado pastures and recommendations for sustainable intensification and savanna restoration. We propose seven classes of pastures based on the ground cover proportions of exotic grass, bare soil, and native vegetation. These lands need to be acknowledged for their biodiversity conservation and potential for sustainable intensification and restoration. In order to make ecological intensification available for the ranchers, research and technology transfer have to embrace native tree species-based silviculture, native-grass-based forage management and enhancement, and value chain of biodiversity-friendly products. The pasture management proposals of this paper are based on a concept of biodiversity as an ecosystem service, promoting local productivity and global ecosystem services.

Productive performance and ingestive behavior of crossbred heifers in integrated livestock-forest systems

The present study aimed to assess the productive performance, ingestive behavior, and thermal condition of crossbred beef heifers in an integrated livestock-forest (ILF) system with different tree-planting designs. Seventy-two ½ Angus ½ Nellore heifers were divided in three treatments­conventional system (CS) without eucalyptus, integrated livestock system with 187 eucalyptus ha−1 (ILF-1L), and integrated livestock system with 446 eucalyptus ha−1 (ILF-3L)­, in the winter and summer. Total dry mass of forage (TDM), chemical analysis of Marandu palisadegrass, average daily gain (ADG), stocking rate (SR), weight gain per area (WGA), behavior, microclimatic variables, and thermal comfort indexes were evaluated. A higher percentage of crude protein and lower TDM and SR were observed in ILF-1L and ILF-3L, with no differences for ADG and WGA. Ambient temperature, temperature-humidity index, black globe-humidity index, and radiant heat load were better in ILF-1L and ILF-3L. Heifers in ILF-1L and ILF-3L carried out grazing, resting, rumination, and other activities in the shade. In the summer, heifers in ILF-1L and ILF-3L spent less time resting and more time in rumination and performing other activities than those in the CS. In conclusion, the better forage quality in ILF-1L and ILF-3L does not alter the performance of heifers or WGA, despite the decreased TDM and SR. Furthermore, ILF-1L and ILF-3L provide better thermal comfort, and heifers that do not have access to shade decrease their activities as a strategy to reduce the use of energy for thermal regulation process.(AU)

Beef cattle behavior in integrated crop-livestock systems / Comportamento de novilhos de corte em sistemas integrados de produção agropecuária

Temperament often depends on the animals' reaction to people, social and environmental conditions. However, little is known about the influence of changes in the pasture environment on cattle temperament. Thus, this study was designed to evaluate if an animals' temperament changes in response to being kept in a silvopastoral system. This study evaluated the effect of the tree components in a pasture environment on the temperament of any grazing cattle in integrated crop-livestock systems. A total of thirty-two Angus steers were allocated to either a livestock (L) or livestock-forest (LF) system and observed from December 2019 to February 2020. Each animal was evaluated for their reactivity score, flight speed, and number of vocalizations. The statistical model established that the animals were random effects and that the treatments and periods were fixed effects using the MIXED procedure, and the means were compared using LSMeans. The flight speed and number of vocalizations were similar in both production systems, while the reactivity score was lower for animals kept in the LF system when compared to those in the L system. This suggested that the LF system interferes positively with the animal's temperament in relation to the L production system. However, additional research is needed to understand the influence of the production system on animal temperament.

As divergências no temperamento dependem da reação dos animais às pessoas e à diferentes situações sociais e ambientais. Contudo, pouco se sabe acerca da influência de alterações no ambiente pastoril sobre o temperamento dos bovinos. Com isso, a hipótese de trabalho é de que o temperamento dos animais pode ser alterado se mantidos em sistemas pastoris arborizados. Para tanto, objetivou-se avaliar o efeito do componente arbóreo em ambiente pastoril sobre o temperamento de bovinos em pastejo em sistemas integrados de produção agropecuária. Foram avaliados 32 novilhos da raça Angus alocados em dois sistemas pecuária (PEC) e pecuária-floresta (PF) durante o período de dezembro de 2019 a fevereiro de 2020, no qual foi mensurado: o escore de reatividade dos animais; a velocidade de fuga e o número de vocalizações. O modelo estatístico utilizado considerou como efeito fixo de tratamentos e períodos e efeitos aleatórios dos animais, utilizando o procedimento MIXED, as médias foram comparadas pelo recurso lsmeans. A velocidade de saída e número de vocalizações foram similares entre os sistemas de produção. O escore de reatividade foi menor para os animais mantidos no sistema PF quando comparados aos do tratamento PEC. O sistema PF interfere positivamente no temperamento animal em relação ao sistema de produção PEC, observado pelo menor escore de reatividade nos animais mantidos neste sistema. Contudo, o estudo sobre a influência da integração de sistemas sobre o temperamento animal exige mais pesquisas para revelar o potencial deste modelo de produção sobre o comportamento animal.

Water buffalo production in the Brazilian Amazon Basin: a review.

The Brazilian Amazon has witnessed, in the last decades, an increase in the water buffalo (Bubalus bubalis) inventory, with interesting productivity results. As the Brazilian Amazon contains the main water buffalo population in the Americas, the aim of this work is to review its most relevant production systems and some peculiarities about meat and milk production in this territory. The opening section describes the Amazon Basin, the most common water buffalo breeds, a brief history of the local livestock farming beginning in 1644. Also, it presents how water buffaloes gradually replaced bovine herds, especially where the latter had a lower productive performance. The use of extensive or more intensified models is pointed out and the ecosystems in which buffaloes are raised are detailed since native or cultivated pastures can be used in floodplains or drylands. Buffalo raising is favored in the Amazon due to the climate, soil, genetic variability of forages, animal adaptability, and physical space. Thus, it is clear that buffaloes have a high potential for meat and milk production and are an alternative in the use of altered areas of the Amazon; and, in the recent past, the low profitability of buffalo farming in traditional production systems in the Amazon was the reason which made this activity economically unattractive. Most recent technologies as outdoor confinements and silvopastoral systems are pointed out as more suitable regarding land-use policies, and buffalo farming for meat and milk production fits perfectly in this context, with productivity and beneficial socioeconomic.

Benefits of Silvopastoral Systems for Keeping Beef Cattle.

The potential benefits of keeping Zebu cattle in silvopastoral systems are well described in tropical regions. In order to obtain information on European breeds of beef cattle (Bos taurus taurus) in temperate climate zones, individual records of body weight and welfare indicators were obtained from 130 beef cattle. These belonged to four herds and were randomly allocated to two contiguous plots: Silvopastoral Systems (SPS) and Open Pastures Systems (OPS). The SPS in this study were areas with exotic trees of Eucalyptus globulus globulus for paper pulp production planted in a 2 × 2 design (two meters between each tree) over diverse, native grasses. The OPS were large open areas with a great diversity of native grasses, herbs, and small plots of trees where the animals could rest and shelter from extreme weather conditions. Over the course of one year, individual body weights and a number of specific animal welfare indicators were measured every 45 days. After a descriptive analysis, a generalized linear mixed model (GLMM) with a Gaussian distribution, with time and system (OPS or SPS) fitted as fixed effects and individuals nested by herd as random intercepts, was used. The results showed that weight gain did not differ between the two systems. None of the animals showed any sign of impaired welfare in either system over the study period. Silvopastoral systems offer animals a sustainable and richer environment that will improves their welfare. The additional income provided by the wood production allows the farmers to maintain their traditional cattle farming lifestyle.

Assessing Sustainability in Cattle Silvopastoral Systems in the Mexican Tropics Using the SAFA Framework.

The sub-humid native rainforest in Yucatan is one of the most endangered in Mexico. Cattle production is one of the main causes of land use change and silvopastoral systems are a feasible alternative. This work compares the sustainable performance of silvopastoral (native and intensive) and monoculture cattle farms in the state of Yucatan using the Sustainability Assessment for Food and Agriculture (SAFA) framework. Questionnaires and semi-structured interviews were applied in 9 farms. Responses were fed to the SAFA Tool to obtain sustainability polygons. Percentages of SAFA themes positively and negatively valuated were calculated. Native farms had positive ratings for Participation, Land, Biodiversity and Cultural Diversity, whereas intensive excelled on Holistic Management. Native farms had limited ratings for Decent Livelihood. Native farms (and one intensive silvopastoral farm) had the highest percentages of themes positively valuated compared to monocultures (and one intensive silvopastoral farm), which scored the lowest. Positive evaluations identified native systems as an option for sustainable production; however, areas of opportunity in all farms were discovered. This is the first comparative study using SAFA to evaluate differences in farming systems in the Mexican tropics, providing valuable information to generate policies and incentives on sustainable livestock production, as well as for improving evaluation tools for local application.

Pod production, and dasometric variables, of the tree Senna spectabilis (Fabaceae) in a tropical dry forest / Producción de vainas, y variables dasométricas, del árbol Senna spectabilis (Fabaceae) en un bosque seco tropical

Introduction: Senna spectabilis is a multipurpose pantropical tree, used in agroforestry systems. Objective: To determine pod production (Pp) and their relationship with dasometric variables in S. spectabilis in the tropical dry forest. Methods: From August 2016 to February 2017, thirty trees in production stage were randomly selected. The random selection was formed of the more isolated trees from the total dispersion. The trees were monitored at the beginning and end of the study period, to determine dasometric measurements such as total height (Th), height to the first branch (Hb), crown height (Ch), Stem diameter (at 0.2 m height from the ground) (Db), crown diameter (Cd), and crown volume (Cv) measured. Pods were harvested by the researcher with cutting and height cutting tongs when their color began to change. Pearson correlations and univariate and multivariate regression analyses were performed between the dasometric variables and pod production. The potential number of trees/ha (NPa) was calculated by determining the occlusion percentage (Op) and the shadow area/tree (Ca); to estimate the production potential of fruits/ha, the production of fruits/tree was multiplied by (NPa). Results: Th was 6.16 ± 1.23 m, Hb 2.75 ± 0.52 m, Ch 3.41 ± 0.98 m, Db 20.43 ± 4.80 cm, Cd 7.46 ± 1.20 m and Cv 108.43 ± 61.38 m3/tree. There was a significant positive correlation between Hb, Cd, Db, with Pp of 0.592**, 0.592**, and 0.446* respectively. Pp was 32.73 ± 16.13 kg/tree and the dry matter production (MSP) was 17.84 ± 8.80 kg/tree. The result of the multivariate regression indicated that the second-order polynomial model presented best goodness of fit. Op was 73.4 7.92 %, the cup area was 49.3 m2/tree, Ca was 36.2 m2/tree, and NPa was 83 trees. Conclusions: The production of fresh pods/ tree in the S. spectabilis presents a potential in its availability as feed for ruminant or seed production. The potential production of pods in silvopastoral with S. spectabilis could be 2.72 t/ ha, and 1.64 t/ ha of dry pods, this shows the importance of trees and of pods production and nutritional contribution obtained for dry ecosystems.

Introducción: Senna spectabilis es un árbol pantropical multipropósito, utilizado en sistemas agroforestales. Objetivo: Determinar la producción de vainas (Pv) y la relación con las variables dasométricas en S. spectabilis en el bosque seco tropical. El número potencial de árboles/ha (NPa) fue calculado determinando el porcentaje de oclusión (Po) y el área de sombra/árbol (As); para calcular la producción potencial de frutos/ha, la producción de frutos/árbol fue multiplicada por (NPa). Métodos: Desde agosto del 2016 hasta febrero de 2017, treinta árboles en etapa de producción fueron seleccionados al azar, los más aislados del total de árboles dispersos fueron seleccionados, y fueron monitoreados al inicio y al final del período de estudio, para determinar las mediciones dasométricas como la altura total (At), altura a la primera rama (Apr), altura de la copa (Ac), diámetro del tallo (a 0.2 m altura desde el suelo) (Dt), diámetro de la copa (Dc) y volumen de copa (Vc). Las vainas se cosecharon cuando su color comenzó a cambiar. Se realizaron correlaciones de Pearson y análisis de regresión univariada y multivariada entre las variables dasométricas y la producción de vainas. El número potencial de árboles/ha (NPa) se calculó determinando el porcentaje de oclusión (Po) y el área de sombra/árbol (Asa); para estimar el potencial de producción de las vainas/ha, la producción de vainas/árbol se multiplicó por NPa. Resultados: La At fue de 6.16 ± 1.23 m, Apr 2.75 ± 0.52 m, Ac 3.41 ± 0.98 m, Db 20.43 ± 4.80 cm, Dc 7.46 ± 1.20 m y Vc 108.43 ± 61.38 m3/árbol. Existió una correlación positiva significativa entre Apr, Dc, Db, Pv de 0.592**, 0.592 ** y 0.446 * respectivamente. La Pv fue de 32.73 ± 16.13 kg y la producción de materia seca (PMS) fue de 17.84 ± 8.80 kg/árbol. El resultado de la regresión multivariada indicó que el modelo polinomial de segundo orden presentó la mejor bondad de ajuste. El Po de los árboles fue de 73.4 % ± 7.92 %, el área de copa fue de 49.3 m2/árbol, el Asa fue de 36.2 m2/árbol, el NPa fue de 83 árboles. Conclusiones: La producción de vainas frescas/árbol en el S. spectabilis presenta un potencial en la disponibilidad de alimento para los rumiantes o la producción de semillas. El potencial de producción de vainas en u arreglos silvopastoriles podría ser de 2.72 t/ha, y 1.64 t/ha de vainas secas, esto muestra la importancia del árbol de producción de vainas y la contribución nutricional para los ecosistemas secos.

Structure and nutritional value of BRS Zuri grass under shading / Estrutura e valor nutritivo do capim BRS Zuri sob sombreamento

The objective was to determine the structural and nutritive parameters for Panicum maximum cv. BRS Zuri under a Eucalyptus shading system, in rainy and dry seasons. At the beginning of each season, the treatments (foliar fertilization levels of 0, 3, 6 and 9 L ha-1) were applied and evaluated at 28, 56, and 84 growing days. The treatments did not affect significantly (p ≥ 0.05) the evaluated parameters. The systems (shading and full sun) and seasons did not change (p ≥ 0.05) forage and root masses. The leaf crude protein content was higher (p ≤ 0.05) in the dry season. Height, leaf mass, stem and dead material, neutral and acid detergent fiber contents, and in vitro dry matter digestibility were affected (p ≤ 0.05) by the system x season. The growing days did not affect (p ≥ 0.05) forage mass. The mass of dead material decreased (p ≤ 0.05) over the evaluated intervals. The other parameters were affected (p ≤ 0.05) by system × growing days. Based on the results, the forage and root masses show that the cv. BRS Zuri is adapted to the shading in the proposed experimental conditions. These masses added to the crude protein content indicate adaptation to low rainfall, inherent to the dry season, while foliar fertilization applied at the beginning of seasons did not affect the structural and nutritive parameters of BRS Zuri grass.

O objetivo foi determinar os parâmetros estruturais e de valor nutritivo do Panicum maximum cv. BRS Zuri sob sistema sombreado por eucalipto, nas estações chuvosa e seca. No começo de cada estação, os tratamentos (níveis de fertilização foliar de 0, 3, 6 and 9 L ha-1) foram aplicados e as avaliações realizadas aos 28, 56 e 84 dias de crescimento. Os tratamentos não afetaram significativamente (p ≥ 0.05) os parâmetros avaliados. Os sistemas (sombreado e a pleno sol) e estações não modificaram (p ≥ 0.05) as massas de forragem e de raízes. O conteúdo de proteína bruta foi maior (p ≤ 0.05) na estação seca. Altura, massas de folhas, colmos e material morto, conteúdos de fibra em detergente ácido e neutro, e digestibilidade in vitro da matéria seca foram significativamente afetados (p ≤ 0.05) pela interação sistema x estação. Os dias de crescimento não afetaram (p ≥ 0.05) a massa de forragem. A massa de material morto diminuiu (p ≤ 0.05) com os intervalos de avaliação. Os outros parâmetros foram afetados (p ≤ 0.05) pela interação sistema x dias de crescimento. Baseado nos resultados observados, as massas de forragem e raízes mostram que o cv. BRS Zuri é adaptado ao sombreamento proposto pelas condições experimentais. Essas massas, somadas ao conteúdo de proteína bruta indica que o capim é adaptado a baixas precipitações, inerentes a estação seca; a fertilização foliar aplicada no começo das estações não afeta os parâmetros estruturais e de valor nutritivo do capim BRS Zuri.

Structure and nutritional value of BRS Zuri grass under shading

ABSTRACT The objective was to determine the structural and nutritive parameters for Panicum maximum cv. BRS Zuri under a Eucalyptus shading system, in rainy and dry seasons. At the beginning of each season, the treatments (foliar fertilization levels of 0, 3, 6 and 9 L ha-1) were applied and evaluated at 28, 56, and 84 growing days. The treatments did not affect significantly (p 0.05) the evaluated parameters. The systems (shading and full sun) and seasons did not change (p 0.05) forage and root masses. The leaf crude protein content was higher (p 0.05) in the dry season. Height, leaf mass, stem and dead material, neutral and acid detergent fiber contents, and in vitro dry matter digestibility were affected (p 0.05) by the system x season. The growing days did not affect (p 0.05) forage mass. The mass of dead material decreased (p 0.05) over the evaluated intervals. The other parameters were affected (p 0.05) by system × growing days. Based on the results, the forage and root masses show that the cv. BRS Zuri is adapted to the shading in the proposed experimental conditions. These masses added to the crude protein content indicate adaptation to low rainfall, inherent to the dry season, while foliar fertilization applied at the beginning of seasons did not affect the structural and nutritive parameters of BRS Zuri grass.

RESUMO O objetivo foi determinar os parâmetros estruturais e de valor nutritivo do Panicum maximum cv. BRS Zuri sob sistema sombreado por eucalipto, nas estações chuvosa e seca. No começo de cada estação, os tratamentos (níveis de fertilização foliar de 0, 3, 6 and 9 L ha-1) foram aplicados e as avaliações realizadas aos 28, 56 e 84 dias de crescimento. Os tratamentos não afetaram significativamente (p 0.05) os parâmetros avaliados. Os sistemas (sombreado e a pleno sol) e estações não modificaram (p 0.05) as massas de forragem e de raízes. O conteúdo de proteína bruta foi maior (p 0.05) na estação seca. Altura, massas de folhas, colmos e material morto, conteúdos de fibra em detergente ácido e neutro, e digestibilidade in vitro da matéria seca foram significativamente afetados (p 0.05) pela interação sistema x estação. Os dias de crescimento não afetaram (p 0.05) a massa de forragem. A massa de material morto diminuiu (p 0.05) com os intervalos de avaliação. Os outros parâmetros foram afetados (p 0.05) pela interação sistema x dias de crescimento. Baseado nos resultados observados, as massas de forragem e raízes mostram que o cv. BRS Zuri é adaptado ao sombreamento proposto pelas condições experimentais. Essas massas, somadas ao conteúdo de proteína bruta indica que o capim é adaptado a baixas precipitações, inerentes a estação seca; a fertilização foliar aplicada no começo das estações não afeta os parâmetros estruturais e de valor nutritivo do capim BRS Zuri.

Structure and nutritional value of BRS Zuri grass under shading / Estrutura e valor nutritivo do capim BRS Zuri sob sombreamento

The objective was to determine the structural and nutritive parameters for Panicum maximum cv. BRS Zuri under a Eucalyptus shading system, in rainy and dry seasons. At the beginning of each season, the treatments (foliar fertilization levels of 0, 3, 6 and 9 L ha-1) were applied and evaluated at 28, 56, and 84 growing days. The treatments did not affect significantly (p ≥ 0.05) the evaluated parameters. The systems (shading and full sun) and seasons did not change (p ≥ 0.05) forage and root masses. The leaf crude protein content was higher (p ≤ 0.05) in the dry season. Height, leaf mass, stem and dead material, neutral and acid detergent fiber contents, and in vitro dry matter digestibility were affected (p ≤ 0.05) by the system x season. The growing days did not affect (p ≥ 0.05) forage mass. The mass of dead material decreased (p ≤ 0.05) over the evaluated intervals. The other parameters were affected (p ≤ 0.05) by system × growing days. Based on the results, the forage and root masses show that the cv. BRS Zuri is adapted to the shading in the proposed experimental conditions. These masses added to the crude protein content indicate adaptation to low rainfall, inherent to the dry season, while foliar fertilization applied at the beginning of seasons did not affect the structural and nutritive parameters of BRS Zuri grass.(AU)

O objetivo foi determinar os parâmetros estruturais e de valor nutritivo do Panicum maximum cv. BRS Zuri sob sistema sombreado por eucalipto, nas estações chuvosa e seca. No começo de cada estação, os tratamentos (níveis de fertilização foliar de 0, 3, 6 and 9 L ha-1) foram aplicados e as avaliações realizadas aos 28, 56 e 84 dias de crescimento. Os tratamentos não afetaram significativamente (p ≥ 0.05) os parâmetros avaliados. Os sistemas (sombreado e a pleno sol) e estações não modificaram (p ≥ 0.05) as massas de forragem e de raízes. O conteúdo de proteína bruta foi maior (p ≤ 0.05) na estação seca. Altura, massas de folhas, colmos e material morto, conteúdos de fibra em detergente ácido e neutro, e digestibilidade in vitro da matéria seca foram significativamente afetados (p ≤ 0.05) pela interação sistema x estação. Os dias de crescimento não afetaram (p ≥ 0.05) a massa de forragem. A massa de material morto diminuiu (p ≤ 0.05) com os intervalos de avaliação. Os outros parâmetros foram afetados (p ≤ 0.05) pela interação sistema x dias de crescimento. Baseado nos resultados observados, as massas de forragem e raízes mostram que o cv. BRS Zuri é adaptado ao sombreamento proposto pelas condições experimentais. Essas massas, somadas ao conteúdo de proteína bruta indica que o capim é adaptado a baixas precipitações, inerentes a estação seca; a fertilização foliar aplicada no começo das estações não afeta os parâmetros estruturais e de valor nutritivo do capim BRS Zuri.(AU)

Efecto del componente arbóreo sobre la dinámica de crecimiento y calidad nutricional de una pradera mixta en trópico alto / Effect of tree component on the growth dynamics and nutritional quality of a mixed grassland in the high tropic

Resumen Los sistemas ganaderos se basan en el monocultivo de gramíneas. El pastoreo comúnmente no tiene en cuenta la fisiología de las especies, lo que afecta la persistencia y calidad del forraje. Los sistemas silvopastoriles favorecen la producción y calidad del forraje. Por eso es importante conocer la dinámica de crecimiento de la pastura para determinar el momento óptimo de pastoreo. Con base en esto, el objetivo de esta investigación fue evaluar el efecto de Acacia melanoxilum sobre la producción y calidad nutricional de una pradera mixta en trópico alto. La investigación se desarrolló en el Centro de Investigación y Capacitación "Santa María del Puyón", ubicado en Sopo, Colombia. Se evaluó una pradera de Cenchrus clandestinum y Lolium perenne, en pasturas en callejones se establecieron parcelas bajo y fuera de los árboles, y se evaluó el crecimiento (15, 30, 45 y 60 días) durante nueve meses. Luego se determinaron las propiedades fisicoquímicas del suelo, la altura sin disturbar del pasto, el número de hojas, el índice de área foliar y la producción y calidad de forraje. Después se utilizó un diseño al azar, y se realizó estadística descriptiva y análisis de varianza, mediante el programa Infostat® para el análisis de datos. Bajo los árboles se observó mayor pH, materia orgánica, minerales y capacidad de intercambio catiónico, mayor altura sin disturbar (p = 0,0001), diferencias en producción de forraje verde (p = 0,0128), composición botánica y mayor proteína cruda (p = 0,0061). Los árboles de A. melanoxilum favorecen el crecimiento y la calidad nutricional de praderas mixtas en trópico alto.

Abstract Livestock systems are based on the monoculture of grasses, grazing does not usually take into account the physiology of the species, this affects the persistence and quality of the forage. Silvopastoral systems favor forage production and quality, it is important to know the growth dynamics of the pasture to determine the optimal grazing moment. The objective of this work was to evaluate the effect of Acacia melanoxilum on the production and nutritional quality of a mixed meadow in the high tropics. The research was carried out at the "Santa María del Puyón" Research and Training Center, located in Sopo, Colombia. A meadow of Cenchrus clandestinum and Lolium perenne was evaluated, in alley pastures, plots were established under and outside the trees, the growth was evaluated (15, 30, 45 and 60 days) for nine months. The physicochemical properties of the soil, undisturbed height, number of leaves, leaf area index, production and quality of forage were determined. A random design was used, descriptive statistics and analysis of variance were performed. The Infostat® program was used for data analysis. Under the trees there is a higher ph, organic matter, minerals and cation exchange capacity, higher undisturbed height (p = 0.0001), differences in green forage production (p = 0.0128), botanical composition, and higher protein crude (p = 0.0061). A. Melanoxilum trees favor the growth and nutritional quality of mixed grasslands in the high tropics.