Agrociencia Uruguay

Physicochemical characterization of georeferenced propolis from 14 locations of Uruguay

Pablo Cracco — 2023-08-30

Honey bee propolis is studied around the world. Its plant origin, associated with different soils and climates, determines different physicochemical properties. These different properties determine diverse medicinal potentials. Uruguay has few scientific papers that characterize the propolis it produces. This study analyzes propolis from 14 locations of Uruguay, obtained over a year. The vegetation environment of these localities was characterized in a radius of 2 km by satellite images. Color (CIELAB) was measured in ethanolic solution, as well as pH and conductivity in aqueous solution, ashes, total polyphenols (Folin-Ciocalteau) and total flavonoids. The similarities of the localities in terms of their vegetation do not correspond to the similarities between propolis; another method of plant characterization must be used. Differences were found between locations, but not between stations within the same location. The parameters L* and a* are correlated with the polyphenolic content of propolis (R2=0.61 and R2=0.81, respectively). Conductivity is correlated (R2=0.66) with ash content, but it would be necessary to determine what minerals are present to use this tool. The polyphenolic and flavonoid content allows regionalizing the country in southwest and northeast. Southwest with high contents (177 to 262 gGAE/kg and 66 to 131 gQE/kg) and northeast zones with lower contents (27 to 88 gGAE/kg and 10 to 27 gQE/kg). It is necessary to continue studying propolis from Uruguay, its mineral and polyphenol content and its profile in other locations for a longer time.

Inorganic contaminants (As, Cd, Pb) in peeled and whole potatoes and sweet potatoes

Alexandra Sixto — 2023-02-27

Vegetables are a rich source of macro and micronutrients. Particularly, potatoes and sweet potatoes are widely consumed and are two of the most important food crops in the world. Therefore, contamination of these products due to their content of inorganic contaminants is of great concern.

Considering the healthy trend of consuming these tubers and roots with their skins, which are rich in fiber and other nutrients, analysis of the whole product could provide valuable information in relation to their food safety. Therefore, the presence of arsenic (As), cadmium (Cd) and lead (Pb) in peeled and whole potatoes and sweet potatoes was studied. To do so, analytical methods were optimized and validated according to the Association of Official Analytical Collaboration International (AOAC) requirements for food analysis. Although the content of As, Cd and Pb was in most cases more than three times below the maximum allowed levels for these contaminants, the presence of Cd was detected in the samples of whole sweet potato but not in the peeled ones. The same behavior was observed for Pb in most of the sweet potato samples analyzed. This information points to the need to generate information on the whole root and tuber contaminants content, and to have analytical methods available to gather data on the occurrence of these contaminants in the whole vegetable in order to perform their risk assessment according to the consumption habits.

First report of Neofusicoccum parvum causing stem canker on cannabis in Uruguay

Elvis Sasia — 2023-07-27

In 2018 and 2019, in Uruguay, pests and fungi associated with diseases were surveyed in cannabis (Cannabis sativa) crops in the south of the country. Neofusicoccum sp. was isolated from plants with canker symptoms on stems in 60% of the crops, occupying the third place of the most frequent fungi. In order to determine the causal agent of stem and branch canker in cannabis, three isolates of Neofusicoccum sp. were characterized by morphological and molecular analysis, as well as pathogenicity in cannabis plants. Neofusicoccum parvum was identified as the causal agent of stem canker in cannabis plants in Uruguay.

Pesticide dependence and associated risks in Uruguayan agriculture

Cintia Palladino — 2023-05-23

Pesticides have become an essential input for agriculture in the last decades. However, the growing concern about the potential impact produced by such dependency on human health and the environmental level has led to strong questionings about the use of pesticides worldwide. This paper aims to analyze the use of pesticides in Uruguay's agriculture and their potential risks with an emphasis on ecotoxicological risks. For such purposes, data on imports and use of pesticides in Uruguay and some other agricultural regions corresponding to the last two decades (2000-2020) were collected. In addition, information on the risks associated with the use of different pesticides compiled in the Pesticide Properties Database of the University of Hertfordshire was reviewed, as well as information generated by related national and international research. The information collected indicates high intensity usage of pesticides in Uruguayan agriculture and uncertainties in relation to environmental risks that may arise from the current forms of use.

Resistance to leaf rust in cultivars and wheat lines of Paraguay

Ruth Scholz — 2023-03-27

Leaf rust (LR) of bread wheat (Triticum aestvium L.), caused by the fungus Puccinia triticina Eriks, is one of the most important diseases in Paraguay, the Southern Cone and worldwide. The economic importance of the disease is clear considering that two or more fungicide applications are necessary to control it in susceptible cultivars. The best strategy for the management of this disease is through genetic resistance. This research was conducted in Uruguay aiming to postulate the LR resistance genes present in 102 lines and wheat cultivars from Paraguay, and to study their field resistance. The presence of 18 major resistance genes expressed at the seedling stage (Lr1, Lr2, Lr3a, Lr3bg, Lr3ka, Lr9, Lr10, Lr11, Lr16, Lr17, Lr23, Lr24, Lr26, Lr27+Lr31, Lr28, Lr30, Lr42) was postulated based on the reaction to different races of the pathogen. The adult plant resistance gene Lr34 was confirmed in 26% of the materials, based on the molecular marker csLV34. This study also allowed differentiating materials with field resistance that can be explained by the seedling resistance and those with adult plant resistance. Knowledge of the resistance genes present in the germplasm of breeding programs is of paramount importance to establish strategies in order to achieve effective and long-lasting resistance based mainly on the combination of race-non-specific minor genes.

Fungi associated to Platanus x acerifolia in Uruguay and failure indicators

Agueda Claudia Scattolini Rimada — 2023-02-09

In the last few years, the interest in keeping the city trees healthy has increased in order to improve their survival and minimize claims due to potential accidents. The pest and diseases, the pollution, and the climate change together with the little genetic diversity of trees in urban areas are some of the factors that contribute to increase the likelihood of death and/or failure of trees in the cities. This work is part of a sanitary and risk of failure assessment of plane street trees (Platanus x acerifolia) carried out between 2019 and 2020. A random sample of 10 city blocks and their 193 plane trees was selected. In these, the presence of cankers, abnormal bark colorations, deformations, and a series of structural attributes that determine likelihood of failure variables were registered. The proportion of individuals with each symptom and the severity main index (SMI) were calculated as a weighted average of the different severity (SEV) levels in the total of evaluated plants. The severity indices were determined according to trunk or branches circumference and the portion of the tree affected (1^st, 2^nd or 3^rd portion from the base). Deformations presented the main incidence (0.6), SMI (1.68) and a correlation with the presence of damages and human injuries. The presence of cankers and reddish bark were the symptoms that most affected the density of the crowns.

Pasture and grassland productivity and foliar elongation of wheatgrass in Southern Patagonia

Victor Utrilla — 2023-07-28

The aim of this work was to show the relationship of the productivity of a pasture and grassland, the living and dead material, and the foliar elongation of wheatgrass with the soil moisture and the thermal sum in Southern Patagonia (Argentina). During the years 2015/16 (Year 1) and 2016/17 (Year 2), in closures excluded from grazing, the plant height, the accumulated aerial biomass (AAB) and the daily growth rate (DGR) of a mixed pasture and grassland were determined monthly from October to February. The forage harvested from the pasture was characterized in live (LM) and dead material (DM), and the live AAB was calculated. In selected wheatgrass plants, the leaf elongation rate (LER) was determined. Soil moisture (SM) was measured and the thermal sum (TS) was calculated. The AAB was analyzed using a factorial arrangement in a completely randomized design. The results were subjected to ANVA with repeated measures analysis and the means were adjusted with the Tukey-Kramer test. DGR, LM, and LER were related to SM and TS by multiple regression analysis. In both Year 1 and Year 2 and same months the AAB of the pasture exceeded the forage accumulated by the grassland. The LM and the LER varied according to the changes in the SM, and the TS explained the variations of the parameters described, which should be considered when developing future management strategies in this type of pasture.

Guided classification measurement of body condition in beef cows

Ana Carolina Espasandin — 2023-08-28

The use of predictive techniques based on image acquisition at field level is presented to improve livestock production. With this, the farmer can plan the management of the herd and the need for supplemental feeding. The use of the Body Condition Score (BCS) measured by visual assessment has been proposed as a method of subjective evaluation of the nutritional status of cattle. Studies show that a good BCS at calving allows increases in the order of 10 to 15% in the following pregnancy rate of the herd. This increase has a significant impact on farm productivity. Although the benefits of the visual assessment scale are recognized, the percentage of breeders using this tool is still low, the main reason being the lack of trained raters to record the BCS. The objective of this study was to develop a practical, repetitive, and non-invasive method to evaluate BCS through a guided grading process using images taken in the field. The results show that the BCS determination method proposed in this paper is presented as a simple and economical tool to evaluate BCS, so that it can be accepted by the breeder for its simplicity and benefits. Additionally, it can serve as a tutorial for the acquisition of experience in calibrating BCS in breeding cows.

Trace elements content and antioxidant capacity in honey from protected phytogeographical regions in Uruguay

Arnaldo Moreni Real — 2023-07-20

Honey is a natural sweet substance produced by honey bees, from the nectars of plant flowers and honey dew. The components of honey vary depending on the geographical site and the existing flora. The objective of this work was to characterize Uruguayan honeys produced in different regions by composition of trace elements (Cu, Fe, Mn, Mo, Zn, I, Se), the antioxidant capacity, the total polyphenols, and the palynological profile. Sixty-six honey samples were obtained in two seasons, spring-summer and summer-autumn, from three regions of protected areas, and a fourth region associated with human activities. The results obtained show that the contents of Cu and Mn were significantly higher (P<0.05) in region C (1.785 ug/g and 4.668 ug/g). For Mo, the Q region presented 1.060 ug/g, being significantly different (P<0.05) from the other regions. The total polyphenol content from region C was significantly higher (P<0.05) (66.442 mg GAE/100g). Likewise, the antioxidant capacity presented significant differences (P<0.05) for region C in the spring-summerseason. Some species, genus or botanical families were only found in a particular region. This work allows us to affirm that honey can be differentiated by its micronutrient content associated with the total polyphenol content, and a higher antioxidant activity for certain regions, given by the floral species present in the region and the type of soil.

Relationship between strains of Holstein cows, feeding strategies and udder health

Jéssica Tatiana Morales - Piñeyrúa — 2023-07-10

Mastitis frequency could be affected by animal and environmental conditions such as dairy cow genetics and feeding strategies. Thus, the objective of this study was to analyze the probability of clinical mastitis and somatic cell count (SCC) for New Zealand (NZ) and North American (NA) Holstein-Friesian cows maintained on two different feeding strategies (pasture or mixed). A total of 120 cows from the experimental dairy farm of the National Agricultural and Livestock Research Institute (INIA, by its Spanish acronym) (Colonia, Uruguay) were grouped into four groups derived from the combination of two feeding strategies: Grass Maximum or Grass Fixed, and two Holstein strains: NZ or NA (n=30). Clinical mastitis and SCC were evaluated monthly during a whole lactation period. There was an interaction between the Holstein strains and parity for clinical mastitis (P=0.04). The NA primiparous cows were the least likely to suffer clinical mastitis (OR: 0.003), while NA multiparous cows were the most likely to show clinical mastitis (OR: 0.12). The NZ cows reported intermediate values of OR (primiparous: 0.082, multiparous: 0.066). Feeding strategies did not affect clinical mastitis or SCC. Similar SCC was found for NZ and NA strains. In conclusion, regardless of the feeding strategy, the probability of clinical mastitis differed by the genetic origin of the Holstein cows. However, this difference was influenced by parity. The SCC was not influenced by the Holstein strain or the feeding strategy.

The Legacy of Charles Darwin

Bettina Tassino — 2023-05-29

Identifying agroecological transition pathways based on the Global Approach to Agricultural Systems

Inés Ferreira Rivaben — 2023-06-06

Agroecology represents one of the main alternatives to production models generated by the green revolution, both in Uruguay and other countries. It appears as a response to climate change, biodiversity management, nature resource restoration, and, more recently, as a response to the COVID-19 pandemic crisis. In Uruguay, agroecology is marginal despite the existence of a law for a National Plan to Encourage Production with Agroecological Bases since 2018. Moreover, research on agroecological transition processes is very incipient. This study aims to identify agroecological practices and possible transition paths towards agroecology of family livestock farmers in northern Uruguay. The methodology used focuses the study on technical, social and organizational practices, allowing access to the operation scheme and understanding the decision-making processes in family-type production systems. The socio-productive practices revealed in the research allowed the elaboration of a typology that represents possible ways for these livestock farmers to move towards agroecological production and management of their farms. The results of this study can be used to strengthen processes of conception or co-conception by selecting and disseminating innovation with actions and public policies closer to farmers.

Comparison of different ways to measure profitability in the Uruguayan agricultural sector through longitudinal clusters

Christian Kuster — 2023-04-10

The use of ROA (Return on Assets) as a profitability indicator is widespread in financial literature; however, there is no agreement on the economic result to be used as a basis for calculation. In the agricultural sector, where financing and land costs are high, the problem takes on great relevance to interpret the economic reality of the farm companies. The study has two objectives: a) to discuss the relevance of using operating ROA —based on economic results without deducting financial and land leasing costs— and financial ROA —which does deduct them— in measuring the evolution of agricultural business profitability; and b) to verify if there are groups of companies that regardless of how their profitability is measured present clear similarities in their evolution. The theoretical framework supporting the use of these indicators is analyzed first, attempting to discern which aspects of profitability they attempt to measure. Then, the results of both indicators are compared in a dynamic analysis using longitudinal cluster methodology on a database composed of the Financial Statements of 713 Uruguayan agricultural companies in the 2010-2017 period. It is concluded, first of all, that there are no relevant differences in the way firms' profitability evolves, whether measured by operating or financial ROA. Secondly, the evidence shows that most firms can be classified into three groups where internal profitability has evolved similarly, regardless of how it is measured, two of them with notable differences in the rate of profitability and some differences in the speed of change of that rate.

Dairy organizations in the eastern basin of Uruguay and the development of the sector

Martín Grau — 2023-02-15

In recent years, Uruguayan dairy has seen significant growth and development. From the territorial point of view, this has shown different intensities. The non-traditional basin of eastern Uruguay, consisting of the departments of Lavalleja, Maldonado and Rocha, showed lower levels of development compared to other areas of the country. This asymmetry would be influenced, at least partially, by weaknesses of the dairy producer organizations present in the eastern region, as they represent collective instruments of support, promotion and defense of the interests of the sector. The objective of this study is to analyze the structure and characteristics of these organizations and to inquire about the causes that limit dairy development in the region. The conceptual framework is based on the vision of social capital as a contributing factor to productive, economic and social development. The research was carried out between 2015 and 2017, and consisted of collecting primary information through semi-structured surveys and consulting secondary information. The results show that dairy producer associations have small social mass, low levels of partner participation and a low degree of articulation and cooperation with other entities of the local and national environment. In general terms and in a broad sense, there are weaknesses in the regional social capital related to dairy, which helps explain the relative lag of the sector in this region compared to the traditional basin.

How to foster changes towards farm sustainability?

Paula Colnago — 2022-12-06

Current global challenges for family farmers, such as the deterioration of arable land and low family income, cannot be addressed only by working on single farm components. Improving the sustainability of family farms requires a multi-objective systems approach and may be seen as an evolutionary process composed of iterative learning cycles. We developed a co-innovation project from 2014 to 2017 that involved characterisation, diagnosis, redesign, and implementation and evaluation of the redesigns on farms. Low family income, low labour productivity and the deterioration of soil quality were the main problems impacting farm sustainability. We identified crop management factors and soil fertility deficiencies as the main causes of low yields. After three cycles of diagnosis, redesign, implementation and monitoring, the average family income increased by 32%, labour productivity increased by 22%, and all the farms implemented soil erosion control measurements. Greater implementation of the farm redesign plans resulted in greater improvements in family income, labour productivity, and crop yields. We identified four types of activities that supported learning throughout the co-innovation process: regular farm visits; meetings to discuss diagnosis, planning and evaluation; field days, and reflection workshops. The strategic use of system analysis tools to promote learning eased communication among different actors, allowing shared learning.

Economic analysis of alternatives for second rotations in Eucalyptus globulus plantations in southeast Uruguay

Gustavo Balmelli — 2023-04-11

Eucalyptus globulus is one of the most planted forest species in Uruguay. However, its high susceptibility to diseases has determined that in recent years most plantations reaching harvest are replaced by other species, mainly E. dunnii and E. smithii. The decision whether to maintain the plantation for an additional rotation as coppice crop or to carry out a replanting depends on the expected economic results of both alternatives. Therefore, the objective of this research was to estimate the profitability of a coppice crop of E. globulus and that of a new plantation, with two different species, E. dunnii and E. smithii. In addition, a sensitivity analysis was carried out to study the impact of eventual variations in plantation productivity, in distance to the point of sale, and in the price of wood. Results showed that the three alternatives analyzed are economically viable, but that the management as coppice crop and the replanting with E. smithii are more profitable than replanting with E. dunnii. On the other hand, the coppice management is the alternative that requires less investment and that presents fewer risks, since it is less sensitive to changes in the main variables that determine the economic result.

Wood production and financial return in two silvopastoral systems

Mariana Boscana — 2023-03-09

Silvopastoral systems combine forestry and livestock activities, establishing productive and economic interactions that must be known in order to project their viability in the medium to long term. Important aspects of these systems are spacing arrangement, wood production and economic return. The present study was carried out on a farm with commercial forestry and aimed at evaluating wood production and its financial return in two silvopastoral systems of Eucalyptus globulus: Conventional Forestry System (CFS) in a plantation arrangement of 3.5×2.7 m, and Silvopastoral System (SSRA) (2×2)+8 m of alley. Each system was evaluated in three strata, at age 68 months. No differences (p> 0.05) were found for Survival (S), Diameter at Breast Height (DBH), Height (H), and Dominant Height (DH) between CFS and SSRA values. However, both systems differed (p <0.05) in wood production values (m³/ha) at age 68 months: CFS produced 83.7 m³/ha, while SSRA produced 60 m³/ha. Optimal technical rotations estimated were 12 and 13 years for CFS and SSRA, respectively. The Equivalent Annual Income (EAI) was 140 and 141 US$/ha/year for CFS and SSRA, respectively. However, SSRA requires a lower plantation investment and provides greater liquidity throughout the rotation. Forestry systems can be designed in ways that allow greater spatial integration of livestock, becoming more complementary systems.