The Revista Ciencias Técnicas Agropecuarias with ISSN: 2071-0054 (online) and 1010-2760 (paper), is a quarterly publication published since 1986 by the Agrarian University of Havana (UNAH) and her Center for Agricultural Mechanization (CEMA). It is the organ of scientific and technological publication of the Latin American and Caribbean Association of Agricultural Engineering (ALIA), and the Mexican Association of Agricultural Engineering (AMIA). Original and unpublished works in Spanish, Portuguese and English, in the form of original articles, technical notes, reviews, points of view, letters to the editor and summaries of doctoral theses are published in it. In its editions, works that cover the following topics of Agricultural Engineering appear: Tractors and Agricultural Machines, Operation and Mechanized Processes, Oil-hydraulic, Repair and Mechanical Technology, Computing and Applied Mathematics, Soil and Water, Use of Energy in Agriculture, Post-harvest: Biology and Technology, Electrification and Rural Construction, Livestock Mechanization, Conservation Agriculture, Precision Farming, Teaching and Training, Test Machines and Animal Traction. It is aimed at professionals and technicians of the branch of Agricultural Engineering and areas related. It is available in more than 60 scientific institutions and universities in Argentina, Austria, Belgium, Brazil, Colombia, Costa Rica, Chile, Spain, USA, France, Philippines, Great Britain, Honduras, Indonesia, Iran, Italy, Japan, Mexico, Peru, Portugal, Uruguay and Venezuela with which exchange is kept. It is an open access journal under the CC Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0), which does not establish costs for processing, publication, or embargo period. The journal is sponsored by:
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Automated system for determining the operating parameters of hydraulic machines
The purpose of this paper is to develop an automated system that determines the operating parameters of rotary hydraulic machines (pumps and motors), as well as the optimal operating regimes of the hydraulic machines, the coefficient of isogonality, and the relationships between pump and motor efficiency. The software results also display curves of the total efficiency of the pump and hydraulic motor as a function of the coefficient of isogonality, ensuring rapid and accurate evaluation.
Copyright (c) 2025 This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial (CC BY-NC 4.0). https://creativecommons.org/licenses/by-nc/4.0
Aerodynamic Analysis of Darrieus Vertical-Axis Wind Turbines
Vertical-axis wind turbines (VAWTs) have characteristics that make them ideal for rural and urban applications, especially at low heights and under low wind speed conditions. This led to the idea of developing VAWTs using indigenous technology in Cuba. However, there is currently no established local technology for the conception, design, manufacture, and installation of such systems. This research was conducted with the objective of analyzing the aerodynamics involved in the design of low-power Darrieus-type vertical-axis wind turbines. Based on a review of relevant literature, a Darrieus H-type turbine was selected for design and performance evaluation using the QBlade v0.96 software, which applies the Double Multiple Streamtube (DMS) simulation model. The results obtained from the study indicate nominal power outputs ranging from 1.1 to 1.4 kW, depending on the proposed rotor configurations.
Copyright (c) 2025 Revista bajo Licencia CC Reconocimiento-NoComercial 4.0 Internacional (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0
Approaches to Efficient Water Management and Use in Rice Cultivation
In the current context of climate change and instability where the availability of water is reduced over the years, the rice sector faces the challenge of making rational use of water, while at the same time needing to mitigate the effects of rice production in the face of a changing climate. Of particular interest in this regard are water-saving irrigation methods and climate-smart agricultural practices such as conservation agriculture that has begun to gain acceptance in rice cultivation. The objective of this work is to review the main approaches for the management and efficient use of water in rice cultivation, reported in the specialized scientific literature.
Copyright (c) 2025 Licencia CC Reconocimiento-NoComercial 4.0 Internacional (CC BY-NC 4.0) https://creativecommons.org/licenses/by-nc/4.0
Factors that lead to degradation of grasslands, important role of mechanization
Among the problems of physical degradation of soils, compaction and densification are the main ones, and these cause strong decreases in subsequent crop yields. The degradation of the soil structure is a problem today in Cuba, which can occur in all soils and at all levels of livestock production. Taking into account the above, this document aims to expose the main changes produced in the internal structure of soils as a result of its degradation. Soil compaction, due to the collapse or reduction of pore spaces, is the most common cause of physical restriction for root growth and development. As an aggravating factor, the degradation of the soil structure is commonly considered the most difficult type of land degradation to locate and reconvert; the reason is that this degradation is a subsurface phenomenon. Finally, it is about establishing some possible solutions to this problem, among which the main method of restoring the porosity of the limiting layers of root growth and that must take into account the chemical and physical factors of the soil, the species, the type of soil and the degree of degradation of the species that are proposed to restore, the use of plowing v+ harrow or plowing alone is the most efficient method for the recovery of pastures of the species
Emergy and Energy in Agricultural Production Systems: Conceptual Basis
Thermodynamics is crucial for understanding and optimizing agricultural and livestock processes, especially in resource use like solar energy, water, and nutrients. The concepts of emergy and exergy are fundamental for assessing energy efficiency and sustainability. Emergy measures the energy of one type used to generate another energy flow, tracking the system's energy "memory." Exergy quantifies the maximum obtainable useful work, reflecting energy quality. Emergy is an ecological-thermodynamic methodology that environmentally values energy, mass, and money flows, quantifying renewable, non-renewable, and market-derived resources. It allows visualizing and calculating flows, determining indices, and facilitating an integrated balance of economy, society, and the environment. Given the increasing demand for livestock products, quantifying energy in quantity, quality, and origin is vital for improving sustainability. This article reviews the theory and application of emergy and exergy in the agricultural sector, analyzing case studies that demonstrate their potential to evaluate and improve energy efficiency and sustainability.
Mathematical Models for Energy Simulation in Livestock Systems: A State of the Art
Bovine production systems represent one of the most significant productive activities in Latin America due to their contribution to food security and their role in the rural peasant economy. However, their progressive development in recent years has raised concerns regarding environmental, economic, and social sustainability-factors that have not evolved favorably alongside such growth. In this context, analyzing energy flows and the adaptation of natural resources within bovine production systems becomes a critical need to advance toward more efficient and sustainable models. This article presents a systematic review of the scientific literature on the application of mathematical, energetic, and emergy-based models in bovine production systems. It explores classical approaches to animal growth, multivariate simulation tools and software, and emergy analysis methods using indicators such as EYR (Emergy Yield Ratio), ELR (Environmental Loading Ratio), and ESI (Emergy Sustainability Index). Additionally, it examines notable case studies from Latin America and Europe, highlighting methodological strengths, limitations, and opportunities for integration. As a result, five strategic lines are proposed for the development of context-specific hybrid modeling frameworks.
Quality indicator of a Vertisol dedicated to rice in the Holguín province, Cuba
Rice is a product of high national demand and its production needs to be increased. In the province of Holguín, Cuba, a transfer is currently being built that will make it possible to have the water necessary for the cultivation of rice in an area of ​​around 2000 hectares. When there are large areas of soil whose suitability must be evaluated for a crop, indicators are required that are feasible to determine without large costs and experimental campaigns, and that can be estimated indirectly. In this research, a soil quality indicator (SQI) is introduced. The procedure followed is explained for which an experimental campaign was carried out in an area of ​​the aforementioned region in which a total of 14 soil properties commonly used to characterize soil quality were determined. A factor analysis was done in order to determine which of the properties contributed the most to the common variability and, based on their weights and the values ​​of the scoring functions that evaluate the good or bad influence of their values, the values ​​were finally calculated. SQI values ​​that allowed us to find that only 31% of the studied area has moderate to very good suitability, located in the northern part of the studied area. The properties that were most important in the study were total nitrogen, phosphorus, potassium, calcium, magnesium, sodium, organic matter and electrical conductivity.
Rake Angle Influence of the Vibrating Subsoiler Arm in Cutting Forces and Soil Failure
In the present work is analyzed the rake angle influence of the vibrating subsoiler arm in the cuttings forces, as well as the soil failure behavior, tilling a silt loam soil (ferralitic), by a soil-tillage tool interaction simulation model, developed applying the Finite Element Model and using the linear elastoplastic Drucker-Prager constitutive model. For modeling was used the Solid Works design software. It was assigned to model the parameters and properties of soil required for simulation, the boundary conditions and acting loads were applied as well as the meshing of the model. As well, several running of the model was realized for three rake angle (15°, 25° y 35°). The results showed the quadratic behavior of draft force with the increasing of subsoiler arm rake angle.
Armando Eloy García de la Figal-Costales
Methodology for the Diagnosis of Lubrication and Lubricants Management in an Enterprise
The objective of this research was to carry out a diagnosis of the management of lubrication and lubricants in a company in Havana, Cuba. It was based on the tool proposed and validated by the Center for Maintenance Engineering Studies CEIM to evaluate the status of said management. For this purpose, techniques specific to the field of research were used, such as: bibliographic search, document review, group of experts, etc. The tool allowed to identify the deficiencies in the management of lubrication and lubricants, providing a number of strategies that contribute to increasing the reliability and availability of tangible fixed assets, as well as reducing the consumption of electric energy, lubricants and spare parts.
Evolutionary State of Soil Properties Due to Land Use Change
A study was carried out on the effect on chemical properties of soil with the cultivation of sugar cane (Saccharum officinals L.) as a monoculture for over 30 years and subsequently the establishment of various crops in soils of the Ferrálíco and Gleysol Groups, in the municipality of Nueva Paz, Mayabeque province, whose results were compared with standard profiles of these Groups, which have never been cultivated. Álvaro Reynoso cited by Humbert (1965) reported that in the last century, in the fertilization of sugar cane, ammonium nitrate was used as a mineral fertilizer, which has acidic characteristics, which led to the acidification of these soils and the washing of the bases. With the establishment of various crops (vegetables, grains, tubers) by farmers, where they have applied organic fertilizers, filter cake and rotation with livestock, the soils have suffered a resilience, both in pH, base content and in the organic carbon content of the soil, which resembles the properties of the standard profiles, where there has been no anthropic activity. In the soils of the Gleysol Groupings, poor drainage begins at 40 cm depth, however, the use of organic amendments has led to an improvement in the properties of soils from 0 - 40 cm and therefore a better crop yield.
Current Status of Agricultural Machinery in the Mechanization Centers of Bolivar Province, Ecuador
Agricultural mechanization plays an important role in improving productivity and sustainability in agriculture. In Ecuador, mechanization centers were implemented to facilitate access to agricultural machinery in rural areas. However, the lack of information on the current state of the equipment limits its operational efficiency. The objective of this study was to diagnose the technical condition of the agricultural machinery in the mechanization centers of Bolivar province. A total of 17 tractors, 38 power tillers and 35 agricultural implements were evaluated in 10 mechanization centers, analyzing their technical condition, safeguarding conditions, maintenance and mechanization index. The results indicate that 64.71% of the tractors are capable of working, they still show some degree of deterioration and 35.29% are inoperative. 100% of the power tillers are without working capacity. One of the main reasons for the deterioration of agricultural machinery is the lack of adequate preventive and corrective maintenance. Some elements were identified as requiring immediate attention due to their critical condition (high urgency), such as tires (12.50%), the electrical system (6.25%) and certain specific elements (21.88%). Adequate safeguards are in place for 100% of the machinery. The mechanization index varies between 0.32 and 1.1 kW/ha, with an average of 0.61 kW/ha, below the recommended standard. In conclusion, it is necessary to improve maintenance strategies, consider a machinery renewal program and strengthen operator training to ensure greater efficiency in agricultural mechanization in the province.
Water estimation model for the agricultural and population sectors of the Tablachaca watershed in Peru
Climate change and human-induced modifications to water resources negatively affect the natural flow regimes of the river. Therefore, understanding hydrological alterations is crucial for water estimation in watersheds. This study analyzed water estimation in the Tablachaca River watershed for the agricultural and population sectors. The water estimation model was developed in Soil and Water Assessment Tool (SWAT), in which the sensitivity analysis was applied to the model, as well as the degree of precision through the Nash-Sutcliffe efficiency coefficient (NSE), percentage bias (PBIAS) and the coefficient of determination (R2). The main results were the water availability of the basin was 40.67 m3/s and 23.29 m3/s for agricultural use and human consumption with a probability of 75 % and 95 %, respectively. Model calibration reached an NSE of 0.79; PBIAS of -5.69 % and R2 of 0.80 and a validation with NSE of 0.75; PBIAS of -19.22 % and R2 of 0.82, which in effect made it possible to obtain a water estimation model with effective performance.
Estimation of Soil Properties by Remote Sensing and Machine Learning
Soil suitability for a crop can be determined by quality indicators, which can be obtained by different methods. The objective of this research was to estimate the properties of a vertisol dedicated to rice cultivation by means of remote sensing and automatic learning. Chemical and physical properties of the soil that affect rice physiology were determined “in situ”, with a completely randomized sampling of 100 points at a depth of 0 m to 0.20 m. Properties were estimated from the Normalized Difference Vegetation Index (NDVI) using machine learning tools. Organic matter, calcium, magnesium and phosphorus can be estimated by linear regression with NDVI, considering that they had Standard Errors of 0.27, 3.41, 4.12 and 1.68, respectively, and coefficients of determination close to 1. The random forest technique showed the best performance, with values in its determination close to 1 and an error in its estimation and validation close to 0.
Spatial environment design in agricultural information systems with Unity XR
Virtual Reality (VR) technologies aim to develop immersive or mixed spatial environments to adapt tasks ranging from video games to scientific research applications, in the topic of digital agriculture the importance of the metaverse in the processes of agronomy has put this sector in the spotlight, glimpsing future results that could revolutionize agriculture 5.0. The requirements of the application are explained based on an "APK" compatible with the Meta Horizon operating system for Meta Quest viewers, which was developed on the Unity VR CORE platform and the XR Interaction Toolkit Plug-ins, showing the architecture of the spatial environment and the interconnection layers, a class diagram is used to explain the composition of the programming structure used. The implementation strategy of the conceptual models is discussed through the formats of sequence diagram, usage and the logical scheme of the database, which were used to trace the layout of the project and thus the three-dimensional construction of the spatial environment in Unity, giving as evidence real-time images with the Oculus Meta Quest 2 interface in the interactivity modes with Touch controls and the Hand Tracking mode. The importance of spatial ecosystems in the metaverse oriented to information systems in digital agriculture is addressed and the work to follow that awaits us in terms of improving the Agroverse.
Mathematical Modeling of the Behavior of Nickel and Copper in a Contaminated Agroecosystem
The need to control the contamination caused by heavy metals is increasingly urgent, which is why it is necessary to study the quality of the soil in order to preserve or improve its productivity for the protection of the environment, animal and human health, and to guarantee food safety. Trace elements in high concentrations in soils are food toxins with negative effects on health that manifest in the long term. The action of some of them has been reported on the increase in cases of cancer, nervous system lesions and genetic diseases in humans, etc. as a result of the consumption of contaminated water and food, whether of animal or plant origin. The objective of this work is to propose mathematical models to predict the behavior of nickel and copper concentrations in an agroecosystem adjacent to the dumping of industrial waste in the municipality of San José de las Lajas. For this purpose, the data on the concentration of heavy metals nickel (Ni) and copper (Cu) provided by the Scientific Group of the Faculty of Agronomy of the UNAH from 2005 to 2018 were taken to predict their behavior based on the use of statistical-mathematical tools until 2034. It was obtained that, according to the mathematical models obtained, these soils should not be used to grow vegetables for consumption, nor allow free grazing of cattle, at least until 10 years after this research.
Spatial Limit of Agricultural risk and its Economic Impact Due to Flooding in the Chillon River, Peru
Agricultural planning and disaster risk management are essential for preventing and preserving socioeconomic development. The study aimed to define the spatial limits of agricultural risk and its direct economic impact due to flooding in the Chillón River in the Carabayllo district, Peru. Geographic Information System (GIS) tools and reliable databases were used for the research. Seven hydrological scenarios were applied with rigorous statistical analysis, along with numerical models for one-dimensional (1D) hydraulic modeling. Agricultural risk was defined by the relationship between hazard and vulnerability, considering the economic impact on different sectors. The main results indicated that the extreme maximum flood scenario reached 102,17 m³/s. The hydraulic modeling identified two agricultural risk limits due to river flooding, affecting the yield of vegetables, poultry farms, and pig production over an area of 0,24 km² and 0,37 km² in the 20 and 1000 year scenarios, causing economic losses of 5,169.14 USD and 6,509.04 USD, respectively. In conclusion, an integrated method was developed to simulate agricultural risk from river flooding.
Raw sugar production: its diagnosis with a value chain approach
This investigation focuses on the Agroindustrial Sugar Company Boris Luis Santa Coloma, belonging to the AZCUBA group. In recent years, this entity has experienced a decrease in its production, between 2019 and 2020 there was a decrease of 6.65% in sugar production and 3.44% in relation to honey. This decreasing trend raises concerns about the competitiveness and sustainability of the company, which is fundamental for economic and social development with an impact on local development, not only due to the high demand for its productions in the territory and the country, but also as crucial source of employment for the community. Based on the above, the objective of this research is to analyze whether the raw sugar production process at the EAA Boris Luis Santa Coloma complies with the value chain approach. To carry out this diagnosis, theoretical, empirical and statistical-mathematical methods were used, as well as tools such as the expert method, the Ishikawa diagram, brainstorming sessions and surveys. The results obtained reveal deficiencies in the value chain model proposed by Michael E. Porter, specifically in primary and support activities. Likewise, the analysis carried out on the production chain reveals irregularities that suggest that the company must address the existing deficiencies in its production process before being able to adequately optimize the cane sugar value chain.
Simulation of non-inverted soil tillage using the discrete element method
In the present work, a simulation model is developed by the discrete element method (DEM) for tillage without soil prism inversion with a paratill type implement. The virtual soil block was generated with macro-particles that respond to the simplified geometry of soil fragments with attributes and physical-mechanical properties of a cohesive soil of the vertisol type. For the virtual model of the implement, the design and resistive study of the paratill is carried out using the finite element method (FEM). The simulation of the interaction between the implement and the soil block made it possible to determine the movement and velocity patterns of the particles, as well as the magnitude of the draft force, and the results showed that the design of the implement fulfills the tensile requirements that allow it to support the tillage activity without permanent deformations. On the other hand, the dynamics of the tillage process allowed establishing the final position of the particles, as well as the specific pressures between them and with the implement. Finally, the average value of the draft force was obtained by simulation, being in correspondence with the soil cohesion and the design of the tillage implement. The analytical validation, by means of the classical mechanics equations, showed adequate results of the draft force.
Comparative Analysis Among the Battery-Powered and Diesel Tractors
The major advances in agriculture began with the beginning of the mechanization. However, this process has also caused significant environmental impacts. The introduction of tractors and other agricultural machines in Cuba have been developed impetuously in the period from 1959, but at the moment the research of options is required for a gradual renovation of the agricultural machinery due to its technical deterioration and obsolescence. The Agricultural Engineering Research Institute has performed an intensive test work and researches of new models of machines like option to the government and the farmers for the acquisition of the most advantageous models. It is objective of the present work to show the results of a comparative study among the electric tractors and those powered by diesel motors, analyzing as methodological aspects the saving of fuel, reduction of expenses in repair and maintenance, operation easiness, and impacts on the environment. The results indicate that the electric tractors have numerous advantages, although for their massive introduction it is necessary to consider some important factors.
Operational Performance of JA-1 and JA-2 Hydraulic Nozzles Used in Hydropneumatic Sprayers
Hydraulic spray nozzles are very important in hydropneumatic sprayers and are primarily responsible for dividing the liquid into droplets. This study evaluates the operational performance of two types of conical jet nozzles at four operating pressures. The nozzle flow rate and the influence of pressure on the discharge coefficient were evaluated. Spray nozzles JA-1 and JA-2 showed flow rates statistically equal to those provided by the manufacturer. The discharge coefficient of both nozzle sets was lower than the value proposed for turbulent flow orifices, with lower values for the series with the smaller orifice diameter. Volumetric distribution varies depending on the flow rate and nominal pressure. To establish operating parameters for spraying equipment, it is essential to understand the characteristics of the spray nozzles and their operating status.
Proposal for the Establishment of Appropriate Anaerobic Biodigestion Technology at the Robeba Farm
The present research was developed on the “Robeba” farm; its objective was to establish the appropriate anaerobic biodigestion technology to be introduced into the farm, transforming waste into biogas and biofertilizer. To do this, the animal species existing in the scenario (cows and pigs) are determined, since these species will contribute the organic waste to the biodigester; Considering the herd movement, the number of animals is determined, which would make it possible to determine the biomass generated daily with the purpose of establishing the sizing of the appropriate biodigester technology and knowing the behavior of the economic and energy parameters. Among the most notable results, it was observed that the implementation of a tubular polyethylene biodigester is more viable compared to the installation of a fixed dome biodigester, representing an economic saving of 19,796 pesos due to technology selection; The necessary volume of this technology must be 20 m3, making it possible to produce 201.3 kg/day of biofertilizers, which represent a daily economic contribution of 2,516 pesos/day (100.65 USD/day), constituting added value, in addition to the energy and economic benefits to be obtained. On the other hand, with the installation of the selected anaerobic biodigestion technology, electrical energy can be produced for the home and the lights, which requires obtaining a 1 kW biogas generator.
Future Prediction of Net Irrigation Requirements for Coffee Trees under Different Production Scenarios
This study aimed to estimate the future net irrigation requirements of coffee trees based on climate variability across different coffee-growing regions in Cuba. Representative sites were selected in the four main mountainous regions of the country where coffee is cultivated. Climate data from the PRECIS model under the RCP 4.5 climate scenario—recommended by the Cuban Institute of Meteorology—were used to evaluate water management needs in each region and crop. The CROPWAT 8.0 modeling program was applied to estimate irrigation requirements for the medium term (2050), based on forecasted climate variability. The obtained results were then compared to the values established in Resolution 17/2020 of the National Institute of Hydraulic Resources. The total net irrigation requirements estimated for coffee trees under future climate conditions indicate an increase ranging from 8.8% in La Palma (equivalent to 8,447.0 m³·ha⁻¹) to 40.5% in Palenque de Yateras (8,793.0 m³·ha⁻¹). The largest differences between total net and reduced irrigation requirements under the RCP 4.5 scenario were found in the western and central regions (48% to 78%), while smaller differences were observed in the eastern region (17% to 51%). A comparison with the values from Resolution 17/2020 shows that future irrigation requirements are between 8.8% and 40.5% higher, indicating increased pressure on water resources in the studied coffee-growing areas.
Validation of productive practices at intervention sites of the ecoVALOR Project
Soil degradation, driven by unsustainable agricultural practices and climate change, threatens food security, ecosystems, and sustainable development. The ecoVALOR Project in Cuba seeks to combat this problem by introducing mechanisms or methods for applying conservation technologies and sustainable agricultural practices. The study was conducted at five intervention sites in three Cuban provinces, in different production units. These units received equipment such as tractors, carts, seeders, and sprayers, allowing for the formation of different work groups. A baseline was identified with geographic indicators, farm management indicators, and soil physical/chemical properties (texture, porosity, organic carbon, etc.), following scientific protocols. Conventional and conservation technologies were compared. Among the main results, through the formation of work groups, improvements in soil properties were found (increased initial humidity, reduced apparent density, increased drainable porosity, increased porosity and structural stability of the soil), economic and environmental benefits (reduction in costs in corn threshing and soil preparation, lower environmental impact with decreased tillage and application of green manures), and strengthening of social indicators, related to the reduction of the use of synthetic inputs and the strengthening of local organizations for sustainable management. The ecoVALOR project, with its multidisciplinary approach (environmental, economic, and social), is replicable to address global challenges such as food security and climate change.
Soil moisture dynamics in the protected cultivation of potato mini-tubers (Solanum tuberosum)
The use of irrigation technologies in protected crops constitutes one of the main challenges for the efficient use of water. This study aims to evaluate irrigation uniformity parameters under grow house conditions with zeolite substrate, using micro-sprinkler and nebulizer methods for the cultivation of potato minitubers (Solanum tuberosum). The research was conducted at the Institute of Plant Biotechnology (IBP), located at the Marta Abreu Central University of Las Villas. The irrigation systems evaluated were the Hadar 7110 nebulizer and the Mamkad 16 micro-sprinkler. To determine the system parameters, a total of 21 collectors were installed in three rows, in a regular 2x2 m grid arrangement. The parameters evaluated were: uniformity coefficient, distribution uniformity, application coefficient of variation, and application efficiency. The spatial distribution of moisture and its variation during the cycle were also determined. The results showed that irrigation quality criteria were met in both cases, with the nebulizer performing as excellent and the micro-sprinkler performing as good. Better spatial moisture distribution was evident in irrigation with the nebulizer, associated with a smaller range of variation. As a result of uninterrupted irrigation, both sprinkler systems achieved substrate moisture levels above 50%. The most stable moisture level was reached in less time in the nebulizer system, and stable values were achieved throughout the remainder of the cycle.
Climate change and irrigation demand for rice (Oriza sativa L.) in Cuba
Given the possible effects of climate change (CC), expressed in the increase in temperatures and the decrease in rainfall, it is expected among the main impacts motivated by CC for rice cultivation in the country the reduction of the crop area, due to the lower availability of water, lower quality crops and total magnitude. Taking into account the above, and the importance of this crop for the country, this work was proposed to study the effect of rainfall variations using the SSP1 2.6 climate scenario and three regional climate models (Hadgem3-gc31-ll-SSP12.6, Mpi-esm1-2-hr-SSP126 and Mri-esm2-0-SSP126), with climatic variables until the year 2050, using the CropWat 8.0 program to calculate irrigation demand at six sites distributed in the Western (2), Central (2) and Eastern (2) regions of the country. Regardless of the model studied for the evaluation of rainfall, there was a decrease in values from west to east, with averages of 1644, 1467,5 and 1239,1 mm year-1 for the western, central and eastern zones, respectively; water demand was higher in the Hadgem3-gc31 model with an average gross water demand of 1337,5 mm for the 6 sites studied for a 130 day cycle and 5,8 and 4,3 % higher for the Mpi-esm1-2hr-SSP126 and Mri-esm2-0-126 models, respectively. It is suggested that further studies on the subject be continued, including the possible effect of temperatures on the decrease of both the cycle and the yield of the crop.
Physical properties of AGROMENAS – G and NEREA fertilizers produced at the Empresa Geominera del Centro
The performance of fertilizer spreaders during mechanized fertilizer application depends on their physical properties. Therefore, it is essential to understand the properties of any new fertilizer. This study aimed to determine the physical properties of AGROMENAS – G and NEREA fertilizers, which influence their mechanized application. The methodology used included determining the particle size distribution, bulk density, moisture content, and angle of repose of the material using well-known methods available in the scientific literature. The results showed that the NEREA zeolite-based fertilizer has a particle size distribution in which 72.61% of the material has particle sizes between 2 and 4 mm, that the bulk density of the material is 1120 kg m-3, the moisture content is 6.03%, and the angle of repose is 31.12°. AGROMENAS - G, on the other hand, has a particle size distribution where 56.6% of the material has particle sizes less than 1 mm, the bulk density is 1350 kg m-3, the moisture content is 6.06%, and the angle of repose is 29.34°.
Introduction of a method for estimating organic matter in the field (Bowman, 1997)
Soil organic matter (SOM) is essential for soil health and agricultural productivity, improving physical, chemical, and biological properties. Its measurement is key for sustainable soil management. Traditional methods (Walkley-Black and loss on ignition) have critical limitations in resource-limited environments: the use of toxic and carcinogenic reagents (sulfuric acid, dichromate), complex waste management, high energy consumption, and the requirement for specialized equipment. Given this, the EDTA (ethylenediaminetetraacetic acid) extraction method proposed by Bowman in 1997 was validated as a safe, rapid, and applicable alternative in situ. The results of both methods were compared in 17 Cuban soil samples with variability in groupings, textures, colors and degree of aggregation, finding i) High linear correlation (R² = 0.76) between optical densities (OD), with OD (EDTA) 2.3 times higher than OD (Walkley-Black), ii) confirmed validity for soils with SOM < 6%, similar to international studies and iii) Elimination of hazardous reagents and reduction of operating costs. In addition, the influence of texture and aggregation percentages were identified as factors that may affect the reading of the values, and pertinent technical recommendations were made. The results support the development of a standardized field kit with local standards, offering a technically robust, safe and accessible solution for SOM monitoring in Cuba.
Evaluation of daily germination in two rice cultivars using linear regression
Among the types of plant seed priming, hydropriming stands out with proven benefits in germination properties and is essential for standardizing germination in rice.The objective was to evaluate the daily dynamics of hydroconditioned germinated seeds of rice cultivars INCA P-5 and IACuba-41 (Oryza sativa L.) using a simple linear regression model. In January 2024, in Río Cauto, Granma, Cuba, the experiment was conducted with 200 rice seeds (100 per cultivar: INCA LP-5 and IACuba-41). The seeds, selected without defects and with moisture adjusted to 9-10%, were imbibed for 72 hours with irrigation water, dried for 48 hours in the shade, and sown in trays with local Vertisol soil. The number of germinated seeds was evaluated daily for 14 days. A simple linear regression model was applied (days as independent variable, germination as dependent) using ordinary least squares, with the slope (a), intercept (b) and their bootstrap confidence intervals with 1,999 repetitions and 95,0 percentile. Heteroscedasticity, autocorrelation of residuals, predicted values and their standard errors were also determined. The results confirm that the germinated seeds per day in both cultivars do not fit a linear regression model with asymmetric stages of dormancy breaking, germination peak and subsequent decline, with a slight lower dispersion or a more concentrated germination of the INCA LP-5 cultivar compared to IACuba-41
Proposal for a model for the implementation of circular biofactories for agricultural goods on Cuban farms
This study proposes a methodological framework for the implementation of economical, circular, and self-sustaining agricultural bioinput biofactories on Cuban family farms. The endogenous conditions of local farms are analyzed and international experiences are reviewed. The current status of farms in the Mayabeque province was identified, and integrated actions for the creation of biofactories under the circular economy model were proposed. It was found that the implementation of biofactories represents a strategic opportunity for the responsible management of natural resources, replacing up to 90% of external inputs. A circular-adaptive model was derived for the implementation of biofactories that contribute to socio-ecological resilience and food sovereignty. Based on the current context identified on the farms, the implementation of agricultural bioinput biofactories was found to provide economic and environmental self-sustainability for the national agricultural landscape.
Calibration of fertilizers for application of AGROMENAS – G and NEREA to sugarcane
FMCM-1 and TATU fertilizer spreaders are used for sugarcane fertilization in Cuba. The objective of this research was to calibrate the FMCM-1 and TATU fertilizer spreaders for the high-productivity application of NEREA fertilizer and AGROMENAS – G organo mineral fertilizer. The methodology included the experimental calibration of the delivery rate in kg min-1 of the fertilizer spreaders and the determination of the effective field capacity during the application of both fertilizers, using known methods. The experimental calibration showed that for AGROMENAS – G, the FMCM-1 only delivers 25,56 kg min⁻¹ and the TATU fertilizer spreader 19,37 kg min⁻¹, both below the flow rate required to meet the application dose, reaching only 34% and 26% respectively. In the case of NEREA, although a flow rate of 37,33 kg min⁻¹ is required, the FMCM-1 delivers 17,37 kg min⁻¹ and the TATU 13,97 kg min⁻¹, which represents less than 50% of the required flow rate. The effective field capacities for the application of NEREA (0.29 and 0.36 ha h⁻¹) and AGROMENAS – G (0.20 and 0.27 ha h⁻¹), working at the speeds that allow the standard delivery dose, are lower than the usual capacity of 0.78 ha h⁻¹ achieved at 7 km h⁻¹. This compromises compliance with production plans and the timely fertilization of sugarcane shoots.