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Studying the relief through morphological analysis allows typifying forms, elements and structures of the karst relief that help in the understanding of the genesis, evolution and dynamics assumed by the erosion of the Red Ferrallitic soils. It is a particularly important circumstance in the Southern karst Plain Havana-Matanzas, to understand how and why certain information is preserved and others are lost as the research is carried out from one scale to another, which has led to certain myths and uncertainties about the degradation processes of these soils. The present work aims to analyze the complex influence of relief and geographic scale on the understanding of karst-erosive processes in the areas of influence of karst depressions from a baseline of more than three decades, which demonstrates the unidirectional advance of karst-erosive dynamics in accordance with the conditions of use and management to which they have been subjected. It is concluded that the recognition and spatio-temporal evolution of erosion forms is only possible at a local scale and not from a simple rescaling of the variables to large areas, in order to avoid different interpretations in the erosion maps of the Red Ferralitic soils in Cuba. [ABSTRACT FROM AUTHOR]

The characterization of conditions of the karst environment at a detailed level contributes to the study of soils in areas of low relief contrast and a window of knowledge where geographic-cartographic information has been overgeneralized and underestimated. Based on studies carried out for more than three decades in the Southern Karstic Plain Havana - Matanzas, specifically in the polje of San José de Las Lajas, the objective was to analyze by means of three integrated indicators the irreversible trend of the degradation of Red Ferrallitic soils in areas of influence of karstic absorption forms (dolines and uvalas), where the geological structure and karstification show different phases of development. The characterization carried out from a baseline in the period t0:1986 - 1996 and subsequent monitoring during the interval t1:1996 - 2019, allowed obtaining criteria on the sequential modification of the karst landscape; changes in the nature and properties of soils and in the unidirectional and irreversible evolution of karst morphogenesis, with a marked tendency towards endorheism in this peculiar ecosystem. [ABSTRACT FROM AUTHOR]

Se realiza una actualización de la morfogénesis kárstica en el polje de San José de las Lajas, con el objetivo de realizar una evaluación cuantitativa del avance de los procesos kárstico-erosivos, a partir de una línea base de más de tres décadas en localidades de referencia, en conformidad con las condiciones de uso y manejo a que han estado sometidos los suelos, que demuestra los efectos de la antropogénesis intensiva en los suelos Ferralíticos Rojos, como resultado de un proceso multifactorial, condicionado no solo por las propiedades intrínsecas de la cobertura edáfica y condiciones de uso, sino dependiente de las condiciones geólogo-geomorfológicas. La aplicación del Sistema Integrador de Métodos Cualitativos y Cuantitativos, permitió caracterizar la influencia compleja del relieve en la evolución de los principales parámetros morfométricos de las dolinas con pérdidas entre 12,33-15,95 t ha-1 año-1, que convertidas en unidades de longitud muestran reducciones en los horizontes A+B entre 0,98-1,20 mm año-1, que sobrepasan los valores umbrales permisibles en términos de erosión propuestos por la USLE y las tasas de formación de suelos derivados de rocas calizas en Cuba, con marcada tendencia a incrementarse, que confirman la necesidad de protección y mejoramiento para que su “inmunidad” a la erosión, deje de ser un mito y se convierta en un asunto de prioridad para la Seguridad Alimentaria en los programas de desarrollo pos Covid-19 en Cuba, ya que estos suelos representan el máximo potencial para satisfacer lo que el país actualmente demanda para las producciones agropecuarias. [ABSTRACT FROM AUTHOR]

The tobacco constitutes an important source of income to the Pinar del Río province. However, production technologies have contributed to the degradation of soils; crop alternating is one of the effective measures to mitigate this effect. The objective of the investigation was to evaluate the incidence of different variants of alternation in some chemical and physic - chemical properties of the soil. The work was developed in areas dedicated to the tobacco crop, the variants of alternation evaluated were uncultivated soil, tobacco - fallow, tobacco - corn and tobacco - polycultures. In the selected areas, 96 samples were collected at depths of 20 cm and 40 cm and 40 producers were surveyed. Descriptive statistical methods were applied to compare the means in each variant of land use. The results showed that the predominant pH was slightly acidic, the tobacco-fallow variant showed values close to neutrality. The content of organic matter did not exceed 1% in the variants of cultivated soils inferior to those not cultivated, changeable bases and cation exchange capacity were similar in the cultivated soils, and the calcium showed the highest values in tobacco-fallow. It is concluded that the different land use variants did not have a marked effect on the pH values. The content of soluble phosphorus increased in all the variants of cultivated soils. The alternation of crops, as the only measure of improvement, does not guarantee an improvement in the chemical and physic - chemical properties of the soils. [ABSTRACT FROM AUTHOR]

For the successful application of the 137Cs technique in soil erosion studies, it is necessary to establish the reference inventory correctly as it represents the total entrance of this radionuclide into the earth's surface. In this sense, a site that has not been perturbed neither for the erosion nor for the deposit, is selected as reference site. In practice to find such sites is usually difficult. The objective of this research was to establish the reference inventory of 137Cs for the studied localities of Cienfuegos province. It was established that the confidence interval at 90% of probability of the 137Cs reference inventory is 1082; 1266 Bq/m², and the variation coefficient of the reference inventory in the researched localities was of 11%. These values are in correspondence with those reported by other authors for similar places. Also the lineal dependence between the inventories of 137Cs and the historical averages of the precipitations was determined, with a correlation coefficient of 0.94. This lineal function will be able to be used to obtain or to confirm the reference inventories from rainfall data. [ABSTRACT FROM AUTHOR]

A wide and detailed review of specialized papers about methods and diagnose index used to soil erosion assessment was done. It was evident the variety of existent methods that allow researchers to select between all of them, those that better satisfy their aims and data availability. Methods based on erosion landform mapping, evaluation and thematic mapping of factors that influence on erosion, field observations, radioactive isotopes, and modeling are described, being remarkable the importance of Geographic Information Systems (GISs) for developing some of them. The exposed methods are classified in qualitative and quantitative taking into consideration the result type they offer. The methods and diagnose index used to soil erosion assessment in Cuba during the last decades was reviewed. [ABSTRACT FROM AUTHOR]