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The effect of Cenchrus purpureus cv. Cuba CT-115 biomass bank technology with ten years of exploitation on the soil fertility and some morphological indicators of this grass was researched. The study was carried out in a filling grayish brown soil, in the dairy unit number 11, belonging to El Abra farm, from El Tablón enterprise, in Cienfuegos. It was found an increase of the OM content (3.19 to 3.55 %, P <0.0094) and a decrease of the assimilable P (24.30 to 18.88 ppm, P <0.0089). Although the physical indicators did not show significant variations, the apparent density showed slight numerical increase. In this scenario, the macrofauna biomass (including the number of worms) and root weight was higher (P <0.001) in the most superficial depth (0- 15 cm), while the indicators tillers bunches-1, dry matter yield, stem thickness and length of the fourth leaf showed adequate values and with little variation in the dry season 2013 and 2014. It is concluded that the soil that occupied the biomass bank had an increase of the OM content and a decrease of the assimilable P after ten years of exploitation. In this area, acceptable values were also found in grass indicators, the macrofauna activity (especially worms) and root biomass, although the CT-115 plants showed low nutritive value. [ABSTRACT FROM AUTHOR]

The effect of Cenchrus purpureus cv. Cuba CT-115 biomass bank technology with ten years of exploitation on the soil fertility and some morphological indicators of this grass was researched. The study was carried out in a filling grayish brown soil, in the dairy unit number 11, belonging to El Abra farm, from El Tablón enterprise, in Cienfuegos. It was found an increase of the OM content (3.19 to 3.55 %, P <0.0094) and a decrease of the assimilable P (24.30 to 18.88 ppm, P <0.0089). Although the physical indicators did not show significant variations, the apparent density showed slight numerical increase. In this scenario, the macrofauna biomass (including the number of worms) and root weight was higher (P <0.001) in the most superficial depth (0- 15 cm), while the indicators tillers bunches-1, dry matter yield, stem thickness and length of the fourth leaf showed adequate values and with little variation in the dry season 2013 and 2014. It is concluded that the soil that occupied the biomass bank had an increase of the OM content and a decrease of the assimilable P after ten years of exploitation. In this area, acceptable values were also found in grass indicators, the macrofauna activity (especially worms) and root biomass, although the CT-115 plants showed low nutritive value. [ABSTRACT FROM AUTHOR]

The change of chemical fertility of a ferrallitic red brown soil in the biomass bank technology of Pennisetum purpureum Cuba CT-115 was researched with different years of exploitation (6, 12 and 18 years, respectively). The pH indicators (in KCL), MO, N, P, K, Ca and Mg were researched. The data were subjected to variance analysis, according to simple classification model and the t-Student test was used in necessary cases. With the longer time of exploitation of 18 years, there was significant increase (P < 0.0001) of the OM (3.07 to 5.16 %), followed by the biomass bank with 12 years (3.04 to 3.71%), while the P content significantly decreased (P < 0.0056) in the biomass bank of 18 years (57.84 to 39.21 ppm), but did not varied in 12 years. The soil in the biomass bank of 6 years did not showed variation of the studied chemical indicators. The results indicated that there is an increase of the soil OM as it is higher the exploitation time of the biomass bank and P content decrease. It is recommended that, under similar soil conditions, the monitoring of the soil fertility state, mainly of the P assimilable content, from 6 years of uninterrupted exploitation with this technology. [ABSTRACT FROM AUTHOR]

The change of chemical fertility of a ferrallitic red brown soil in the biomass bank technology of Pennisetum purpureum Cuba CT-115 was researched with different years of exploitation (6, 12 and 18 years, respectively). The pH indicators (in KCL), MO, N, P, K, Ca and Mg were researched. The data were subjected to variance analysis, according to simple classification model and the t-Student test was used in necessary cases. With the longer time of exploitation of 18 years, there was significant increase (P < 0.0001) of the OM (3.07 to 5.16 %), followed by the biomass bank with 12 years (3.04 to 3.71%), while the P content significantly decreased (P < 0.0056) in the biomass bank of 18 years (57.84 to 39.21 ppm),but did not varied in 12 years. The soil in the biomass bank of 6 years did not showed variation of the studied chemical indicators. The results indicated that there is an increase of the soil OM as it is higher the exploitation time of the biomass bank and P content decrease. It is recommended that, under similar soil conditions, the monitoring of the soil fertility state, mainly of the P assimilable content, from 6 years of uninterrupted exploitation with this technology. [ABSTRACT FROM AUTHOR]

Se reconocen cinco períodos bien diferenciados, que denotan cambios cualitativos que han tenido lugar en la concepción de las investigaciones desarrolladas en el Instituto de Ciencia Animal en lo que respecta la fertilidad del suelo y su relación con la producción de pastos y forrajes. En la primera etapa, correspondiente a los años 1965 – 1970, los estudios se centraron en la identificación de los nutrientes que limitaban la producción de los pastos y las vías para su corrección y adecuada fertilización. El hecho de que el N se identificara como el principal nutriente que limita la fertilidad del suelo motivó el desarrollo de numerosas investigaciones desde 1970 – 1980, relacionadas con el efecto de la aplicación de N en la producción y calidad de los pastos más utilizados en el país, así como la mejor forma de distribuir dicho fertilizante para disminuir el efecto estacional de la producción de los pastos. También se estudió la influencia de la fertilización nitrogenada en diferentes indicadores de la producción y la salud animal y en la acción de las continuadas aplicaciones en las propiedades agroquímicas de los suelos. Este tipo de investigaciones continuó desarrollándose en el período 1980 – 1990, etapa en la que se profundizó en los factores de mayor incidencia para elevar la eficiencia del uso del N, principalmente la influencia de los factores climáticos. En este período también se intensificaron las investigaciones acerca de métodos de laboratorio para la determinación de contenidos de N asimilable del suelo y la influencia de las zeolitas naturales cubanas en la mejora de la eficiencia de utilización del N por las gramíneas. A mediados de la década de 1981 – 1990 comenzaron investigaciones relacionadas con el papel de los excrementos animales en la fertilidad del suelo y la producción de pastos. En 1983 quedó claro el efecto de la cantidad y distribución de las excretas animales en la fertilidad del suelo y en la productividad del pastizal, y en 1984 se describen las diferentes formas de utilización de este recurso y la sinergia del mismo con el fertilizante nitrogenado. Con el nuevo paradigma de la concepción agroecológica en el manejo de la agricultura, se abrió un novedoso enfoque en el tema de la fertilidad del suelo. En este sentido se desarrollaron más de doce investigaciones durante los años 1995 y 2000, que sirvieron como base de datos para conformar un programa que permite conocer el estado del balance de los nutrientes en diferentes sistemas de producción animal. Desde principios de este siglo, las investigaciones se han centrado en estudios de sistemas, relacionados principalmente con el impacto de tecnologías de producción animal en indicadores del pastizal y el suelo. Las investigaciones realizadas han mostrado un desarrollo evolutivo satisfactorio, que ha marchado de acuerdo con las necesidades impuestas por las nuevas tendencias científicas. Las investigaciones futuras permitirán proponer alternativas para la adopción de tecnologías que incrementen sostenidamente la fertilidad general de los suelos en las áreas ganaderas del país. [ABSTRACT FROM AUTHOR]

Five well differentiated periods are recognize, that show qualitative changes that have taken place in the researches conception developed in Instituto of Ciencia Animal concerning soil fertility and its relation with pastures and forages production. In the first stage, corresponding to 1965-1970, the studies were centered in nutrients identification that limited pastures production and ways for their correction and appropriate fertilization .The fact that N was identified as the main nutrient that limits soil fertility motivated the development of many researches from 1970-1980, related with the effect of N application on the production and pasture quantity used in the country, as well as the best way of distributing this fertilizer to decrease the seasonal effect of pastures production. The influence of nitrogenous fertilization was also studied in different indicators production and animal health and in the action of continuous applications in soils agro-chemicals properties. This type of researches continued developing in 1980- 1990, stage in which was deepened in the high incidence factors to elevate the efficiency of N use, mainly the influence of climatic factors. In this period the researches were also intensified about laboratory methods for the determination of N assimilable contents from the soil and the influence of Cuban natural zeolite in the improvement of the efficiency of N use by grasses. By the middle of 1981-1990 decade researchers related with the role of animals excrements in the soil fertility and pastures production began. In 1983was clear the effect of quantity and distribution of animals excrete on soil fertility and grassland productivity, and in 1984 different ways of use of this resource and synergy of it with the fertilizer are described. With the new paradigm of the agro-ecological conception in the agricultural use, an original approach in soil fertility topic was opened. In this sense more than twelve researches during the years 1995 and 2000 were developed, that were use as database to form a program that allows knowing the result of nutrients balance in different systems of animal production. More recently, from the beginning of this century, researches have been centered in system studies, mainly related with the impact of animal production technologies in grassland and soil indicators. The researches have shown an evolutionary satisfactory development, which have gone in agreement with the imposed necessities by the new scientific tendencies. Furthers researches will allow to propose alternatives for the adoption of technologies that constantly increase the general soils fertility in cattle areas of the country. [ABSTRACT FROM AUTHOR]

An update in the progress of the scientific researches related to the functions of the soil organisms in the grassland ecosystem is shown. The performance of different microorganisms in this ecosystem is recognized, focusing, mainly, on the functions of primary decomposers, like beetles, worms and termites. It is emphasized that these organisms, responsible for decomposing the excretions of mammals and the litter of the grasslands, increase the general fertility of soils and grassland productivity. The interactions between the primary decomposers and the microorganisms, which live in their gastrointestinal track and in the soil, are determinant in the functioning of this ecosystem. Worms, beetles, and termites have an important function in recycling nutrients in ecosystems of well-managed grasslands. [ABSTRACT FROM AUTHOR]

En un pastizal basado en la mezcla de leguminosas rastreras (Pueraria phaseoloides, Macroptilium atropurpureum y Neonotonia wightii) para la ceba de ganado vacuno en desarrollo, se determinó el comportamiento de indicadores del suelo y el pasto durante tres años consecutivos y se seleccionaron aquellos que mejor reflejan su estabilidad. Mediante el análisis de componentes principales, se obtuvieron tres grupos de indicadores: vegetación, físico-químicos y biológicos del suelo. Se escogieron aquellos con valor de preponderancia mayor que ± 0.78 y que explicaron, al menos, 65 % de la varianza acumulada. En la vegetación, se estudiaron 37 indicadores y se seleccionaron 9, entre los que estuvieron: la cobertura vegetal, el suelo descubierto, la densidad del pasto base, la presencia de pastos naturales y la composición botánica. De los 71 indicadores del suelo, se seleccionaron ocho de los físico-químicos, en los que el índice de plasticidad, la distribución de agregados en húmedo y en seco, la estabilidad estructural, el valor n y la resistencia a la penetración tuvieron el mayor aporte a la variabilidad del sistema; mientras que, de los indicadores biológicos, se seleccionaron también ocho en los que la fitomasa subterránea, la macrofauna y la mesofauna tuvieron su mayor aporte. El pastizal progresó en el tiempo por el incremento de la población del pasto base (Neonotonia wightii) de 11.2 a 34.4 plantas m-2 y por su estabilidad en la disponibilidad de biomasa, la que no tuvo diferencias entre años para cada época climática, con valores de 2.69 y 3.76 t MS ha-1 para las épocas poco lluviosa y lluviosa, respectivamente. Además, hubo mejora de sus características edáficas que se manifestó en la distribución de agregados en seco menores de 1 mm de diámetro y el índice de plasticidad, los que disminuyeron con el tiempo de explotación del sistema. En este estudio, se presentan tablas con rangos de valores de confianza para los indicadores propuestos, que podrán servir como herramientas útiles, confiables y sensibles para conocer los cambios que ocurren en este tipo de pastizal y que se podrán usar en la investigación, la docencia y la producción. [ABSTRACT FROM AUTHOR]

En un diseño experimental de bloques al azar con cuatro réplicas, se estudió el efecto de aplicar 3 dosis de abono verde de tithonia 12 y 24 t/ha) en el establecimiento y la producción de biomasa del forraje P. purpureum vc. Cuba CT-169 y en algunos indicadores suelo ferrálico rojo en La Habana. En el primer corte de establecimiento no se encontró efecto de los tratamientos en la altura de las plan Sin embargo, el número de plantones/m² (2.4 -- 2.5), el número de hijos/planta (10.4 -- 10.6) y el rendimiento de MS/ha (16.2 -- 18.6 t incrementó significativamente con los tratamientos de abono verde, sin diferencias significativas entre las dos dosis aplicadas. En el segundo corte (efecto residual), efectuado tres meses después del primero (febrero 2009), tampoco se encontró diferencia entre tratamientos p la altura de las plantas, pero los indicadores plantones/m² , hijos/planta y rendimiento de MS se incrementaron significativamente hast mayor dosis de aplicación del abono verde. Las dosis de abono verde redujeron significativamente (P < 0.01) la densidad aparente del su (1.01, 0.79 y 0.68 g/cm³ con las dosis de 0, 12 y 24 t/ha) e incrementaron los contenidos de MO (4.2%) y N-total (0.30%). Se recomienda el uso de T. diversifolia como abono verde para mejorar la fertilidad del suelo y aumentar la producción del forraje Cuba CT-169 e suelo ferralítico rojo. [ABSTRACT FROM AUTHOR]

In an experimental design of random blocks with four replicates, it was studied the effect of applying three doses of green manure of tithonia (0, 12, and 24 t/ha) on the establishment and production of biomass from P. purpureum cv. Cuba CT-169 forage and on some indicators of red ferrallitic soil. In the first establishment cut, there was no effect of the treatments on the height of the plants. However, the number of tufts/m² (2.4 - 2.5), the number of tillers/plant (10.4 - 10.6), and the DM yield /ha (16.2 - 18.6 t) were increased significantly in the treatments with green manure, without significant differences between the doses applied. In the second cut (residual effect), conducted three months after the first (February 2009), there were no differences either between treatments for the height of the plants, but the indicators tufts/m², tillers/plant, and DM yield were increased significantly up to the highest dose of green manure application. The green manure doses reduced significantly (P < 0.01) the apparent soil density (1.01, 0.79, and 0.68 g/cm³ with doses of 0, 12, and 24 t/ha) and increased the contents of OM (4.2%) and N-total (0.30%). The use of T. diversifolia is recommended as green manure to enhance the soil fertility and increase the production of Cuba CT-169 forage on red ferrallitic soil. [ABSTRACT FROM AUTHOR]

A detailed analysis of the results obtained in the maps of Cuban soils is performed, at scale 1:250 000 and 1:25 000. There was a growing trend to the decline in the phosphorus and potassium contents in the dynamics of cattle soil fertility between 1977 and 2000, and the low contents of organic matter and potassium were extremely acute, as well as the low natural fertility in forage areas, seeds, and intensive grazing. Among the most serious problems faced by Cuba cattle rearing, there are the degradation of the soils and the careless attention to the process provoking it. This affects seriously the future of this economic activity. When the agricultural systems include the plant cover, the multiple mixtures of legumes, the silvopastoral systems, and the contribution of organic and mineral fertilizers, the physical, chemical, and biological conditions of the degraded soil are recovered. The soil properties that showed higher degree of sensibility to man's management are organic matter, available phosphorus, structural stability, stable aggregates, the factor of structure, and water-air ratio. The measures that should be taken at short term are recommended to recover the degraded soils. [ABSTRACT FROM AUTHOR]

The cattle rearing development reached by Latin America in the last years is emphasized, although it has implied a marked deterioration of the environmental conditions. The necessity of establishing silvopastoral systems that favor the environment and, thus, enhance soil fertility and recover grasslands is indicated. Soil degradation, which is more intense everyday, is one of the most urgent problems in cattle regions. In this sense, the association of grasslands with trees produces favorable effects. This influence is shown, mainly, in the gradual inclusion of nutrients to the soil-pasture-animal system, through the tree leaf litter and the herbaceous stratum, as well as the nutrients transfer from the soil deepest layer to the surface. Frequently, researches show increase in the contents of organic carbon, nitrogen, phosphorous, potassium, calcium, and magnesium on the soil of grasslands with trees. The marked differences between the silvopastoral systems are explained, in respect to the capture of CO2 from the atmosphere and to the increase of the soil carbon. It is shown that different tree components improve markedly the nutrients recycling in the silvopastoral systems. It is proved that, as exploitation time of the silvopastoral system goes on, there are increases on animal production, plant biomass availability, leaf litter production, nutrients recycling and soil fertility. It is concluded that these systems are an imperious necessity for recovering the soil fertility and grasslands productivity in the degraded areas of American tropics. [ABSTRACT FROM AUTHOR]

A methodology is proposed according to fertility indicators of the soil (organic matter, total nitrogen, assimilable phosphorous, calcium, pH, resistance to penetration, leaf litter, infiltration and biological activity) previously selected in grasslands of six cattle units of Havana province. It is based on radial figures that represent, according to the value scale, the state of each indicator and allow estimating the general fertility state of the soil of the cattle unit. Results showed that, with higher frequency, infiltration and leaf litter were the less favourable indicators. The possible relations between the obtained points and the characteristics of the plants and the type of soil are discussed. The proposed methodology allows a more integral interpretation of the soil fertility and could be a favourable tool for the selection of sustainable techniques to improve the less favourable indicators. It is recommended to widen the validation of this methodology. [ABSTRACT FROM AUTHOR]

Se propone una metodología a partir de indicadores de fertilidad del suelo (materia orgánica, nitrógeno total, fósforo asimilable, calcio, pH, resistencia a la penetración, hojarasca, infiltración y actividad biológica), previamente seleccionados en pastizales de seis vaquerías de la provincia La Habana. Esta se basa en figuras radiales que representan, según la escala de valores, el estado de cada indicador, y permite estimar el estado general de fertilidad del suelo de la unidad ganadera. Los resultados indicaron que, con mayor frecuencia, la infiltración y la hojarasca, fueron los indicadores menos favorables. Se discuten las posibles relaciones entre las puntuaciones obtenidas y las características de la vegetación y el tipo de suelo. La metodología que se propone permite la interpretación más integral de la fertilidad del suelo, y podría constituir una favorable herramienta de trabajo para seleccionar técnicas sostenibles para el mejoramiento de los indicadores menos favorables. Se recomienda ampliar la validación de la presente metodología. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the development of the techniques for the control of soil fertility in the world, the role of mathematical models, their practical validation, as well as the advances, limitations and future of high-precision. It discusses the factors decreasing the world's demand for the chemical analyses of soils and plants as a means of determining nutrient requirements and application to crops. Moreover, the idea of using fertilizers came up considering the spatial variability of the soils and the harvest yields.

The article highlights the results of a study on the distribution of cattle dungs in two agroecosystems, namely a stargrass field and a grassland comprising star grasses and carob trees. The distribution of dungs in the first grassland was determined by counting 7,500 square meter paddock during 8 consecutive rotations. Dungs occupied 17.01 square meters as average in the paddock, which represented 0.23 percent in one rotation. The distribution of dungs was higher in the second grassland.