Search

The influence of strategic fertilization with nitrogen (150 kgN/ha) applied in the rainy season in Cenchrus purpureus varieties tolerant to drought (CT-600, CT-601, CT-602, CT-603, CT-604, CT-605, CT-608 y CT-609) compared with CT-115 as control was studied. A random block design with five replications was used. In the dry season only CT-604 had the highest (P<0.001) dry matter percentage of leaf, stem and the hole plant. The highest (P<0.001) leaves content was showed by CT-605 (60.07 and 60.17 % in the rainy and dry season, respectively). The varieties CT-605, CT-608 and CT-609 (5.0, 5.6 and 5.2 tDM/ha, respectively) exceeded (P<0.001) the yield of CT-115 (3.4 tDM/ha) in the dry season. The leaf area varied (P<0.001) between varieties, while CT-604 showed the lower population (P<0.001) in both climatic seasons (7.2 and 4.6 tillers/5min the dry and rainy season, respectively). The varieties CT-605, CT-608 and CT-609 increased their yield in the dry season with adequate leaves contents and adequate population. It is suggest expanding this information with the chemical composition and extending these varieties in the western region, always you had the nitrogenous fertilizer. [ABSTRACT FROM AUTHOR]

A three-year experiment was carried out to evaluate the agronomic performance of new varieties of Cenchrus purpureus (CT-600, CT-601, CT-602, CT-603, CT-605, CT-607, CT-608 and CT -609), tolerant to drought, obtained by in vitro tissue culture, and compared with its parent (CT-115) through a completely random design with five replications. There were significant differences between the height of the varieties and in both seasonal periods CT-605 stood out with values higher (P<0.05) at 90 cm. The leaves content (%) was only significantly different between the varieties in the dry season during the experimental stage, while the percentage of stems showed a similar response pattern. There were varieties that exceeded the DM yield of the control and especially the CT-605 with values of 21.82, 16.37 and 9.05 t DM/ha/year for the first, second and third year, respectively. With the exception of the first year, the varieties did not express their potential for biomass production under water stress conditions and future researches are suggested where rainfalls is less than 800 mm, as well as studying the effect of strategic fertilization on regimes of greater rainfall. [ABSTRACT FROM AUTHOR]

The objective of this paper deal with the analyses of the information obtained in Cuba related to the influence of climatic factors on the production and quality of grasses and forages. The results showed that: the species within the genus and varieties showed a particular and specific response to climatic factors; the same variety of grass responded differently in both seasons of the year; minimum temperatures lower than 15 ºC and maximum lower than 27 ºC, as well as the number rainy days, had a marked effect; the models between yield and quality with the elements of the climate had high complexity and when comparing Pennisetum purpureum (as an experimental model) it showed higher height and lower yield in the 2000s compared to the ´60s. The results showed the specific response of each grass against the climate indicators, like the mathematical models that relate it, as well as the change that the climate has undergone. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyze the composition of some mineral nutrients of Cenchrus purpureus cv. Cuba CT-115 after grazing when used as a biomass bank. For this, a completely randomized sampling design with 15 repetitions was used. Treatments consisted on regrowth age or grass rest from the time of departure of animals from the paddock (time zero) and in accordance with the biomass bank technology. Results indicated that contents of ash, calcium, phosphorus and magnesium had a variable performance, while nitrogen was reduced with the regrowth age for all grazing cycles of this technology. Ash contents ranged between 3.89% and 15.41% (P <0.01), while calcium and phosphorus were between 0.30 and 0.83% (P <0.05) and between 0.17 and 0.43% (P <0.05), respectively. All the studied indicators had higher values in leaves than in stems for tillers and for residue with their new growth. Phosphorus and magnesium contents found in leaves and stems for some regrowth ages were lower than those required for proper growth and development of the grass, so the use of maintenance fertilization might be necessary. It is recommended to use these results to design other management options. [ABSTRACT FROM AUTHOR]

Using a randomized block design with four replications, clones of Cenchrus purpureus (CT-6, CT-9, CT-13, CT-15, CT-24 and CT-28) obtained by in vitro tissue culture were evaluated and compared with their progenitor (CT-115) in typical red Ferralitic soil, for two years without irrigation and fertilization. In both evaluation years during the seasonal periods the height differed (P<0.001) between the clones and the CT-28 surpassed the CT-115 was highlighted. There were differences (P <0.001) in the percent of DM and their values varied in narrow range (17-23% and 19-21% in the dry and rainy season, respectively). With the exception of CT-24, the rest of clones showed leaves contents higher than 50% and differed among them, but the highest value (64.88%, P <0.001) was showed by CT-28 during the rainy season. The leaves length varied (P <0.0001) between clones and CT-9 was highlighted in both years (73.73 and 84.23 cm for the dry and rainy season, respectively for the first year and 68.6 and 76.7 cm for similar stages of the second year). Similar response pattern was obtained in the leaf width. The leaf area also differed between clones and the highest values were recorded in the rainy season of both years. There were significant differences between the clones in the seasonal and annual DM yield and the clones CT-9, CT-15, CT-24 and CT-28 were highlighted. There were also significant differences in the population of the clones at the beginning and end of the experiment, but when comparing these two stages there were not variation and the values ranged between 5.43 and 9.49 bunches/5m. In general terms, the studied indicators varied when comparing the studied years. There is a group of clones with favorable characteristics for forage production, where CT-9 and CT-28 were highlighted. Future studies using strategic fertilization and irrigation of promising clones are suggested. [ABSTRACT FROM AUTHOR]

During two years the relation between some climatic factors and the chemical composition of Tithonia diversifolia was studied, using a completely randomized design and five replications, in brown soil with carbonate. The chemical composition indicators consisted of: NDF, ADF, lignin, cellulose, hemicellulose, cell content, organic matter, ashes, N, Si, P, Ca and Mg; while the climatic factors were the maximum, minimum and average temperatures, rain and number of rainy days. The results are expressed by the Pearson correlation coefficient in each seasonal period. In the rainy season, high and positive correlation coefficients were found between total rain and NDF, ADF, lignin and organic matter (0.87-0.97) and were negative for cellulose, cell content, ashes and N (between -0.88 and -0.97). The relation with the temperatures were variable and the highest value (r = 0.92) was recorded between the P and the average temperature. For the number of rainy days, there was a similar performance to that described above, but the coefficients were higher. In the dry season, there was a positive correlation between total rain and NDF, ADF, lignin, hemicellulose, ashes, P and Ca (0.52-0.88) and were negative with cellulose, cell content, organic matter and N (between - 0.55 and -0.88). For the number of rainy days there was similar performance, but the coefficients were higher and there was relation with the Si (r = -0.45). The linear multiple equations were established between the chemical composition indicators and some climatic factors, with high values of the determination coefficient, low standard error and high significance. The chemical composition indicators showed a specific response to climatic factors in each seasonal period, but the higher effect, expressed by the correlation coefficient, is related to the amount and distribution of precipitation. It is recommended to determine the mathematical model that allows to predict the performance of each indicator of the chemical composition with the climatic factors, as well as to perform this study in other plants of economic importance for animal feeding and to extend it to the secondary metabolites or antinutritional factors. [ABSTRACT FROM AUTHOR]

Pearson correlation coefficients were established among secondary metabolites of Leucaena leucocephala and some climatic factors (maximum, minimum and mean temperature, rainfall and number of rainy days), primary metabolites and digestibility (organic matter, dry matter, protein and NDF). The metabolites were A) secondary: total tannins, total phenols, total condensed tannins, free condensed tannins, alkaloids, saponins, triterpenes, steroids and flavonoids and B) primary: glucose, fructose, sucrose and N. Secondary metabolites were correlated with the maximum temperature and the highest coefficient (r = 0.78) was for steroids. Similar result was obtained for condensed tannins bound to the fiber, but with the minimum temperature (r = -0.90). The highest coefficient for the number of rainy days was presented in flavonoids (r = 0.99), while for total rainfall coefficient, it was for total phenols (r = -0.90). Correlation coefficients between the secondary metabolites and OMD ranged from -0.57 to -0.74. For the in vitro of dry matter digestibility, they ranged between -0.65 and -0.94 and for NDF between -0.91 and -0.98. For PBD, the values were the lowest (-0.39 and 0.55). Considering the phenolic compounds as independent variables and related to alkaloids, saponins, triterpenes, steroids and flavonoids, the highest coefficients (=0.80) were recorded by total tannins, total phenols, total condensed tannins and condensed tannins bound to fiber. When the secondary metabolites were related to the primary metabolites (glucose, fructose, sucrose and N), coefficients were negative and varied between -0.41 and -0.98. It can be concluded that the elements of the climate influenced the studied metabolites. All digestibility expressions were negatively affected by the presence of the secondary metabolites. Phenolic compounds were positively correlated with flavonoids, alkaloids, saponins, triterpenes and steroids, while primary metabolites correlated negatively with secondary metabolites. It is recommended to consider the results of this study in Leucaena leucocephala to assess the effect of climate change on the secondary metabolites, counteract the negative effect of these compounds on ruminant feeding systems, conduct future research to establish its maximum allowable value in the diet and apply the simulatio n and mathematical modeling to predict the performance of these substances in this and other plants. [ABSTRACT FROM AUTHOR]

With the new clones of Pennisetum purpureum drought tolerant, obtained from the progenitor Cuba CT-115, agronomic and biomass quality studies were carried out in an ecosystem of intense seasonal drought in Valle del Cauto. With these results, a multivariate analysis was performed to determine the weight variables in the agronomic performance and its relative contribution to the classification of the promising clones for drought conditions. In the analysis for the rainy season, two components that explained 71.04 % of the total variance were extracted. The weight variables were height, length and wide of leaf, stem thickness, yield of total DM and leaves , absolute growth rate and leaf area. For the dry season, two components that explained 76.63 % of the total variance were extracted, the weight variables coincided, except the stem thickness, and the number of green leaves / plant and the number of branches was also significant. In the grouping dendograms, three groups at each time of the year were formed. In rainy season, one group showed a promising performance (CT-600, CT-601, CT-603, CT-605, CT-608 and CT-609). With the exception of leaf wide, this group achieved the highest expression of the weight variables; another group achieved an intermediate performance including Control Cuba CT-115, CT-602 and CT-607. The group formed by CT-604 and CT-606 had lower height, lower absolute growth rate and lower yields of dry matter. In the dry season, a poor performance group appeared, with CT-604, CT-606 and CT-602. The remaining groups showed some similarity. It is concluded that the performance of these clones is very marked by the season of the year. The CT-606, CT-604 and CT-602 are highlighted for their low biomass production. [ABSTRACT FROM AUTHOR]

The productive performance of growing females of the Cuban Charolais breed under a silvopastoral system with Leucaena leucocephala cv. Peru, in a 3 x 5 sowing frame, associated with an improved grass (Cynodon nlemfuensis) was studied compared to a monoculture. The experiment was conducted at the Empresa de Genética y Cría “Manuel Fajardo”, Granma province, Cuba. Thirty animals per cycle were used and the experiment lasted three years. Data were processed through a multivariate analysis and measurement of the impact index. The best live weights gains with 0.55 kg.animal.d-1 and age at incorporation to reproduction of the females of 19 months of age were obtained in the leucaena silvopastoral system. The best gain and the lowest cost per animals were recorded in the silvopastoral system. It is recommended using this leucaena sowing density for maintaining favorable total pasture productions, live weight gains and adequate weight for age relationship at the incorporation in rearing systems of replacement Cuban Charolais growing females. [ABSTRACT FROM AUTHOR]

This research was carried out with the objective of studying the performance of some morphophysiological indicators after grazing P. purpureum cv. Cuba CT-115 used as biomass bank. A completely randomized sampling was used and a total of 15 tufts were collected (experimental unit) immediately after grazing and every 15 days until to complete each growth cycle. The treatments consisted on the age of the grass regrowth from the moment the animals exit the paddock (zero time) and according to the biomass bank technology. During the first year and for each resting cycle the regrowth age influenced (P<0.001) on the plant height. For more of the cycles the length and width of leaves, and the leaf area increased (P<0.001) with the age and the higher values were in the cycles with more favorable climatic conditions for growth and leaf expansion, reaching the leaf area values of 246 cm2 for the fourth cycle of the first year and 204 cm2 for the fifth cycle of the second year. It was also determined the total yield performance with the regrowth age and growth indexes as Culture Growth Rate (CGR) and Net Assimilation Rate (NAR).The results showed that the growth cycles of the studied crop have an specific response pattern in function of the regrowth age and climatic characteristics. The CGR and the NAR have specific response for each cycle and are appropriate indicators for the analysis and characterization of grass growth. It was also proven that the increase of dry matter yield is done with low efficiency (NAR) from the high Culture Growth Rate is reached. It is recommended to incorporate the growth indexes studied in this research as novel tool for the management of other grasses and forage species. [ABSTRACT FROM AUTHOR]

Se informan los resultados de cuatro experimentos, con duración mínima de dos años, realizados en suelo ferralítico rojo típico, mediante diseños de bloques al azar con cinco réplicas, para establecer la influencia de la fertilización estratégica con N en los clones de Pennisetum purpureum tolerantes a la sequía y determinar las diferencias entre otros que pudieran ser empleados para la producción de forraje o el pastoreo. Varios clones tolerantes a la sequía mostraron su superioridad en el período poco lluvioso (CT-601, CT-602, CT-604, CT-605, CT-608 y CT-609) con respecto al CT-115, cuando se fertilizaron en el período lluvioso. Otros clones (14, 18, 19, 20 y 21) mostraron capacidad para producir forraje en la etapa poco lluviosa, mientras que el 41 y 43 manifestaron características para el pastoreo. Se sugiere llevar a cabo estudios básicos y de composición química, que permitan explicar las diferencias entre los clones, así como experimentos en pastoreo con los clones promisorios. Se propone además, comenzar la introducción en la práctica social de los clones destacados, tolerantes a la sequía que se fertilizan estratégicamente con N en el período lluvioso. [ABSTRACT FROM AUTHOR]

The plant Páramo grasslands ecosystem characterization was carried out by means of field expeditions to eight protected areas that Ecuador maintains through the Ministry of Environment. The expeditions were carried out every two months during three years, to evaluate in situ the botanical composition, frequency, density, height, basal cover and aerial cover. The observations were registered during two periods per year, at 60, 90, 120, 150 and 180 d, for a total of 36 evaluations in each study place. The soil pH varied between 5.0 and 8.5, it is volcanic, with sandy and loamy characteristics. The identified species in the Ecuadorians heathlands were: 169 plants with forage importance, 90 grasses, 14 legumes, 28 compounds and 37 belonging to Equitaceas, Oxalidaceas, Liliaceas, Scrophulariaceas, Rosaceas, Ciperaceas, Poligonaceas, Plantaginaceas, Arbustivas, Orchideaceas, Ranunculaceas and Gentianaceas. A total of eighteen species showed good performance, when locating, at least, in a place. Those of great persistence and adaptation were Agrostis breviculmis, Agrostis exigua, Arrhenatherum pratensis, Arrhenatherum elatius, Bromus lanatus, Bouteloua curtipendula, Calamagrostis bolanderi, Calamagrostis tarmensis, Digitaria floridona, Eragrostis curvula, Euchlaena mexicana, Festuca weberbaueri, Holcus lanatus, Paspalum plicatulum, Paspalum bomplandianum, Poa pratensis, Stipa plumeris and Stipa plumosa. For the production of green and dry forage, respectively, the best were Euchlaena mexicana, with 25.9 and 6.7 t/ha/cut, and Arrhenatherum elatius, with 24.4 and 6.9 t/ha/cut; also Arrhenatherum pratense, with 23.0 and 6.1 t/ha/cut and Stipa plumeris, with 21.9 and 6.8 t/ha/cut. There was great plants biodiversity that can be use for animal feeding, which is observed from other studies of chemical composition and management. [ABSTRACT FROM AUTHOR]

This research was carried out in the Ecuadorian Páramo grasslands, between 2900 and 4200 m o.s.l, in Loja, Zamora Chinchipe, Azuay, Cañar, Chimborazo, Bolívar, Tungurahua, Cotopaxi, Pichincha, Imbabura and Carchi provinces. For the identification and taxonomical classification of species there were taken herborized samples and identified by agrostologists. The Hitchcock, Gould, Lombardo and Tovar taxonomic keys were used for the identification. From the grasses family, in the eight study places, 90 species were identified, including 37 genus, being the mains, with higher number of species: Festuca (14), Paspalum (10), Agrostis (7), Calamagrostis (7), Bromus (6), Stipa (5), Poa (5), Agropirum (3), Arrhenatherum (2), Brisa (2) and Andropogon (2).The species that prevailed in the study places were: Agrostis breviculmis, Agrostis exigua, Bromus lanatus, Calamagrostis tarmensis, Festuca humilior, Festuca ortophylla, Festuca weberbaueri and Paspalum bomplandianum. The diversity indexes of the existent meadow species showed values from mean (0.72) to high (0.90), as for their uniformity. This allowed determining that the biodiversity is variable, according to the environmental conditions of the studied Páramo grassland ecosystems. Similar performance was obtained for trees grasses species. [ABSTRACT FROM AUTHOR]

This research was carried out in the Ecuadorian Páramo grasslands, between 2900 and 4200 m o.s.l, in Loja, Zamora Chinchipe, Azuay, Cañar, Chimborazo, Bolívar, Tungurahua, Cotopaxi, Pichincha, Imbabura and Carchi provinces. For the identification and taxonomical classification of species there were taken herborized samples and identified by agrostologists. The Hitchcock, Gould, Lombardo and Tovar taxonomic keys were used for the identification. From the grasses family, in the eight study places, 90 species were identified, including 37 genus, being the mains, with higher number of species: Festuca (14), Paspalum (10), Agrostis (7), Calamagrostis (7), Bromus (6), Stipa (5), Poa (5), Agropirum (3), Arrhenatherum (2), Brisa (2) and Andropogon (2).The species that prevailed in the study places were: Agrostis breviculmis, Agrostis exigua, Bromus lanatus, Calamagrostis tarmensis, Festuca humilior, Festuca ortophylla, Festuca weberbaueri and Paspalum bomplandianum. The diversity indexes of the existent meadow species showed values from mean (0.72) to high (0.90), as for their uniformity. This allowed determining that the biodiversity is variable, according to the environmental conditions of the studied Páramo grassland ecosystems. Similar performance was obtained for trees grasses species. [ABSTRACT FROM AUTHOR]

Se presentan los resultados principales de la evaluación de gramíneas pratenses, correspondientes al período 1965-2014, obtenidos en el Instituto de Ciencia Animal. Las evaluaciones tuvieron en cuenta aspectos relacionados con las especies y variedades, preparación del suelo, siembra y establecimiento, intercalamiento, rehabilitación, nutrición, producción de biomasa y de semilla, plagas y su control, aspectos fisiológicos, composición química y calidad. Se hace referencia además, a la repercusión de estas gramíneas en la producción de biomasa y se sugieren algunas directrices a seguir en investigaciones futuras. [ABSTRACT FROM AUTHOR]

This study deals with the main results of the evaluation of grasses in the Instituto de Ciencia Animal from 1965 to 2014. Evaluations took into consideration aspects related to species and varieties, soil preparation, sown and establishment, intercropping, rehabilitation, nutrition, production of biomass and seeds, plagues and their control, physiological aspects, chemical composition and quality. In addition, the study refers to the effect of these grasses on biomass production and some guidelines are suggested for further researches. [ABSTRACT FROM AUTHOR]

The performance of the edaphic macrofauna was evaluated in a Leucaena leucocephala-Cynodon nlemfuensis silvopastoral system at the Cattle Breeding Enterprise "Manuel Fajardo", located in the municipality of Jiguaní, Granma province. An area of 6.71 ha distributed in six paddocks was used in a completely randomized design with six replications in a carbonated brown soil. The study was conducted in the litter strata, 0-10, 10-20 and 20-30 cm depth. The taxonomical composition, density and biomass of the macrofauna organisms were determined. The taxonomic composition consisted of 216 individuals, represented by three types, five classes and seven orders. From them, the most represented was the class Insecta. In the density of individuals there were differences (P < 0.05), from the litter of 8.08 individuals/m<>2 to 1.83 individuals/m<>2, at the 20-30 cm depth. For the biomass, there were differences (P < 0.05) and varied from 0.16 to 0.03 g/m<>2 for the litter at 20-30 cm, respectively. Also, in total density there was growth, following tree incorporation (6.07 ind./m<>2) and after total biomass grew by 0.18 g/m<>2, thus proportional abundance increased with the appearance of Hymenopterous, Diplopodous and Lepidopterous. The silvopastoral system improved the macrofauna with advantages for their exploitation as time went by. [ABSTRACT FROM AUTHOR]

To study the performance of some growth indexes of Pennisetum purpureum cv. Cuba CT - 115, when it is used as biomass bank, it was applied a completely randomized sampling design, with 15 repetitions, (bunches as experimental unit) .The treatments consisted on the regrowth age or grass rest . The culture growth rate (CGR), the net assimilation rate (NAR) and the specific foliar area (SFA) were determined to describe the growing of this cultivar. The culture growth rate was characterized, generally, by its gradual increase from 15 days, to get the maximum growth rate that was specific for each cycle and, from that moment on, began to decrease. The maximum productivity during the first year was reached at 71, 57 and 61 days of re-growth for cycles one, two and four, respectively. In the second year, it was obtained at 86, 46, 45, and 69 days of re-growth for cycles one, two, three and five, respectively. The specific foliar area did not vary in the first rest cycle with age in the first year, and decreased in the remaining cycles. The net assimilation rate shows specificity in its response pattern to the re-growth age in each rest cycle. It is concluded that CGR, SFA and NAR had specific response for each cycle, regarding the re-growth age and the climatic characteristics, and showed to be adequate indicators for the analysis of the growing of Cuba CT-115 cultivar. It is recommended the use of growth indexes of this grass as a tool for the management of biomass banks, as well as its utilization in the studies of other species of Pennisetum genre and in the design of other management options. [ABSTRACT FROM AUTHOR]

A random block design with five replications and thirteen treatments was applied. Treatments consisted of three varieties of Pennisetum purpureum (king grass, Cuba CT-115 and Cuba CT-169) cut two (August and February), four (May, July, September and February) and five times a year (November, February, May, July and September) and two of Saccharum officinarum (Jaronú 60-5 and Villa Clara 21), cut one (February) and two (February and August) times a year for determining their influence on some forage quality indicators. The experiment was conducted in a red ferrallitic soil for four years with fertilization (100-60-80 kg/ha/year of N, P2O5 and K2O, respectively) and irrigation during the dry period. There were differences (P < 0.001) in the CP content of the varieties according to the cutting frequency. The highest values were registered in leaves, stems and the whole plant of the Pennisetum varieties with ranging values of 7.6-10, 4.2-5.9 and 5.1-7.3 %, respectively when cut five times a year. Crude fiber differed (P < 0.001) and the lowest values were recorded in the Pennisetum varieties with the highest cutting frequency. For in vitro organic matter digestibility there were differences (P < 0.001) favorable to the highest cutting frequency. Best results were attained when the Pennisetum varieties were cut five times per year. Cutting Saccharum two times per year propitiated the disappearance of Jaronú 60-5 at the end of the second year of study. The best balance of the studied indicators was obtained when Pennisetum and Saccharum varieties were cut five and once per year, respectively. There is available information that will allow improving the management of these varieties, for using them efficiently and attaining greater longevity of the plantation. [ABSTRACT FROM AUTHOR]

The effect of regrowth age (30, 45, 60, 75 and 90 d) in the content of secondary metabolites from Neonotonia wightii was evaluated through a random blocks design, with six replications. The experiment took place from January to March (dry season) and from May to July (rainy season), in a carbonated brown soil, without irrigation and fertilization. Total tannins, total phenols, total condensed tannins, total mixed condensed tannins, free condensed tannins, flavonoids, saponins, alkaloids, triterpenes and steroids increased (P < 0.05) with age and the highest values were obtained at 90 d (5.24; 10.07; 77.67; 76.72; 0.95; 3.29; 0.53; 0.30; 8.58 and 0.63 g/kg DM during May-June-July and 3.12; 8.24; 96.64; 94.68; 1.96; 3.99; 0.52; 0.30; 8.51 and 0.69 g/kg DM during January-February-March, respectively). It can be concluded that regrowth age and climatic factors had a marked effect on the concentration of secondary metabolites. It was demonstrated that while the plant was maturing, the tenors of secondary metabolites increased. Only total condensed tannins and total mixed condensed tannins surpassed the limits in which the ruminant fermentation could be affected. It is recommended not to use this plant with an regrowth age higher than 75 d old. A similar study is suggested to be conducted with this and other legumes, in different environmental conditions, and to determine the relation between these metabolites and the digestibility and intake of these plants. [ABSTRACT FROM AUTHOR]

Se aplicó un diseño de bloques al azar con cinco réplicas y trece tratamientos, que consistieron en tres variedades de Pennisetum purpureum (king grass, Cuba CT-115 y Cuba CT-169), cortadas dos (agosto y febrero), cuatro (mayo, julio, septiembre y febrero) y cinco veces al año (noviembre, febrero, mayo, julio y septiembre), y dos de Saccharum officinarum (Jaronú 60-5 y Villa Clara 21), cortadas una (febrero) y dos (febrero y agosto) veces por año, para determinar su influencia en algunos indicadores de la calidad de los forrajes. El experimento se condujo en suelo ferralítico rojo durante cuatro años, con fertilización (100-60-80 kg/ha/año de N, P2O5 y KƻO, respectivamente) y riego durante el período poco lluvioso. Hubo diferencias (P < 0.001) en el tenor de PB de las variedades de acuerdo con la frecuencia de corte. Los mayores valores se registraron en las hojas, tallos y planta íntegra de las variedades de Pennisetum, con rango de valores de 7.6-10, 4.2-5.9 y 5.1-7.3 % respectivamente, cuando se cortaron cinco veces al año. La fibra cruda difirió (P < 0.001) y los menores valores se registraron en las variedades de Pennisetum con la mayor frecuencia de corte. Para la digestibilidad in vitro de la materia orgánica hubo diferencias (P < 0.001) favorables a la mayor frecuencia de corte. Los mejores resultados se alcanzaron cuando las variedades de Pennisetum se cortaron cinco veces al año. Cortar dos veces al año a Saccharum repercutió en que la Jaronú 60-5 desapareciera al finalizar el segundo año de estudio. El mejor balance de los indicadores estudiados se obtuvo cuando las variedades de Pennisetum y Saccharum se cortaron cinco y una vez al año, respectivamente. Se dispone de información que permite mejorar el manejo de estas variedades, utilizarlas eficientemente y lograr mayor longevidad de la plantación. [ABSTRACT FROM AUTHOR]

Se evaluó el comportamiento de la macrofauna edáfica en un sistema silvopastoril Leucaena leucocephala - Cynodon nlemfuensis en la Empresa de Genética “Manuel Fajardo", ubicada en el municipio Jiguaní, provincia Granma, Cuba. Se utilizó un área de 6.71 ha, distribuidas en seis cuartones en un diseño totalmente aleatorizado, con seis réplicas, en suelo pardo con carbonato. El estudio se realizó en los estratos hojarasca, 0-10, 10-20 y 20-30 cm de profundidad. Se determinó la composición taxonómica, densidad y biomasa de organismos de la macrofauna. La composición taxonómica estuvo compuesta por 216 individuos, representados en tres tipos, cinco clases y siete órdenes. De ellos, el más representado fue la clase Insecta. En la densidad de individuos hubo diferencias (P < 0.05), desde la hojarasca de 8.08 individuos/m2 hasta 1.83 individuos/m2, en la profundidad de 20-30 cm. En la biomasa hubo diferencias (P < 0.05) y varió desde 0.16 hasta 0.03 g/m2 para la hojarasca y 20-30 cm, respectivamente. Además, en la densidad total hubo crecimiento, después de la incorporación de los árboles en 6.07 ind/m2 y la biomasa total creciera en 0.18 g/m2, por lo que la abundancia proporcional aumentó con la aparición de Hymenopteros, Diplópodos y Lepidopteros. El sistema silvopastoril mejoró la macrofauna, con ventajas en su explotación en la medida que transcurrió el tiempo. [ABSTRACT FROM AUTHOR]

Para estudiar el comportamiento de algunos índices de crecimiento del Pennisetum purpureum vc. Cuba CT-115, cuando se utiliza como banco de biomasa, se aplicó un diseño de muestreo completamente aleatorizado, con 15 repeticiones (macollas como unidad experimental). Los tratamientos consistieron en la edad de rebrote o reposo del pasto. Se determinaron la tasa de crecimiento del cultivo (TCC), la tasa de asimilación neta (TAN) y el área foliar específica (AFE) para describir el crecimiento de este cultivar. La TCC se caracterizó, generalmente, por su incremento gradual a partir de los 15 d de edad, hasta llegar a la máxima tasa de crecimiento que fue específica para cada ciclo y, a partir de ese momento, comenzó a descender. La máxima productividad durante el primer año se alcanzó a los 71, 57 y 61 d de rebrote para los ciclos uno, dos y cuatro, respectivamente. En el segundo año se obtuvo a los 86, 46, 45 y 69 d de rebrote para los ciclos uno, dos, tres y cinco, respectivamente. El AFE no varió en el primer ciclo de reposo con la edad en el primer año, y disminuyó en los restantes ciclos. La TAN mostró especificidad en su patrón de respuesta a la edad de rebrote en cada ciclo de reposo. Se concluye que la TCC, el AFE y la TAN tuvieron respuesta específica para cada ciclo, en función de la edad de rebrote y de las características climáticas y mostraron ser indicadores adecuados para el análisis del crecimiento del cultivar Cuba CT-115. Se recomienda utilizar los índices de crecimiento de este pasto como herramienta para el manejo de los bancos de biomasa, así como su utilización en los estudios de otras especies del género Pennisetum y en el diseño de otras opciones de manejo. [ABSTRACT FROM AUTHOR]

Biomass production performance of nine Pennisetum purpureum clones was evaluated in function of air temperature, rainfall and number of rainy days. The research was based on an experimental study developed at the Institute of Animal Science during the period 2009-2010 in a typical red ferrallitic soil without applying fertilization or irrigation. A completely randomized design was used and nine cuttings with four replications were practiced. Average yields of the two years of evaluation were 2.32 - 4.08 t/ha in the rainy period which were higher to those obtained in the dry period (0.75 - 1.36 t/ha). Yield had a decreasing tendency in time The highest significant correlations were achieved with the temperature (0.33-0.70) besides the number of rainy days. The coefficients of determination ranged between 58 and 80 %. It is concluded that forage production of P. purpureum was connected with the performance of the rainfall and temperature, and constitute a viable alternative for biomass production. [ABSTRACT FROM AUTHOR]

Biomass production performance of nine Pennisetum purpureum clones was evaluated in function of air temperature, rainfall and number of rainy days. The research was based on an experimental study developed at the Institute of Animal Science during the period 2009-2010 in a typical red ferrallitic soil without applying fertilization or irrigation. A completely randomized design was used and nine cuttings with four replications were practiced. Average yields of the two years of evaluation were 2.32 – 4.08 t/ha in the rainy period which were higher to those obtained in the dry period (0.75 – 1.36 t/ha). Yield had a decreasing tendency in time The highest significant correlations were achieved with the temperature (0.33-0.70) besides the number of rainy days. The coefficients of determination ranged between 58 and 80 %. It is concluded that forage production of P. purpureum was connected with the performance of the rainfall and temperature, and constitute a viable alternative for biomass production. [ABSTRACT FROM AUTHOR]

An experiment was conducted during two years to establish the variability of the agronomic indicators of Pennisetum purpureum cv. Cuba CT-115. Samples were taken at different sampling distances (1, 2, 3, 4 and 5 m length). The data of an experiment with random block design and four replicates were used. The lowest variance, standard deviation and coefficient of variation were obtained with sampling distance of five meters for the height (4.3, 2.1 and 1.88, and 1.1, 1.0 and 0.99 for the rainy and dry season, respectively). Similar performance had the per cent of leaves and dry matter of the whole plant. The sampling distance of five meters propitiated lower yield variability (18.04 and 12.35% in the rainy season and dry season, respectively). Similar performance had the number of bunches/m (8.34 and 12.27, in that same order). In all the indicators, the lowest width of the values range was obtained, in general, in the distance of five meters. When sampling the population, five bunches/m recorded the lowest variability compared with 11 bunches/m. It is concluded that for the best estimation of the agronomic indicators, the samplings should be conducted in five linear meters. No less than five bunches as sample units should be taken. Similar studies in grasslands with different growing habits are recommended. [ABSTRACT FROM AUTHOR]

An experiment was carried out to determine the agronomical indicators, expressed in humid basis, most contributing to account for the variability in 49 clones of Pennisetum purpureum, obtained by in vitro tissue culture from the apical tissue of P. purpureum cv Cuba CT-115. A completely random design with five replications was applied. The experiment lasted one year. The analysis of the main components indicated that in the rainy period two components accounted for 81.65% of the variability among clones integrated by height, leaf and stem contents and length of the fourth leaf completely opened, internode length and fresh matter yield. In the dry period two main components accounted for 84.68% of the variability between clones integrated by the same indicators than in the rainy period. It is concluded that the above mentioned indicators, expressed in humid basis, can be used for establishing the variability among Pennisetum clones. This determines savings in time and resources, without losing the quality and scientific rigor in the research. Similar studies are recommended under different environmental conditions and with other pasture varieties including other indicators. [ABSTRACT FROM AUTHOR]

The influence of sampling distance (1, 2, 3, 4 and 5 meters) on the agronomical indicators of Pennisetum purpureum cv. Cuba CT-115, cultivated in a typical red ferrallitic soil without irrigation or fertilization was studied using a random block design with four replications. The experiment was developed during two years and samplings were practiced every 90 d. In both seasonal periods, plant height differed (P < 0.001) between sampling distances, the same as the dry matter percentages of leaves, stems and the whole plant. Similar performance showed the leaf and stem contents. The highest (P < 0.001) DM yields were obtained in the highest sampling distances and varied between 0.39 - 2.01 and 0.13 - 1.48 kg for five and one meter, respectively. The number of sprouts/m showed the same performance ranging between 8.0 and 9.8 for the distance of five meters regarding to 2.25 - 2.59 for the distance of one meter. The best sampling distance was five meters, due to lower variability of the agronomical indicators and high representativeness. Similar studies with grasses of different growing habits as well as with legumes are recommended. [ABSTRACT FROM AUTHOR]

Through a completely randomized design with six replicates, the effect of the re-growth age (30, 45, 60, 75 and 90 d) on the nutritive quality of Neonotonia wightii was assessed, as well as the relation between its digestibility, ME and tannins. The experiment was conducted during the trimesters January-February-March (dry season) and May-June-July (rainy season), on a brown soil with carbonate, without irrigation or fertilization. The DM, silica (Si), NDF, ADF and lignin increased (P < 0.05) with age and the highest values were obtained at 180 d, while the CP, DM in vitro digestibility and ME diminished (P < 0.05). The highest values were reached at 30 d. The total phenols, total tannins and total condensed tannins increased (P < 0.05) with the re-growth age in both seasons and reached the maximum concentrations at 90 d (10.7, 5.24 and 77.66 g/kg DM in May-June-July and 8.24, 3.12 and 96.64 g/kg DM in January-February-March, respectively). In both seasons, high negative correlations (between -0.82 and -0.99) were obtained between the total phenols, total tannins and total condensed tannins and the DM in vitro digestibility, OMD, DM in situ digestibility, true digestibility (TD) and ME. It is concluded that age had a marked effect on the indicators assessed, more highlighted in the rainy season, when the nutritive quality diminished due to the increase of the fiber fraction, diminishing of the protein, digestibility and ME, and due to the inverse relation between the two last indicators and the phenolic compounds. Studies on other legumes under different edafoclimatic and management conditions are suggested. [ABSTRACT FROM AUTHOR]

The performance of some agronomic indicators of 12 new Pennisetum purpureum clones (14,18,19,20,21,24, 30, 36, 39,41,42 and 43) obtained by in vitro tissue culture was assessed during a year and they were compared to their progenitor (P. purpuereum vc. Cuba CT-115) through a completely random design with four repetitions. Plots of 25m2, without irrigation and fertilization, were used. The samplings were conducted every 60 and 90 d in the rainy and dry seasons, respectively. There were differences (P < 0.001) in the clones' height, but none of them surpassed the control (67.9 cm) in the rainy season, while the 14, 18, 20, 30 and 36 highlighted in dry season (P < 0.001). Similar performance was recorded for the leaves' length during the rainy season. The highest (P < 0.001) width was for the clones 39 (3.7cm) and 43 (3.1cm) in the rainy and dry seasons, respectively. The highest (P < 0.001) leaves percentages were reached by the clones 41 and 43 (65.8 and 66.1 %, respectively) in the rainy season and the 39, 41 and 43 (53.5; 53.1 and 54.8 % respectively) in the dry season. The clone 20 recorded the highest (P < 0.001) total yield (14.9 tDM/ha/year), but only produced the 28.2 % in the dry season. This clone also had the highest population (17.6 bunch/5m) at the end of the experiment. There are new clones of P. purpureum with favorable productive characteristics increasing the available gene-fund of this species, mainly the clone 20 that surpassed the control in the yield, content of leaves and population. Basic studies to explain the differences found between clones are necessary, as well as the study of their responses when using maintenance fertilization. [ABSTRACT FROM AUTHOR]

In a random block design with four replications, quality indicators related to the climate and age of Pennisetum purpureum cv. Cuba CT-169 were determined in both seasonal periods. The experiment was carried out in a fluvisol soil, under non-irrigation conditions and without fertilization. A multivariate analysis of main components was made, considering the climatic factors and the quality indicators. The preponderance value, equal or higher than 0.75 was considered as the selection factor. Linear multiple equations and the values of the coefficient of determination were above 0.88. The highest R2 were obtained for DMD and OMD (equation II = a + b*CF + d* Age, P < 0.001). Pennisetum purpureum cv. Cuba CT-169 can be characterized by rainfall, temperature (minimum, mean, maximum) and relative humidity, also through CP, CF, ADF, L, CW, DMD, OMD, ME, FNE, CC and cellulose. Linear multiple regression equations were established between DMD, OMD, ME and FNE considering: a) CP, CC and age; b) CF, CW and age; c) CP, L and age, with high R2 and low standard errors of estimation and square mean of the error. Further studies on regrowth physiology in other varieties and types of soil are recommended. More studies mainly on the performance of the chemical composition indicators are suggested to collect more information about the climatic conditions of Cauto Valley so as to validate results in other regions of the country. [ABSTRACT FROM AUTHOR]

A completely random sampling design was used to study the chemical composition of CT-115 used as biomass bank. The treatments corresponded with the re-growth ages of the pasture from the moment the animals went out to the paddock (zero time) to completing each growth cycle, according to the technology of biomass bank. In all the cycles, the re-growth age diminished the CP value (P < 0.001) and the cell content (P < 0.01) in the basal tillers as in the residue. The higher protein values were found in the leaves of the basal tillers and the residue (P < 0.001), with 14.3 %and 11.9 % respectively, at 15 d in cycle one. The cell wall increased (P < 0.01) with age in all cycles. The leaves had lower values than the stems. The highest values were, generally, in the residue stems (84.07 %), at 105 d of re-growth for cycle four. The cellulose and lignin contents increased with age in most of the cycles, with maximum values in the leaves of 38.8 % and 7.9 %, respectively. The lignin values were inferior in leaves and stems of the basal tillers. The results of this study allow concluding that the cell wall, cellulose and lignin increased with the re-growth age. The CP and the cell content reduced similarly in the rest of the pastures. However, these indicators in the leaves of CT-115 get to the 105 d with an acceptable quality for cattle. Due to the leaves quality in this variety of Pennisetum, grazing with a high defoliation index up to the height desired by the animal is recommended and, therefore, a higher productivity would be achieved. [ABSTRACT FROM AUTHOR]

Rainfall performance in the farm of the Institute of Animal Science (ICA) in Cuba during the period 1970-2009 was studied with data recorded at the agro-meteorological station. The methodology of analysis of seasonal series was applied and the performance of its components: seasonal variations, trend, cyclicity and random component of the time series were studied. It was confirmed that the seasonal character of rainfall was maintained each year, but showed stability during the last decade, as well as decrease of the minimum and maximum values. There was a very high variability and it was confirmed by the analysis of the coefficients of variation, which reached values above 41% in all months, particularly, in the poor rainy period, with average fluctuations of 200 mm. Also in this stage there was a decrease in the amount of rainfall of 324 mm in the period 1970-1980 to 225 mm presently. It is foreseen that this decrease will continue and that the difference between periods will increase, with a probability of 1105.7 mm for 95%. In general, rainy days also showed a decreasing trend. Regarding rainfall cyclicity at ICA, the duration was variable. It can be concluded that the high rainfall inter-annual variability, the inequality of its distribution throughout the year and the decrease of the rainy days favor the instability of these events at ICA's farm. [ABSTRACT FROM AUTHOR]

En un diseño de bloques al azar con cuatro réplicas se determinaron los indicadores de calidad y se relacionaron con el clima y la edad de Pennisetum purpureum vc. Cuba CT- 169 en ambos períodos estacionales. El experimento se desarrolló en un suelo de tipo fluvisol, en secano y sin fertilización. Se realizó análisis multivariado de componentes principales, tendiendo en cuenta los factores climáticos y los indicadores de calidad. Se consideró, como factor de selección, el valor de preponderancia, igual o mayor que 0.80. Las ecuaciones múltiples lineales y los valores del coeficiente de determinación estuvieron por encima de 0.88. Los mayores R2 se obtuvieron para la DMS y DMO (ecuación II=a+b*FB+c*PC+d* Edad, P < 0.001). Pennisetum purpureum vc. Cuba CT-169 se puede caracterizar mediante las lluvias, temperature mínima, media, máxima y humedad relativa, además por la PB, FB, FAD, L, PC, DMS, DMO, EM, ENL, CC y celulosa. Se establecieron ecuaciones de regresión múltiple lineal entre la DMS, DMO, EM y ENL, considerando: a) PB, CC y edad, b) FB, PC y edad, c) PB, L y edad, con altos R2 y bajos errores estándar de estimación y cuadrado medio del error. Se recomienda continuar estudios de la fisiología del rebrote en otras variedades y tipos de suelo. Se sugiere profundizar fundamentalmente en investigaciones acerca del comportamiento de los indicadores de composición química para recopilar más información acerca de las condiciones climáticas del Valle del Cauto y avalar los resultados en otras regiones del país. [ABSTRACT FROM AUTHOR]

En un diseño de bloques al azar con seis réplicas se evaluó la influencia de la edad de rebrote (30 a 75 d) y los factores del clima en la calidad nutritiva del pasto Panicum maximum vc. Mombasa. El experimento se enmarcó en los trimestres enero-febrero-marzo (poca lluvia) y mayo-junio-julio (lluvia), en suelo de tipo pardo con carbonato, sin riego ni fertilización. Las correlaciones más altas se presentaron entre los indicadores de calidad y edad, temperatura media, humedad relativa máxima y lluvias. Las ecuaciones de regresión lineal durante el período lluvioso presentaron R2 que variaron entre 0.97 y 0.99. Se destacaron MS, FND, celulosa, hemicelulosa, y digestibilidad in situ. Los menores errores estándar de estimación se obtuvieron en FND, celulosa y hemicelulosa. Se concluye que la edad de rebrote y las condiciones climáticas tuvieron efecto marcado en el valor nutritivo. Se recomienda continuar estudios de estos indicadores en diferentes tipos de suelos, en las condiciones edafoclimáticas del Valle del Cauto, con el objetivo de disponer de más información. [ABSTRACT FROM AUTHOR]

In a random block design with six replicates, the influence of the regrowth age (30 to 75 d) and the climatic factors were evaluated in the nutritive quality of the pasture Panicum maximum cv Mombasa. The experiment was conducted in the trimesters January-February-March (dry season) and May-June-July (rainy season), on soil of the brown type with carbonate, without irrigation or fertilization. The highest correlations were between the indicators quality and age, mean temperature, maximum relative humidity and rainfall. The equations of linear regression during the rainy season had R² that varied between 0.97 and 0.99. DM, NDF, cellulose, hemicellulose, and in situ digestibility were outstanding. The lowest standard errors of estimation were obtained in NDF, cellulose, and hemicellulose. It is concluded that the regrowth age and the climatic conditions had marked effect on the nutritive value. Further studies on these indicators are recommended in different types of soils, in the edaphoclimatic conditions of the Cauto Valley, with the aim of having more information available. [ABSTRACT FROM AUTHOR]

Se utilizaron los datos de calidad y rendimiento de Pennisetum purpureum vc. Cuba CT-169, provenientes de un experimento con diseño de bloques al azar con cuatro réplicas, para relacionarlos con factores del clima. El experimento se desarrolló en un suelo de tipo fluvisol, en secano y sin fertilización. Se realizó análisis de correlación lineal entre los indicadores de rendimiento, calidad y elementos del clima en cada período. Además, se determinaron entre ellos ecuaciones múltiples lineales. Se obtuvieron altas correlaciones (coeficientes mayores que 0.80) con las precipitaciones y la temperatura media (excepto el rendimiento, porcentaje de hojas y tallos, PB, hemicelulosa, ceniza y MO). Con la humedad relativa sobresalió la FAD, lignina, fósforo, celulosa, ceniza y MO en el período lluvioso. En el poco lluvioso se destacó el rendimiento, PB, FB, pared celular, fósforo, contenido celular, hemicelulosa, EM y ENL. Se determinaron ecuaciones múltiples lineales y los valores del coeficiente de determinación estuvieron por encima de 0.92. En el período lluvioso, los mayores R2 se obtuvieron para PB, y en el poco lluvioso para DMS, EM y ENL (P < 0.001). Se estableció el grado de relación entre algunos factores climáticos, rendimiento y calidad del CT-169 en el Valle del Cauto. Se establecieron ecuaciones de regresión múltiples lineales que relacionan rendimiento, PB, FB, lignina, DMS, DMO, EM y ENL con las lluvias, temperatura máxima y humedad. Esto permite realizar un cálculo aproximado de los indicadores referidos, a partir del conocimiento de los factores climáticos mencionados. Se sugiere continuar este tipo de estudio con otras especies y condiciones ambientales, de modo que se puedan ampliar los resultados informados. [ABSTRACT FROM AUTHOR]

Quality and yield data of Pennisetum purpureum cv. Cuba CT-169 were used. The data were from an experiment using a random block design with four replicates, connecting them with climate factors. The experiment was carried out on soil of the fluvisol type, and without fertilization and irrigation. An analysis of linear correlation was performed between the indicators of yield, quality, and climate elements in each period. Besides, multiple linear equations were determined between them. High correlations were obtained (coefficients higher than 0.80) with the rainfall and the average temperature (except for the yield, the percentage of leaves and stems, CP, hemicellulose, ash, and OM). With the relative humidity, ADF, lignin, phosphorus, cellulose, ash, and OM were oustanding in the rainy season. In the rainy season, the yield, CP, CF, cell wall, phosphorus, cell content, hemicellulose, ME and NFE were outstanding. Multiple linear equations were determined and the values of the coefficient of determination were above 0.92. In the rainy season, the highest R2 were obtained for CP, and, in the dry season, for DMD, ME and NFE (P < 0.001). It was established the degree of relation between some climatic factors, the yield, and the quality of the CT-169 in the Cauto Valley. Equation sof multiple linear regression were established relating the yield, CP, CF, lignin, DMD, OMD, ME, and NFE with the rainfall, maximum temperature and humidity. This allows to make an approximate calculation of the indicators, out of the knowledge of the climatic factors. This type of study should be continued with other species and environmental conditions, in a way that the results could be further spread. [ABSTRACT FROM AUTHOR]

Para estudiar el comportamiento de algunos indicadores morfoagronómicos en los estratos de Pennisetum purpureum vc. Cuba CT-115 se utilizó un diseño de muestreo completamente aleatorizado, con 15 repeticiones. Los tratamientos consistieron en cinco estratos: 0-30 cm, 30-60 cm, 60-90 cm, 90-120 cm y más de 120 cm. Los resultados indicaron que en el rechazo (inmediatamente después del pastoreo) el rendimiento del residuo se estabilizó hacia los estratos superiores (P < 0.05), mientras que a los 30 y 60 d de rebrote no hubo diferencias. A los 90 d de rebrote apareció material vegetal en el estrato mayor de 120 cm, con valores de 0.64 kg MS/macolla, que difirió del resto de los estratos (P < 0.001), excepto del estrato basal (0-30 cm). Los porcentajes de hojas del residuo para todas las edades de rebrote se incrementaron hacia los estratos superiores, con valores máximos de 18.67, 19.45, 21.66 y 46.51 % para el rechazo, 30, 60 y 90 d de rebrote, respectivamente. Sin embargo, los porcentajes de tallos y de material muerto (MM) se redujeron. Los hijos basales surgieron a partir de los 60 d de rebrote, sin mostrar diferencias en cuanto al rendimiento de los mismos entre estratos. El porcentaje de hojas en los hijos basales mostró incremento (P < 0.001) hacia el estrato de 30-60 cm, con valores de 60.37 y 63.33 %, para 60 y 90 d, respectivamente. Los tallos tuvieron un comportamiento inverso. Se concluye que los estratos superiores presentaron los mayores porcentajes de hojas, menores de tallo y material muerto, en los hijos basales como en el residuo, para todas las edades de rebrote, lo que favorece el valor nutritivo del forraje. Se recomienda utilizar esta información para diseñar otras opciones de manejo. [ABSTRACT FROM AUTHOR]

In order to study the performance of some morpho-agronomic indicators in strata of Pennisetum purpureum cv. Cuba CT-115, a completely randomized design was used with 15 repetitions. The treatments consisted of five strata: 0-30 cm, 30-60 cm, 60-90 cm, 90-120 cm and more than 120 cm. The results indicated that in the rejected material (immediately after grazing) the residue yield was stabilized up to the upper strata (P < 0.05), whereas there were no differences at 30 and 60 d of regrowth. At 90 d of regrowth it appeared plant material in the stratum of more than120 cm, with values of 0.64 kg DM/tuft, differing from the rest of the strata (P < 0.001), except the basal stratum (0-30 cm). The percentages of leaves from the residue for all regrowth ages were increased up to the upper strata, with maximum values of 18.67, 19.45, 21.66, and 46.51 % for the rejected material, 30, 60, and 90 d of regrowth, respectively. However, the percentages of stems and dead material were reduced. The basal tillers emerged since 60 d of regrowth, not showing differences so as to their yield between strata. The percentage of leaves in the basal tillers was increased (P < 0.001) up to the stratum of 30-60 cm, with values of 60.37 and 63.33 %, for 60 y 90 d, respectively. The stems had an inverse performance. It was concluded that the upper strata had the highest percent-ages of leaves, the lowest of stems and dead material, in the basal tillers as in the residue, for all the regrowth ages, favoring the nutritive value of the forage. Using this information for designing other management choices is recommended. [ABSTRACT FROM AUTHOR]