Evaluation of alfalfa varieties in the province of Salamanca

XLV Reunión Científica de la SEEP (Sesión: Producción Vegetal)Se realiza un estudio comparativo de 26 variedades registradas de alfalfa (Medicago sativa L.), cultivadas en regadío en la provincia de Salamanca, evaluando la producción y contenido de proteína bruta. El primer año del experimento se realizaron cuatro cortes, siendo la producción en el primer corte significativamente más baja que en el resto. La producción total anual oscila entre 8160 kg ha-1 en la variedad “Baraka” y 10109 kg ha-1 en “Bar MS 82439”, con un valor medio sobre todas las variedades de 9370 kg ha-1. El contenido de proteína bruta oscila entre 19,30% en la variedad “Almar” y 23,47% en la variedad “Aragón”.{ENG}Dry matter production and protein content were evaluated in 26 alfalfa (Medicago sativa L.) varieties grown under irrigation in the province of Salamanca. In the first year four harvests were made. The dry matter production of the first haverst was the lowest. The annual dry matter production ranged between 8160 kg ha-1 in “Baraka” and 10109 kg ha-1 in “Bar MS 82439”, with a mean value across varieties of 9370 kg ha-1. The protein content ranged between 19.30% in “Almar” and 23.47% in “Aragón” variety.Este trabajo ha sido realizado con financiación del Ministerio de Ciencia y Tecnología (AGL2002-02766 AGR-FOR

The symbiosis with the fungal endophyte Epichloe festucae affects the phosphorus content of Festuca rubra.

XLIV Reunión Científica de la Sociedad Española para el Estudio de los Pastos. 10-14 de mayo de 2004, Salamanca (España){ESP}En los pastos de dehesas de Salamanca cerca del 70%. de las plantas de Festuca rubra están permanentemente infectadas por el hongo endofítico Epichloe festucae. Se realizó un experimento de campo en el cual se comparó el contenido de fósforo en cinco líneas de F. rubra, cada una de las cuales estaba compuesta por una versión endofítica y otra no infectada. En plantas en estado vegetativo se detectó un aumento estadísticamente significativo del contenido de P en las plantas infectadas de todas las líneas. Este efecto también se observó en plantas en estado reproductivo, pero en este caso no hubo diferencias tan pronunciadas debidas a la infección. También se ha observado una tendencia a una mayor producción de biomasa por parte de las plantas infectadas por Epichloe festucae.{ENG}In the dehesa grasslands of the province of Salamanca, close to 70% of the Festuca rubra plants are infected by the fungal endophyte Epichloe festucae. An experiment was done to compare the phosphorus content in five half-sib families of Festuca rubra. Each family was composed by an endophyte infected and an endophyte free version of the half-sib plants. In plants in vegetative state, the P content was significantly higher for infected plants in analyses conducted at two different years. During the reproductive state of the plants, a non-significant similar trend was observed. Biomass production was also higherin infected that in non-infected plants.Este trabajo se ha financiado con el proyecto AGL 2002-02766 del Plan Nacional 1 +D. Agradecemos la colaboración de María Romo, Yolanda Arnaiz y Carlos Estévez

Mineral content in semiarid grassland systems affected by community structure and soil characteristics

This work was supported by the European Union project nº 8001-CT90-0021.Mineral element concentrations in plants and their relationships with botanical composition and soil characteristics were analyzed over two consecutive years in herbage samples from semiarid grassland systems (central-western Spain) affected by a topographic gradient. There were not significant differences in the mineral concentration of the plant community between sampling years suggesting that factors other than those related to interannual climatic variation are more important in determining the mineral concentration of plant community in semiarid grasslands. A significant effect of slope position on aboveground biomass production, soil characteristics and plant tissue nutrient contents was found. As compared to the upper and middle zones, the lower zones of slope showed greater aboveground biomass production, a lower proportion of forbs, a higher proportion of grasses, higher concentrations of N, Ca, Mg and Na in botanical groups, and lower concentrations of P and K in botanical components. Stepwise multiple regression analysis showed that most of the variation in N, P, K, Ca, and Mg concentrations in the plant community along the slope can be explained by botanical composition and its specific mineral content. Several soil properties (organic matter, total N, total C, coarse sand) proved to be significantly correlated with the N, Ca, Mg, and Na concentrations of grasses, legumes and forbs, indicating an increase in plant tissue concentrations with increasing eutrophic status in soil from the upper to the lower zones of the slope. The P and K concentrations of legumes and forbs varied according to the phosphorus or potassium contents in soil, which decreased from the upper and middle to the lower zones. The results showed that the mineral concentrations of botanical components were dependent on soil characteristics in different ways.Peer reviewe

Estimation of mineral content in natural grasslands by near infrared reflectance spectroscopy

Near infrared reflectance spectroscopy (NIRS) was tested to predict nitrogen and mineral concentration (N, P, K, Ca, Mg, Na, Mn, Fe, Cu and Zn) in natural grassland samples. The samples were taken from different community types according to the topographic gradient, at different maturation stages and during a period of four consecutive years. A subset of 95 samples was selected on the basis of the spectral variation. Chemical values from the calibratíon sample set were regressed on the corresponding spectral data using a stepwise multiple regression analysís. Another subset of 75 samples was used as the validation set. Standard errors of prediction and correlation coefficients, respectively, were: 0.71 and 0.97 (N), 0.22 and 0.73 (P), 1.83 and 0.84 (K), 0.83 and 0.92 (Ca), 0.15 and 0.92 (Mg), 3.94 and 0.66 (Na), 44 and 0.84 (Mn), 19 and 0.75 (Fe), 1.01 and 0.77 (Cu), 3.9 and 0.79 (Zn).This work was supported by the European Uníon (Contract N 8001-CT90-0021). Thanks are due to L.G. Criado, C. Estévez and M. Hernández for their assistance in the field work.Peer reviewe

Infection with the fungal endophyte Epichloë festucae may alter the allelopathic potential of red fescue

16 páginas, 3 tablas, 2 figurasRed fescue (Festuca rubra) is a perennial grass used as both forage and turfgrass. Asymptomatic plants of this species are systemically infected by the fungal endophyte Epichloë festucae, which has a beneficial effect on the infected plants. The aim of this study was to determine the effect of the endophyte Epichloë festucae on the allelopathic potential of Festuca rubra against four associated pasture species that are also considered as weeds in lawns, Trifolium pratense, Trifolium repens, Lotus corniculatus, and Plantago lanceolata. Two experiments were designed to evaluate the allelopathic effect of extracts from the roots and leaves of endophyte-infected (E+) and non-infected (E-) plants on the germination and seedling growth of the four target species. Regardless of the endophyte status of the host plant, leaf extracts elicited a stronger reduction in germination and seedling growth than root extracts. Extracts from E+ plants reduced the speed of germination index of Trifolium spp. to a greater extent than those from E- plants. Radicle length of the target species was the parameter most affected by the presence of the endophyte in F. rubra. Root extracts from E+ plants had a greater inhibitory effect on the radicle growth of the target species than did root extracts from E- plants. A greater concentration in total phenolic compounds was found in the roots of E+ plants than of E-; however, this difference was not observed in the leaves. Thus, the allelopathic potential of F. rubra is altered in infected plants.This work was funded by project AGL2008-01159AGR from the Spanish Ministry of Science and Innovation and FEDER. Thanks are due to Dr. Nuria Pedrol for helpful comments in the experimental design and procedures and to Dr. Iñigo Zabalgogeazcoa for comments that improved the manuscript.Peer reviewe

Estudio de especies pratenses en regadío de zonas semiaridas. I. Gramineas

25 páginas, 18 figuras, 1 tabla.-- Con la colaboración técnica de: J.C. Estévez González, M.A. Sánchez Rodríguez y M. Hernández Martín[EN]The present work compares the grasses production of 155 cultivars (58 of Lolium perenne, 48 of Lolium multiflorum, 27 of Dactylis glomerata, 17 of Festuca arundinacea, 3 of Festuca pratensis and 2 of Festuca rubra) during three consecutive years. The average production of D.M. per species per year were 1.358, 715, 1.090 and the average over thee years was 1.054 g/m2 for L. perenne; 1.664, 905,1.253 and an average of 1.274 g/m2 L. multiflorum; 1.031, 1.296,1.412 and an average of 1.246 g/m2 for D. glomerata, 1.010, 1.186, 1.300 and an average of 1.166 g/m2 for F. arudinacea, 849, 1.171, 1.230 and average of 1.084 g/m2 for F. pratensis. The differences between the cultivars studied are very pronounced, even for the same species, The greatest variations in production (D.M.) take place in the first year: 272-2.122 g/m2 for the cultivars of "REAL" and "ABERYSTWYTH S-24" (L. perenne); 1.183-2.396 g/m2 for de cultivars of "TRETONE" and "FAT" (L. multiflorum), 583-l.417 g/m2 for de cultivars of "SCOTIA" and "PHYLLOX" (D. glomerata); 212-1.898 g/m2 for the cultivars of "SYN-2" and "MANADE (E)" (F. arundinacea) and 631.1.209 g/m2 for the cultivars of "BARKAS" and "GARANTA" (F. pratensis). Greatest production is obtained during the first year in L. perenne and L. multiflorum while that of D. glomerata and F. pratensis in reached in the third year of control.[ES]Se estudían las posibilidades pratícolas de gramíneas(58 de Lolium perenne, 48 de Lolium multiflorum, 27 de Dactylis glomerata, 17 de Festuca arundinaca, 3 de Festuca pratensis y 2 de Festuca rubra) durante tres años consecutivos. Las producciones medias de s.s. por especie y año fueron: 1.358, 715, 1.090 y en los tres años 1.054 g/m2, para Lolium perenne; 1.664, 905, 1.253 y 1.274 g/m2, para Lolium multiflorum; 1.031, 1.296, 1.412 y 1.246 g/m2, para Dactylis glomerata, 1.010. 1.186, 1.300 y 1.166 g/m2, para Festuca arundinacea; 849, 1.171, 1.230 y 1.084 g/m2 para Festuca pratensis. Las diferencias entre los distintos cultivares son muy acusadas, incluso para los de la misma especie. Las mayores variaciones de crecimiento (s.s) se producen durante el primer año, siendo éstas: 272 a 2.122 g/m2 entre los cultivares "REAL" y "ABERYSTWYTH S-24" (Lolium perenne); 1.183 a 2.396 g/m2 entre los cultivares "TETRONE" y "FAT" (Lolium multiflorum); 583 a 1.471 g/m2 entre SCOTIA y PHYLLOX" (Dactylis glomerata); 212 a 1.898 g/m2 entre "SYN-2" Y "MANADE (E) (Festuca arundinacea) y 613 a 1,209 g/m2 entre "BARKAS" Y "GARANTA" (Festuca pratensis). Asimismo, las mayores producciones se obtienen durante el primer año de control en las especies L. perenne y L. multiflorum, mientras que en los de Dactylis glomerata, Festuca arundinacea y Festuca pratensis se alcanza en el tercer año.Peer reviewe

Producción de cultívares del género Trifolium en regadio

6 páginas.-- Con la colaboración técnica de: Jose Carlos Estévez González, Mª Angeles Sánchez Rodríguez y Manuel Hernández Martín[EN]A comparative study was carried out on the production of dry material of 96 cultivars (27 of T. repens L. and 69 of T. pratense L.) over three consecutive years in an irrigated semi-arid zone. The mean productions recorded per species and year together with the mean over three year were 729, 1376, 1346 and 1150 g/m2 for T. repens and 877, 1630, 843 and 1116 g/m2 for T. pratense. The productions of the individual cultivars were seen to be very different, even within the same species. The greatest fluctuation was observed, in the first year, in the ARIA cultivars (146 g/m2) and MERIT LADINO (967 g/m2) of T. repens, and in the second year in the CELTIC (648 g/m2) and Lakeland (2177 g/m2) cultivars of T. pratense. Regarding the distribution of seasonal production, T. repens was seen to reach the highest, mean in spring; followed by summer and autumn (564, 378 and 208 g/m2, respectively) and T. pratense was seen to be practically the same in spring and summer, while the autumn values was five times lower (506, 511 and 99 g/m2, respectively).[ES]Se hace un estudio comparativo de la producción de materia seca de 96 cultivares (27 de Trifolium repens L. y 69 de Trifolium pratense L.), durante tres años consecutivos, en zona semiárida de regadío. Las producciones medias alcanzadas por especie y año, así como la media de los tres años fueron: 729, 1376, 1346 y 1150 g/m2 para Trifolium repens y 877, 1630, 843 y 1116 g/m2 para Trifolium pratense. Las producciones de los distintos cultivares son muy diferentes, aún dentro de la misma especie. La mayor fluctuación se produce, durante el primer año, en los cultivares ARIA (146 g/m2) y MERIT LADINO (967 g/m2) de Trifolium repens, y, en el segundo año, en los cultivares CELTIC (648 g/m2) y LAKELAND (2177 g/m2 de Trifolium pratense. Al considerar la distribución de la producción estacional, Trifolium repens alcanza el valor medio más alto en primavera, seguido de verano y otoño (564, 378 y 208 g/m2 respectivamente); en Trifolium pratense es práctivamente igual en primavera y verano, siendo el valor de otoño 5 veces inferior (506, 511 y 99 g/m2, respectivamente).Peer reviewe

Influencia del estado de madurez sobre la composición mineral de especies pratenses. I. Cultivares de los géneros Trifolium y Medicago

17 páginas, 4 figuras, 2 tablas.-- Con la colaboración técnica de: M.I. Díaz-Güemes Pérez, J.C. Estévez Gonzáles, M.A. Sánchez Rodríguez y M. Martín Hernández[EN] This work studies the variation in the mineral composicion (ashes, N, P, K, Ca, Mg, Na, Fe, Mn, Cu and Zn) along the plant maturity advance in seven cultivars of T. repens (2cv). T. pratense (2cv), and Medicago sativa (3cv). N, P, K, Fe and Zn concentrations decrease with maturity and so the ashes percentages do; those of Ca and Mg show a tendency, though not quite clear, to slightly increasing. Na and Cu do not present a generalizable tendency, moreover, the Na shows a great variability in its concentrations and fluctuation margins, to spatial level as much as to cultivar. The Mn evolution varies according to species and cultivar. T. repens cultivars reach superior mean concentrations for most of its elements, however, major elemental uptake generally correspond to those of T. pratense.[ES]Se estudia la variación en la composición mineral (cenizas, N, P, K, Ca, Mg, Na, Fe, Mn, Cu y Zn) con el avance de madurez de la planta, en siete cultivares de Trifolium repens (2cv), Trifolium pratense (2cv) y Medicago sativa (3 cv). Las concentraciones de N, P, K, Fe y Zn disminuyen con la madurez, así como también los porcentajes de cenizas. Las de Ca y Mg manifiestan una tendencia, aunque no muy clara, a incrementarse ligeramente. Para Na y Cu no se aprecia una tendencia generalizable, presentando además el Na gran variabilidad en sus concentraciones y márgenes de fluctuación, tanto a nivel de especie como de cultivar. Las evoluciones de Mn varían según la especie y cultivar. Los cultivares de T. repens alcanzan las concentraciones medias superiores para la mayoría de los elementos, sin embargo las extracciones mayores, corresponden, en general, a los de T. pratense.Peer reviewe

Praderas temporales en regadío de diversas mezclas de especies pratenses

17 páginas, 5 figuras, 6 tablas.-- Con la colaboración técnica de: C. Estévez González, Mª. A. Sánchez Rodríguez y M. Hernández Martín.[EN]A comparison was made of 9 different mixtures of forage species under irrigation including different association of Dactylis glomerata, Festuca arundinacea, Lolium multiflorum, Trifolium repens and Trifolium pratense. The assay was carried out in irrigated areas of the middle basin of the River Tormes (province of Salamanca, Spain) over three consecutive years. The mean annual yields, considering the whole series of samples, were very similar; 1876, 1881 and 1889 g/m2 of dry matter respectively, for the first, second and third years. However, significant differences could be observed between the different mixtures, according to the year. The greastest variations in yield between the mixtures appeared in the first year, specially between mixture 2 (1945 g/m2) and 3 (2300 g/m2). This latter, together with mixture 9 (1990 g/m2) and 8 (1975 g/m2) were the most productive, respectively. Contrarywise, mixtures 2.1 and 8 gave lower yields. The mean annual percentages of grasses and legumes, across the whole series of samples, were for both, per year: 87.8, 68.8 and 6l.1%; 4.0, 31.5 and 39.0%, respectively. These proportions were seen to differ considerably from one mixture to another, according to the year in question. Outstanding, during the third year, was mixture 3, with a relative yield in grasses of 38.8%, compared with mixture 1, in which these species reached 78.81%. The mean seasonal yield, for the whole series of samples, were similar for the three years studied for the same season, though they differed considerably from season to season. The greatest yields were obtained in spring, followed by those of summer, while those of autumn were much lower (8-10 fold less than in spring). Also, as could be expected, marked differences between the mixtures could be appreciated for the same season. The most productive mixtures and the best balanced in their components were seen to be those formed by associations of three species (nº 4, 5 and 6) of two grasses (Festuca arundinacea, Lolium multiflorum or Dactylis glomerata) and of one legume (Trifolium repens). Other mixtures, assayed either gave lower yields or the proportion in specific elements constituting them were considered unadvisable. This was the case of mixture nº 3.[ES]Se comparan nueve mezclas de especies pratenses en regadío, formadas con diversas asociaciones de Dactylis glomerata, Festuca arundinacea, Lolium multiflorum, Trifolium repens y Trifolium pratense. El ensayo se llevó a cabo en los regadíos de la cuenca media del río Tormes, durante tres años consecutivos. Las producciones medias anuales, considerando el conjunto de las mezclas son muy semejantes, 1876, 1881 y 1889 g/m2 de sustancia seca, respectivamente para 1º, 2º, 3er año. Sin embargo, se aprecian diferencias significativas entre las diversas mezclas según el año. Las mayores variaciones de producción entre mezclas, aparecen en el primer año, especialmente entre las mezclas 2 (1495 g/m2) y la 3 (2300 g/m2). Esta última, 9 (1990 g/m2) y 7 (1975 g/m2) fueron las más productivas, respectivamente en cada uno de los años. Por el contrario, las mezclas 2, 1 y 8 alcanzaron los menores rendimientos. Los porcentajes anuales medios de gramíneas y leguminosas, en el conjunto de las mezclas, fueron respectivamente para ambas y años: 87.8 68.8 y 61.1%, 4.0, 31.5 y 39.0%. Estas proporciones difieren mucho de unas mezclas a otras y según el año que se considere. Destacan, en el 3er año, la mezcla nº 3 con una producción relativa de gramíneas del 38.8%, frente a la nº 1 en la que éstas alcanzan el 78.8%. Las producciones medias estacionales, al considerar el conjunto de las mezclas, son semejantes en los tres años para la misma estación, pero difieren notablemente entre estaciones. Los mayores rendimientos se obtienen en primavera, siguen los de verano y los de otoño se encuentran muy distantes (8 a 10 veces menores que en primavera). También, como era de espera, para una misma estación se aprecian diferencias acusadas en mezclas. Las mezclas más productivas y equilibradas en sus componentes son la formadas por asociaciones de tres especies (nº 4, 5 y 6), dos gramineas (Festuca arundinacea, Lolium multiflorum o Dactylis glomerata) y una leguminosa (Trifolium repens). Otras mezclas ensayadas, con mayor o menor número de especies presentan menores rendimientos o las proporciones en elementos específicos que las conforman no son aconsejables. Este el caso de la mezcla nº 3.Peer reviewe

Nivel y produción de proteina en cultivares de trebol subterraneo.

12 páginas, 5 tablas.-- Con la colaboración técnica de: M.A Sánchez Rodríguez, J.C. Estévez González y M. Hernández Martin[EN]In order to avoid any external dependence of plant protein on dehesa ecosystems a research project is under way to investigate the introduction, selection and evaluation of field species in semi-arid zones in which subterranean clover occupies an important place. Accordingly, assays have been carried out during the periodos l979- 1980 and 1980-1981 in order to determine the possible establishment and level of this species together with its protein producing level in 86 cultivars from different countries (20 from Spain, 10 au´toctonos ecotypes of the province of Salamanca, 22 from Australia, 16 from Turkey and 10 from Morocco). The average level and protein production found were 8.61% and l.62 g/plant (aerial part) and 14.04 and 18.14 g/m2, respectively, for first and second control years. However, there are considerable differences between the cultivars; these parameters range between 6.24-11.66% and 0.32-9.95 g/plant; 11.05-19.06% and 3.83-48.00 g/m2, also respectively for both years.[ES] Para evitar toda dependencia exterior de proteina vegetal en los ecosistemas de dehesa, se esta desarrollando un proyecto de investigación sobre introducción, selección y evaluación de especies pratenses en zonas semiáridas, en el que el trébol subterraneo ocupa un lugar destacado. A este respecto, se han realizado ensayos, durante los años 1979-80 y 1981-82, para determinar su posible establecimiento y nivel y capacidad productiva de proteina de 86 cultivares procedentes de diversos países (20 de España, 10 ecotipos autóctonos de la provincia de Salamanca, 22 de Australia, 16 de Turquía, 8 de Tunez y l0 de Marruecos). El nivel y producción media de proteína encontrados fueron: 8.61% y 1.62 g/planta (parte aérea) y 14.04 y 18.14 g/m2, respectivamente para el primero y segundo años de control. Sin embargo, entre los distinos cultivares existen diferencias muy notables, dichos parámetros fluctuan entre 6.24-11.66% y 0.32-9.95 g/plantas; 11.05-19.36% y 3.83-48.60 g/2, tambien respectivamente para ambos años.Peer reviewe