Characterization of Brachypodium varieties as tree cover crops in Mediterranean conditions

Trabajo presentado en la 4th International Brachypodium Conference, celebrada en Huesca del 25 al 28 de junio de 2019.Accelerated water erosion is a major environmental problem in tree crops under Mediterranean conditions, which threat-ens their long term sustainability (Gómez, 2017). Despite of the practical use of cover crops under these conditions, there is limited information on the prediction of the flowering and maturity dates of Brachypodium species for different tree growing areas within the Mediterranean. Different areas within this region, despite sharing the same climate type, present significant differences in their temperature regimes. This communication presents the preliminary results of the first year of a study aimed to calibrate a temperature-based phenology model for Brachypodium in Southern Spain. The four varieties currently registered in the EU: two B. hybridum (Ibros and Iskyri) and two B. distachyon (Zulema, and Kypello) were used for the study.In two different locations in Southern Spain with contrasting temperature regimes, Córdoba (warmer with 17.8 ºC average annual temperature) and Lanjarón (colder with 14.5 ºC average annual temperature) a controlled experiment was carried out during the agricultural year 2018-19. At each site 8 pots (15 l in volume each) were seeded in late October with two replications of each of the four varieties. Each pod was seeded at a seed density of 1gr m-2 and they were irrigated regu-larly to prevent water stress according to the rainfall distribution of the season. The air temperature and the plants height was recorded automatically at a 30 minutes interval.The phenological evolution of the plants was assessed regularly during the growing seasons according to Meier (2001). A phenology model based on growing degree days, GDD Eq. 1, was developed using the Richard equation following the procedure described by Gómez and Soriano (2019). Basically the models were calibrated using the experimental data of the season 2016-17 minimizing the root mean square error between predicted and observed days since sowing for each of the registered phenological stages using the solver function of Excel ®. The developed models were validated using the experimental data of season 2017-2018.This communication presents the preliminary results of the differences in phenology among these four varieties, the calibration of the phenology model and the implications of these differences for their use as cover crops different areas among the region

Erosión en olivar ecológico. Manual de campo: diagnóstico y recomendaciones

Es una guía práctica para el reconocimiento del riesgo de erosión en olivare ecológicos y su prevención. No obstante, gran parte de las mismas, se puede aplicar a casi cualquier tipo de olivares no ecológicos.Peer reviewe

What do farmers mean when they say they practice conservation agriculture? A comprehensive case study from southern Spain

14 páginas.-- 1 figuras.-- 6 tablas.-- 62 referencias.-- Appendix A. SSupplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.agee.2015.07.028Conservation agriculture (CA), which is promoted worldwide to conserve soil, water and energy and to reduce production costs, has had limited success in Europe. The objectives of this study were to assess annual crop systems currently managed under CA in southern Spain, identify obstacles to CA adoption, and recommend strategies to overcome those obstacles. We employed the following methods: (i) examination of original government data used to monitor CA; (ii) survey of CA farmers to characterize their practices and perceptions; (iii) agronomic, economic and energy use comparison of minimum tillage (MT) and conventional tillage (CT); and (iv) a stakeholder focus group to identify strategies for improving CA. Farmers selectively implemented some components of CA while disregarding others as a strategy to adapt to local conditions. Although most researchers define CA as a system that combines minimum soil disturbance, maintenance of crop residues, and crop rotation, in practice most farmers and organizations equated CA with direct seeding of cereals without considering residues or crop rotation. Official national statistics did not include all of these CA components either. Examination of government data revealed that only 13% of monitored plots were not tilled consecutively. The most common CA system (50% of farms) was direct seeded wheat rotated with tilled sunflower. This system (classified as MT) and CT were not significantly different with regard to wheat yield, soil quality, net return or energy use in either crop, which was likely due to similar residues management, recurrent soil disturbance in MT, and disuse of moldboards in CT. In wheat, fertilizers represented the largest energy input (68% TEI) in both systems followed by diesel consumption (12% and 19% in MT and CT, respectively). To overcome the most important identified problems in CA, we highlight the need for collaborative research with farmers and other stakeholders to develop appropriate drill technology for spring crops, identify non-cereal crops that are better adapted to CA than sunflower, improve residues management, increase energy efficiency through better fertilizer management, and promote CA among farmer groups excluded by socioeconomic barriers. Finally, international standards to guide data collection and statistical analyses on all components of CA will enable researchers and institutions to compare information and find solutions to common problems. © 2015 Elsevier B.V.This study was supported by the Spanish Ministry of Economy and Competitiveness (Projects: AGL2010-22050, AGL2013-49062 and 201440E100) and FEDER funds. We thank the Consejería de Agricultura Pesca y Desarrollo Rural (Junta de Andalucía) for providing original data on the area of direct seeded crops. J.J. Pérez and AEAC/SV helped identify farmers practicing CA in western Andalusia and R. Gil facilitated the focus group. M. Panettieri, R. Luque, R. Gutierrez and M. Salmoral provided technical support in field measurements and laboratory analyses. We are grateful to the farmers for their collaboration in this study.Peer reviewe

Evaluation of potential as cover crops of three autochthonous species for Mediterranean conditions in Southern Spain through calibration and validation of a temperature-based phenology model

Trabajo presentado en la EGU General Assembly 2019, celebrada en Viena del 3 al 8 de mayo de 2019.The provision of ecosystem services is increasingly relevant in the definition of agricultural policies and covercrops can play a major role in it. Blanco-Canqui et al. (2015) discussed how the provision of ecosystem servicesby cover crops needs to reach a balance between a high production of biomass by the cover and agriculturalproduction, indicating that this balance is much more difficult to achieve in regions with limited available water forcultivation. One of these regions is the Mediterranean where use of cover crops is usually mentioned as necessaryto reduce soil degradation (e.g. Gómez, 2017). Several studies, e.g. Gómez (2017), Winter et al. (2018), noted therisk of decreasing yield in this agricultural system if the use of temporary cover crops is not properly managed.The literature shows that still been necessary the identification of new species better adapted to serve as covercrops for Mediterranean conditions. Studies for this identification will have higher impact if they could go beyondthe local conditions in which they have been performed.This study present the evaluation of three natives species of annual plants, Bromus rubens, Anthemis ar-vensis and Medicago truncatula, as cover crops in Andalusia, Southern Spain. A phenological model for wascalibrated and validated experimentally for each of this species. Using these models their maturity dates wereanalysed for seven locations in Andalusia for two different germination dates assumptions: fixed on October 20thor with the first significant after September 1st. These results provided the probability distribution of maturitydates and allowed the determination of an empirical model for determining the average maturity date in the regionbased on the average daily mean Tª. This model was used to calculate a regional map of maturity dates based onlong-term average daily Tª. The analysis shown how the management of a temporary cover crop based on an earlykilling date (early April) to prevent competition for soil water with the tree crops needs to be regionalized andadapted to the specific conditions of the tree crops. While in the western part of the Guadalquivir River valley thethree species can produce viable seed by early April, especially Anthemis arvensis and Medicago truncatula, in therest of the region management of the cover crop needs to be adapted to allow a lower maturity date. Our analysissuggests that new cover crop species with shorter cycles are needed, particularly grasses. Our calibrated modelsand approach might be directly applicable to similar areas in the Mediterranean or re-calibrated, for differentconditions or species, with relatively simple experiments.Peer reviewe

Evaluation of the suitability of three autochthonous herbaceous species as cover crops under Mediterranean conditions through the calibration and validation of a temperature-based phenology model

This study presents the analysis of the suitability of three native species of annual plants, Bromus rubens, Medicago truncatula and Anthemis arvensis, as cover crops in Andalusia, Southern Spain. We used experimental data from two agricultural years to calibrate and validate degree-day-based phenological models for these cover crop species. From these developed models, we determined the seed maturity dates for the three species for seven locations in Andalusia for two different date assumptions regarding conditions for seed germination: fixed on October 20 or with the first significant rainfall (25 mm on four consecutive days) in late summer or early autumn, using an 18 year dataset of daily temperature and precipitation. This analysis enabled us to determine the probability distribution of seed maturity dates for the three plant species at each location, and determine an empirical linear regression model to calculate the average seed maturity date for each species in the region. This empirical model enabled us to calculate a regional map of maturity dates for the three cover crop species based on long-term average daily temperatures across the region. The analysis showed how the management of a temporary cover crop needs to be regionalised and adapted to the specific edaphoclimatic conditions of each orchard. Thus, whereas in the western part of the Guadalquivir river valley the three species can produce viable seeds in early April, especially A. arvensis and M. truncatula, in the rest of the region management of these cover crops needs to be adapted to combine seed production for self-seeding with minimising the risk of competition for soil water with the trees. This can be done with systems allowing partial killing of the cover crop in late winter, leaving a tiny fraction of the cover alive to produce seed for the next year. Our analysis suggests that new cover crop species with shorter cycles are needed, particularly grasses. In this search another key trait should be ease of seed dispersal. Our thermal time phenological models and approach may be directly applicable to similar areas in the Mediterranean or re-calibrated for different conditions or plant species with relatively simple experiments.This work was supported by the AGL2012-40128-C03-01 (Spanish Ministry of Economy and Competiveness), P12-AGR-931 projects (Andalusian Government), and EU‒FEDER funds, whose support is gratefully acknowledged.Peer reviewe

Evaluación de la fecha de madurez de la semilla de tres especies autóctonas para cubierta vegetal en olivar en Andalucía

Trabajo presentado en el XIX Simposio Científico-Técnico EXPOLIVA, celebrado en Jaén del 15 al 17 de mayo de 2019.Este estudio presenta el análisis de la idoneidad de tres especies autóctonas de plantas anuales, Bromus rubens, Anthemis arvensis y Medicago truncatula, como cubierta vegetal en olivar para las condiciones de Andalucía, utilizando los datos experimentales de dos años agrícolas para calibrar y validar modelos fenológicos basados en tiempo térmico. A partir de estos modelos, se determinó la fecha de madurez de la semilla de las tres especies para siete localidades en Andalucía y para dos supuestos de fecha de condiciones de germinación: fijada el 20 de octubre o con la primera precipitación significativa (25 mm en dos días) a final del verano-principios del otoño. Estos resultados permitieron calcular la distribución de probabilidad de la fecha de madurez de la semilla y calibrar un modelo empírico para determinar la fecha de madurez promedio para cada especie en la región, a partir de la temperatura media anual en cada localización. Se generaron mapas regionales de fecha media de madurez de la semilla para las tres especies. A partir de estos se discuten varios aspectos, entre ellos: en qué zonas de la región las tres especies pueden producir semillas viables a principios de abril, y las zonas en las que el manejo debe adaptarse a una madurez más tardía para combinar la producción de semillas para auto-siembra con minimizar la competencia con el olivo por el agua del suelo.Este trabajo fue financiado por los proyectos AGL2012-40128-C03-01 y P12-AGR-931, y fondos FEDER, cuyo apoyo se reconoce y agradece

Asesoramiento para investigación colaborativa en control de erosión en olivar a diferentes escalas

El uso de cubiertas vegetales de especies autóctonas es un tema de creciente interés en el olivar, en especial en relación a la provisión de diferentes servicios ecosistémicos (p.ej., aumento de la biodiversidad, secuestro de carbono, reciclado de nutrientes, …) que se añaden a su papel clave en la protección del suelo frente a la erosión hídrica. Sin embargo, en muchas situaciones su implementación presenta serios obstáculos de tipo práctico. Entre estos, la dificultad de establecer una cubierta vegetal efectiva en zonas con alta densidad de conejos y/o en suelos muy degradados, donde el banco de semillas es prácticamente inexistente. La elección de las especies, junto a la incertidumbre acerca de su desarrollo fenológico en zonas con diferencias en el régimen térmico, y en la distribución de lluvia, también es un aspecto clave, sobre todo en el caso del olivar de secano, donde la cubierta vegetal puede competir con el olivo, en primavera, por el agua del suelo. El consumo de agua por la cubierta vegetal, que podría penalizar el rendimiento del olivar, es una cuestión clave para muchos agricultores escépticos sobre su uso.El objetivo de este trabajo fue la implantación de un ensayo de demostración de diversas especies herbáceas autóctonas para su uso como cubierta vegetal temporal, mono y multiespecífica, en una parcela de olivar con suelo muy degradado y gran abundancia de conejos, localizada dentro del marco de la DOP Estepa.N

Characterization of cover crops for use in olive groves and vineyards in certified systems under Mediterranean conditions

Trabajo persentado en el 10th International Symposium on Agriculture and the Environment (AgroEnviron), celebrado en West Lafayette (US) del 23 al 27 de mayo de 2016.The aim of this study was to characterize alternative cover-crops (monospecific and multispecific) for use as an agro-environmental technique in olive groves and vineyards, especially in certified production systems in Andalusia. For this, three native plant species (Bromus rubens (B), Medicago truncatula (M), and Anthemis arvensis (A)), which are respectively a grass, legume and composite plant, having short growing seasons, and three mixtures (B+M, B+A, B+M+A), using three differ ent proportions of each in each mixture, were selected as treatments. In addition, we used the mixture of varieties of Brachypodium distachyon registered under the trade name of “Vegeta”. All alternatives were sown in autumn under two different soil and climatic conditions in the province of Córdoba (“ Vega del Guadalquivir”, VG, and “Sierra Morena”, SM) using a dose of 2.66 (B), 1.70 (M), 0.10 (A) and 3.35 (Vegeta) g-seed/m2 in monospecific cover-crops. During the growing cycle we characterized the phenological stage (BBCH-scale), evolution of the vegetative cover (periodic measurements of ground cover), production of aerial and fine root biomass, and fine root length density and vertical distribution (sampling of plants and soil in early spring and end of the growing season), evolution of soil moisture (periodic measurements with neutron probe), and N supply to soil.N

Caracterización de nuevas cubiertas vegetales mono y multiespecíficas para olivar

Trabajo presentado en el I Congreso Iberico de Olivicultura, celebrado en Badajoz del 13 al 15 de abril de 2016.Las zonas de olivar en Andalucía se vienen señalando repetidamente como intensamente degradadas por la erosión hídrica. El manejo del suelo del olivar mediante el uso de cubiertas vegetales ha mostrado su efectividad sobre la reducción de la erosión, aumento de la biodiversidad y mejora de las propiedades del suelo. Sin embargo, existen numerosas dificultades de tipo práctico a la hora de difundir e introducir el manejo del suelo con cubierta vegetal en olivares comerciales. Por ejemplo, el riesgo de competencia por el agua con el olivo cuando la cubierta vegetal es manejada de forma inadecuada, debido a la gran variabilidad de la fecha de siega óptima, según las características del suelo, clima y plantación. El objetivo de este trabajo es la caracterización de alternativas de cubiertas vegetales (monoespecíficas y multiespecíficas) para su uso como técnica agroambiental en olivar, para las condiciones de Andalucía. Para ello se seleccionaron tres especies autóctonas (Bromus rubens (B), Medicago truncatula (M) y Anthemis arvensis (A)), respectivamente una gramínea, una leguminosa y una compuesta de ciclos cortos, y tres mezclas (B+M, B+A y B+M+A), usando tres proporciones distintas de cada especie en cada mezcla. Además, la mezcla de variedades de Brachypodium distachyon registrada comercialmente como ‘Vegeta’. Todas las alternativas se sembraron en otoño, en dos condiciones edafoclimáticas diferentes (Vega del Guadalquivir y Sierra; Córdoba), utilizando dosis de 2,66 (B), 1,70 (M), 0,10 (A) y 3,35 (Vegeta) g-semilla/m2 en las siembras monoespecíficas. Durante su ciclo se ha caracterizado el estado fenológico (escala BBCH), evolución de la cubierta vegetal (medidas periódicas de cobertura del suelo), producción de biomasa aérea y densidad y distribución de raíces (al inicio de primavera y final del ciclo), evolución de la humedad del suelo (sonda de neutrones) y aporte de N al suelo. Los resultados del primer año de ensayo (2014-2015) mostraron un rápido establecimiento de las cubiertas vegetales, pese a la siembra tardía (7-10 noviembre, Vega del Guadalquivir), con porcentajes de cobertura del suelo (12-enero) del 57% (B), 40% (Vegeta), 33% (M) y 20% (A), variando entre 43-52% en las mezclas. El ciclo más corto fue el de A (floración: 25-marzo), seguido de M (31-marzo) y B (6-abril), siendo más tardía Vegeta. La producción de biomasa aérea (principios primavera) fue similar en B, M y en las mezclas (6,2 t/ha), seguido de Vegeta y A (4,4 y 3,7 t/ha). La biomasa y la profundidad radicales siguieron la secuencia B>Vegeta>M>A.N

Hydrological behavior of a Vertisol under different soil management systems in a rain-fed olive orchard

Trabajo presentado en la EGU General Assembly 2016 (European Geosciences Union), celebrada en Viena del 17 al 22 de abril de 2016.N