Efectos alelopáticos de extractos acuosos de arvenses sobre la germinación de trigo duro y Lolium Rigidum

We analyzed the allelopathic effects of aqueous extracts of plants on durum wheat (Triticum durum Desf.) and Lolium rigidum Gaud., together with joint germination of both plants. Results showed that several extracts stimulated root development and hypocotyl, being proportional to the concentration of the extract, highlighting Urtica sp., Chenopodium murale, Sinapis arvensis and Diplotaxis virgata while Matricaria chamomilla inhibited growth. The extracts tested on L. rigidum decreased root development in the case of Malva parviflora, Daucus carota, Plantago lanceolata, Borago sp. and Papaver rhoeas. Moreover, the joint seed germination of T. durum and L. rigidum resulted in increased both germination and root development of both species.Se han analizado los efectos alelopáticos de extractos acuosos de varias plantas sobre trigo duro (Triticum durum Desf.) y Lolium rigidum Gaud., y la germinación conjunta de las semillas de ambas especies. Los resultados han mostrado que varios extractos estimularon el desarrollo radicular y del hipocótilo, siendo el efecto proporcional a la concentración del extracto, destacando Urtica sp., Chenopodium murale, Sinapis arvensis y Diplotaxis virgata, mientras que Matricaria chamomilla inhibió el crecimiento. Los extractos ensayados sobre L. rigidum disminuyeron el desarrollo radicular en el caso de Malva parviflora, Daucus carota, Plantago lanceolata, Borago sp. y Papaver rhoeas. Por otra parte, la germinación conjunta de semillas del trigo duro y L. rigidum incrementó la germinación y el desarrollo radicular de ambas especie

Development and preliminary results of a mobile application to perform pre-inspection of sprayer equipment

Por todos es conocido que el presente y futuro de las aplicaciones de productos agroquímicos pasa por una buena regulación, calibración y mantenimiento de los equipos que se utilizan. Tanto Europa como los países miembros y sus comunidades autónomas, en el caso de España, a través de sus instituciones (Universidades, Consejerías, etc.), están trabajando concienzudamente en el protocolo de inspección. Es de prever que en muchos equipos la primera inspección será desfavorable, y además supondrá un coste económico alto para el propietario, independientemente de que el equipo pase la inspección de forma favorable o no. Este hecho hace que el agricultor no conciba este control con la “percepción beneficiosa” que pueda tener la administración. Por todo ello, el Laboratorio de Agricultura de Precisión de la Universidad de Sevilla ha decidido centrarse en el término “pre-inspección” y desarrollar una aplicación gratuita de autocontrol para dispositivos móviles que permita al propietario o su técnico agrícola conocer el estado de su equipo de aplicación antes de acudir a una inspección “oficial” y de esta forma solventar los posibles problemas detectados. En los primeros equipos que han formado parte de este estudio se ha conseguido, por una parte poner en conocimiento y mostrar los elementos y aspectos a controlar y por otra, generar de forma gratuita y fácil un informe donde se indica los elementos y aspectos a solventar antes de ir a una inspección. Esta aplicación de pre-inspección ha sido una herramienta muy valorada por los usuarios como mantenimiento preventivo.It is widely acknowledged that the present and future practice of pesticide applications requires good regulation, calibration and maintenance of the equipment used. European countries and their regional governments, in the case of Spain, through its institutions (Universities, Councils, etc.), are working conscientiously towards inspection protocol. It is expected that many sprayers will not pass the first inspection, and there will be a significant cost to the owner, whether the equipment passes the inspection or not. This fact makes this inspection protocol is not conceived with the “beneficial perception” as the administration may have. Therefore, the Precision Agriculture Laboratory at University of Sevilla has decided to focus on the term “pre-inspection” and develop a free mobile application for self-assessment that allows the owner or agricultural technician check the status of the sprayer before inspection. This would address the possible problem idenfified. For the first spayers considered in this study there have been several achievements: firstly informing about and showing those elements and aspects of the sprayer which need to be controlled and secondly, generating simply and without cost a report describing those elements and aspects which must be resolved before going for an inspection. This approach to pre-inspection has proved to be highly very valued by users as a tool for preventive maintenance

Competencia de las malas hierbas en remolacha azucarera de siembra otoñal

La competencia de las malas hierbas en remolacha puede llegar a ocasionar hasta un 40% de pérdidas de rendimiento, ¡casi la mitad de la cosecha! — Periodo de Tolerancia: se ha verificado que las emergencias más problemáticas de malas hierbas son las que coinciden con la emergencia de la remolacha y que a partir de un cultivo en 4 hojas verdaderas pueden ocasionar pérdidas de rendimiento. Por tanto, ¡no espere a que nazcan todas las hierbas para controlarlas! — Periodo Libre: las emergencias de malas hierbas posteriores también pueden afectar al rendimiento. En casos de infestaciones severas, pueden llegar hasta las 16 hojas de la remolacha. Por tanto, debe controlar las nuevas emergencias tras la primera otoñada y mantener limpio el cultivo hasta el cierre de calles

Role of quail in weed agroecology (I). Seed consumption

La codorniz (Coturnix coturnix) es un ave granívora frecuente en los campos de cultivo de España, que puede tener un papel relevante en la predación y dispersión de semillas de malas hierbas. Se ha realizado un estudio con semillas de 7 especies de malas hierbas (géneros Chrysanthemum, Centaurea, Sinapis, Lolium, Malva, Phalaris, Rumex) y 30 individuos de codorniz. Los resultados obtenidos permiten concluir que: a) la codorniz consume semillas de las siete especies estudiadas; b) la codorniz es más voraz consumiendo semillas de C. cyanus tanto en peso como en número; c) las codornices hembra son más voraces que los machos; d) no se encontró relación lineal entre el peso del ave y el consumo cuando el análisis se hizo por separado para cada especie de mala hierba y sexo de la codorniz.Quail (Coturnix coturnix) is a granivorous bird common in farms of Spain, and it may have a relevant role in predation and dispersion of weed seeds. An experiment has been conducted with seeds of 7 weed species (genera Chrysanthemum, Centaurea, Sinapis, Lolium, Malva, Phalaris, Rumex) and 30 individuals of quail. Results show that: a) quail eats seeds of the 7 weed species studied; b) quail is more voracious eating C. cyanus seeds, both in weight and number of seeds; c) female quails are more voracious than males; d) no lineal relation was detected between bird weight and consumption when analysis was performed separately by weed species and bird sex

Opciones para el control de Cyperus difformis resistente a penoxsulam

El cultivo del arroz en países mediterráneos es particularmente vulnerable a la aparición de resistencias a herbicidas. Cyperus difformis es una mala hierba problemática en este cultivo y recientemente se ha descrito la existencia de biotipos resistentes a penoxsulam. El objetivo del trabajo fue evaluar las posibilidades de varias materias activas, alternativas al penoxsulam, que pudieran ser utilizadas para controlar C. difformis. En el estudio se utilizaron 6 poblaciones, dos de las cuales eran resistentes al penoxsulam y otras dos sensibles. Los tratamientos aplicados fueron: 1) penoxsulam+triclopyr, 2) bentazona + MCPA, 3) triclopyr, 4) bentazona, 5) MCPA, 6) fluroxipyr, 7) azimsulfuron y 8) Testigo no tratado. Los resultados indican que bentazona y triclopyr son los mejores candidatos para ser incluidos en un programa de control alternativo frente a C. difformis.Options to control Cyperus difformis resistant to penoxulam Rice crop in the mediterranean countries is particularly prone to herbicide resistance. Cyperus difformis is a major weed problem in rice crop, and penoxsulam resistance has been recently reported. The aim of the paper was to evaluate the chances of several herbicides to be included in an alternative control to penoxsulam of C. difformis. Six populations of C. difformis were used. Two of them were penoxsulam resistant and two were penoxsulam susceptible. The treatments were: 1) penoxsulam+triclopyr, 2) bentazona + MCPA, 3) triclopyr, 4) bentazona, 5) MCPA, 6) fluroxipyr, 7) azimsulfuron and 8) Untreated check. Results indicate that bentazona and triclopyr are the best candidates to be included in an alternative control

An investigation to enhance understanding of the stimulation of weed seedling emergence by soil disturbance

Enhanced understanding of soil disturbance effects on weed seedling recruitment will help guide improved management approaches. Field experiments were conducted at 16 site-years at 10 research farms across Europe and North America to (i) quantify superficial soil disturbance (SSD) effects onChenopodium album emergence and (ii) clarify adaptive emergence behaviour in frequently disturbed environments. Each site-year contained factorial combinations of two seed populations (local and common, with the common population studied at all site-years) and six SSD timings [0, 50, 100, 150, 200 day-degrees (d°C, base temperature 3°C) after first emergence from undisturbed soil]. Analytical units in this study were emergence flushes. Flush magnitudes (maximum weekly emergence per count flush) and flush frequencies (flushes year−1) were compared between disturbed and undisturbed seedbanks. One year after burial, SSD promoted seedling emergence relative to undisturbed seedbanks by increasing flush magnitude rather than increasing flush frequency. Two years after burial, SSD promoted emergence through increased flush magnitude and flush frequency. The promotional effects of SSD on emergence were strongest within 500 d°C following SSD; however, low levels of SSD-induced emergence were detected as late as 3000 d°C following SSD. Accordingly, stale seedbed practices that eliminate weed seedlings should occur within 500 d°C of disturbance, because few seedlings emerge after this time. However, implementation of stale seedbed practices will probably cause slight increases in weed population densities throughout the year. Compared with the common population, local populations exhibited reduced variance in total emergence measured within sites and across SSD treatments, suggesting thatC. albumadaptation to local pedo-climatic conditions involves increased consistency in SSD-induced emergence

Effects of reduced and conventional tillage on weed communities: results of a long-term experiment in Southwestern Spain.

An important drawback in adopting minimum tillage (MT) and no-tillage (NT) techniques is the frequently observed weed shift promoting adapted species and achieving poorer weed control. These changes can be detected best with long-term experiments, and results might differ depending on soil characteristics and the local flora. The objectives of this work were to evaluate the effect of reduced tillage on weed seed distribution in the soil profile and to identify possible consequences on weed diversity on a long-term experiment maintained during 24 years in Seville (Spain) with three tillage systems: NT, MT and conventional tillage (CT) including moldboard plow on a vertisol. For this purpose, soil seedbanks at 0-8 cm and 8-16 cm depths were enumerated in autumn 2005 and in-field emerged plants in autumn 2005 and winter 2006. Shannon diversity index (H) and evenness (J’) were calculated for seedbank and aboveground weed communities. Total weed seed density was highest for NT and lowest for CT. Some big-seeded species, such as Chrozophora tinctorea L., showed highest seed density in CT. NT increased the relative density of Amaranthus blitoides S. Watson seeds in the seedbank and the abundance of emerged plants of Malva parviflora L., Anagallis arvensis L. and Picris echioides L. Overall, MT led to a less diverse seedbank in the 0-8 cm depth of soil than CT. The frequent drought-induced deep fractures in the expandable clay soil caused natural tillage, which probably resulted in fewer differences in weed seed and seedling densities among tillage treatments compared to what might be expected in other soil types.Uma desvantagem importante na adoção de técnicas de cultivo mínimo (MT) e plantio direto (NT) é o deslocamento de plantas daninhas frequentemente observado, promovendo espécies adaptadas e, com isso, um controle de plantas daninhas mais precário. Essas mudanças só podem ser detectadas com experimentos de longo prazo, e os resultados podem diferir, dependendo das características do solo e da flora local. Os objetivos deste trabalho foram avaliar o efeito da lavoura reduzida sobre a distribuição de sementes de plantas daninhas no perfil do solo e identificar possíveis consequências na diversidade de plantas daninhas em um experimento de longa duração mantido durante 24 anos em Sevilha (Espanha) com três sistemas de plantio: NT, MT e preparo convencional (CT), incluindo arado de aiveca em um Vertissolo. Com esse propósito, amostras de solo com 0-8 e 8-16 cm de profundidade foram coletadas no inverno de 2005 e na primavera de 2006, e as plântulas de plantas daninhas emergentes foram registradas. O índice de diversidade de Shannon (H) e a uniformidade (J’) foram calculados para comunidades de banco de sementes e plantas daninhas acima do solo. A densidade total de sementes de plantas daninhas foi maior para NT e menor para CT. Algumas espécies de sementes grandes, como Chrozophora tinctorea L., apresentaram maior densidade de sementes no CT. NT aumentou a densidade relativa de sementes de Amaranthus blitoides S. Watson no banco de sementes e a presença de plantas emergidas de Malva parviflora L., Anagallis arvensis L. e Picris echioides L. Com relação aos resultados gerais, a TM levou a um banco de sementes menos diversificado na profundidade de 0 a 8 cm do solo do que a CT. As frequentes fraturas profundas na argila expansível do solo provocam um preparo natural, originando provavelmente menos diferenças dos parâmetros analisados do que em outros tipos de solo

Most worrysome weeds in Spain

Se presentan los resultados de una encuesta realizada durante el periodo de junio a octubre de 2014, y en la que participaron 315 técnicos de campo de toda España. Los datos están disponibles en Internet y su análisis permite concluir que a) las malas hierbas preocupan tanto como las plagas y enfermedades; b) respecto a los métodos de control, el control químico con herbicidas es el más usado y el considerado más eficaz; se han detectado las malas hierbas más preocupantes en una serie de cultivos, incluyendo el motivo de la preocupación. En cultivos leñosos, destaca “Conyza” por su dificultad de control, en arroz destacan “Echinochloa” y “Cyperus”; en algodón y maíz preocupan “Abutilon”, “Chenopodium”, “Cyperus”, Echinochloa y Sorghum; en cultivos extensivos de secano, la preocupación no está tan concentrada en pocas especies, destacando malas hierbas gramíneas en trigo y cebada junto con Centaurea, que es considerada preocupante adicionalmente en el cultivo del girasol. Finalmente, se seleccionan arvenses de preocupación creciente, entre las que destacan “Abutilon”, “Centaurea”, “Chenopodium” y “Sorghum”.Since June to October 2014, 315 Spanish field advisors participated in a survey. Data is available on internet and results show that a) weeds are as worrying as other pests and diseases; b) chemical control is the most used weed control method and is considered to be the most efficient one; c) knowledge transfer in weed management is largely dependant on herbicide industry; d) most worrying weeds have been identified for several crops, as well as the reasons why they are considered worrysome. In permanent crops, “Conyza” is refered to be by far the worst weed, mainly because it is difficult to control; in rice, the worst weeds are “Echinochloa” and “Cyperus”; in corn and cotton “Abutilon”, “Chenopodium”, “Cyperus”, “Echinochloa” and “Sorghum”; in annual dryland crops weed problems are less focused, being the most worrying weeds annual grasses in wheat and barley, besides “Centaurea”, which is also considered to be a problem in sunflower. Finally, there are weeds of increasing threat like “Abutilon”, “Centaurea”, “Chenopodium” and “Sorghum”