Agroecology

Energy exchanges and the energy efficiency of household ponds in the dike pond System of the Zhujiang Delta

by Kenneth Ruddle

(1986) Bulletin of the National Museum of Ethnology 11(1): 323 343 (K.Ruddle, H.Z.Deng and G.H.Liang).

Traditional Integrated Farming Systems and Rural Development: The Example of Ricefield Fisheries In Southeast Asia

by Kenneth Ruddle

(1982) Agricultural Administration 10 (1): 1 11, (K.Ruddle).

An energy flow model of the mulberry dike carp pond farming system of the Zhujiang Delta, Guangdong Province, China

by Kenneth Ruddle

(1993) in Trophic Models of Aquatic Ecosystems Christensen, V. and D. Pauly (eds.), ICLARM Conference Proceedings 26, Manila, ICLARM, pp. 48-55 (K.Ruddle and V. Christensen)

Assessing potential nutritional and household economic benefits of developing integrated farming systems

by Kenneth Ruddle

(1997) In Integrated Fish farming, Mathias, J.A, Charles, A.T. and Hu, B. (eds.). 111- 121. Boca Raton and New York: CRC Press (K. Ruddle and M. Prein).

Riqueza de Plantas e Estrutura de Quintais Familiares no Semi-árido Norte Mineiro

by Gustavo Soldati

Reinaldo Duque-Brasil; Gustavo Taboada Soldati; Fernanda Vieira da Costa; Amanda Aparecida Marcatti; Ronaldo Reis-Jr.; France Maria Gontijo Coelho

A CRITICAL ASSESSMENT OF THE IMPORTANCE OF SEEDLING AGE IN THE SYSTEM OF RICE INTENSIFICATION (SRI) IN EASTERN INDIA.

by Debal Deb

METALES PESADOS EN LA PRODUCCIÓN DE CERDOS A CAMPO.

by Santiago Monteverde

Autores: Santiago Monteverde; Amabelia del Pino; José Piaggio; Hugo Naya
2011.

Los metales pesados se acumulan en el suelo y dependiendo de los elementos y las propiedades del suelo, con tiempos de... more Los metales pesados se acumulan en el suelo y dependiendo de los elementos y las propiedades del suelo, con tiempos de residencia que pueden variar desde cientos hasta miles de años, pueden generar problemas ambientales de mediano y largo plazo. Por la presencia de concentraciones importantes de zinc y cobre en las deyecciones de los cerdos alimentados con dietas convencionales, su aplicación en el suelo ha sido motivo de estudio en varios sistemas de producción. En sistemas de producción de cerdos a campo las entradas de Cu y Zn son fundamentalmente por la ración, siendo menos importantes el uso de fertilizantes y otras fuentes, en tanto las salidas se asocian principalmente a los productos animales. Con el objetivo de estudiar la acumulación de Zn y Cu en el suelo, luego de 12 años de implementado el sistema de cría de cerdos a campo desarrollado en la Unidad de Producción de Cerdos del Centro Regional Sur (Facultad de Agronomía), se muestreó en superficie (0-15 cm) 3 zonas de 6 parcelas de 1500 m2 y un área testigo (sin cerdos) en un Brunosol (sobre formación Libertad). Las zonas correspondieron al área de servicio (I) sin pastura implantada (incluye bebedero, comedero y refugios) y dentro del resto del área con pastura implantada la zona de pastoreo (III) y de transición entre ambas (II). La carga animal fue equivalente a 6 cerdas•ha-1•año-, alimentadas con dietas convencionales y acceso permanente a pasturas. Las pasturas utilizadas fueron alfalfa y mezcla de trébol rojo, blanco y achicoria. Se determinó Zn y Cu luego de extracción con Mechlich III, N-NO3, fósforo Bray, K extractable y conductividad eléctrica (CE). El sistema aumento significativamente el contenido de Zn extractable pero no el Cu. La variabilidad entre muestras (n=24) fue mayor para Zn que en Cu (CV= 66% y 8% respectivamente). El leve incremento de Cu respecto al testigo no se asoció a las diferentes zonas de manejo, posiblemente este relacionado a entradas reducidas en la ración y al alto contenido no antrópico de Cu de este tipo de suelos. El contenido de Zn estuvo altamente correlacionado con N-NO3, P, K y CE (R2 = 0,74; 0,90; 0,89; 0,85 respectivamente p<0,001), asociados a las excreciones animales y pérdida de ración de los comederos. Relevamientos nacionales en pasturas y cultivos de pastoreo animal, muestran en algunos sitios contenidos de Zn y Cu en hoja por debajo del rango de suficiencia limitando la producción. Los niveles de incremento de Zn observados aún en la zona de servicio estuvieron levemente por encima del rango de suficiencia de varios cultivos. Incrementos de Zn en los niveles observados incluso serían favorables en sistemas de pastoreo para disminuir el riesgo de problemas asociados a la deficiencia de este micronutriente como anorexia, retraso de crecimiento de lechones y paraqueratosis. En base a los resultados obtenidos la acumulación de Zn y Cu en el suelo por el sistema de cerdos a campo desarrollado, lejos de ser un problema podrían llegar a considerarse beneficiosas para los cerdos y en muchas situaciones de suelos del Uruguay como beneficiosas para la producción animal y vegetal.

The robustness and restoration of a network of ecological networks

by Darren Evans

published in Science

Understanding species’ interactions and the robustness of interaction networks to species loss is essential to... more Understanding species’ interactions and the robustness of interaction networks to species loss is essential to understand the effects of species’ declines and extinctions. In most studies, different types of networks (such as food webs, parasitoid webs, seed dispersal networks, and pollination networks) have been studied separately. We sampled such multiple networks simultaneously in an agroecosystem. We show that the networks varied in their robustness; networks including pollinators appeared to be particularly fragile. We show that, overall, networks did not strongly covary in their robustness, which suggests that ecological restoration (for example, through agri-environment schemes) benefitting one functional group will not inevitably benefit others. Some individual plant species were disproportionately well linked to many other species. This type of information can be used in restoration management, because it identifies the plant taxa that can potentially lead to disproportionate gains in biodiversity.

Cambios en los contenidos nutricionales en suelos arenosos de sabana bajo fertilización orgánica prolongada

by Ismael Hernández Valencia

Hernández-Valencia, I., López, A. y López-Hernández, D. 1999. Cambios en los contenidos nutricionales en suelos arenosos de sabana bajo fertilización orgánica prolongada. Ecotrópicos (12):9-14

Nutrition and the Forest

by Sabrina Hardenbergh

Sources of Resistance to Stem Rust (Ug99) in Bread Wheat and Durum Wheat Identified Using Focused Identification of Germplasm Strategy (FIGS)

by Dag Endresen

Dag Terje Filip Endresen, Kenneth Street, Michael Mackay, Abdallah Bari, Ahmed Amri, Eddy De Pauw, Kumarse Nazari, and Amor Yahyaoui (2012). Sources of Resistance to Stem Rust (Ug99) in Bread Wheat and Durum Wheat Identified Using Focused Identification of Germplasm Strategy (FIGS). Crop Science 52(2): 764-773. doi: 10.2135/cropsci2011.08.0427.

The Focused Identification of Germplasm Strategy (FIGS) has been validated using predictive computer models in... more The Focused Identification of Germplasm Strategy (FIGS) has been validated using predictive computer models in simulation studies to predict a priori known trait scores. This study was designed as a "blind" study where the person calculating the computer model did not know the actual trait scores. This study design provides a more realistic test of the predictive capacity of the FIGS approach compared to previous studies. Furthermore this study also explored the suitability of FIGS for the identification of resistance in bread wheat (Triticum aestivum L. ssp. aestivum) and durum wheat (Triticum turgidum L. ssp. durum) to Ug99 – a strain of stem rust (Puccinia graminis Pers f.sp. tritici Eriks. & Henn.) and typified to race TTKSK. The predictions were validated against a dataset with the screening of wheat accessions conducted in Yemen in 2008. Only a small training set representing 20% of the trait screening results was disclosed to the person conducting the data analysis for the calibration of the prediction model. The hit rate for identification of Ug99-resistant accessions was more than two times higher when using the FIGS approach compared to a random selection of accessions. These results suggested that FIGS was well suited for the identification of samples with resistance to fungal pathogens. It is therefore recommended that FIGS approach be used as a complement to expert knowledge and experience when selecting accessions for plant breeding and crop research activities.

Predictive Association between Biotic Stress Traits and Eco-Geographic Data for Wheat and Barley Landraces

by Dag Endresen

Dag Terje Filip Endresen, Kenneth Street, Michael Mackay, Abdallah Bari, and Eddy De Pauw (2011). Predictive Association between Biotic Stress Traits and Eco-Geographic Data for Wheat and Barley Landraces. Crop Science 51 (5): 2036-2055. doi: 10.2135/cropsci2010.12.0717

Collections of crop genetic resources are a valuable source of new genetic variation for economically important... more Collections of crop genetic resources are a valuable source of new genetic variation for economically important traits, including resistance to crop diseases. New sources of useful crop traits are often identified through evaluation in field trials. The number of relevant accessions in genebank collections available to be evaluated is often substantially larger than the capacity of the evaluation project. The focused identification of germplasm strategy (FIGS) is an approach used to select subsets of germplasm from genetic resource collections in such a way as to maximize the likelihood of capturing a specific trait. This strategy uses a range of methods to link the expression of a specific trait (of a target crop) with the eco-geographic parameters of the original collection site. This study contributes to the development of the approach by which a FIGS subset could be assembled for biotic traits. We have evaluated trait-specific subset selection methods for two fungal crop diseases, namely stem rust (Puccinia graminis Pers.) in wheat (Triticum aestivum L. and Triticum turgidum L.) and net blotch (Pyrenophora teres Drechs.) in barley (Hordeum vulgare L.). The results indicate that the climate layers from freely available eco-geographic databases are well suited to model and predict the reaction in these crops to biotic stress traits. This result has the potential to improve the efficiency of field screening trials to find novel sources of economically valuable crop traits.

Predictive Association between Trait Data and Ecogeographic Data for Nordic Barley Landraces

by Dag Endresen

Endresen, D.T.F. (2010). Predictive association between trait data and ecogeographic data for Nordic barley landraces. Crop Sci. 50(6):2418-2430. doi: 10.2135/cropsci2010.03.0174

Focused Identification of Germplasm (FIGS) is a new method to select plant genetic resources for the improvement of... more Focused Identification of Germplasm (FIGS) is a new method to select plant genetic resources for the improvement of food crops. Traditional cultivars (landraces) and crop wild relatives (CWR) provide a valuable source for novel alleles in crop improvement programs, but conserved landraces and CWR often lack important documentation. Genebank collections worldwide provide ready access to plant genetic resources including online documentation. However, incomplete documentation, and in particular the lack of relevant characterization and evaluation data (traits), often limit the efficient use of plant genetic resources. This current study demonstrates how trait mining with the new FIGS method can be used to predict missing trait information for landraces. Ecogeographic data from the location of origin for 14 Nordic landraces of barley (Hordeum vulgare L.) was successfully correlated to morphological traits using a modern multilinear data modeling method (multilinear partial least squares [N-PLS]). This result suggests that trait mining can efficiently be used as a targeted germplasm selection method and complement or replace the current core selection method in situations when the requirements for the trait mining method are fulfilled.

History of South Indian Agriculture and Agroecosystems

by Kathleen Morrison

Co-authored with K.R. Krishna
Book chapter in "South Indian Agroecosystems: Nutrient Dynamics and Productivity," Brown Walker, 2009.

Labile carbon and other soil quality indicators in two tillage systems during transition to organic agriculture

by David Lewis

David Bruce Lewis, Jason P. Kaye, Randa Jabbour, and Mary E. Barbercheck
Renewable Agriculture and Food Systems (2011) 26:342–353

Weed management is one of the primary challenges for producers transitioning from conventional to organic agriculture.... more Weed management is one of the primary challenges for producers transitioning from conventional to organic agriculture. Tillage and the use of cover crops are two weed control tactics available to farmers transitioning to organic management, but little is known about their interactive effects on soil quality during the transition period. We investigated the response of soils to tillage and initial cover crop during the 3-year transition to organic in a cover crop–soybean (Glycine max)–maize (Zea mays) rotation in the Mid-Atlantic region of the USA. The tillage treatment contrasted full, inversion tillage with moldboard plowing (FT) versus reduced tillage with chisel plowing (RT). The cover crop treatment contrasted annual versus mostly perennial species during the first year of the rotation. The experiment was initiated twice (Start 1 and Start 2), in consecutive years in adjacent fields. By the end of the experiment, labile carbon, electrical conductivity, pH and soil moisture were all greater under RT than under FT in both starts. Soil organic matter and several other soil attributes were greater under RT than under FT in Start 1, but not in Start 2, perhaps owing to differences between starts in initial field conditions and realized weather. Soil attributes did not differ between the two cover crop treatments. Combining our soils results with agronomic and economic analyses on these plots suggests that using RT during the organic transition can increase soil quality without compromising yield and profitability.

Seeds in farmland food-webs: Resource importance, distribution and the impacts of farm management

by Darren Evans

Whilst considerable research effort in Europe has linked agricultural intensification with dramatic declines of... more Whilst considerable research effort in Europe has linked agricultural intensification with dramatic declines of seed-feeding birds, surprisingly little is known about the wider importance of seeds in animal food-webs. Moreover, understanding the dynamics of farmland seed food resources for species of conservation concern is of considerable research interest.

We examined the distribution of berries and soil-surface seeds in the managed and unmanaged habitats of a 125 ha organic farm. We took soil suction-samples over a year, counted and identified all seeds, and compared abundances and species-richness between habitats. We constructed ecological networks from literature records and by rearing insects to investigate the importance of these seeds for insects, birds and mammals. We predicted the impacts of management on seed biomass, energy and the ecosystem service of pest control across the whole farm.

We estimated seed and berry food resources of up to 33 metric tons of biomass and 560 GJ of energy on the farm. Potentially, more than 330 species use the seeds as a food resource, the overwhelming majority of which are invertebrates (82%) relying predominantly on non-crop and weed species. Generally, uncultivated semi-natural habitats such as woodland and mature hedgerows were more species-rich and had higher seed biomass and energy than crop habitats throughout the year, but fallow land was disproportionately important for seeds during the summer. Models of increased management intensity revealed declines of up to 19% in seed biomass and energy and cascades through the network that resulted in a substantial decrease in potentially pest-controlling parasitoids.

Agroecology and the Struggle for Food Sovereignty In the Americas.

by Avery Cohn

co-edited with Jonathan Cook, Margarita Fernandez, Rebecca Reider, & Corrina Steward

This publication is based on the workshop “Food Sovereignty, Conservation, and Social Movements for Sustainable... more This publication is based on the workshop “Food Sovereignty, Conservation, and Social Movements for Sustainable Agriculture in the Americas,” held at the Yale School of Forestry & Environmental Studies in April of 2004. Many of the articles
are summaries of speaker presentations and breakout session discussions that took place at the workshop. In addition, the publication includes academic pieces that reflect on issues raised during the workshop; case studies of local struggles and
successes in the U.S. and Latin America; and interviews with farmers and farmer representatives who presented at the workshop.

Diversifying crop rotations with temporary grasslands: potentials for weed management and farmland biodiversity

by Helmut Meiss

Perennial lucerne affects weed community trajectories in grain crop rotations

by Helmut Meiss

Co-authored with
Safia Médiène,
Rainer Waldhardt,
Jacques Caneill,
Vincent Bretagnolle,
Xavier Reboud, and
Nicolas Munier-Jolain.

Complex crop rotations may be beneficial for weed management. We analysed how pluri-annual forage crops may affect... more Complex crop rotations may be beneficial for weed management. We analysed how pluri-annual forage crops may affect weed composition during cereal-based crop rotations. Using a space-for-time-substitution design, we compared weed composition and diversity before, during and after perennial crops. We surveyed four groups of fields a) winter wheats (Triticum aestivum L.) following annual crops, b) 1-year old alfalfas (Medicago sativa L.) following annual crops, c) 2-6 years old alfalfas and d) winter wheats following pluriannual alfalfas in western France (N=420 fields). Weed composition varied among the four groups, suggesting a cyclic trajectory corresponding to the phases of the crop rotation. Indicator Species Analysis showed that these differences due to at least 40 species, including the most common weeds. A functional group analysis showed that perennial alfalfa crops shifted the communities away from several problematic weeds, especially annual broad-leaved species with an upright or climbing morphology. This effect was also visible in the wheats following alfalfas. Other species (including perennials, annuals with rosettes, and some grasses) benefited from the particular growth conditions in alfalfas but decreased in the following wheats. The diversification of arable crop rotations with perennial crops may thus be useful for Integrated Weed Management, reducing the need for herbicides. At the same time, other species less harmful to annual crops were favoured, resulting in increased floristic diversity.

Providing resources for diverging ecological needs of natural enemies: biological control in tomato cultivations

by Mario V. Balzan

[Conference Proceedings]
12th EEF Congress (2011), Avila, Spain

The potential of field margins in providing resources for antagonist species and enhancing ecosystem services is well... more The potential of field margins in providing resources for antagonist species and enhancing ecosystem services is well established. Yet, relatively limited research is available on the influence of within-field habitats on community structure, and the ability of different groups to provide ecosystem services. This study investigates the availability of floral resources in conventionally managed tomato cultivations in Tuscany, and their influence on community structure and biocontrol. Within-field assessment of crop damage, from the fruit-attacking lepidoptera, was carried out for 10 fields. This pest complex, composed mainly of Helicoverpa armigera (Hűbner) and Tuta absoluta (Meyrick), which was recently introduced to the Mediterranean region, is one of the most important pests as larvae directly damage the fruit. The floristic composition, availability of floral resources and diversity of separate edges were determined. Another experiment involved collecting T. absoluta larvae from damaged fruit, which were subsequently reared to identify the level of parasitisation. Results indicate that reduced floristic species richness and diversity within herbaceous strips are associated with higher levels of yield loss from noctuids but not of T. absoluta. A new parasitoid of T. absoluta was collected, but the level of parasitisation was found to be particularly low. A multivariate approach was used to analyse the association of several insect groups, and subsequently these results were fitted on environmental data relating to the herbaceous strips characteristics, including vegetation and functional group composition and diversity. An important issue which arises from these results is the diverging and complex ecological requirements of different functional groups.