Papers by Clara I. Nicholls
Modern agroecosystems require systemic change, but new redesigned farming systems will not emerge... more Modern agroecosystems require systemic change, but new redesigned farming systems will not emerge from simply implementing a set of practices (rotations, composting, cover cropping, etc.), but rather from the application of already well defined agroecological principles. These principles can be applied by way of various practices and strategies, and each will have different effects on productivity, stability and resiliency within the farm system. By breaking the monoculture nature of farming systems, agroecological diversification mimic natural ecological processes leading to optimal recycling of nutrients and organic matter turnover, soil biological activation, closed energy flows, water and soil conservation and balanced pest-natural enemy populations, all key processes in maintaining the agroecosystem’s health, productivity and its self-sustaining capacity. By enhancing functional biodiversity, a major goal of the conversion process is achieved: strengthening the weak ecological ...
Diverse, severe and location-specific impacts on agricultural production are anticipated with cli... more Diverse, severe and location-specific impacts on agricultural production are anticipated with climate change.Temperature and water availability remain key factors in determining crop growth and productivity, predicted changes in these factors will lead to reduced crop yields. Climate induced changes in insect pest, pathogen and weed population dynamics and invasiveness could compound such effects. Undoubtedly climate and weather induced instability will affect levels of and access to food supply. Changes that will not radically modify the monoculture nature of dominant agroecosystems may temporarily moderate negative impacts. The biggest and most durable benefits will likely result from more radical agroecological measures that will strengthen the resilience of farmers and rural communities, such as diversification of agroecosytems in the form of polycultures, agroforestry systems and crop-livestock mixed systems accompanied by organic soil management, water conservation and harvest...
Agroecological conversion of conventional production systems: theory, strategies and assessment. ... more Agroecological conversion of conventional production systems: theory, strategies and assessment. The conversion of high input conventional monocultures to diversified, low external input agroecosystems is based on two agroecological pillars: habitat diversification and organic soil management. Te optimal function of agroecosystems depends on the spatial-temporal designs that promote synergies between above and below ground key biodiversity components, which in turn determine the expression of ecological processes such as pest regulation, nutrient cycling and productivity. The evolution of this agroecological transition can be monitored using sustainability indicators which assess soil quality and plant health.
Agro Sur, 2020
Although there are many methodologies available to assess agroecosystem performance (sustainabili... more Although there are many methodologies available to assess agroecosystem performance (sustainability, resilience, soil quality and plant health, biodiversity levels, etc.), there is still a need to develop a methodology to be used at the field level by researchers and farmers to assess if surveyed farming systems are or not based on agroecological principles. Developing such practical tool is key to determine if farmers in transition are on the right agroecological path. To fulfill this need for a farm-level assessment, a methodological tool was developed and tested with the participation of nine Japanese farmers in three prefectures (Kyoto, Hiroshima and Hyogo). The methodology consists of two parts. The first is a simple and rapid assessment survey based on the grading of eight indicators that match practices used by farmers with agroecological principles. The second part uses the same indicators to define a "threshold level", below which it is estimated that a farm system is not yet "agroecologically based." This process enables farmers to reflect and use the tool as a guide to adopt or adjust their practices based on agroecology principles, by changing farm design and management, in order to further optimize the performance of their agroecosystems.
Revista de Ciencias Ambientales, 2018
A pesar de que existe conciencia general y alarma sobre la emergencia planetaria que representa e... more A pesar de que existe conciencia general y alarma sobre la emergencia planetaria que representa el cambio climático, las emisiones de carbono siguen incrementándose y no se vislumbran soluciones inmediatas y drásticas para frenar el calentamiento global. Parte del problema es que se requiere un cambio revolucionario que va en contra del crecimiento económico y de la hegemonía política-económica que mantiene a todo costo el sistema capitalista imperante. Es así que la agricultura industrial de monocultivos, pieza clave del sistema dominante, pretende reproducirse mediante estrategias como la Agricultura Climáticamente Inteligente (CSA), que no desafía la estructura del monocultivo ni las relaciones de poder que los mantienen. La agroecología, por el contrario, es una ciencia y movimiento que pretende derrocar las fuerzas perpetuantes del hambre y de la degradación ambiental. En gran parte, está liderada por movimientos sociales rurales que valoran el legado de la agricultura tradicional, la cual, a través de la innovación campesina e indígena, ha sido capaz de enfrentar la variabilidad climática por siglos por lo que representa un patrimonio humano de principios de resiliencia, claves para diseñar una nueva agricultura capaz de enfrentar el cambio climático.
Acta Horticulturae, 2008
We present the results of studies in organic vineyards in Mendocino and Sonoma counties, Californ... more We present the results of studies in organic vineyards in Mendocino and Sonoma counties, California, in an effort to systematize the emerging lessons from our experience on vineyard biodiversity enhancement for ecologically-based pest management. In the Mendocino study, a vegetational corridor connected to a riparian forest channeled insect biodiversity from surrounding habitats into the vineyard, thus overcoming the restricted spatial limits to which the positive influence of adjacent vegetation on vineyard pest dynamics is usually confined. In addition, summer cover crops substantially enhanced biological control of leafhoppers and thrips, by breaking the virtual monoculture that vineyards become in the summer after winter cover crops dry out or are plowed under. In the Sonoma vineyard, an island of flowering shrubs and herbs provided season-long flower resources and alternate preys/hosts for natural enemies, which slowly built up in the adjacent vineyard. The island acted as a push-pull system for natural enemies, enhancing their activity but confining them mostly to the adjacent vine rows. Planting strips of summer cover crops could be a strategy to overcome the push effect of the island.
Sustainability, 2017
Most efforts to improve agricultural production remain focused on practices driven by an intensif... more Most efforts to improve agricultural production remain focused on practices driven by an intensification agenda and not by an agroecological one. Agroecology transcends the reformist notion of organic agriculture and sustainable intensification proponents who contend that changes can be achieved within the dominant agroindustrial system with minor adjustments or "greening" of the current neoliberal agricultural model. In the technological realm, merely modifying practices to reduce input use is a step in the right direction but does not necessarily lead to the redesign of a more self sufficient and autonomous farming system. A true agroecological technological conversion calls into question monoculture and the dependency on external inputs. Traditional farming systems provide models that promote biodiversity, thrive without agrochemicals, and sustain year-round yields. Conversion of conventional agriculture also requires major social and political changes which are beyond the scope of this paper.
Conversión agroecológica de sistemas convencionales de producción: teoría, estrategias y evaluaci... more Conversión agroecológica de sistemas convencionales de producción: teoría, estrategias y evaluación. La conversion de sistemas convencionales de produccion, caracterizados por monocultivos manejados con altos insumos a sistemas diversificados de bajos insumos, se basa en dos pilares agroecologicos: la diversificacion del habitat y el manejo organico del suelo. El funcionamiento optimo del agroecosistema depende de disenos espaciales y temporales que promueven sinergias entre los componentes de la biodiversidad arriba y abajo del suelo, las cuales condicionan procesos ecologicos claves como la regulacion biotica, el reciclaje de nutrientes y la productividad. La evolucion de la transicion agroecologica puede ser monitoreada por un conjunto de indicadores de sustentabilidad que estiman la calidad del suelo y la salud del cultivo. Palabras claves: agroecologia, conversion, biodiversidad, indicadores de sustentabilidad Agroecological conversion of conventional production systems: theory, strategies and assessment. The conversion of high input conventional monocultures to diversified, low external input agroecosystems is based on two agroecological pillars: habitat diversification and organic soil management. Te optimal function of agroecosystems depends on the spatial-temporal designs that promote synergies between above and below ground key biodiversity components, which in turn determine the expression of ecological processes such as pest regulation, nutrient cycling and productivity. The evolution of this agroecological transition can be monitored using sustainability indicators which assess soil quality and plant health.
Agroecologia, 2013
La mayoría de las estadísticas disponibles que predicen impactos climáticos sobre la agricultura ... more La mayoría de las estadísticas disponibles que predicen impactos climáticos sobre la agricultura campesina son aproximaciones muy burdas que no toman en cuenta la heterogeneidad de la agricultura campesina-indígena, ni la diversidad de estrategias que los campesinos han utilizado y aun utilizan para enfrentar las sequías, inundaciones, huracanes, etc. Alrededor del mundo muchos campesinos y agricultores tradicionales han respondido a las condiciones climáticas cambiantes demostrando innovación y resiliencia frente al cambio climático. Un gran número de agricultores tradicionales poseen lecciones importantes de resiliencia para los agricultores modernos y diversos expertos han sugerido que el rescate de los sistemas tradicionales de manejo, en combinación con el uso de estrategias agroecológicas, puede representar la única ruta viable y sólida para incrementar la productividad, la sostenibilidad y la resiliencia de la producción agrícola. En este trabajo se define un marco conceptual y metodológico para poder descifrar los principios y mecanismos claves que explican la resiliencia de los sistemas diversificados, de manera de que estos puedan ser transmitidos a otros agricultores en cada región y así mejoren la capacidad de resistencia y de recuperación de sus fincas. Por esto la urgencia de la necesidad de desarrollar una metodología que permita evaluar la capacidad de los agroecosistemas a resistir y recuperarse de los eventos climáticos severos, con especial énfasis en entender los procesos que explican la resiliencia socio-ecológica observada.
Revista Facultad Nacional De Agronomia, Apr 24, 2012
From several decades ago the importance of natural enemies of the noxious organisms has been reco... more From several decades ago the importance of natural enemies of the noxious organisms has been recognized. Unfortunalely the introduclion of the biological control has not had the desired dimensión. The indiscriminate use of biocide produCls has altered the biodiversity of the agroecosystem. The parasitoids and predators have suffered the noxious effects ofthe plaguicides. These natural enemies of the plagues play a momentous paper in the reguLalion of noxious insects population.
Agroecologia, 2011
Ecologically based food production systems for thew XXI Century Agroecology provides the scientif... more Ecologically based food production systems for thew XXI Century Agroecology provides the scientific and methodological basis for transition strategies toward new paradigms of rural development. The cultural, social and productive basis for this new paradigm resides on the ethonecological rationale of pea snat agriculture, a source of an important legacy of indigenous knowledge, agrobiodiversity and food sovereignity strategies. Organic agriculture comprises another alternative model that produces food with less environmental impact and energy use, but this agriculture needs to transition beyond input subsitution and should emphasize local and national markets in order to realize its food security potential, freeing itself from its dependence on international markets that make it susceptible to the control by multinationals that dominate the globalization circles. The agroecological scaling-up examples from Cuba and the Philippines that emphasize farmer led participation and extension, demonstrate that the human resource and its innovation capacity are the keystone of all development strategies of rural people and especially for resource-por farmers.
Métodos culturales de manejo de suelos tales como la fertilización afectan la susceptibilidad de ... more Métodos culturales de manejo de suelos tales como la fertilización afectan la susceptibilidad de plantas al ataque de insectos plaga vía alteraciones de los niveles de nutrientes en los tejidos. Investigaciones revelan que la habilidad de una planta a tolerar la incidencia de plagas o enfermedades está ligada a las condiciones óptimas del suelo, en particular las propiedades biológicas. Cultivos que crecen en suelos con un alto contenido de materia orgánica y con alta actividad biólogica exhiben por lo general menor incidencia de plagas. Estas reducciones parecen atribuirse a niveles menores de nitratos libres en el follaje. Por el contrario, prácticas agrícolas como el uso excesivo de fertilizantes que crean imbalances nutricionales tienden a reducir la defensa de las plantas. Hay varios estudios comparativos que reportan menor incidencia en cultivos orgánicos que aquellos en sistemas convencionales. Entender los mecanismos claves que explican porque la fertilización orgánica parec...
En este artículo se analizan las potencialidades de la agroecología basada en el control de las c... more En este artículo se analizan las potencialidades de la agroecología basada en el control de las comunidades locales para hacer frente a enormes problemas humanos como el hambre y el deterioro ambiental. Para ello se revisa la literatura existente y se analizan diversas experiencias locales como la milpa mexicana, las ANAP cubanas y la MASIPAG filipina. Se concluye que se trata de verdaderas alternativas al modelo agroindustrial responsable de muchos de los problemas actuales.
Agroforestry Systems
In northwestern Portugal, peasants have developed complex vineyard (Vitis vinifera) systems compr... more In northwestern Portugal, peasants have developed complex vineyard (Vitis vinifera) systems comprising agroforests composed of host trees, vines, annual crops and in some cases animals. Until recently these vineyards suffered very few pest problems and received relatively low pesticide loads. In the last few years, new policy and market forces have prompted the conversion of many of these systems to monoculture thereby decreasing the biodiversity inherent to traditional vineyards. Many scientists are concerned that with accelerating rates of vineyard simplification insect pest and disease problems may increase due to lack of habitat and resources for natural enemies or to a concentration of preferred host plants for specific pathogens and herbivores. During the growing seasons of 1997 and 1999 we conducted several farm surveys of traditional agroforestry and modernized, monoculture farms. We conducted field measurements to elucidate trends in insect pest and disease incidence in bot...
Agriculture and Human Values
An emergent contradiction in the contemporary development of biological control is that of the pr... more An emergent contradiction in the contemporary development of biological control is that of the prevalence of the substitution of periodic releases of natural enemies for chemical insecticides and the dominance of biotechnologically developed transgenic crops. Input substitution leaves in place the monoculture nature of agroecosystems, which in itself is a key factor in encouraging pest problems. Biotechnology, now under corporate control, creates more dependency and can potentially lead to Bt resistance, thus excluding from the market a key biopesticide. Approaches for putting back biological control into the hands of farmers (from artesanal biotechnology for grassroots biopesticide production Cuban style to farmer-to-farmer IPM networks, etc.) have been developed as a way to create a farmer centered approach to biological control
Landscape Ecology
During 1996 and 1997, two adjacent 2.5 has organic vineyard blocks (A and B) were monitored to as... more During 1996 and 1997, two adjacent 2.5 has organic vineyard blocks (A and B) were monitored to assess the distributional and abundance patterns of the Western grape leafhopper Erythroneura elegantula Osborn (Homoptera: Cicadellidae) and its parasitoid Anagrus epos Girault (Hymenoptera: Mymaridae), Western flower thrips Frankliniella occidentalis (Pergande) and generalist predators. The main difference between blocks was that block A was cut across by a corridor composed of 65 flowering plant species which was connected to the surrounding riparian habitat, whereas block B had no plant corridor. In both years, leafhopper adults and nymphs and thrips tended to be more numerous in the middle rows of block A and less abundant in border rows close to the forest and corridor where predators were more abundant. The complex of predators circulating through the corridor moved to the adjacent vine rows and exerted a regulatory impact on herbivores present in such rows. In block B all insects w...
Biodiversity and Insect Pests, 2012
ch5. This article may be used for non-commercial purposes in accordance with Wiley Terms and Cond... more ch5. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.
Integrated Pest Management Reviews, 2002
This paper describes the evolution of IPM in Cuba during three pre- and post-revolutionary period... more This paper describes the evolution of IPM in Cuba during three pre- and post-revolutionary periods. The state of the art of IPM after the collapse of Cuba's relations with the soviet block is analyzed in detail. During this 'special period' Cuba is undergoing a major conversion from conventional agriculture dependent on external inputs to a semi-organic agriculture dependent on local
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Papers by Clara I. Nicholls