Conservation agriculture in the dry Mediterranean climate

The objective of this article is to review: (a) the concepts and principles that underpin Conservation Agriculture (CA) ecologically and operationally; (b) the potential benefits that can be harnessed through CA systems in the dry Mediterranean climates; (c) current status of adoption and spread of CA in the dry Mediterranean climate countries; and (d) opportunities for CA in the Central and West Asia and North Africa (CWANA) region. CA, comprising minimum mechanical soil disturbance and no-tillage seeding, organic mulch cover, and crop diversification is now practised on some 125 million ha, corresponding to about 9% of the global arable cropped land. Globally, the area under CA is spread across all continents and all agro-ecologies, including the dryland climates in the Mediterranean basin region as well as in the Mediterranean climates elsewhere in the world. Worldwide empirical and scientific evidence is available to show that significant productivity, economic, social and environmental benefits exist that can be harnessed through the adoption of CA principles for sustainable production intensification in the dry Mediterranean climates, including those in the CWANA region. The benefits include: fundamental change for the better in the sustainability of production systems and ecosystem services; higher stable yields and incomes; climate change adaptation and reduced vulnerability to the highly erratic rainfall distribution; and reduced greenhouse gas emissions. CA has taken off globally and is now spreading in several Mediterranean climates outside the Mediterranean basin particularly in South America, South Africa and Australia. In the dry Mediterranean climates in the CWANA region, CA is perceived to be a powerful tool of land management but CA has not yet taken off. Research on CA in the CWANA region has shown that there are opportunities for CA adoption in rainfed and irrigated farming systems involving arable and perennial crops as well as livestock

Earthworm richness in no-till sites in Paraguay.

ISEE 10

Examining the potential for climate change mitigation from zero tillage

The benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (7·7% over 10 years). In several cases yield reductions have been recorded e.g. c. 1–8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security

Fitomassa de adubos verdes e controle de plantas daninhas em diferentes densidades populacionias de leguminosas.

O objetivo deste trabalho foi avaliar a fitomassa de calopogônio, mucuna-preta, mucunarajada,feijão-de-porco, guandu de porte alto, Crotalaria spectabilis e C. breviflora sob diferentes densidades de semeadura (10, 20, 40, 80 e 160 sementes viáveis m-2), e o crescimento de plantas daninhas nessas densidades, em área de tabuleiros costeiros. O experimento foi desenvolvido de maio a agosto de 1996, no Campo Experimental “Antônio Martins”(EMDAGRO/Embrapa-CPATC), em Lagarto, SE. O número de plantas vivas na floração (NPVF) e a matéria seca da parte aérea das leguminosas (MSPA) foram determinados quando, em cada espécie, cerca de 50% das plantas floresceram. Maiores incrementos de MSPA, em resposta ao adensamento populacional, foram observados em C. spectabilis e C. breviflora, seguidas pelo calopogônio, mucuna-preta e mucuna-rajada. Em relação ao feijão-de-porco, a resposta foi negativa, enquanto com o guandu não houve influência. Quanto ao NPVF, as respostas ao adensamento foram lineares e positivas em C. spectabilis, C. breviflora e calopogônio, e quadráticas com ponto de máxima em feijão-de-porco,guandu e mucuna-rajada. Embora nenhum modelo tenha sido ajustado para expressar a relação entre NPVF e adensamento na semeadura de mucuna-preta, a sobrevivência dessa espécie foi reduzida em todas as densidades. Maiores inibições de plantas daninhas ocorreram nas parcelas de mucuna-preta e feijão-de-porco

Overview of the Worldwide Spread of Conservation Agriculture

The global empirical evidence shows that farmer-led transformation of agricultural production systems based on Conservation Agriculture (CA) principles is already occurring and gathering momentum globally as a new paradigm for the 21st century. The data presented in this paper has been collected by the Food and Agriculture Organization of the United Nations from several sources including estimates made by ministries of agriculture, by farmer organizations, and well-informed individuals in research or development organizations; they provide an overview of CA adoption and spread by country, as well as the extent of CA adoption by continent. CA systems, comprising no or minimum mechanical soil disturbance, organic mulch soil cover, and crop species diversification, in conjunction with other good practices of crop and production management, are now (in 2013) practiced globally on about 157 M ha, corresponding to about 11% of field cropland, in all continents and most land-based agricultural ecologies, including in the various temperate environments. This change constitutes a difference of some 47% globally since 2008/09 when the spread was recorded as 106 M ha. The current total of 157 M ha represents an increase in adoption of CA by more countries but the estimate is on the conservative side as the updated database does not capture all the CA cropland. While in 1973/74 CA systems covered only 2.8 M ha worldwide, the area had grown in 1999, to 45 M ha, and by 2003 the area had grown to 72 M ha. In the last 10 years CA cropland has expanded at an average rate of more than 8.3 M ha per year and since 2008/2009 at the rate of some 10 M ha per year, showing the increased interest of farmers and national governments in this alternate production concept and method. Adoption has been intense mainly in North and South America as well as in Australia and Asia, and more recently in Europe and Africa where the awareness of and support for CA is on the increase. The paper presents an update of the adoption of CA since 2008/09.Au vu des données empiriques mondiales, la transformation des systèmes de production agricole, qui s’appuient sur les principes de l’Agriculture de Conservation (AC), conduite par les agriculteurs eux-mêmes, est déjà engagée et s’impose peu à peu comme un nouveau modèle mondial pour le 21ème siècle. Les données de cet article ont été recueillies par l'Organisation des Nations Unies pour l’Alimentation et l’Agriculture (FAO) auprès de plusieurs sources et sont notamment issues d'études réalisées par des ministères de l'agriculture, des organisations d'agriculteurs et des experts d'organismes de recherche et développement ; elles donnent un aperçu par pays et par continent du niveau d’adoption et de progression de l’AC. Les pratiques de l’AC, qui englobent la perturbation mécanique minimale, voire aucune perturbation mécanique du sol, l’utilisation des paillis organiques et la diversification des espèces cultivées, associées à d’autres bonnes pratiques de gestion des cultures et de la production, sont aujourd’hui (en 2013) mises en œuvre sur près de 157 millions d’hectares, soit près de 11 % des terres cultivées, sur tous les continents et dans la plupart des écologies agricoles, notamment dans les divers environnements tempérés. Cette évolution représente un écart de près de 47 % au niveau mondial par rapport aux années 2008/09, où l'AC était pratiquée sur 106 millions d’hectares. Le chiffre actuel de 157 millions d’hectares reflète une adoption plus large de l'AC dans un nombre croissant de pays mais il s'agit là d'une estimation prudente, la base de données actualisée ne prenant pas en compte la totalité des terres cultivées en AC. Alors que l'AC couvrait seulement 2,8 M ha dans le monde en 1973/74, elle s'est étendue à 45 M ha en 1999 et 72 M ha en 2003. Au cours des dix dernières années, la surface de terres cultivées en AC s’est développée à un rythme moyen de plus de 8,3 M ha par an et d'environ 10 M ha par an depuis 2008/2009, illustrant l’intérêt croissant des agriculteurs et des gouvernements pour ce concept et ces méthodes de production alternatifs. L'adoption de l'AC a été particulièrement soutenue en Amérique du Nord et en Amérique du Sud, ainsi qu'en Australie et en Asie, et, plus récemment, en Europe et en Afrique, où la sensibilisation aux principes de l'AC et l’encouragement de leur adoption ne cessent d'augmenter. Cet article présente un état des lieux de l'adoption de l'AC depuis 2008/09.Las pruebas empíricas a nivel mundial muestran que la transformación de los sistemas de producción agrícola guiada por los agricultores y basada en los principios de la agricultura de conservación ya se está produciendo y está cobrando impulso en todo el mundo como un nuevo paradigma para el siglo XXI. Los datos presentados en este trabajo han sido obtenidos por la Organización de las Naciones Unidas para la Agricultura y la Alimentación de varias fuentes, entre las que se incluyen las estimaciones realizadas por ministerios de agricultura, organizaciones de agricultores y otros entendidos en la materia de organizaciones de investigación o desarrollo, y proporcionan una perspectiva general de la adopción y la propagación de la agricultura de conservación por país, así como el alcance de la adopción de la agricultura de conservación en los distintos continentes. Los sistemas de agricultura de conservación, que incluyen una perturbación mecánica mínima o nula de la tierra, el uso de una capa de mantillo natural y la diversificación de las especies de cultivo, en combinación con otras prácticas positivas de gestión de cultivos y de la producción, se utilizan actualmente (en 2013) a nivel mundial en unos 157 millones de hectáreas, lo que corresponde aproximadamente al 11 % de las tierras de cultivo, en todos los continentes y la mayoría de las agroecologías basadas en el suelo, incluidos los ambientes templados. Este cambio constituye una diferencia de aproximadamente el 47 % en todo el mundo desde los años 2008-2009 cuando la propagación era de 106 millones de hectáreas. La cifra total actual de 157 millones de hectáreas representa un aumento en la adopción de la agricultura de conservación por parte de más países si bien esta estimación es conservadora ya que la base de datos actualizada no abarca todas las tierras de cultivo en las que se practica la agricultura de conservación. Mientras en los años 1973-1974 los sistemas de agricultura de conservación ocupaban solo 2,8 millones de hectáreas en el mundo, esta extensión fue creciendo hasta alcanzar los 45 millones de hectáreas en 1999 y los 72 millones de hectáreas en 2003. En los últimos 10 años las tierras de cultivo en las que se practica la agricultura de conservación se han extendido a un ritmo medio de más de 8,3 millones de hectáreas por año y desde los años 2008-2009 a un ritmo de unos 10 millones de hectáreas por año, lo que demuestra el creciente interés de los agricultores y los gobiernos nacionales en este concepto y método de producción alternativa. La adopción ha sido especialmente importante en América del Norte y del Sur, así como en Australia y Asia, y más recientemente en Europa y África, donde la concienciación y el apoyo a la agricultura de conservación son cada vez mayores. Este trabajo presenta información actualizada sobre la adopción de la agricultura de conservación desde los años 2008-2009

A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions

Conservation agriculture involves reduced tillage, permanent soil cover and crop rotations to enhance soil fertility and to supply food from a dwindling land resource. Recently, conservation agriculture has been promoted in Southern Africa, mainly for maize-based farming systems. However, maize yields under rain-fed conditions are often variable. There is therefore a need to identify factors that influence crop yield under conservation agriculture and rain-fed conditions. Here, we studied maize grain yield data from experiments lasting 5 years and more under rain-fed conditions. We assessed the effect of long-term tillage and residue retention on maize grain yield under contrasting soil textures, nitrogen input and climate. Yield variability was measured by stability analysis. Our results show an increase in maize yield over time with conservation agriculture practices that include rotation and high input use in low rainfall areas. But we observed no difference in system stability under those conditions. We observed a strong relationship between maize grain yield and annual rainfall. Our meta-analysis gave the following findings: (1) 92% of the data show that mulch cover in high rainfall areas leads to lower yields due to waterlogging; (2) 85% of data show that soil texture is important in the temporal development of conservation agriculture effects, improved yields are likely on well-drained soils; (3) 73% of the data show that conservation agriculture practices require high inputs especially N for improved yield; (4) 63% of data show that increased yields are obtained with rotation but calculations often do not include the variations in rainfall within and between seasons; (5) 56% of the data show that reduced tillage with no mulch cover leads to lower yields in semi-arid areas; and (6) when adequate fertiliser is available, rainfall is the most important determinant of yield in southern Africa. It is clear from our results that conservation agriculture needs to be targeted and adapted to specific biophysical conditions for improved impact

Plantio direto, adubação verde e suplementação com esterco de aves na produção orgânica de berinjela.

Sob manejo orgânico, foram avaliados, em Seropédica, RJ, os sistemas de plantio direto da berinjela(Solanum melongena) nas palhadas de Crotalaria juncea (crotalária), Pennisetum glaucum (milheto, cv. BRS 1501)e vegetação espontânea (pousio), em comparação com o plantio convencional (aração e gradagem ou enxada rotativa). Simultaneamente, foram avaliados três tipos de cultivo: berinjela em monocultura, em consórcio com crotalária e em consórcio com caupi (Vigna unguiculata, cv. Mauá). Não houve diferença entre os sistemas de plantio direto e convencional quanto à produção comercial da berinjela. A palhada da crotalária foi mais eficiente que a do milheto e do pousio para cobertura morta do solo e conseqüentemente o controle de plantas espontâneas foi maior. O cultivo simultâneo com as leguminosas não acarretou redução da produtividade da berinjela.Em um segundo estudo, foram comparados plantio direto (palhadas de crotalária e da vegetação espontânea) e plantio convencional, combinados com doses crescentes de cama de aviário (0, 100, 200 e 400 kg ha-1 de N)aplicada em cobertura. Em termos de aporte de biomassa, a crotalária foi novamente superior à vegetação espontânea.A berinjela respondeu à adubação orgânica, com produtividade máxima de 50,6 t ha-1 , correspondendo à maior dose empregada, contra 36,9 t ha-1 referentes ao controle

Overview of the Global Spread of Conservation Agriculture

The global empirical evidence shows that farmer-led transformation of agricultural production systems based on Conservation Agriculture (CA) principles is already occurring and gathering momentum worldwide as a new paradigm for the 21st century. The data presented in this paper, mainly based on estimates made by farmer organizations, agro-industry, and well-informed individuals provide an overview of CA adoption and spread by country, as well as the extent of CA adoption by continent. CA systems, comprising minimum mechanical soil disturbance, organic mulch cover, and crop species diversification, in conjunction with other good practices of crop and production management, are now practiced globally on about 125 M ha in all continents and all agricultural ecologies, including in the various temperate environments. While in 1973/74 CA systems covered only 2.8 M ha worldwide, the area had grown in 1999 to 45 M ha, and by 2003 to 72 M ha. In the last 11 years CA systems have expanded at an average rate of more than 7 M ha per year showing the increased interest of farmers and national governments in this alternate production method. Adoption has been intense in North and South America as well as in Australia and New Zealand, and more recently in Asia and Africa where the awareness and adoption of CA is on the increase. The paper presents the history of adoption and analyses reasons and actual regional trends for adoption to draw conclusions about future promotion of CA.Au vu des données empiriques mondiales, la transformation des systèmes de production agricole suivant les principes de l’Agriculture de Conservation (AC), conduite par les agriculteurs eux-mêmes, est déjà engagée et s’impose peu à peu dans le monde entier comme un nouveau modèle pour le 21ème siècle. Les données de cet article, principalement fondées sur les estimations d’organisations d’agriculteurs, de représentants de l’agro-industrie et d’autres experts, donnent un aperçu par pays et par continent du niveau d’adoption et de progression de l’AC. Les pratiques de l’AC, qui englobent la perturbation mécanique minimale du sol, l’utilisation des paillis organiques et la diversification des espèces cultivées, associées à d’autres bonnes pratiques de gestion des cultures et de la production, sont aujourd’hui mises en œuvre sur près de 125 millions d’hectares sur tous les continents et dans toutes les écologies agricoles, notamment dans les divers environnements tempérés. Alors que l’AC concernait seulement 2,8 M ha dans le monde en 1973/74, elle s’est étendue à 45 M ha en 1999 et 72 M ha en 2003. Au cours des onze dernières années, elle s’est développée à un rythme moyen de plus de 7 M ha par an, illustrant l’intérêt croissant des agriculteurs et des gouvernements pour ce système de production alternatif. L’adoption de l’AC a été soutenue en Amérique du Nord et en Amérique du Sud, ainsi qu’en Australie et en Nouvelle-Zélande et, plus récemment, en Asie et en Afrique, où la sensibilisation aux principes de l’AC et leur application ne cessent d’augmenter. Cet article retrace l’historique du choix de l’agriculture de conservation et analyse les raisons et les tendances régionales actuelles de ce choix afin d’en tirer les conclusions pour son développement futur.Las pruebas empíricas a nivel mundial muestran que la transformación de los sistemas de producción agrícola guiada por los agricultores y basada en los principios de la agricultura de conservación ya se está produciendo y está cobrando impulso en todo el mundo como un nuevo paradigma para el siglo XXI. Los datos presentados en este trabajo, basados principalmente en estimaciones realizadas por organizaciones de agricultores, la agroindustria y otros entendidos en la materia, proporcionan una perspectiva general de la adopción y la propagación de la agricultura de conservación en diferentes países, así como el alcance de la adopción de este tipo de agricultura en los distintos continentes. Los sistemas de agricultura de conservación, que incluyen una perturbación mecánica mínima de la tierra, el uso de una capa de mantillo natural y la diversificación de las especies de cultivo, en combinación con otras prácticas positivas de gestión de cultivos y de la producción, se utilizan actualmente a nivel mundial en unos 125 millones de hectáreas en todos los continentes y en todas las agroecologías, incluidos los ambientes templados.  Mientras en los años 1973-1974 los sistemas agrícolas de conservación ocupaban solo 2,8 millones de hectáreas en el mundo, esta extensión fue creciendo hasta alcanzar los 45 millones de hectáreas en 1999 y los 72 millones en 2003. En los últimos 11 años los sistemas de agricultura de conservación se han extendido a un ritmo medio de más de 7 millones de hectáreas por año, lo que demuestra el creciente interés de los agricultores y los gobiernos nacionales en este método de producción alternativa. La adopción de estos sistemas ha sido especialmente importante en América del Norte y del Sur, así como en Australia y Nueva Zelanda, y más recientemente en Asia y África, donde la concienciación y la adopción de la agricultura de conservación son cada vez mayores. El trabajo presenta la historia de la adopción de estos métodos y analiza los motivos y las tendencias regionales actuales para poder extraer conclusiones sobre el futuro fomento de la agricultura de conservación