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Soil functioning is affected by agriculture. Therefore, sustainable soil use requires frequent soil health monitoring. Soil health indicators (ISE) allow to do soil health evaluation simply and periodically. The carbon (C) dioxide emission during short aerobic incubations (Cmin) could be used as an ISE. However, its performance as ISE has not been sufficiently evaluated. The objective of this work was to evaluate the sensitivity of Cmin at 2 [Cmin(2)], 4 [Cmin(4)], 6 [Cmin(6)], and 10 [Cmin(10)] days of incubation to the effect of different management practices and their relationship with total (COT), mineral associated (COA), particulate (COP), potentially mineralizable (C0), and potassium permanganate oxidizable (CoxP) organic C, anaerobically mineralized nitrogen (NAN), and aggregate stability of a Mollisol from the southeastern Buenos Aires province. We determined Cmin(2), Cmin(4), Cmin(6), and Cmin(10), COT, COA, COP, C0, CoxP, NAN, and EA (remnant mass of macroaggregates, MasaMAMV) in soil samples (0-5 and 5-20 cm) from a long-term experiment in Balcarce including crop-pasture rotations under conventional tillage and no-tillage (SD). As expected, the Cmin showed a similar pattern as the rest of the variables reflecting the effect of the different management practices with greater values observed under pasture and SD, especially at 0-5 and 0-20 cm. The ability of the Cmin to show the effect of the management practices evaluated increased with the increase of the duration of the incubation. The Cmin correlated (Pearson r) to COT, COP, C0, CoxP, NAN, and MasaMAMV (r=0.52 to r=0.96) (P<0.01) with coefficients increasing with the days of incubation. It is concluded that Cmin4 (r=0.59 to r=0.88) or Cmin6 (r=0.52 to r=0.93) could be used as adequate ISE. It is necessary to continue studying these relationships under contrasting soil, climate and management conditions. [ABSTRACT FROM AUTHOR]

Los cultivos intercalados ofrecen beneficios significativos para la agricultura al fijar nitrógeno, proteger contra plagas y enfermedades, y optimizar la producción. En este sentido, se analizó el efecto de los cultivos intercalados y unicultivos de yuca, maní y maíz sobre los índices de crecimiento y Uso Equivalente de la Tierra (UET). Los resultados mostraron que la yuca presentó una mayor Tasa de Crecimiento Absoluto en los cultivos intercalados en comparación con el unicultivo a las 12, 24 y 36 Semanas Después de la Siembra (SDS). Por otro lado, el maní mostró los mayores valores de la Tasa Relativa de Crecimiento a las 4SDS y disminuyó a lo largo del tiempo. En cuanto al maíz, el unicultivo tuvo una Tasa de Asimilación Neta más alta desde las 4SDS hasta las 12SDS. En términos del UET, el sistema de cultivo maíz y yuca resultó ser el más eficiente con un valor de 1,30, seguido del cultivo intercalado de yuca, maní y maíz con 1,24, indicando un uso óptimo de la tierra y una mayor producción de los cultivos; en contraste, el cultivo intercalado de maní y maíz fue el menos eficiente, con 0,59, valor inferior al UET de los unicultivos. Los cultivos intercalados de yuca, maní y maíz tienen el potencial de estimular el crecimiento, mejorar la eficiencia fisiológica y optimizar el uso de la tierra en comparación con los unicultivos, siempre y cuando se planifiquen adecuadamente para aprovechar las interacciones beneficiosas entre las especies.

En la última década, la industria acuícola ha aumentado exponencialmente y se considera que proveerá de alimento a la creciente población. El cultivo de organismos acuáticos como la tilapia representa una excelente opción por proporcionar una rica fuente de proteínas y ácidos grasos de alta calidad para la dieta humana. Sin embargo, los cultivos acuícolas están en constante amenaza por infecciones microbianas, por lo que el uso de microorganismos en forma de probióticos representa una alternativa sustentable que ofrece múltiples ventajas tanto a los organismos cultivados como a los consumidores finales por estimular la producción y buen funcionamiento del sistema inmunológico del pez, con lo cual se evita el uso indiscriminado de antibióticos. Este artículo es una revisión del uso de microorganismos utilizados como probióticos, con especial interés en los cultivos de tilapia y sus posibilidades futuras.

The objective of this work was to evaluate the agronomic performance of two strawberry genotypes submitted to different cultivation technologies in an organic production system. The genotypes tested were CREA FRF LAM 269.19 (short-day) and CREA FRF 114.01(day-neutral). The plants were grown in soil, troughs, slabs and pots. The experimental design was completely randomized in a factorial arrangement. The parameters evaluated were: dates of bloom onset, fructification and harvesting; several plant features; several fruit features; and yield components - total production; number of fruits, commercial production; production of small fruits and; total productivity. The dayneutral genotype allowed earlier onset of harvesting and greater vegetative development. Trough and bed cultivation provided higher fruit yield and quality in both genotypes. In beds, the fruits presented higher soluble solids content in both genotypes. In sum, the dayneutral genotype associated with the cultivation in beds provided the best agronomic performance in an organic cultivation system. [ABSTRACT FROM AUTHOR]

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The intercropped of cultures and biological organisms are sustainable ways to produce due to the benefits for the environment, soil, and plant, in addition to reducing costs in cultivation. The objective was to evaluate the influence of doses of Azospirillum brasilense in two soil classes in the cultivation of single maize and in intercropping with Brachiaria ruziziensis. The experimental design was in randomized block, in a 2 × 2 × 3 factorial scheme, with six replications. First factor being two soils: Latossolo Vermelho Eutrófico (clayish) and Latossolo Vermelho Distrófico (sandy); the second factor two types of cultivation: single maize and intercropped with B. ruziziensis; the third inoculation factor: without inoculant, with one dose (120 mL per 50 kg of seed), and with two doses of A. brasilense. The potential of clayey soils had high values in relation to sandy soil for the trait hundred grain weight, and, also when associated in intercrop of maize with brachiaria for plant height, number of grains per ear had higher values than in sandy soils. One or two doses of A. brasilense in clayey soil and intercropped of maize with brachiaria resulted in higher maize grain yield. [ABSTRACT FROM AUTHOR]

El uso de modelos de la dinámica del carbono orgánico en los suelos ha sido enfatizado para la implementación de diferentes programas públicos, incluidos los inventarios de gases efecto invernadero. El modelo RothC-26.3 (RothC) es de los más usados en el mundo en el estudio de la dinámica del carbono, por lo que fue revisado a detalle. El objetivo fue hacer una síntesis del desempeño del modelo RothC en la predicción de cambios del COS en parcelas, sitios, sistemas y regiones. Así como su aplicación en escenarios de cambio de uso de suelo (CUS) y sistemas de cultivo a partir de bases de datos de corta o media duración (

Soil biological activity (i.e. mineralized carbon (C) (Cmin)) is a crucial property to evaluate soil health and its changes due to soil use. In the southeastern Buenos Aires province (SEB) there is scarce information about how agriculture ecological intensification (IEA) affects soil global biological activity and the potentially mineralized C (C0) to improve the comprehension of the mechanisms that regulate soil C dynamics. It would be relevant to determine the adequate incubation time at which the determination of Cmin can predict C0 in soils from the SEB. Moreover, the Cmin determined in early incubation days has been proposed as a quick alternative to estimate C0. It has been hypothesized that it is necessary to run longer incubations to correctly evaluate C0 of soils of the SEB and that the CO2 emitted during short incubation periods is a good estimator of C0. Soil samples were taken (0-5 and 5-20 cm) from a long-term experiment on crop-pasture rotations on Mollisols at Balcarce with different levels of IEA under conventional tillage and no-tillage (SD). Total (COT), particulate (COP) and associated organic C were determined, as it was the Cmin from aerobic incubations under controlled conditions at 2, 4, 6, 10, 16, 22, 28, and 63 days. The C0 was estimated from the Cmin at 22, 28, and 63 days. The Cmin and C0 showed similar patterns among cropping systems. The estimations of C0 from the Cmin at 63 days were the most trustable (mean of C0 466,9 and 517,8 mg C kg-1 from Cmin(28) and Cmin(63), respectively). Furthermore, the Cmin at a few days of incubation showed high correlation coefficients with C0 (r between 0.68 and 0.92 at 0-20 cm for 2 to 10 incubation days) and therefore short incubations would be promising to estimate C0. [ABSTRACT FROM AUTHOR]

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El efecto de prácticas de manejo que inciden sobre el carbono (C) orgánico del suelo (COS) puede ser estudiada usando modelos de simulación. RothC es un modelo sencillo desarrollado para agricultura y labranza convencional (LC). Para los suelos del Sudeste Bonaerense (SEB) se hipotetiza que RothC simulará satisfactoriamente cambios en el COS: 1) bajo rotaciones mixtas y 2) bajo siembra directa (SD). Se calcularon indicadores estadísticos basados en la diferencia entre valores de COS observados en la capa arable de un ensayo de larga duración y los simulados. Se evaluó el total de datos y discriminando entre tratamientos de fertilización con nitrógeno (N) (Con N y Sin N), sistemas de labranza (SD y LC) y períodos bajo agricultura y bajo pastura. En general (todos los datos o separados en Con N y Sin N), el modelo representó satisfactoriamente la variación del COS. Por otro lado, RothC tuvo un comportamiento aceptable en los periodos bajo agricultura y bajo pastura en rotación mixta. No obstante, el desempeño del modelo fue algo más pobre cuando las pasturas en la rotación eran de más de dos años o de tres años asociadas a periodos agrícolas previos prolongados. Bajo pastura continua RothC simuló correctamente la variación del COS. En los períodos agrícolas de las rotaciones mixtas, el desempeño del modelo fue bueno y similar bajo LC y SD. Bajo agricultura continua con SD el modelo presentó un muy buen comportamiento. Se concluye que, para suelos del SEB, RothC simuló adecuadamente cambios en el COS bajo rotaciones mixtas y bajo SD. Sin embargo, existieron desviaciones en los resultados de las simulaciones con RothC que podrían deberse a la forma de estimación de algunos datos para ingresar al modelo y que deberían ser ajustados para mejorar aún más las simulaciones.

Se estudiaron aspectos de la biología de la oropendola crestada Psarocolius decumanus y la mirla parda Turdus grayi en la Estación Agraria Cotové de la Universidad Nacional de Colombia. La estación está ubicada en el municipio de Santa Fe de Antioquia, área geográfica del bosque seco tropical. La Estación funciona con un sistema silvopastoral, que integra el uso de árboles y pastizales en la producción ganadera, conservando así hábitats para especies silvestres. Se realizaron seis muestreos de campo entre diciembre de 2009 y octubre de 2010, cada dos meses. Se realizaron registros de la presencia de estas dos especies en los diferentes hábitats disponibles. De esta manera se hizo evidente el papel que los fragmentos de bosque y los sistemas de silvopastoreo desempeñan en favor de la conservación de la diversidad de aves, y en particular de la oropéndola crestada y la mirla parda. Psarocolius decumanus y Turdus grayi utilizan la Estación Agraria como lugar de forrajeo y predominan en bordes boscosos. Las dos especies son muy susceptibles a la perdida y fragmentación del bosque natural y a la transformación de estos ecosistemas en tierras dedicadas a la agricultura y ganadería, principalmente la oropéndola crestada especie que no registró actividad reproductiva durante el estudio. Por su parte, Turdus grayi registró actividad reproductiva en los meses de abril y junio de 2010.

Vegetable intercropping has advantages over single cultivation in terms of less environmental impact. However, to convince farmers to adopt this production system, it is necessary to prove greater efficiency in the production of more food per unit area and therefore an increase in productivity. An experiment was carried out aiming to evaluate the effect of the chicory transplant time in intercrops with collard greens on crop yields and land use efficiency index (LUE). The experimental design was a randomized block, with nine treatments in a 2 × 4 + 1 factorial scheme, and four replications. Crop systems (intercrop and monoculture) and chicory transplant time (0, 14, 28 and 42 days after transplant (DAT) of collard greens) were evaluated. The collard greens yield increased as the chicory transplant time was delayed. The total and per harvest yields of chicory were not influenced by its transplant time. Regardless of chicory transplant time, collard greens and chicory intercropping provided greater LUE than their monocultures and reached the maximum value (52% higher) when the chicory was transplanted 42 days after collard greens. [ABSTRACT FROM AUTHOR]

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Introducción. La producción de rumiantes depende casi exclusivamente de forrajes que deseablemente ostenten una calidad nutritiva alta, por lo que estudios actualizados sobre ese atributo, son requeridos. Para el presente estudio, se realizó un análisis del asocio de gramíneas y leguminosas como alternativas para incrementar el valor nutricional de los forrajes. Objetivo. Valorar el comportamiento agronómico y bromatológico de asocios de maíz con leguminosas de hábito trepador IV para la alimentación bovina. Materiales y métodos. Se utilizó un diseño de bloques completos al azar con 7 tratamientos y 3 repeticiones conformados por: T1-6 = Maíz+ Lago azul, Beijín, Chi tou, Pritkar, Judías, CIAT 16806 y T7= Maíz ICA-V305. Se evaluó la altura de la planta (AP), biomasa fresca, índice de equivalencia de área (IEA), índice de selección ponderada (ISP), materia seca (MS), proteína bruta (PB), extracto etéreo (EE), fibra detergente neutro (FDN), fibra detergente ácida (FDA) y lignina (LDA). Los datos fueron analizados estadísticamente y sometidos al ISP e IEA. Resultados. Se incrementó la cantidad de biomasa fresca en asocios (promedio 72,2±5 ton.ha-1) respecto al monocultivo de maíz (64,82 ton.ha-1). La concentración de MS se afectó (r= -0,37 Pearson

En la Región Sur del Ecuador se comparó la producción de avena (Avena sativa L.) y trigo (Triticum vulgare L.) obtenida a partir de un sistema de forraje verde hidropónico (FVH), frente al sistema de producción convencional o a campo abierto (CA). El experimento para cada sistema y cultivo se estableció bajo un diseño de bloques al azar, instalando cuatro tratamientos (dos en FVH y dos a CA), con tres repeticiones cada uno. Se evaluó la altura de la planta (AP) de cada cultivo para cada sistema productivo, mientras que para cada sistema y cultivo se determinó la producción de biomasa, la proteína cruda (PC) (p

Com o aumento da demanda de produção agropecuária e florestal no Brasil e no mundo, tornou-se necessária a maximização da produção numa mesma área, de forma sustentável, onde o sistema silvipastoril torna-se uma forma de integração de desempenho crescente. Objetivou-se avaliar os atributos físicos de dois sistemas de uso do solo: pastagem pura com Panicum maximum cv. Aruana e um sistema silvipastoril com Peltophorum dubium em linhas e pastagem nas entrelinhas. Foram abertas quatro minitrincheiras (repetições) em cada área (linha, entrelinha e pastagem pura de P. maximum cv. Aruana), subdivididas em quatro profundidades (00-10; 10-20; 20-40 e 40-60 cm), compondo 48 amostras de solo, coletadas com anel volumétrico. As amostras foram analisadas quanto à densidade, macroporosidade, microporosidade e porosidade total. A macroporosidade e a microporosidade variam com a profundidade, inversa e diretamente, respectivamente. A maior densidade do solo se deu na pastagem pura, entretanto sem atingir valores impeditivos ao crescimento radicular. Embora a porosidade total do solo não tenha apresentado diferenças significativas, essa sofre interferência do manejo aplicado sobre a área. O efeito do uso de leguminosa arbórea no sistema silvipastoril já é perceptível, apesar de ainda incipiente.

Con el objetivo de determinar el efecto de la densidad de siembra sobre los caracteres morfoproductivos de Jatropha curcas intercalada con cultivos en rotación, se estudiaron en un diseño completamente aleatorizado los siguientes tratamientos-sistemas (S): S1 (testigo): J. curcas a 2,5 x 2,0 m (2 000 plantas/ha), S2: 50 % del área con J. curcas a 2,5 x 2,0 m y 50 % del área de cultivos en rotación (2 000 plantas/ha), S3: J. curcas intercalada con cultivos a 5,0 x 2,0 m (1 000 plantas/ha), S4 (testigo): cultivos en rotación. Para interpretar los resultados de la altura de la planta (A), el número de ramas primarias (RP), el grosor del tallo y de las ramas primarias, la cantidad de racimos (NR) y la producción de frutos (FC) se utilizó un ANOVA de clasificación simple, y fueron correlacionadas A, RP y NR; mientras que se usó estadística descriptiva para el número de frutos por racimo (FR), el peso y las dimensiones de las semillas y el rendimiento de los cultivos . A y RP fueron mayores para S1 y S2; sin embargo, se obtuvo mayor NR con S3, y este último no difirió en cuanto a FC (p < 0,05) del testigo (S1). Existió una correlación alta y positiva (r = 0,84) entre A y RP, pero estos no estuvieron correlacionados con NR. En S3, el rendimiento de los cultivos asociados fue de 1,023; 4,281 y 0,320 t/ha para frijol, boniato y ajonjolí, respectivamente. Se concluye que al utilizar 1 000 plantas/ha de J. curcas en sistemas de asociación, se pueden obtener adecuados rendimientos y diversidad de especies vegetales.

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Tillage systems (SL) are a fundamental tool in agriculture since they allow manipulating the soil to achieve the necessary conditions for crop growth and development. The objective of this work was to evaluate the effect of different SL on bulk density (DA), mechanical penetration resistance (RMP), infiltration rate (VI) and aggregate stability (EA) of a Mollisol in the southeastern Buenos Aires province. Soil samples and determinations were taken in a long-term SL experiment carried out at Balcarce, Southeastern Buenos Aires Province. Five SL were evaluated: conventional tillage (LC), no-tillage (SD), combined tillage (Lcom), vertical tillage (LV) and disk tillage (LD). Bulk density was the lowest under Lcom and the highest under LD at 5-20 cm depth, but there were no differences between SL in the upper 5 cm. Infiltration rate was not affected by SL. Mechanical penetration resistance was higher under SD from 2.5 cm up to 10 cm depth, being higher under LD beyond that depth. Conventional tillage and Lcom did not show significant differences in RMP at any of the analyzed depths. Both LC and Lcom showed lower RMP than SD from 2.5 cm to 20 cm depth. At the 0-5 cm depth, LC presented lower EA than the other SL (which did not differ among them). Although the decrease in EA was not as marked as the increase in the degree of disturbance, less aggressive SL such as SD, Lcom and LD showed higher EA as compared to LC. [ABSTRACT FROM AUTHOR]

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O presente estudo analisou a contaminação parasitológica em alfaces crespas (Lactuca sativa) cultivadas em diferentes sistemas de produção (convencional, orgânico e hidropônico), fornecidas por uma cooperativa de produtores da agricultura familiar, no município de Presidente Prudente, São Paulo. As coletas foram repetidas em intervalos semanais, durante um período cinco meses, totalizando 180 amostras de hortaliças (60 amostras de alface por tipo de produção). As folhas das alfaces foram lavadas com Extran MA 02 a 0.5% e o fluído resultante submetido às técnicas de sedimentação e de centrífugo-flutuação, para recuperação das estruturas parasitárias. Observou-se que do total de 180 amostras, 71 (39,4%) estavam contaminadas por pelo menos uma estrutura parasitária, sendo 34 (47,9%) das alfaces cultivadas no sistema hidropônico, 20 (28,2%) no orgânico e 17 (23,9%) no sistema convencional. Cistos de Entamoeba spp. foram as estruturas parasitárias mais frequentes nas hortaliças, com maior contagem de cistos naquelas produzidas no sistema hidropônico (p=0,003). Conclui-se que independentemente do sistema de cultivo (convencional, orgânico e hidropônico), existe a possibilidade de contaminação de alfaces por enteroparasitos. Medidas que propiciem a melhoria na qualidade higiênico-sanitária na produção, assim como a adequada higienização das verduras antes do consumo “in natura” podem ser importantes para a redução da contaminação e consequente transmissão de doenças parasitárias pelo consumo “in natura” de hortaliças.

Objetivou-se analisar a composição florística e caracterizar a estrutura da vegetação em áreas sob dois sistemas agroflorestais (AGP e SILV), em plantio tradicional (TRAD0), em pousios de seis (TRAD6) e nove (TRAD9) anos e em Caatinga conservada (MATA). Adotou-se o método de parcelas, sendo determinadas densidades e frequências absolutas de todas as espécies e distribuição diamétrica dos indivíduos arbóreos/arbustivos. Observou-se que, no estrato herbáceo, as espécies com maior frequência e densidade foram Alternanthera ficoidea em AGP, Amaranthus em SILV e TRAD0 e Commelina virginica em AGP, TRAD6, TRAD9 e MATA. No estrato arbóreo/arbustivo, as espécies com maior densidade e frequência foram Cordia oncocalyx em AGP, MATA e SILV e Mimosa caesalpiniifolia e Croton blachetianus em TRAD6 e TRAD9, respectivamente. SILV apresentou menor número de espécies arbóreas e maior número de espécies herbáceas, em relação à MATA e às áreas em pousio. Nas áreas em pousio por seis e nove anos ocorreu recuperação da vegetação quanto à composição florística, porém observou-se mais indivíduos com menores diâmetros, quando comparado à MATA.

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Com o aumento da demanda de produção agropecuária e florestal no Brasil e no mundo, tornou-se necessária a maximização da produção numa mesma área, de forma sustentável, onde o sistema silvipastoril torna-se uma forma de integração de desempenho crescente. Objetivou-se avaliar os atributos físicos de dois sistemas de uso do solo: pastagem pura com Panicum maximum cv. Aruana e um sistema silvipastoril com Peltophorum dubium em linhas e pastagem nas entrelinhas. Foram abertas quatro minitrincheiras (repetições) em cada área (linha, entrelinha e pastagem pura de P. maximum cv. Aruana), subdivididas em quatro profundidades (00-10; 10-20; 20-40 e 40-60 cm), compondo 48 amostras de solo, coletadas com anel volumétrico. As amostras foram analisadas quanto à densidade, macroporosidade, microporosidade e porosidade total. A macroporosidade e a microporosidade variam com a profundidade, inversa e diretamente, respectivamente. A maior densidade do solo se deu na pastagem pura, entretanto sem atingir valores impeditivos ao crescimento radicular. Embora a porosidade total do solo não tenha apresentado diferenças significativas, essa sofre interferência do manejo aplicado sobre a área. O efeito do uso de leguminosa arbórea no sistema silvipastoril já é perceptível, apesar de ainda incipiente. With the increasing demand for agricultural, livestock and forestry production in Brazil and in the World, it has become necessary to maximize production in the same area, in a sustainable way, where the silvopastoral system becomes a form of integration of increasing performance. The objective of this work was to evaluate the physical attributes of two land use systems: pure pasture with Panicum maximum cv. Aruana and a silvipastoril system with Peltophorum dubium in the lines and Aruana grass between the lines. Four mini trenches (repetitions) were opened in each area (line, between lines and pure pasture of Aruana grass), subdivided into 4 depths (00-10, 10-20, 20-40 and 40-60 cm), composing 48 soil samples, collected with volumetric ring. The samples were analyzed for density, macroporosity, microporosity and total porosity. Macroporosity and microporosity varied with depth, inversely and directly, respectively. The highest soil density occurred in pure pasture, however, without reaching values that limit root growth. Although the total porosity of the soil did not present statistically significant differences, this one undergoes interference of the applied management over the area. The effect of the use of leguminous wood species in silvopastoral system may already be noticed, although still incipient. [ABSTRACT FROM AUTHOR]

The effect of management practices that affect soil organic carbon (COS) can be studied through simulation models. RothC is a simple model developed for cropping under conventional tillage (LC). For the soils of the Southeastern Buenos Aires Province (SEB) is has been hypothesized that RothC will simulate satisfactorily change in COS: 1) under crop-pasture rotations, and 2) under no-tillage (SD). Statistical indicators were based on the difference between observed COS values in the arable layer along a long-term experiment and the simulated ones. This was evaluated both the whole data set and discriminated between treatments of nitrogen (N) fertilization (with (Con N) and without (Sin N) N), tillage systems (SD and LC), and periods under cropping and under pasture. In general (the whole set of data or discriminated between Con N and Sin N), the model represented COS variation satisfactorily along time. On the other hand, RothC showed an acceptable behavior along periods either under cropping or under pasture in crop-pasture rotation. However, model behavior was somehow poorer when pastures in the rotation lasted more than two or three years but with prolonged previous cropping periods. Under continuous pasture RothC simulated COS variation very well. In the periods under cropping of crop-pasture rotations, changes in COS were simulated satisfactorily without difference between SD and LC. Under continuous cropping with SD, model performance was very good. It is concluded that for soils of the SEB, RothC adequately simulated changes in COS both under crop-pasture rotations and SD. However, some deviations existed in some simulations that could be attributed to the way some input data were estimated. These estimations should be adjusted to improve simulations even more. [ABSTRACT FROM AUTHOR]

De acuerdo con el Panel Intergubernamental sobre el Cambio Climático (PICC), deben reportarse los almacenes y cambios del carbono orgánico del suelo (COS) en el tiempo. El modelo RothC-26.3 (RothC) es uno de los más usados en el mundo para estudiar la dinámica del C en diferentes sistemas. Se evaluó el desempeño del RothC en la simulación de los cambios del COS, a nivel de parcela, en experimentos de corta duración. Se evaluaron nueve sitios y los sistemas: agrícola con residuos vegetales (A+R), agrícola sin residuos (A-R), forestales (F), praderas (PR) y agostaderos (AGOS). Las parcelas experimentales se ubicaron en los estados de México, Tlaxcala, Michoacán, Guanajuato, Oaxaca, Jalisco y Nuevo León. El RothC se ejecutó (i) con el COSinicial, medido en cada punto de muestreo (*CIPUN) en parcelas de la Sierra Norte de Oaxaca y, (ii) con el COSinicial promedio medido por parcela (*CIPAR) en el resto de los sitios. Se midieron y estimaron los parámetros de entrada al modelo, como residuos vegetales y abonos orgánicos. El grado de asociación entre el COS medido y el simulado fue de 0.76 y hasta 1.0 en todos los sitios. La eficiencia del modelo (EF) varió entre 0.53 y 0.93, excepto en el Batán, donde se evaluaron sistemas de labranza (EF= −0.60). La r, en ambas formas de simulación, varió entre 0.63 y 0.97, excepto en AGOS; EF en los agrícolas fue de 0.48 a 0.84 y de 0.81 en F *CIPAR. La EF fue insatisfactoria obtenida para los AGOS (*CIPAR) y forestales y praderas (*CPUN). Considerando los resultados de los sitios y sistemas y, la forma de simulación *CIPAR, el modelo RothC se puede usar con buena aceptación para simular los cambios de COS a nivel de parcela en los sistemas agrícolas y forestales, mediana en praderas y baja en agostaderos.

Este trabalho avaliou o desempenho ambiental dos cachos de frutos de dendê na região do Baixo Sul do estado da Bahia, comparando os cultivos convencional e orgânico. A avaliação seguiu os passos indicados pelas normas ISO 14040 e 14044 para avaliar as categorias de impacto: acidificação, aquecimento global e uso de recursos não renováveis. O cultivo orgânico apresentou o melhor desempenho, reduzindo, comparativamente ao cultivo convencional, os impactos em 27,6% para o aquecimento global, 69,0% para o uso de recursos não renováveis e 89,4% para a acidificação. O principal fluxo elementar no sistema de cultivo convencional foi o uso de fertilizantes sintéticos, devido a seu elevado consumo energético e emissões na fase de uso. Para o cultivo orgânico, o principal fluxo elementar foi o transporte do fertilizante orgânico, com consumo de recursos fósseis (diesel) e emissões relacionadas ao aquecimento global e à acidificação. Apesar dos indicadores favorecerem o cultivo orgânico, é importante considerar a interdependência entre os sistemas produtivos.

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to determine the effect of planting density on the morpho-productive traits of Jatropha curcas intercropped with crops under rotation, the following treatments-systems (S) were studied in a completely randomized design: S1 (control): J. curcas at 2,5 x 2,0 m (2 000 plants/ha), S2: 50% of the area with J. curcas at 2,5 x 2,0 m and 50% of the area with crops under rotation (2 000 plants/ha), S3: J. curcas intercropped with crops at 5,0 x 2,0 m (1 000 plants/ha), S4 (control): crops under rotation. To interpret the results of plant height (H), number of primary branches (PB), stem diameter and primary branch diameter, quantity of racemes (NR) and fruit production (FP), a simple classification ANOVA was used and H, PB and NR were correlated; while descriptive statistics was used for the number of fruits per raceme (FR), weight and size of the seeds and crop yield. H and PB were higher for S1 and S2; nevertheless, higher NR was obtained with S3, and this last one did not differ regarding FP (p < 0,05) from the control (S1). There was high and positive correlation (r = 0,84) between H and PB, but they were not correlated with NR. In S3, the yield of the associated crops was 1,023; 4,281 and 0,320 t/ha for beans, sweet potato and sesame, respectively. It is concluded that when using 1 000 plants/ha in association systems, adequate yields and diversity of plant species can be obtained. [ABSTRACT FROM AUTHOR]

This study shows the effect of three plant growth-promoting rhizobacteria (PGPR) strains of the genus Bacillus on blackberry (Rubus glaucus Benth.) development under semi cover and field conditions (cropping systems). Endogenous strain Bacillus subtilis GIBI-200, B. pumilus GIBI-206, its mixture (B. subtilis GIBI-200 + B. pumilus GIBI-206), and commercial strain B. subtilis QST-713 were compared to conventional mineral fertilization (Control) in each cropping system. Field condition system presented higher values (P<0.001) than semi cover in: total number of branches (7.32), number of productive branches (7.0), flowers per raceme (26.2), and the lowest percentage of unproductive branches (6.1%). Significant differences (P<0.05) were obtained in total number of branches over time by bacterial strains. Nonetheless, last observation of this variable did not present statistical differences among strains and mineral fertilization. No significant differences were evident in terms of number, length, diameter and flowers in the productive branches regarding to bacterial strains and Control. B. subtilis GIBI-200 + B. pumilus GIBI-206 showed a similar statistical behavior compare to mineral fertilization in the number of clusters (8.3) and percentage of unproductive branches (11.1%). In addition, GIBI-200 + GIBI-206, despite statistical equality, exposed greater values than individual strains. Field condition system remains the most promising alternative for the development of blackberry crop and PGPR acts as biofertilizers achieving effects in the long-term growth of blackberry similar to mineral fertilization. Mixtures of PGPR can produce a synergic effect and new combinations should be evaluated in future studies. [ABSTRACT FROM AUTHOR]

Soil management, in terms of tillage and cropping systems, strongly influences the biological properties of soil involved in the suppression of plant diseases. Fungistasis mediated by soil microbiota is an important component of disease-suppressive soils. We evaluated the influence of different management systems on fungistasis against Fusarium graminearum, the relationship of fungistasis to the bacterial profile of the soil, and the possible mechanisms involved in this process. Samples were taken from a long-term experiment set up in a Paleudult soil under conventional tillage or no-tillage management and three cropping systems: black oat (Avena strigose L.) + vetch (Vicia sativa L.)/maize (Zea mays L.) + cowpea (Vigna sinensis L.), black oat/maize, and vetch/maize. Soil fungistasis was evaluated in terms of reduction of radial growth of F. graminearum, and bacterial diversity was assessed using ribosomal intergenic spacer analysis (RISA). A total of 120 bacterial isolates were obtained and evaluated for antibiosis, and production of volatile compounds and siderophores. No-tillage soil samples showed the highest level of F. graminearum fungistasis by sharply reducing the development of this pathogen. Of the cropping systems tested, the vetch + black oat/maize + cowpea system showed the highest fungistasis and the oat/maize system showed the lowest. The management system also affected the genetic profile of the bacteria isolated, with the systems from fungistatic soils showing greater similarity. Although there was no clear relationship between soil management and the characteristics of the bacterial isolates, we may conclude that antibiosis and the production of siderophores were the main mechanisms accounting for fungistasis.

http://dx.doi.org/10.5902/1980509814565They are still few the information on the influence of the brightness in the production of biomass as well as in the concentration of some nutritious in leaves of Ilex paraguariensis. This work aimed to evaluate the production of dry matter of the aerial part of the Ilex paraguariensis A. St. Hil. (branches and leaves) and the concentration of nitrogen, potassium, magnesium and iron in leaves produced in two systems of cultivations, intercropping with Pinus elliottii Engel. and single, along the seasons in the municipality of FredericoWestphalen, Rio Grande do Sul state. The results showed that the production of biomass of the Ilex paraguariensis (leaves + branches) is larger in the single cultivation when compared to the intercropping. However, when comparing the two cropping systems with respect to phosphorus, but especially calcium and magnesium, there was a small variation for different periods of the year, which indicates a more constant metabolic activity of the plant yerba mate in a more shaded condition, which makes it an important factor in the final quality of the product.

O sorgo forrageiro é uma gramínea indicada para cultivo em ambientes secos e quentes, nos quais a produtividade de outras forrageiras pode ser antieconômica. Objetivou-se, com este trabalho, estudar diferentes sistemas de manejo e diferentes velocidades de semeadura, no desenvolvimento do sorgo forrageiro cv. BRS 610. O solo da área experimental foi um Nitossolo Vermelho distroférrico. O experimento foi instalado em condições de campo, na FCA/UNESP, Campus de Botucatu-SP, utilizando-se o delineamento em blocos ao acaso, em esquema de parcela subdividida, com dezesseis tratamentos (quatro sistemas de manejo e quatro velocidades de semeadura). Os sistemas de manejo utilizados foram: semeadura direta; gradagem pesada; gradagem pesada + duas gradagens leves e escarificação. As velocidades na operação de semeadura utilizadas foram: 3, 5, 6 e 9 km h-1. Foram analisadas as seguintes variáveis: população de plantas, altura de plantas, diâmetro do colmo, massa de mil grãos e produtividades de massa verde e de massa seca. O sistema de semeadura direta foi o que proporcionou maior população de plantas, maior diâmetro do colmo e maior produção de massas verde e seca. Com o aumento da velocidade na operação de semeadura, houve redução da população de plantas e aumento do diâmetro do colmo. A velocidade de 5 km h-1 foi a que proporcionou maior produção de massas verde e seca (kg ha-1), seguida da velocidade de 3 km h-1.

Agriculture is a co-evolutionary process between society and nature. Agroecology is an environmental science which focuses on ecosystem-culture and society-nature interactive systems, the effect of human intervention in the transformation of ecosystems. The central objects are agroecosystems and the units of study are production units. These production units are conceived of as agricultural systems and are found in the crossroads of multiple interactions between biophysical, socioeconomical, cultural, and production components, which must be analyzed with an integrated concept. In the present study, a characterization and typification of the citrus agroecosystems of the department of Meta were pursued (Colombia). The pertinence of implementing the methodology designed by the Latin-American Center for Rural Development (Centro Latinoamericano para el Desarrollo Rural-RIMISP) was evaluated, grouping the variables with a focus on an analysis of livelihoods. A survey and interview were defined as methods of collecting the primary information in the municipalities of Puerto López, Villavicencio, Granada, Lejanías, Guamal and San Martin, where 78.4% of the citrus area of the department is found. This study involved the selection and definition of the evaluation variables, validation and adjustment of said variables, collection of primary and secondary information, and the application of multivariate statistical analysis techniques to conform and characterize the recommendation domains or groups. The more important results indicated that it is possible to increase knowledge of the interrelations that exist between the different components of farm agroecosystems and their relationship with the principal agroecological structure. The existence of six agricultural groups or recommendation domains was established, with some productive characteristics very similar within the group but very heterogeneous to the outside of the group, with particular necessities.

With the purpose to evaluate the performance of crispy lettuce cultivars grown under the hidroponic system using seedlings produced in floating and phenolic foam was carry out this experiment in the greenhouse of Experimental Farm, of Marília University. The experimental design was a completely randomized arranged in a factorial scheme 2 x 2 with five replicates, whose factors corresponded respectively to two cultivation systems for the production of seedlings (floating and phenolic foam) and two cultivars of crisp lettuce (Julie and TPC). The characteristics fresh and dry mass of the shoot, number of leaves per plant and stem length were evaluated. There were significant differences between cultivars for all evaluated traits. Significant statistical difference between cropping systems was observed only for stem length. The interaction cultivar x cropping systems was not significant for any of the characters evaluated. In the number of leaves per plant TPC cultivar was superior to "Jullie" regardless of the culture system. As for stem length, it was found that the two cultivars showed higher values in the floating system in relation to the phenolic foam and that the Jullie cultivar had a longer stem length than the "TPC" in the phenolic foam. These higher values are undesirable, as they are responsible for early tillage in lettuce. For the dry mass of the aerial part, it was verified that the cultivar Jullie was superior to "TPC" in the phenolic foam, but did not occur difference between them in the floating system. It was concluded that under the conditions in which the experiment was conducted, the Jullie cultivar showed a higher fresh shoot biomass than the TPC cultivar and that in the number of leaves the "TPC" stood out in relation to "Jullie" and that the systems did not influence the yield of the cultivars. [ABSTRACT FROM AUTHOR]

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En el Centro Agropecuario Cotové, en el municipio de Santa Fe de Antioquia (Colombia), se estudió la diversidad de aves utilizando las metodologías de puntos fijos de conteo y redes de niebla en cinco usos del suelo (Frutales, Sistema silvopastoril, Bosque secundario, Pastoreo con baja densidad de árboles y Pastos de corte), para analizar la influencia sobre la composición, riqueza y abundancia de la avifauna. Se registraron 6 633 individuos de 101 especies, de las cuales 11 especies son migratorias. En términos de abundancia, la mayoría de las especies fueron raras y pocas comunes. Los gremios alimenticios mejor representados fueron insectívoros y frugívoros. El índice de Shannon indica que el Sistema silvopastoril presenta los valores de diversidad alfa más altos y los frutales los más bajos. Los usos del suelo que compartieron más especies fueron sistema Silvopastoril y Pastoreo con baja densidad de árboles. La heterogeneidad ambiental del centro actúa de forma diferente para las especies, beneficia en su mayoría aves de baja y media especificidad de hábitat, y con preferencia de hábitats de borde y áreas abiertas, por lo que se deben implementar acciones de manejo dirigidas a la conservación de áreas de regeneración natural y conectividad entre usos del suelo, para que las poblaciones de especies de aves presentes en la zona puedan ser mantenidas en el tiempo.

O objetivo deste estudo foi avaliar indicadores de qualidade de um Latossolo Vermelho-Amarelo distrófico sob vegetação nativa de floresta, pastagem (Brachiaria brizantha cv. marandu), plantio convencional, cultivo mínimo e sistema de plantio direto. Foram determinados o carbono e o nitrogênio da biomassa microbiana do solo, o carbono orgânico e o nitrogênio total do solo, quocientes microbianos para carbono e nitrogênio e relações entre carbono orgânico e nitrogênio total do solo (C/N tot) e entre carbono e nitrogênio da biomassa microbiana (C/N mic). As amostras foram coletadas em Cerejeiras/RO, em duas profundidades (0-10 e 10-20 cm) nos cinco tratamentos, com cinco repetições. A análise estatística consistiu na análise de dados discrepantes, pelo método de Chauvenet, e dos pressupostos das variâncias, pelo teste de Bartlett e de Shapiro-Wilk, seguidos do teste de Kruskal-Wallis, entre os tratamentos, e comparação das variáveis entre as profundidades, pelo teste de Mann-Whitney, e ainda da análise de agrupamentos utilizando o método de Ward, todos ao nível de 5% de probabilidade. Os diferentes usos do solo influenciam as variáveis avaliadas, com exceção da relação C/N tot, sendo que as variáveis microbiológicas demonstram-se mais sensíveis às mudanças do uso e manejo do solo. O sistema de plantio convencional é o tratamento que apresenta maior homogeneidade entre as profundidades. A análise de agrupamentos evidencia que o solo sob plantio direto, sistema de cultivo mínimo e plantio convencional apresenta semelhanças entre si, assim como, o solo sob vegetação nativa de floresta e pastagem também se assemelham.The aim of this study was to assess quality indicators of a dystrophic Red Yellow Latosol (Oxisol) soil under native forest, pasture (Brachiaria brizantha cv. marandu), conventional tillage, minimum tillage system and no till system. It was determined the soil carbon and soil nitrogen in the microbial biomass, organic carbon and total nitrogen, ratios for microbial carbon and nitrogen and relationships between organic carbon and total nitrogen (C/N tot) and between carbon and soil nitrogen in the microbial biomass (C/N mic). The soil samples were collected in the Municipality of Cerejeiras/RO, at two depths (0-10 and 10-20 cm) in five treatments with five replications. The statistical analysis consisted of outliers analysis by Chauvenet method, and assumptions of variances by Bartlett's test and Shapiro-Wilk, followed by Kruskal-Wallis, between treatments, and comparison the variables between the depths, by Mann-Whitney' test, and the group analysis using Ward's method, all at 5% probability. The results show that different uses influence the variables, except for ration C/N tot, and the microbiology variables showed themselves more sensitive to changes in land use and management than other. The conventional tillage is the treatment that has greater homogeneity among the depths. The group analysis shows that the soil under no till system, minimum tillage system and conventional tillage have similarities among well as the soil under native forest and pasture are similar.

O manejo adequado do solo é uma das bases para a sustentabilidade do sistema agrícola. O objetivo do estudo foi avaliar atributos químicos de um Cambissolo Húmico Alumínico após 12 anos em dois sistemas de preparo do solo, com rotação e sucessão de culturas. O experimento foi conduzido em Lages, SC, utilizando preparo convencional (PC) e semeadura direta (SD), sob rotação (r) e sucessão (s) de culturas. O delineamento experimental foi inteiramente casualizado com quatro repetições. As sequências de cultivo foram: feijão-pousio-milho-pousio-soja-pousio no PCr; milho-pousio no PCs; feijão-aveia-milho-nabo-soja-ervilhaca na SDr; e milho-ervilhaca na SDs. As amostras de solo foram coletadas nas camadas 0-2,5; 2,5-5; 5-10; e 10-20cm. Avaliou-se carbono orgânico total (COT), cálcio, magnésio, alumínio trocável, fósforo, potássio, nitrogênio total (NT) e pH em água. A SD aumentou os teores de COT e nutrientes em comparação ao PC, especialmente na camada superficial do solo. O cultivo de milho e ervilhaca em sucessão aumentou os teores de COT e NT na camada superficial do solo em comparação com a rotação sob semeadura direta.Suitable soil management is one of the bases for sustainability in agricultural systems. The study aimed to evaluate chemical properties of a Humic Dystrudept for 12 years under two tillage systems, with crops rotation and succession. The experiment was carried out in Lages, SC, under conventional tillage (CT) and no-till (NT), with rotation (r) and succession (s) cropping systems, using crop sequences of beans-fallow-maize-fallow-soybean in CTr; maize-fallow in CTs; beans-oats-maize-fodder radish-soybean-vetch in NTr; and maize-vetch in NTs. The experimental design was completely randomized with four replicates. The soil samples were collected in the layers 0-2.5, 2.5-5, 5-10 and 10-20cm. The variables assessed were total organic carbon (TOC), calcium, magnesium, exchangeable aluminum, phosphorus, potassium, total nitrogen (TN) and water pH. The no-tillage system increased TOC and nutrient levels in comparison with conventional tillage, especially in the surface soil layer. Maize and vetch crop succession had higher TOC and TN contents in the surface soil layer compared to crop rotation under no-tillage.

O coentro (Coriandrum sativum L.) é uma hortaliça amplamente consumida no Brasil como condimento. É muito importante, especialmente para a horticultura do Norte e Nordeste do Brasil. É provável que, em relação ao valor de mercado, seja a segunda hortaliça folhosa em importância para o Brasil, com grande volume de importação e produção nacional de sementes. Problemas relacionados ao baixo vigor das sementes e ao estabelecimento da cultura são uma constante nesta espécie. O presente trabalho teve como objetivo verificar a influência do sistema de produção orgânico e convencional sobre o potencial fisiológico das sementes de coentro. Foram avaliados lotes de sementes de coentro, cultivar Verdão, provenientes de sistemas de cultivo convencional e orgânico. O delineamento experimental foi inteiramente casualizado com seis tratamentos e quatro repetições de cinqüenta sementes. Foram avaliados o grau de umidade, porcentagem de emergência, primeira contagem do teste de emergência, peso de mil sementes, índice de velocidade de emergência de plântulas e teste de condutividade. As avaliações realizadas mostraram que os sistemas de cultivo de modo geral não diferem entre si quanto ao potencial fisiológico das sementes.The coriander (Coriandum sativum L.) is an herb widely consumed in Brazil as a condiment. It is very important, particularly for horticulture in North and Northeast of Brazil. IT is likely that, in terms of market value, it is the second herb hardwood dusts in importance for Brazil, losing only to the lettuce and the high volume of imports and domestic production of seed. Problems related to the low seed vigor and the establishment of culture are a constant in this species. In the present work lots of coriander seeds, the cv. Verdão, from systems of conventional and organic were evaluated, having as objective is to verify the influence of the physiological potential of the seeds on the initial development of plants grown under organic system. They were evaluated degree of humidity, percentage of emergency, first count of the test of emergency, weight of 1,000 seeds, index of emergency speed of seedlings and conductivity test. The experimental design was a completely randomized design with four replicates of 50 seeds. The assessments carried out showed that the cultivation systems in general does not differ as to the physiological potential of the seeds.

This study aimed at assessing the level of weed infestation indifferent areas that were submitted to different soil management for 16 years. Four management systems were studied: (1) agriculture only under conventional tillage system; (2) agriculture only under no-till system; (3) crop-livestock integrationcrop-livestock integration; (4) livestock only. These areas were sampled at three soil depths (0-5, 5-10 and 10-15 cm), and soil was stored in plastic pots and taken to a greenhouse, where soil moisture and weight were standardized. Soil was kept near 70% moisture field capacity, being revolved every 20 days when all seedling emerged from soil were counted, identified and collected for dry mass assessment. The soil coverage by weeds, number of weed seedlings and dry mass of the weedy community were assessed. A phytoecological analysis was conducted. Weed composition is differentdifferent among management systems after 16 years. Areas with livestock showed much smaller number of weed species in comparison to systems where only grain crops are grown. The presence of livestock affects the potential of germination of soil seed bank. Agriculture systems are similar in terms of weed composition along soil profile, while systems involving livestock show little relation in what regards such sampled depths. Conservationist models of land exploration contribute to reduce severity of weed species occurrence in the long term.Objetivou-se avaliar o nível de infestação por plantas daninhas em áreas submetidas a manejos distintos por 16 anos: (1) agricultura em sistema convencional de preparo; (2) agricultura em sistema plantio direto; (3) integração lavoura/pecuária; (4) somente pecuária. Amostras de solos destas áreas foram coletadas em três profundidades (0-5, 5-10 and 10-15 cm), depositadas em potes plásticos e levadas a casa de vegetação. O solo era revolvido a cada 20 dias, quando as plantas daninhas presentes eram identificadas e coletadas. Foram avaliados cobertura por plantas daninhas; densidade de plantas daninhas e massa seca da comunidade infestante. Foi também conduzida análise fitoecológica em função dos distintos manejos e profundidades. Áreas onde pastagens estiveram presentes tiveram menor infestação por plantas daninhas que áreas onde somente agricultura era utilizada. A composição florística difere entre sistemas de manejo. Áreas onde a pecuária está presente apresentaram número de plântulas de espécies daninhas muito inferior a sistemas onde somente agricultura está presente. A presença de criação de gado afeta o potencial de emergência das espécies presentes no banco de sementes do solo. Sistemas de agricultura sem integração apresentam alta similaridade em termos de composição de espécies ao longo do perfil do solo enquanto sistemas integrados com pecuária apresentam pouca relação entre as profundidades amostradas. Modelos conservacionistas de exploração do solo contribuem com a redução da severidade de ocorrência de espécies daninhas a longo prazo.

Four experiments were carried out at the São Paulo State University, Brazil, with the aim of determining the agronomic viability of intercropping tomato and lettuce, under greenhouse conditions. The studied intercropping systems were established by transplanting lettuce at 0, 10, 20 and 30 days after transplanting (DAT) tomato and by transplanting tomato at 0, 10, 20 and 30 DAT lettuce. Intercropped tomato and lettuce were evaluated during two seasons and compared to their sole cropping. The experimental design was a randomized complete block with nine treatments. The productivity and the classification of the tomato fruits were not influenced by having lettuce intercropped with it, but lettuce production was lowered when tomato was intercropped with it. The longer the delay in lettuce transplanting, the greater the reduction in its productivity. There was an effect of cropping season on the extent of the agronomic advantage of intercropping over sole cropping. In the first cropping season, intercropping established by transplanting lettuce during the interval between 30 days before up to 20 DAT tomato yielded land use efficiency (LUE) indices of 1.63 to 2.22. In the second period, intercropping established with the transplanting of lettuce up to 30 days before tomato yielded LUE indices of 1.57 to 2.05.Quatro experimentos foram conduzidos na Unesp, Brasil, com o objetivo de determinar a viabilidade agronômica de cultivos consorciados de alface e tomate em ambiente protegido. Consórcios estabelecidos por transplantes da alface aos 0, 10, 20 e 30 dias após o transplante (DAT) do tomate e de tomate aos 0, 10, 20 e 30 DAT da alface, foram avaliados em duas épocas e comparados às suas monoculturas. Cada experimento foi conduzido em delineamento de blocos ao acaso, com nove tratamentos. Verificou-se que a produtividade do tomate e a classificação dos frutos não foram influenciadas pela alface, mas a produção da alface foi menor em consórcio. Quanto mais atrasado o transplante da alface menor foi a sua produtividade. Houve efeito de época de cultivo sobre a dimensão da vantagem agronômica do consórcio sobre a monocultura. Na primeira época de cultivo, os consórcios estabelecidos com o transplante da alface de 30 dias antes e até 20 dias após o transplante do tomate proporcionaram índices de eficiência do uso da área (EUA) de 1,63 a 2,22. Na segunda época, os consórcios estabelecidos com o transplante da alface antes do tomate, em até 30 dias, proporcionaram índices EUA de 1,57 a 2,05.

This study aims to assess the composition of weed communities as a function of distinct selection factors, at neighboring areas submitted to distinct soil management and diverse use for sixteen years. Four areas submitted to distinct managements (conventional tillage system; no-till system; integration crop/livestock and continuous livestock) were sampled in relation to the occurrence and severity of weed species by the beginning of the planting season, being estimated the relative abundance, relative frequency and relative dominance of each weed species under each area, as well as the Importance Value Index for each species. Areas were also compared by the Sørensen's similarity coefficient. Areas where pasture and grazing were never present, exhibited a number of seedlings of weed species 250% higher than areas periodically or continuously under grazing, while the area of soil covered by weeds was 87% superior at the conventional tillage system in relation to the average of the other treatments. Grass weeds were the most important at the conventional tillage area while broadleaved weeds where more important at the no-till area, probably due also to herbicide selection factors. Under crop/livestock integration there may be the need to care about controlling seedlings of the forage species inside grain crops in succession.Objetivou-se com este estudo avaliar a composição de comunidades infestantes em função de distintos fatores de seleção, em áreas vizinhas submetidas a distintos manejos de solo e usos por 16 anos. Quatro áreas submetidas a manejos distintos (sistema de cultivo convencional, sistema plantio direto, integração lavoura/pecuária e pecuária contínua) foram amostradas em relação a ocorrência e severidade de espécies de plantas daninhas no início da estação de cultivo, sendo estimadas a abundância relativa, frequência relativa e dominância relativa de cada espécie daninha em cada área, bem como o Índice de Valor de Importância para cada espécie. As áreas também foram comparadas pelo coeficiente de similaridade de Sørensen. Áreas onde forragens e pastejo não estão inseridas na rotação apresentaram número de plântulas de espécies daninhas 250% superior em relação a áreas periodicamente ou continuamente sob pastejo, enquanto a área de solo coberta pela comunidade de plantas infestantes foi 87% superior no tratamento com preparo convencional do solo, em relação a média dos demais tratamentos. Plantas daninhas de folhas estreitas foram predominantes na área de preparo convencional do solo enquanto folhas largas predominaram na área de plantio direto, provavelmente devido também a fatores de seleção relativos ao herbicida. Na área de integração lavoura/pecuária pode haver a necessidade de controle de plântulas da espécie semeada como forrageira durante o cultivo em sucessão a pastagem.

El trabajo tuvo como objetivo evaluar la influencia de los sistemas de cultivo de café: orgánico, convencional y orgánico-mineral, sobre las fracciones de fósforo (P) en suelos del departamento del Valle del Cauca, Colombia. Las mediciones por fraccionamiento secuencial reducido se hicieron en el Laboratorio de Suelos del Centro Internacional de Agricultura Tropical (CIAT). El análisis estadístico se ajustó a un modelo de diseño completamente aleatorio en un arreglo en parcelas divididas con tres tratamientos y tres repeticiones. Los resultados mostraron que los contenidos de las fracciones orgánicas de P disponible y P moderadamente disponible variaron (P < 0.05) entre los sistemas de manejo orgánico y el convencional, este último, presentó los valores más bajos. El sistema orgánico-mineral mostró los mayores contenidos de P orgánico e inorgánico, y el sistema convencional presentó los valores más bajos de ambas fracciones de P. La fracción de P no-disponible fue más alta en los sistemas orgánicos comparado con el sistema convencional, mientras que en el sistema orgánico mineral se encontraron diferencias (P < 0.05) con respecto a los restantes sistemas. El P total mostró un comportamiento similar al de las fracciones. Los bajos contenidos de P en el sistema convencional se deben, posiblemente, a prácticas de manejo, como el uso de fertilizantes de síntesis química, la siembra a libre exposición en monocultivo y la ausencia de coberturas entre plantas.This study was conducted in the department of Valle del Cauca (Colombia) coffee growing zone to evaluate the response of planting coffee under different cropping systems: organic, conventional and organicmineral, on soil phosphorus fractions with volcanic influence. Sequential fractionation methodology adapted by the International Center of Tropical Agriculture was used. The statistical analysis consisted of a Complete Randomized Block Design under a split plot arrangement with three treatments and three replications. The results showed that contents of the organic fraction of available P and the moderately available P showed significant differences among the systems in which organic and conventional management was included, the conventional system had the lowest values. The organic-mineral system showed the highest contents of organic and inorganic phosphorus and the conventional system showed the lowest for these fractions of P. For the non available P fraction, it was found that organic systems had higher P content than the conventional system and, the organic-mineral system showed significant differences with respect to the rest. The total P showed a similar pattern to the fractions described. The low content in the conventional system can be explained by specific aspects of management such as the use of synthetic chemical fertilizers, planting without shade in monoculture and lack of soil coverage between plants.

Estudou-se a comunidade de nematoides do solo em quatro sistemas de manejo no Sistema Integrado de Produção Agroecológica (SIPA): pasto, capoeira, figo com Paspalum notatum e horta. As amostras de solo foram coletadas a cada quatro meses durante um ano. A comunidade de nematoides foi identificada e descrita com os parâmetros: riqueza de famílias, diversidade de Shannon-Weaner, de dominância de Simpson, além da diversidade trófica e dominância trófica. Os fitoparasitas e bacteriófagos dominaram as comunidades de nematoides nas áreas. Osonívoros foram menos abundantes em todos os sistemas estudados. O sistema pasto apresentou maior diversidade de famílias de nematoides enquanto que, no sistema capoeira se encontraram valores de diversidade baixos, porém constantes no tempo, indicando condição de maior estabilidade. A ação antrópica induzida pelo manejo modificou a distribuição trófica em benefício dos nematoides bacteriófagos, normalmente associados à maior taxa de decomposição da matériaorgânica. Nematoides fitoparasitas e bacteriófagos foram dominantes nos sistemas estudados, o que sugere a influência de densidade radicular elevada no pasto e alta taxa de mineralização na horta. A distribuição relativa de grupos tróficos de nematoides do solo confirmou ser uma eficiente forma de se determinar o nível de perturbação de solos submetidos a distintos manejos.microfauna, sistemas de cultivo, diversidade.Soil nematode communities were studied in four differents crop systems at the Integrated System of Agroecological Production. Soil samples were collected at four-month intervals during one year, with three replications for each location. Nematode communities were measured by the following parameters: family richness, Shannon-Weaner’s index, Simpson’s index, trophic diversity (T) and dominance index (Ig). These data were submitted to ANOVA statistical analysis at 5% level of Tukey’s test. The population of bacterivores and herbivore nematodes was high in all areas. Omnivores were found in lower abundance in all systems. The highest diversity of nematode families was found on pasture. In forests, the values of richness and abundance were always lower but constant in time, suggesting an ecosystem of higher stability. Soil management induced the proliferation of bacterivores usually associated with higher decomposition rates of organic matter. Herbivores and bacterivores were dominant in all systems, suggesting it is important to have high root (for pasture) or high decomposition rates (for horticulture system). The relative distribution of trophic groups of soil nematodes proved to be a good way to determine the level of perturbation of ecosystems.

Although energy analysis is a way to evaluate the sustainability of production systems, this practice is not often used in the agribusiness. In this context, the castor bean (Ricinus communis L) is an agricultural crop not yet well studied despite its great potential in the Brazilian energetic scenario. This article aimed to evaluate the productive potential of the castor bean oil, using an energetic view applied to two management systems: low (System 1) and medium (System 2) technologies. The quantification of the used material fluxes was made converting these factors in energy units. The input energy fluxes were 3,170.6 MJ ha¹ and 10,366.0 MJ ha¹ for Systems 1 and 2, respectively. The energy balance of System 1 was 11,938.2 MJ ha¹ and that of System 2 16,296.5 MJ ha¹. The net energetic gain or the energy gain over the invested energy (EROI) of System 1 was 3.8 and of System 2, 2.6. Although presenting a greater energy demand and a lower EROI, System 2 had a greater energy balance, demonstrating a better viability of this cultivation system for the production of castor bean oil.A análise energética é uma forma de se avaliar a sustentabilidade de um sistema produtivo, apesar de ainda pouco utilizada no setor agropecuário. Inserida neste setor encontra-se a produção da mamoneira (Ricinus communis L.), cultura ainda pouco estudada e que apresenta grande importância para o agronegócio brasileiro. Avaliou-se sob a ótica energética a produção potencial de óleo de mamona em dois sistemas de cultivo: com baixa (Sistema 1) e média (Sistema 2) tecnologias. Foi realizada a quantificação dos fluxos de materiais empregados nos dois sistemas de produção e conversão destes fatores em unidades de energia. Os fluxos de energia de entrada foram de 3.170,6 MJ ha¹ e 10.366 MJ ha¹ para os sistemas 1 e 2, respectivamente. O balanço de energia foi de 11.938,2 MJ ha¹ no sistema 1 e 16.296,5 MJ ha¹ no sistema 2. A lucratividade energética, retorno em energia sobre energia investida (EROI) do sistema 1 foi de 3,8 e no sistema 2 de 2,6. Apesar de apresentar uma maior demanda energética e menor EROI, o sistema 2 obteve maior balanço energético, demonstrando a maior viabilidade deste tipo de cultivo para a cultura da mamoneira.

Conduziu-se este estudo, com o objetivo de avaliar o crescimento e a produção de alface (Lactuca sativa L.) e jateikaá (Achyrocline alata (Kunth) DC.) em cultivo solteiro e em consórcio. Os tratamentos em estudo foram três e quatro fileiras de alface por canteiro, duas fileiras de jateikaá espaçadas de 35 cm e 50 cm, quatro fileiras de alface alternadas com duas fileiras de jateikaá (A25J50) e três fileiras de alface alternadas com duas fileiras de jateikaá (A35J35). Foi utilizado o delineamento blocos casualizados, com quatro repetições. Foram avaliadas as massas frescas e secas, diâmetro e altura das cabeças de alface, massas frescas e secas das inflorescências e das partes aéreas sem inflorescências de jateikaá. Realizou-se o teste antioxidante para amostras de inflorescências de jateikaá nos tratamentos estudados. O tipo de cultivo e os espaçamentos entre fileiras não influenciaram significativamente as características avaliadas para alface e para o jateikaá, com exceção das massas fresca e seca de inflorescências, cuja produção foi superior no espaçamento de 50 cm. A altura média obtida para as plantas de jateikaá foi de 1,12 m. A razão de área equivalente para o consórcio A25J50 foi de 1,87 e para o A35J35 foi de 2,10. No caso de recomendação agronômica, optar-se-ía pelo consórcio A35J35. Observou-se atividade antioxidante em todas as amostras analisadas, sendo que o padrão de inibição apresentou semelhança tanto para cultivo solteiro quanto para o consorciado, demonstrando que os constituintes químicos do jateikaá apresentaram um alto potencial antioxidante.This study aimed to evaluate the production of lettuce (Lactuca sativa L.) e jateikaá (Achyrocline alata (Kunth) DC.) as a single culture and intercropped. The treatments in study were three and four rows of lettuce and two rows of jateikaá spaced 35 cm or 50 cm, four rows of lettuce alternated with two rows of jateikaá (A25J50) and three alternated rows of lettuce with two rows of jateikaá (A35J35). The experiment design was randomized blocks, with four replications. Fresh and dry masses, diameter and height of the lettuce heads and height, fresh and dry masses of inflorescence and aerial parts without inflorescence of jateikaá were evaluated. The antioxidant activity of jateikaá's inflorescence was studied. The culture type and spacing between rows did not influence the characteristics evaluated for lettuce and for jateikaá, with exception of the fresh and dry masses of inflorescences, with production was superior in the 50 cm spacing of plants with height average of 1.12 m for the jateikaá plants. The land equivalent ratio, for intercropping A25J50 was 1.88 and for the A35J35 was 2.05. Intercropping A35J35 might be recommended. Antioxidant activity was observed in all samples. The inhibition standard was similar for both single culture and intercropping, demonstrating that the chemical constituent of jateikaá had presented a high antioxidant potential.