Chemical control of different digitaria insularis populations and management of a glyphosate-resistant population

This study aimed to control different populations of Digitaria insularis by glyphosate herbicide, isolated and mixed, besides the combination of methods (chemical and mechanical) to manage resistant adult plants. Three experiments were conducted, one in pots which were maintained under non-controlled conditions and two under field conditions. In the experiment in pots, twelve populations of D. insularis were sprayed with isolated glyphosate (1.44 and 2.16 kg a.e. ha(-1)) and mixed (1.44 and 2.16 kg a.e. ha(-1)) with quizalofop-p tefuryl (0.12 kg i.a. ha(-1)). The treatment of 1.44 kg a.e. ha(-1) of glyphosate plus 0.12 kg a.i. ha(-1) of quizalofop was sufficient for adequate control (>95%) of all populations. Population 11 (area of grain production in Itumbiara, GO) was considered sensitive to glyphosate. Others populations were moderately sensitive or tolerant to the herbicide. In the field, the plants of D. insularis of one of the experiments were mowed and, in the other, there were not. Eight treatments with herbicides [isolated glyphosate (1.44 and 2.16 kg a.e. ha(-1)) and mixed (1.44 and 2.16 kg a.e. ha(-1)) with quizalofop-p-tefuryl at 0.12 kg a.i. ha(-1)), clethodim at 0.108 kg a.i. ha(-1)) or nicosulfuron at 0.06 kg a.i. ha(-1))] were assessed, in combination with or without sequential application of the standard treatment, sprayed 15 days after the first application. The combination of the mechanic control with the application of glyphosate (2.16 and 1.44 kg a.e. ha(-1)) plus quizalofop-p-tefuryl (0.12 kg a.i. ha(-1)) or clethodim (0.108 kg a.i. ha(-1)), associated to the sequential application, was the most effective strategy for the management of adult plants of resistant D. insularis.

Desempenho e uso eficiente da terra de modalidades de consorciação com milho e forrageiras

This study was developed with the aim of evaluating the performance and land use efficiency of different arrangements of intercropping with maize and forage. The field experiment was conducted in Tangar da Serra/MT. The experimental design was a randomized block in factorial scheme 3x2 + 1, were as three arrangements of intercropping, two species of forage and an additional treatment with maize monoculture in four replication. In maize monoculture and intercropping were evaluated: plant height and ear insertion height, plant population, weight of 100 grains, productivity, number of grain rows and number of grain per row. In forages intercropping with maize were evaluated plant population and dry matter accumulation. The arrangements with Maize + Forage sown in the line and Maize + Forage sown in two rows between rows with the species Urochloa hybrid promoted best corn yields. The modality and species affect both the productivity of maize as forages species. Grain yield of maize is higher in monoculture. The higher dry matter accumulation of Urochloa hybrid occurs in the Maize + Forage sown in one row between rows, while, for the Urochloa brizantha the arrangements studied do not affect their yields. The arrangement with best land use efficiency is Maize + Forage sown in two rows between rows for both study forage species.

Sequential sampling of Euschistus heros (Heteroptera: Pentatomidae) in soybean

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho técnico e econômico de forrageiras tropicais em sistema integrado de produção no cerrado de baixa altitude

Pós-graduação em Agronomia - FEIS

Fertilizantes e sistemas de irrigação: emissões de gases de efeito estufa no cultivo do milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Qualidade da operação de semeadura de uma semeadora adubadora de plantio direto em função do tipo de martelete e velocidade de deslocamento

The current paper had as its objective to analyze the precision planter's operational performance according to five different displacement velocities and two types of jumpers for planting no-tillage corn. The utilized experimental delineation consisted of blocks at random with parcels subdivided in factorial scheme 2x5, two types of jumpers (4 and 5 staples) and five different displacement velocities (3.0; 4.5; 5.0; 7.0 e 9.0 km h-1) with four repetitions and by applying the average comparation test, as for the jumpers effects as for the displacement velocities effects, to the significance level of 5%. It was evaluated the data concerned to the longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, survival indices, mechanical harm on seeds, germination tests and grain production. It was also observed the planter displacement velocity effect of on variables as: longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, mechanical harm and yield. The survival indice of plants were high for all the studied velocities and jumpers. Among the studied velocities, the one of 5.0 km h-1 presented the highest yield to both types of jumpers.

Adubação mineral com cobalto e molibdênio na cultura da soja

Altas produtividades de soja requerem grandes quantidades de nitrogênio, que podem ser obtidas principalmente, a partir da fixação simbiótica. No entanto, há possibilidade da eficiência desse processo biológico ser prejudicada pela deficiência de micronutrientes, especialmente de cobalto e molibdênio. Nesse contexto, objetivou-se com o presente trabalho avaliar a eficiência agronômica e a forma de aplicação de adubação mineral com cobalto e molibdênio na cultura da soja. Para tanto, a cultivar CD-206 foi submetida a diferentes tratamentos que consistiram da combinação entre aplicação de Co e Mo via tratamento de sementes e adubação foliar. As características agronômicas avaliadas foram o número de nódulos, massa seca da parte aérea, massa seca de raiz, número de vagens, número de grãos, massa de mil grãos e produção de grãos. A aplicação de molibdênio e cobalto via sementes e/ ou adubação foliar no estádio V4 (terceira folha trifoliolada completamente desenvolvida, quarto nó) promoveram incrementos significativos no rendimento da cultura. Respostas positivas ao cobalto e molibdênio também foram observadas no número de nódulos, vagens e grãos, com aumentos de até 240 kg ha-1 no rendimento da cultura. Os parâmetros agronômicos avaliados foram afetados positivamente pela aplicação de Co e Mo, principalmente quanto aplicado tanto via semente como foliar (TS + V4), inclusive para a produtividade de grãos. A forma de aplicação não foi significativamente distinta, ou seja, tanto a aplicação via semente como via foliar foram eficientes no fornecimento destes nutrientes para a cultura da soja.

Dry spell mitigation to upgrade semi-arid rainfed agriculture : Water harvesting and soil nutrient management for smallholder maize cultivation in Machakos, Kenya

Improvements in on-farm water and soil fertility management through water harvesting may prove key to up-grade smallholder farming systems in dry sub-humid and semi-arid sub-Sahara Africa (SSA). The currently experienced yield levels are usually less than 1 t ha-1, i.e., 3-5 times lower than potential levels obtained by commercial farmers and researchers for similar agro-hydrological conditions. The low yield levels are ascribed to the poor crop water availability due to variable rainfall, losses in on-farm water balance and inherently low soil nutrient levels. To meet an increased food demand with less use of water and land in the region, requires farming systems that provide more yields per water unit and/or land area in the future. This thesis presents the results of a project on water harvesting system aiming to upgrade currently practised water management for maize (Zea mays, L.) in semi-arid SSA. The objectives were to a) quantify dry spell occurrence and potential impact in currently practised small-holder grain production systems, b) test agro-hydrological viability and compare maize yields in an on-farm experiment using combinations supplemental irrigation (SI) and fertilizers for maize, and c) estimate long-term changes in water balance and grain yields of a system with SI compared to farmers currently practised in-situ water harvesting. Water balance changes and crop growth were simulated in a 20-year perspective with models MAIZE1&2. Dry spell analyses showed that potentially yield-limiting dry spells occur at least 75% of seasons for 2 locations in semi-arid East Africa during a 20-year period. Dry spell occurrence was more frequent for crop cultivated on soil with low water-holding capacity than on high water-holding capacity. The analysis indicated large on-farm water losses as deep percolation and run-off during seasons despite seasonal crop water deficits. An on-farm experiment was set up during 1998-2001 in Machakos district, semi-arid Kenya. Surface run-off was collected and stored in a 300m3 earth dam. Gravity-fed supplemental irrigation was carried out to a maize field downstream of the dam. Combinations of no irrigation (NI), SI and 3 levels of N fertilizers (0, 30, 80 kg N ha-1) were applied. Over 5 seasons with rainfall ranging from 200 to 550 mm, the crop with SI and low nitrogen fertilizer gave 40% higher yields (**) than the farmers’ conventional in-situ water harvesting system. Adding only SI or only low nitrogen did not result in significantly different yields. Accounting for actual ability of a storage system and SI to mitigate dry spells, it was estimated that a farmer would make economic returns (after deduction of household consumption) between year 2-7 after investment in dam construction depending on dam sealant and labour cost used. Simulating maize growth and site water balance in a system of maize with SI increased annual grain yield with 35 % as a result of timely applications of SI. Field water balance changes in actual evapotranspiration (ETa) and deep percolation were insignificant with SI, although the absolute amount of ETa increased with 30 mm y-1 for crop with SI compared to NI. The dam water balance showed 30% productive outtake as SI of harvested water. Large losses due to seepage and spill-flow occurred from the dam. Water productivity (WP, of ETa) for maize with SI was on average 1 796 m3 per ton grain, and for maize without SI 2 254 m3 per ton grain, i.e, a decerase of WP with 25%. The water harvesting system for supplemental irrigation of maize was shown to be both biophysically and economically viable. However, adoption by farmers will depend on other factors, including investment capacity, know-how and legislative possibilities. Viability of increased water harvesting implementation in a catchment scale needs to be assessed so that other down-stream uses of water remains uncompromised.

Incidencia de la fertilización en amaranto : zona semiárida pampenana (Argentina)

El objetivo fue evaluar la producción y la calidad de biomasa de Amaranthus mantegazzianus Pass. cv. Don Juan, en condiciones de secano, con fertilización de NPK y agregado de urea al momento de los cortes para obtención de materia verde y posterior producción de grano. Se sembró en el Campo Experimental de la Facultad de Agronomía de la Universidad Nacional de La Pampa, Argentina, el 18/11/ 2004 en parcelas con cinco surcos distanciados 0.35 m. Se establecieron dos tratamientos: un testigo sin fertilizar y otro fertilizado con NPK (19-19-19) 50 kg ha-1 como fertilizante base y urea (100 kg ha-1) al momento del corte, en un diseño en bloques al azar con cuatro repeticiones. Las condiciones ambientales adversas solamente permitieron la realización de un corte e imposibilitaron la obtención de grano. Se midió: producción de biomasa, porcentaje de materia seca, tamaño promedio de hojas (largo x ancho), ancho promedio del tallo, largo promedio del pecíolo, número de hojas por planta cortada. Se calculó la relación lámina de la hoja/largo de pecíolo. Se determinó el contenido de proteína cruda y minerales. La fertilización realizada aumenta la relación lámina de la hoja/pecíolo. Las variables medidas y el contenido de nutrientes no presentaron diferencias significativas entre las plantas fertilizadas y sin fertilizar.

Entre puertos, campos y acopios : Trabajo y transporte de granos en torno al Sudeste bonaerense

En este artículo, se analiza el proceso de trabajo en el transporte automotor de granos en torno al sudeste bonaerense. Desde un abordaje cualitativo, se describen y analizan las prácticas durante la cosecha y pos-cosecha, y los trayectos campo-acopio, acopio-puerto. También se analizan las relaciones laborales a partir de una perspectiva ampliada de las relaciones laborales clásicas (asalariadas, estables, protegidas).Los rasgos que asume el trabajo en el transporte de granos están asociados a los cambios técnicos y tecnológicos de la producción de granos, así como a procesos de flexibilización laboral, vinculados a la disponibilidad permanente para fletar, la extensión de la jornada laboral y la intensidad del trabajo camionero

Territorio, trabajo y salud : Una mirada desde dos actividades productivas. Producción granífera en Zona Núcleo y producción ladrillera en el sudeste santiagueño

El objetivo de este artículo es analizar los cambios en la dinámica territorial de la producción de ladrillos en el sudeste santiagueño y de granos en la Zona Núcleo Granífera, y su impacto en la relación urbano-rural y en la salud de los trabajadores. Para ello, recurrimos a técnicas cuantitativas (elaboración de bases de datos sobre la base de registros epidemiológicos institucionales) y a técnicas cualitativas de investigación (entrevistas, observación participante, análisis documental y bibliográfico). En el marco del avance de la frontera agrícola, la sojización y la agriculturización, analizamos la relación entre trabajo y territorio para comprender el proceso de salud-enfermedad-atención en dos zoonosis regionales: enfermedad de Chagas y Fiebre Hemorrágica Argentina

Entre puertos, campos y acopios : Trabajo y transporte de granos en torno al Sudeste bonaerense

En este artículo, se analiza el proceso de trabajo en el transporte automotor de granos en torno al sudeste bonaerense. Desde un abordaje cualitativo, se describen y analizan las prácticas durante la cosecha y pos-cosecha, y los trayectos campo-acopio, acopio-puerto. También se analizan las relaciones laborales a partir de una perspectiva ampliada de las relaciones laborales clásicas (asalariadas, estables, protegidas).Los rasgos que asume el trabajo en el transporte de granos están asociados a los cambios técnicos y tecnológicos de la producción de granos, así como a procesos de flexibilización laboral, vinculados a la disponibilidad permanente para fletar, la extensión de la jornada laboral y la intensidad del trabajo camionero

Entre puertos, campos y acopios : Trabajo y transporte de granos en torno al Sudeste bonaerense

En este artículo, se analiza el proceso de trabajo en el transporte automotor de granos en torno al sudeste bonaerense. Desde un abordaje cualitativo, se describen y analizan las prácticas durante la cosecha y pos-cosecha, y los trayectos campo-acopio, acopio-puerto. También se analizan las relaciones laborales a partir de una perspectiva ampliada de las relaciones laborales clásicas (asalariadas, estables, protegidas).Los rasgos que asume el trabajo en el transporte de granos están asociados a los cambios técnicos y tecnológicos de la producción de granos, así como a procesos de flexibilización laboral, vinculados a la disponibilidad permanente para fletar, la extensión de la jornada laboral y la intensidad del trabajo camionero

Territorio, trabajo y salud : Una mirada desde dos actividades productivas. Producción granífera en Zona Núcleo y producción ladrillera en el sudeste santiagueño

El objetivo de este artículo es analizar los cambios en la dinámica territorial de la producción de ladrillos en el sudeste santiagueño y de granos en la Zona Núcleo Granífera, y su impacto en la relación urbano-rural y en la salud de los trabajadores. Para ello, recurrimos a técnicas cuantitativas (elaboración de bases de datos sobre la base de registros epidemiológicos institucionales) y a técnicas cualitativas de investigación (entrevistas, observación participante, análisis documental y bibliográfico). En el marco del avance de la frontera agrícola, la sojización y la agriculturización, analizamos la relación entre trabajo y territorio para comprender el proceso de salud-enfermedad-atención en dos zoonosis regionales: enfermedad de Chagas y Fiebre Hemorrágica Argentina

Entre puertos, campos y acopios : Trabajo y transporte de granos en torno al Sudeste bonaerense

En este artículo, se analiza el proceso de trabajo en el transporte automotor de granos en torno al sudeste bonaerense. Desde un abordaje cualitativo, se describen y analizan las prácticas durante la cosecha y pos-cosecha, y los trayectos campo-acopio, acopio-puerto. También se analizan las relaciones laborales a partir de una perspectiva ampliada de las relaciones laborales clásicas (asalariadas, estables, protegidas).Los rasgos que asume el trabajo en el transporte de granos están asociados a los cambios técnicos y tecnológicos de la producción de granos, así como a procesos de flexibilización laboral, vinculados a la disponibilidad permanente para fletar, la extensión de la jornada laboral y la intensidad del trabajo camionero