Weed competition limits wheat yield by reducing the availability of essential resources for its growth and development. In this sense, this study aimed to estimate the economic threshold level (ETL) of wild radish (Raphanus raphanistrum) in competition with wheat cultivars. Treatments were arranged in a factorial scheme. The factor wheat cultivar consisted of early (BRS 328), medium (BRS 177), and late (BRS Umbu) cycles and the factor wild radish population ranged from 0 to 564 plants m-2 (10 populations) for the cultivar BRS 328, 0 to 472 plants m-2 for the cultivar BRS 177 (11 populations), and 0 to 724 plants m-2 for the cultivar BRS Umbu (10 populations). The early-cycle BRS 328 presented a higher competitive ability when compared to the medium-cycle BRS 177 and late-cycle BRS Umbu. Yield losses of wheat grains due to wild radish interference can be satisfactorily estimated by the rectangular hyperbola model using the variables plant population, shoot dry matter, soil cover, and leaf area of the weed. ETL values varied as a function of the cultivar cycle, being higher for the cultivar BRS 328 (early) > BRS 177 (medium) > BRS Umbu (late). Wild radish is competitive in wheat crop, requiring at least 1.6 plants m-2 for control to be justified.

-The objective of this study was to assess performance of wheat seeds after application of three components [fungicide, zinc (Zn), and polymer], separately or with their combinations, as well as assessing seed quality and yield. Thus, the treatments consisted in combinations of fungicide + zinc (Zn) + polymer, totaling six treatments, with four replicates per treatment, as follow: T0 -without application of Zn, fungicide, or polymer (control); T1 -Zn; T2 -Zn + polymer; T3 -polymer; T4 -fungicide; T5 -polymer + fungicide; and T6 -Zn + polymer + fungicide. The performance of the seeds originating from plants whose seeds had been pre-treated was assessed by tests of germination and vigor, in addition to analyzes of growth and yield. It was concluded that wheat seeds treated with zinc, fungicide and polymer are positively influenced until 30 days after emergence. The germination of wheat seeds is positively influenced by the treatment with fungicide, as much when separately applied as in combined application with zinc and polymer. The yield per plant increases when seeds are treated with Zn.Index terms: Triticum aestivum L, germination, vigor.Tratamento de sementes de trigo com zinco, fungicida e polímero: qualidade e rendimento de sementes RESUMO -O objetivo deste estudo foi avaliar o desempenho de sementes de trigo após a aplicação de três componentes [fungicida, zinco (Zn) e polímero] isoladamente, ou com a combinação destes produtos, bem como avaliar a qualidade e o rendimento das sementes produzidas. Deste modo, os tratamentos consistiram nas combinações de fungicida + Zn + polímero, totalizando seis tratamentos, com quatro repetições para cada tratamento: T0 -sem aplicação de Zn, fungicida ou polímero (testemunha); T1 -Zn; T2 -Zn + polímero; T3 -polímero; T4 -fungicida; T5-polímero + fungicida; e T6-Zn + polímero + fungicida. O desempenho das sementes produzidas, oriundas das sementes tratadas, foi avaliado por testes de vigor e germinação, além de análises de crescimento e rendimento. Pelos resultados obtidos conclui-se que sementes de trigo tratadas com Zn, fungicida e polímero são positivamente influenciadas até 30 dias após a emergência. A germinação das sementes é positivamente influenciada pelo tratamento com fungicida, tanto quando este é aplicado isoladamente quanto em aplicação combinada com Zn e polímero. O rendimento por planta aumenta quando as sementes de trigo são tratadas com Zn.Termos para indexação: Triticum aestivum, germinação, vigor.1

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ABSTRACT:Revegetation is essential to improve the quality of constructed soils. This study investigated effects of perennial grasses on total organic carbon (TOC) stock, organic matter (OM) fractions and on quality of a recently constructed soil, after coal mining. Soil samples were collected from the 0.00-0.03 m layer two years after the beginning of the experiment. The treatments consisted of Cynodon dactylon cv vaquero (T1); Urochloa brizantha (T2); Panicum maximun (T3); Urochloa humidicola (T4); Hemarthria altissima (T5); Cynodon dactylon cv tifton (T6); bare constructed soil (T8); and natural soil (T9). The treatments with grass species increased the TOC stock by 57 % and increased the OM lability in comparison with T8. Higher C accumulation in the coarse and free light fractions and a higher C management index were observed in T2 and T3, indicating greater suitability of these species for the initial recovery of OM of the constructed soil.

A utilização de sementes de alta qualidade é fator fundamental para a obtenção de emergência mais rápida e estande uniforme. O presente estudo objetivou avaliar a germinação e o vigor de sementes de abóbora tratadas com tiametoxam. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 3 x 5 (lotes de sementes de abóbora e doses de tiametoxam - 0 mL kg-1, 2 mL kg-1, 4 mL kg-1, 6 mL kg-1 e 8 mL kg-1de sementes), com quatro repetições. A qualidade das sementes tratadas foi avaliada pelos testes de primeira contagem de germinação, germinação, frio, envelhecimento acelerado e emergência, em casa-de-vegetação. O tiametoxam influencia positivamente a qualidade fisiológica de sementes de abóbora e o lote de sementes de menor qualidade tratado com tiametoxam apresenta maior incremento no vigor. O tratamento com doses de 4-6 mL de tiametoxam por kg de sementes apresenta maior eficiência sobre a qualidade fisiológica das sementes.