Resumo: O objetivo deste trabalho foi avaliar o efeito dos herbicidas pré-emergentes indaziflam, indaziflam+metribuzim e diuron+hexazinone sobre o banco de sementes do solo de lavoura de cana-de-açúcar, durante quatro safras consecutivas. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições, em parcelas subdivididas. Os tratamentos consistiram de doses dos seguintes herbicidas: indaziflam, 75, 100 e 150 g i.a. ha-1; indaziflam+metribuzim, 75 + 960 g i.a. ha-1; e diuron+hexazinone, 936 + 264 g i.a. ha-1; além de área capinada, como testemunha. O banco de sementes foi analisado nas camadas do solo de 0,00-0,10 e 0,10‒0,20 m. Realizaram-se a contagem e a identificação de plântulas emergidas, e calcularam-se a densidade, a frequência e a abundância absolutas e relativas, bem como o índice de valor de importância. Nos tratamentos 100 e 150 g i.a. ha-1 de indaziflam, houve maior redução do banco de sementes total e do índice de valor de importância das espécies de Poaceae e Asteraceae. O banco de sementes total, na camada de 0,10‒0,20 m, e o da espécie Portulaca oleracea, nas duas camadas avaliadas, não são influenciados pelos herbicidas. O uso dos herbicidas pré-emergentes, durante quatro safras consecutivas, reduz o banco de sementes do solo na camada de 0,0‒0,10 m, em lavoura de cana-de-açúcar.

Abstract: The objective of this work was to evaluate the effect of the pre-emergent herbicides indaziflam, indaziflam+metribuzin, and diuron+hexazinone on the soil seed bank of a sugarcane crop, during four consecutive harvests. The experimental design was a randomized complete block with four replicates in a split plot. Treatments consisted of doses of the following herbicides: indaziflam, 75, 100, and 150 g a.i. ha-1; indaziflam+metribuzin, 75 + 960 g a.i. ha-1; and diuron+hexazinone, 936 + 264 g a.i. ha-1; besides a clean area, used as a reference. The soil seed bank was analyzed in the 0.00‒0.10 and 0.10‒0.20-m soil layers. Emerged seedlings were counted and identified, and absolute and relative density, frequency and abundance, as well as the importance value index, were calculated. In the treatments 100 and 150 g a.i. ha-1 indaziflam, there was a greater reduction in the total seed bank and in the importance value index of species of Poaceae and Asteraceae. The total seed bank, in the 0.10‒0.20-m layer, and that of the species Portulaca oleracea, in both evaluated layers, are not affected by the herbicides. The use of pre-emergent herbicides during four consecutive harvests decreases the soil seed bank in the 0.00‒0.10-m layer under a sugarcane crop.

Cymbopogon citratus (lemongrass) is an aromatic species whose essential oil is rich in citral, with industrial applications due to its lemon scent. The effects of environmental factors on the percentage and composition of essential oils are the main challenges in commercial cultivation. Various studies have indicated the positive effect of cytokinin on terpene production. The present work aimed to evaluate the effect of N6-benzylaminopurine (BAP) associated with light intensity on the production and composition of essential lemongrass oil. Plants were grown under field conditions (FIELD) and shade (SHADE). The study employed a 2x7 factorial scheme with two growing environments, seven BAP concentrations, and five replicates. After seven months of growth, a single application of the synthetic cytokinin BAP was performed at concentrations 0, 30, 60, 90, 120, 150, and 180 mg L-1. One week after the BAP application, plants were harvested and the essential oil was extracted in a Clevenger apparatus. The chemical composition of the essential oil of plants treated with 60, 120, and 180 mg L-1 of BAP was determined by Gas Chromatography (GC). The essential oil percentage was not affected by the treatments, showing 1.08% on average. On the other hand, the citral percentage was negatively influenced by BAP, and light intensity had no effects. In plants treated with 60 mg L-1 of BAP, citral percentage was 72%, on average, while in plants treated with 180 mg L-1, the mean percentage of citral was 33%.

Para a conservação adequada das sementes é fundamental estabelecer, previamente, as condições ideais para o seu armazenamento. Sendo assim, o objetivo deste estudo foi avaliar a influência do tipo de embalagem e das condições ambientais de armazenamento na qualidade fisiológica de sementes de erva-doce. Para isso, sementes desta planta foram acondicionadas em três diferentes tipos de embalagem (algodão, papel multifoliado e vidro) e armazenadas sob duas condições ambientais (laboratório e câmara fria) durante doze meses. A qualidade fisiológica das sementes foi avaliada antes do armazenamento e a cada dois meses após, por meio dos testes de: germinação; índice de velocidade de germinação e condutividade elétrica. O experimento foi instalado em delineamento experimental inteiramente casualizado, com os tratamentos dispostos em esquema de parcelas sub-subdivididas no tempo (duas condições ambientais x três tipos de embalagens x seis períodos de armazenamento + uma testemunha), com quatro repetições. As sementes acondicionadas em embalagem de vidro mantiveram a sua qualidade fisiológica estável, durante os doze meses de armazenamento, independentemente das condições ambientais, sendo considerado o melhor recipiente; e a embalagem de algodão foi considerada a menos eficiente para o armazenamento, tanto em condições ambientais de laboratório quanto em condições ambientais de câmara fria.

For an adequate conservation of seeds it is essential previously establishing the ideal conditions for their storage. Thereby, this study aimed at evaluating influence of packaging types and storage environmental conditions on physiological quality of fennel seeds. The seeds were stored into three different packaging types (cotton bags, multiwall paper bags, and glass containers), and stored under two environmental conditions (laboratory and cold chamber) during a twelve months period. Physiological seed quality was assessed before storage and at every two months after storage through tests of germination, germination speed index, and electrical conductivity. Experiment was performed on a completely randomized design with treatments arranged in a split-split plot arrangement in time (two environmental storage conditions x three packaging types x six storage periods + a control treatment), with four replications. Fennel seeds packaged into glass containers have maintained their physiological quality stable over the twelve storage months regardless storage environmental conditions; being considered the best container for storing fennel seeds; and cotton packaging was considered as the least efficient for both storage under laboratory environmental conditions as well as for storage under cold chamber conditions.

O objetivo foi avaliar a eficiência de trifloxysulfuron-sodium isolado, em mistura, ou em aplicação sequencial a outros herbicidas no controle de Cyperus rotundus L. na cultura da cana-de-açúcar. O estudo foi realizado em área de produção comercial do cultivar RB 72-454 na Usina Paraíso e em casa de vegetação da Universidade Estadual do Norte Fluminense Darcy Ribeiro, em Campos dos Goytacazes, Rio de Janeiro. As parcelas no campo foram submetidas a nove tratamentos: 2,4-D; trifloxysulfuron-sodium + ametryn; trifloxysulturon-sodium; 2,4-D + 2,4-D (20 dias após a primeira aplicação -DAP); 2,4-D + trifloxysulfuron-sodium + ametryn (20 DAP); 2,4-D + trifloxysulfuron-sodium (20 DAP); halosulfuron (20 DAP) e testemunha com e sem capina. Em casa de vegetação avaliou-se a viabilidade dos bulbos de C. rotundus em função dos tratamentos utilizados no experimento instalado em campo. Os resultados indicaram que o trifloxysulfuron-sodium isolado ou em mistura com ametryn, em aplicação sequencial ao 2,4-D, foi excelente no controle de C. rotundus. Esse herbicida e o halosulfuron, aplicados isoladamente, reduziram a capacidade de reinfestação da espécie daninha em razão da redução de sua propagação e do seu crescimento.

The aim of this study was to evaluate the efficiency of trifloxysulfuron-sodium used alone, mixed or in sequential application with other herbicides to control Cyperus rotundus L. in sugar cane. The study was conducted in an area of commercial production of variety RB 72-454 at "Paraíso Plant" and a greenhouse at the State University "Darcy Ribeiro", Campos dos Goytacazes, RJ. The field plots were subjected to nine treatments: 2,4-D; trifloxysulfuron-sodium + ametryn; trifloxysulturon-sodium, 2,4-D + 2,4-D (20 days after the first application -DAP) 2, 4-D + ametryn trifloxysulfuron-sodium (20 DAP), 2,4-D + trifloxysulfuron-sodium (20 DAP); halosulfuron (20 DAP), control with and without hand weeding. The greenhouse trial evaluated the viability of purple nutsedge bulbs as a function of the treatments used in the experiment carried out in the field. The results indicated that the trifloxysulfuron-sodium applied alone or mixed with ametryn in sequential application to 2,4-D was excellent in controlling C. rotundus. These herbicides, along with halosulfuron applied alone reduced the capacity for reinfestation of this specie by reducing propagation and growth.

O objetivo deste trabalho foi avaliar o potencial da palha da cana-de-açúcar e a associação entre ela e a mistura comercial de trifloxysulfuron sodium + ametryn no controle de Rottboellia exaltata L. O experimento foi desenvolvido na Unidade de Apoio à Pesquisa da UENF, no período de setembro a novembro de 2004. O delineamento experimental utilizado foi o de blocos casualizados com os tratamentos dispostos em esquema fatorial: cinco camadas de palha (0; 4; 8; 12 e 16 t ha-1) e cinco doses de trifloxysulfuron sodium + ametryn (0,0; 1,0; 1,5; 2,0 e 2,5 kg ha-1), em quatro repetições. Aplicaram-se os herbicidas em pós-emergência, quando as plântulas de R. exaltata estavam com altura entre 5 e 10 cm. Avaliou-se o número de plântulas aos 15, 30, 45 e 60 dias após a aplicação dos herbicidas. Determinou-se o ponto que corresponde à concentração do herbicida que inibe 50% da planta daninha (I50). Aos 60 dias, a parte aérea das plantas de R. exaltata foi coletada e transferida para estufa para avaliação da biomassa seca. A interação quantidade de palha e doses de trifloxysulfuron sodium + ametryn foi significativa. Observou-se que camadas de palha com 16 t ha-1 (sem aplicação de herbicida) e 2,5 kg ha-1 de trifloxysulfuron sodium + ametryn (isolado) foram eficientes no controle de R. exaltata. Níveis de palha entre 8 e 12 t ha-1 interceptaram o herbicida, o que elevou o valor de I50, ou seja, a concentração do herbicida para inibir 50% do crescimento da planta foi maior do que quando se utilizou 4 t de palha.

The objective of this work was to evaluate the sugarcane straw potential and the association between the straw and the commercial mix of the trifloxysulfuron sodium + ametryn to control itchgrass (Rottboellia exaltata L.). The experiment was developed in the Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes Rio de Janeiro State, Brazil, from September to November 2004. It was carried out in randomized blocks, with the treatments arranged in a factorial scheme: five layers of straw (0; 4; 8; 12 e 16 t ha-1) and five doses of trifloxysulfuron sodium + ametryn (0,0; 1,0; 1,5; 2,0 e 2,5 kg ha-1), with four replications. The herbicide was applied in post-emergence, when weeds (R. exaltata) height was between 5 and 10 cm. Number of weeds was evaluated at 15, 30, 45 and 60 days after herbicide application. The herbicide concentration that inhibits 50% of the weed emergency (I50) was determined. In the sixty day, the itchgrass plants were collected and dry biomass was determined. The interaction between straw quantity and doses of trifloxysulfuron sodium + ametryn was significant. Straw layer of 16 tha-1 without herbicide addition was efficient to control R. exaltata and the herbicide trifloxysulfuron sodium + ametryn at 2,5 kg ha-1 used alone was efficient to control this weed. Straw levels between 8 and 12 t ha-1 intercepted the herbicide and consequently, increased the I50 value. In other words, the concentration of the herbicide to inhibit 50% of the weeds growth was greater when there were 8 and 12 t ha-1 than when there was 4 t ha-1 of straw.

Foi realizado um ensaio visando a avaliar o efeito residual da mistura pronta fluazifop-p-butil + fomesafen (160+200g ha-1), presente nos solos ARGISSOLO AMARELO (PA) e LATOSSOLO AMARELO (LA), no crescimento de abóbora, pepino, milho e maracujá, utilizados como plantas-teste. Verificou-se que não houve diferença com relação à matéria seca da parte aérea das plantas-teste dentro do mesmo solo, o mesmo se constatando para matéria seca das raízes, com exceção das plantas de maracujá em LA. Independentemente dos solos analisados, o resíduo do herbicida presente no substrato resultou em redução de plantas daninhas de folhas largas germinadas, sem contudo reduzir o número total de plantas daninhas.

It was carried out an assay in order to evaluate the residual effect of the ready mixture fluazifop-p-buthyl + fomesafen (160+200g ha-1), present in the soils yellow Argisoil (YA) and yellow Latosol (YL), in the increase of pumpkin, cucumber, maize and passion fruit, used as test plant. It was not verified difference in relation to dry matter of the aerial part of test plant in the same soil, the same was verified to dry matter of the root, excepted passion fruit in La. Independently of the analyzed soils, the herbicide residues present in the substrate resulted in reduction of germinated broadleaved weed, without reducing the total number of weed.