Effectivity and selectivity of herbicides applied in pre-emergence in the sesame (Sesamum indicum L.) crop

Weed control in the sesame crop (Sesamum indicum L.) is a fundamental practice that ensures high grain yield. Choosing adequate control methods is a crucial step to reduce costs and reach success in weed management. Among these methods, application of chemicals shows high efficiency and low cost for farmers. However, the use of this method in sesame crops is limited because there is a restricted number of herbicides registered for pre- and post-emergence applications. Considering the importance of chemical methods for weed management, the objective of this research was to select herbicides to be applied in pre-emergence that could be used to control weeds in the sesame crop. Two experiments were carried out, one to determine the efficiency and another to determine the selectivity of herbicides applied in pre emergence. The experiments were performed in a randomized complete block design (CBD) with four replicates. The treatments consisted of seven herbicides, a mixture of herbicides applied in pre-emergence, and two control treatments, one weed-free and one with weeds. Diuron and flumioxazin were found to be selective for pre-emergence. Metribuzin exhibited high toxicity to sesame, but it was effective to control several weed species, and metolachlor did not provoke high phytotoxicity in sesame, but reduced yield. Highlights: The control of weeds in the sesame crop is a fundamental practice for the productivity of this oilseed. The chemical method applied is the most used due to its high efficiency and low cost. Few herbicides applied in preemergence are registered for sesame cultivation. The selectivity and efficiency of 8 herbicides applied pre-emergence in sesame was studied. The herbicides Diuron and flumioxazin were selective for the cultivation of sesame and efficient in the control of weeds.Weed control in the sesame crop (Sesamum indicum L.) is a fundamental practice that ensures high grain yield. Choosing adequate control methods is a crucial step to reduce costs and reach success in weed management. Among these methods, application of chemicals shows high efficiency and low cost for farmers. However, the use of this method in sesame crops is limited because there is a restricted number of herbicides registered for pre- and post-emergence applications. Considering the importance of chemical methods for weed management, the objective of this research was to select herbicides to be applied in pre-emergence that could be used to control weeds in the sesame crop. Two experiments were carried out, one to determine the efficiency and another to determine the selectivity of herbicides applied in pre emergence. The experiments were performed in a randomized complete block design (CBD) with four replicates. The treatments consisted of seven herbicides, a mixture of herbicides applied in pre-emergence, and two control treatments, one weed-free and one with weeds. Diuron and flumioxazin were found to be selective for pre-emergence. Metribuzin exhibited high toxicity to sesame, but it was effective to control several weed species, and metolachlor did not provoke high phytotoxicity in sesame, but reduced yield. Highlights: The control of weeds in the sesame crop is a fundamental practice for the productivity of this oilseed. The chemical method applied is the most used due to its high efficiency and low cost. Few herbicides applied in preemergence are registered for sesame cultivation. The selectivity and efficiency of 8 herbicides applied pre-emergence in sesame was studied. The herbicides Diuron and flumioxazin were selective for the cultivation of sesame and efficient in the control of weeds

Períodos de interferência de plantas daninhas na cultura do pimentão nos sistemas de plantio direto e convencional

Objetivou-se com este trabalho avaliar os períodos de interferências das plantas daninhas no pimentão (Capsicum annum L.), cultivado nos sistemas de plantio direto (SPD) e convencional (SPC). Para isso, foi realizado um experimento em esquema de parcelas subdivididas, distribuídas no delineamento em blocos casualizados com quatro repetições. O SPD e o SPC foram avaliados nas parcelas, e nas subparcelas, os sete períodos de controle e convivência entre as plantas daninhas e o pimentão: 0; 0–14; 0–28; 0–49; 0–70; 0–91 e 0–112 dias após transplantio (DAT). Antes de cada capina e na ocasião da colheita, foram avaliadas as espécies, a densidade e a matéria seca das plantas daninhas. Na cultura do pimentão foram avaliados diâmetro, comprimento, número, peso médio dos frutos e produtividade. Verificou-se menor incidência de plantas daninhas no SPD em relação ao SPC. Quando mantida livre da competição com as plantas daninhas, a produtividade de pimentão foi 69,57% menor no SPC em relação ao SPD. O período crítico de prevenção à interferência foi de 19 a 95 DAT no SPD e de 11 a 100 DAT no SPC

Sorption and desorption of ametryn in different types of soils

Knowledge of factors related to the dynamics of herbicides in the environment is of fundamental importance to predicting the behavior of herbicides in soils with different attributes, to select appropriate dosages, as well as to avoid harmful effects on the environment and subsequent crops. The objective of this work was to evaluate the sorption and desorption of ametryn in seven soils with different attributes. Initially, the equilibrium time was determined by the "Batch Equilibrium". Then, it was performed the sorption test with different concentrations (0.5; 1; 2; 4; 8; 16; 24 and 32 mg L-1) of ametryn in 0.01 mol L-1 CaCl2. 10 mL of these solutions were added to samples of 2.00 g of each soil, remaining under rotary shaking for 4 hours. After centrifugation and filtration, the ametryn concentration in the supernatant was determined by high-performance liquid chromatography. Desorption was evaluated using the tubes containing 16 mg L-1 prior to sorption testing. The results indicated that the sorption and desorption of ametryn depend on the physicochemical attributes of the soil. Sorption was higher in soils with high organic matter content and high ion exchange capacity, while desorption was inversely proportional to sorption

Eficácia e seletividade de herbicidas em cultivares de feijão-caupi

Despite the extensive cultivated area in Brazil and the growing demand for information about weed control, few studies are found in literature reporting the efficacy and selectivity of herbicides for cowpea (Vigna unguiculata). View of this, this work was developed in order to evaluate the selectivity and efficacy of herbicides for cultivars of cowpea. The experiment was conducted in a randomized block design in factorial scheme 2 x 13, with two cowpea cultivars (BRS Xiquexique and BRS Guariba) and 13 strategies for weed management (1: S-metolachlor, 2: metribuzin + fluazifop, 3: imazamox + fluazifop, 4: bentazon + fluazifop, 5: imazamox + bentazon + fluazifop, 6: imazetapyr + fluazifop, 7: fomesafen + fluazifop, 8: lactofen + fluazifop, 9: chlorimuron + fluazifop, 10: chlorimuron + lactofen + fluazifop, 11: fluazifop + capina, 12: weeded control and 13: control without weeding). It was verified that there is no difference in the selectivity of the evaluated herbicides for the cultivars BRS Guariba and BRS Xiquexique. The herbicides 1; 3; 4; 5 and 6 are selective for the cultivation of cowpea; The mixtures of herbicides 7 and 8 caused severe intoxication, prolonging the cycle and reduce the productivity of cowpea; Herbicides 2; 9; 10 are not selective for the cowpea; The mixtures of herbicides 5 and 6 were effective in the control of weed species present in the area with yield equivalent to the hand weeded; The effectiveness of herbicides or mixtures of herbicides for weed control depends on the weed community.Apesar da extensa área cultivada no Brasil e da crescente demanda sobre informações acerca do controle de plantas daninhas, poucos trabalhos são encontrados na literatura relatando a eficácia e a seletividade de herbicidas para a cultura do feijão-caupi (Vigna unguiculata). Diante disso, conduziu-se este trabalho com o objetivo avaliar a seletividade e eficácia de herbicidas para cultivares de feijão-caupi. Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 2 x 13, com dois cultivares (BRS Xiquexique e BRS Guariba) e 13 estratégias de manejo de plantas daninhas (1: S-metolachlor, 2: metribuzin + fluazifop, 3: imazamox + fluazifop, 4: bentazon + fluazifop, 5: imazamox + bentazon + fluazifop, 6: imazetapyr + fluazifop, 7: fomesafen + fluazifop, 8: lactofen + fluazifop, 9: chlorimuron + fluazifop, 10: chlorimuron + lactofen + fluazifop, 11: capina + fluazifop, 12: testemunha capinada e 13: testemunha sem capina). Verificou-se que não há diferença de seletividade dos herbicidas avaliados para os cultivares BRS Guariba e BRS Xiquexique; os herbicidas 1, 3, 4, 5, e 6 são seletivos para a cultura do feijão-caupi; as misturas 7 e 8 causaram severa intoxicação, prolongamento do ciclo e redução na produtividade do feijão-caupi; Os herbicidas 2, 9 e 10 não são seletivos para o feijão-caupi; as misturas de herbicidas 5 e 6 foram eficazes no controle das espécies de plantas daninhas presentes na área com produtividade equivalente à testemunha capinada; a eficácia de herbicidas ou misturas de herbicidas para o controle de plantas daninhas depende da comunidade infestante

Selectivity and herbicides efficiency pre-emergence applied in papaya crop

Na cultura do mamoeiro, são escassas as informações sobre herbicidas seletivos quando aplicados em pré-emergência. Um experimento de campo foi realizado para avaliar a seletividade e eficácia de herbicidas aplicados em pré-emergência para o controle de plantas daninhas na cultura do mamoeiro. O experimento foi conduzido no delineamento experimental em blocos casualizados, com quatro repetições. Os tratamentos avaliados foram: ametryn (1500 g ha-1 i.a.), diuron (1500 g ha-1 i.a), ametryn + diuron (1500 + 1500 g ha-1 i.a.), flumioxazin (50 g ha-1 i.a.) e isoxaflutole (150 g ha-1 i.a.), aplicados em pré-emergência das plantas daninhas e antes do transplante das mudas de mamoeiro, além de duas testemunhas, sendo uma mantida no limpo por meio de capinas e outra sem controle de plantas daninhas. Aos 7, 14, 21 e 28 dias após aplicação (DAA) dos herbicidas foram realizadas avaliações visuais de intoxicação nas plantas de mamão, aos 0, 28, 42, 56 e 72 DAA, avaliou-se altura de plantas e diâmetro do caule, e aos 21, 42 e 63 DAA avaliou-se a massa da matéria seca das plantas daninhas. Os herbicidas ametryn, diuron, flumioxazin e a mistura ametryn + diuron causaram a morte das mudas de mamoeiro e isoxaflutole causou intoxicação nas mudas com posterior recuperação. A interferência das plantas daninhas resultou em plantas de mamão com menor diâmetro do caule, embora a altura de plantas não tenha sido influenciada. In papaya culture, there is little information on selective herbicides when pre-emergence applied. A field experiment was conducted to evaluate the selectivity and efficacy of herbicides pre-emergence applied to control weeds in papaya cultivation. The experiment was conducted in a randomized blocks design with four replications. The treatments were: ametryn (1500 g ha-1 i.a.), diuron (1500 g ha-1 i.a), ametryn + diuron (1500 + 1500 g ha-1 i.a.), flumioxazin (50 g ha-1 i.a.) and isoxaflutole (150 g ha-1 i.a.), applied pre-emergence of weeds and before transplanting the papaya seedlings, as well as two controls, one kept in clean through hoeing and another without weed control. At 7, 14, 21 and 28 days after application (DAA) of the herbicides visual assessments of intoxication in papaya plants were made at 0, 28, 42, 56 and 72 DAA, plant height and stem diameter were evaluated, and at 21, 42 and 63 DAA the dry matter weight of the weed plants were evaluated. The herbicides ametryne, diuron, flumioxazin and the mixture ametryn + diuron caused the death of papaya seedlings, and isoxaflutole caused poisoning in seedlings with subsequent recovery. The weed interference resulted in papaya plants with smaller stem diameter, although the plant height was not influenced.

VIDA ÚTIL PÓS-COLHEITA DE CINCO HIBRIDOS DE MELÃO AMARELO PRODUZIDOS NO AGROPÓLO MOSSORÓ-ASSU

The goal of this paper is to evaluate the shelf-life of five yellow melon hybrids (AF-5107, AF6742, AF-9136, AF and AF-6798-7719) produced in the Mossoró-Assu agropole. The yellow melon hybrids were grown in soil fertilized and irrigated following the demand of culture. Reaching the stage of commercial maturity, fruit were harvested and brought to the Postharvest Laboratory at the Universidade Federal Rural do Semi-árido, where were taken12 fruits at random for characterization of each hybrid at time zero. Afterwards the other fruits were weighed, identified and stored in cold room regulated at 10 ± 1 ºC and 90 ± 2% RH, where they remained for 14, 21, 28, 35, 42 and 49 days. At each time interval, the following analyses were realized: mass loss, external and internal appearance, pulp firmness and soluble solids. The experimental design was completely randomized in factorial scheme 5 x 7, five hybrids and seven periods of storage. We used four replications, and the experimental unit consists of three fruits. There was significant interaction between hybrid and storage period only for the soluble solids. For the other characteristics evaluated, we observed the isolated effect of the main factors. The hybrid AF-9136 stood out compared to other hybrids tested by greater pulp firmness and soluble solids

Qualidade pós-colheita de cenoura durante o desenvolvimento em monocultivo e consorciada com rabanete Quality carrot powder-crop during development in monoculture and associated radish

O trabalho objetivou avaliar a qualidade pós-colheita de cenoura 'Brasília' durante o desenvolvimento em monocultivo e consorciada com rabanete 'Crimson Gigante'. A semeadura foi realizada sob canteiros da horta experimental da Universidade Federal Rural do Semi-Árido (UFERSA), localizada no município de Mossoró-RN. A adubação foi efetuada conforme as exigências da cultura. O experimento foi conduzido em delineamento de blocos casualizados, no esquema fatorial 2 x 4 (dois sistemas de cultivo e quatro épocas de colheita) com quatro repetições. As raízes de cenoura foram colhidas nos intervalos de 83; 91; 99 e 107 dias após a semeadura, e em seguida foram transportadas para o Laboratório de Pós-Colheita da UFERSA, onde procederam-se as seguintes análises físicas e físico-químicas das raízes: massa fresca, comprimento, diâmetro, firmeza, sólidos solúveis, potencial hidrogeniônico, acidez titulável e vitamina C. As variáveis estudadas foram submetidos à análise de variância e os níveis do fator qualitativo (sistemas de cultivo) foram comparados pelo teste de Tukey, enquanto para o fator quantitativo (épocas de colheita) procedeu-se o ajuste de modelos de regressão. O sistema de produção consorciado de cenoura e rabanete não propiciou diferença nas características avaliadas. Exceto para o diâmetro das raízes, que foi menor em cultivo consorciado. A época de colheita das raízes influenciou no diâmetro, pH, acidez titulável e vitamina C. Com exceção do pH, as demais características aumentaram com a época de colheita.<br>The work had for objective to evaluate the quality carrot 'Brasília ' powder-crop during the development in monoculture and intercropped with radish 'Crimson Gigante '. The sowing was accomplished in stonemasons of the experimental vegetable garden of the Universidade Federal Rural do Semi-Árido (UFERSA), in Mossoró-RN. The manuring was made according to the demands of the culture. The experiment was conducted in randomized blocks, in the factorial design 2 x 4 (two cropping systems and four crop times) with four repetitions. The carrot roots were harvested in the intervals of 83, 91, 99 and 107 days after the sowing, and soon afterwards they were transported to the Postharvest Laboratory of UFERSA, where the following analyses were proceeded: fresh mass, length, diameter, firmness, soluble solids, pH, titrabable acidity and vitamin C. The studied variables were submitted the variance analysis, the qualitative factor (cropping systems) were compared by Tukey test and the quantitative factor (crop times) were compared by regression analysis. The associated production system of carrot and radish did not influence the characteristics assessed. Except for the diameter of the roots, that was smaller in associated system. The time of the crop, and of the roots influenced in the diameter, pH, titrabable acidity and vitamin C. Except for the pH, the other characteristics increased with the crop time

INTERFERENCIA DE PLANTAS DANINHAS NA QUALIDADE DA MELANCIA NOS SISTEMAS DE PLANTIO DIRETO E CONVENCIONAL

This work aimed to evaluate strategies for weed management on the quality of watermelon in the subsequent growing melons in no-tillage (NT) and conventional (SPC). The experiment was conducted in split plot in randomized block design with four replications. The plots were evaluated both tillage systems (no tillage and conventional tillage) and sub-plots, nine strategies for weed management (covering with polyethylene film, with weeding at 14 days after transplanting (DAT) at 14 and DAT 28, 14 and 42 DAT, at 14, 28 and 42 DAT, the DAT 28, at 28 and 42 DAT, the DAT 42 and a control without weeding). We evaluated density and weed dry weight at 14, 28 and 42 DAT and at harvest of watermelon (80 DAT). For watermelon, were evaluated for fruit quality characteristics (longitudinal and transverse length, pulp thickness, firmness, pH and soluble solids). The SPD reduced the density and dry mass of weeds, requiring the completion of only one weeding between 28 and 42 DAT, whereas the SPC was necessary to carry out weeding at 14 and 28 DAT. The SPD and the polyethylene film in the conventional tillage system allow the realization a second crop in the area in succession to the melon, reducing weed interference and providing satisfactory results in the quality characteristics of watermelon

Períodos de interferência de plantas daninhas na cultura do pimentão nos sistemas de plantio direto e convencional

Objetivou-se com este trabalho avaliar os períodos de interferências das plantas daninhas no pimentão (Capsicum annum L.), cultivado nos sistemas de plantio direto (SPD) e convencional (SPC). Para isso, foi realizado um experimento em esquema de parcelas subdivididas, distribuídas no delineamento em blocos casualizados com quatro repetições. O SPD e o SPC foram avaliados nas parcelas, e nas subparcelas, os sete períodos de controle e convivência entre as plantas daninhas e o pimentão: 0; 0–14; 0–28; 0–49; 0–70; 0–91 e 0–112 dias após transplantio (DAT). Antes de cada capina e na ocasião da colheita, foram avaliadas as espécies, a densidade e a matéria seca das plantas daninhas. Na cultura do pimentão foram avaliados diâmetro, comprimento, número, peso médio dos frutos e produtividade. Verificou-se menor incidência de plantas daninhas no SPD em relação ao SPC. Quando mantida livre da competição com as plantas daninhas, a produtividade de pimentão foi 69,57% menor no SPC em relação ao SPD. O período crítico de prevenção à interferência foi de 19 a 95 DAT no SPD e de 11 a 100 DAT no SPC

Weed interference in sweet pepper in no-tillage and conventional planting systems = Períodos de interferência de plantas daninhas na cultura do pimentão nos sistemas de plantio direto e convencional

The subject of this work is evaluate the periods of weeds interference on yield of sweet pepper (Capsicum annum L.), cultivated in no-tillage and conventional systems. Therefore, an experiment was conducted in randomized blocks of a distributed split plots with four replications design. The no-tillage and conventional systems were evaluated in plots and subplots, during the seven periods of control and coexistence among sweet peppers and weeds: 0; 0–14; 0–28; 0–49; 0–70; 0–91 and 0–112 days after transplanting (DAT). Before weeding and harvest time, they were evaluated species, density and dry mass of weeds. In the sweet peppers crops, diameter, length, number, average fruit weight and yield were evaluated. It was observed less weeds in no-tillage than conventional system. Without competitors, these weet peppers productivity was 69.57% less in conventional than no-tillage system. The critical period of weeds interference was from 19 to 95 DAT in no-tillage system and from 11 to 100 DAT in convention tillage = Objetivou-se com este trabalho avaliar os períodos de interferências das plantas daninhas no pimentão (Capsicum annum L.), cultivado nos sistemas de plantio direto (SPD) e convencional (SPC). Para isso, foi realizado um experimento em esquema de parcelas subdivididas, distribuídas no delineamento em blocos casualizados com quatro repetições. O SPD e o SPC foram avaliados nas parcelas, e nas subparcelas, os sete períodos de controle e convivência entre as plantas daninhas e o pimentão: 0; 0–14; 0–28; 0–49; 0–70; 0–91 e 0–112 dias após transplantio (DAT). Antes de cada capina e na ocasião da colheita, foram avaliadas as espécies, a densidade e a matéria seca das plantas daninhas. Na cultura do pimentão foram avaliados diâmetro, comprimento, número, peso médio dos frutos e produtividade. Verificou-se menor incidência de plantas daninhas no SPD em relação ao SPC. Quando mantida livre da competição com as plantas daninhas, a produtividade de pimentão foi 69,57% menor no SPC em relação ao SPD. O período crítico de prevenção à interferência foi de 19 a 95 DAT no SPD e de 11 a 100 DAT no SPC