19 research outputs found
Screening of Microorganisms for Biodegradation of Simazine Pollution (Obsolete Pesticide Azotop 50 WP)
The capability of environmental microorganisms to biodegrade simazineâan active substance of 2-chloro-s-triazine herbicides (pesticide waste since 2007)âwas assessed. An enormous metabolic potential of microorganisms impels to explore the possibilities of using them as an alternative way for thermal and chemical methods of utilization. First, the biotope rich in microorganisms resistant to simazine was examined. Only the higher dose of simazine (100Â mg/l) had an actual influence on quantity of bacteria and environmental fungi incubated on substrate with simazine. Most simazine-resistant bacteria populated activated sludge and biohumus (vermicompost); the biggest strain of resistant fungi was found in floral soil and risosphere soil of maize. Compost and biohumus were the sources of microorganisms which biodegraded simazine, though either of them was the dominant considering the quantity of simazine-resistant microorganisms. In both cases of periodic culture (microorganisms from biohumus and compost), nearly 100% of simazine (50Â mg/l) was degraded (within 8Â days). After the repeated enrichment culture with simazine, the rate of its degradation highly accelerated, and just after 24Â h, the significant decrease of simazine (20% in compost and 80% in biohumus) was noted. Although a dozen attempts of isolating various strains responsible for biodegradation of simazine from compost and biohumus were performed, only the strain identified as Arthrobacter urefaciens (NC) was obtained, and it biodegraded simazine with almost 100% efficiency (within 4Â days)
The effect of pod scarification by soil inhabiting insects on the quality of groundnuts ( Arachis hypogaea
Farmers' opinions and influence of cultural practices on soil pest damage to groundnut in West Africa
Perspectives and implications for the proliferation of nonâlethal weapons in the context of contemporary conflict, security interests and arms control
Ultrastructural Study of Systemic Lesions induced by Peanut Rosette Virus in Peanut Leaves
Efeito de perĂodo de controle de plantas daninhas na cultura de amendoim Effects of weed control periods on peanut crop
Dois experimentos foram conduzidos com o objetivo de avaliar os efeitos de diferentes perĂodos de controle das plantas daninhas, sobre algumas caracterĂsticas produtivas da cultura do amendoim. Os experimentos foram instalados no municĂpio de Taquaritinga-SP, em duas Ă©pocas de semeadura, sendo uma no cultivo "das secas", semeada durante o mĂȘs de março, e outra no cultivo "das ĂĄguas", semeada durante o mĂȘs de setembro. Os tratamentos foram perĂodos de controle das plantas daninhas entre 017, 0-31, 0-45, 0-59, 0-73, 17-31, 17-45, 17-59, 17-73, 31-45, 31-59, 31-73, 45-59, 45-73 e 59-73 dias apĂłs a emergĂȘncia da cultura. Foram mantidas duas testemunhas, uma sem controle e outra com controle das plantas daninhas durante todo o ciclo da cultura. A principal planta daninha, nos dois experimentos, foi Digitaria horizontalis. A comunidade infestante e a cultura foram influenciadas pela Ă©poca de semeadura, modificando suas relaçÔes de interferĂȘncia. No cultivo da Ă©poca "das ĂĄguas", os efeitos da convivĂȘncia da comunidade infestante foram mais drĂĄsticos, afetando com maior intensidade a produtividade da cultura. Dentre as caracterĂsticas produtivas avaliadas, o nĂșmero de vagens por planta foi o principal fator na redução da produtividade. No cultivo "das ĂĄguas", o controle somente foi necessĂĄrio apĂłs os 45 dias iniciais de convivĂȘncia, e na cultura "das secas", apĂłs os 59 dias, caracterizando os perĂodos anteriores Ă interferĂȘncia. Nas duas Ă©pocas de semeadura o controle das plantas daninhas, realizado atĂ© 17 dias apĂłs a emergĂȘncia, foi suficiente para garantir a produtividade da cultura semelhante Ă testemunha capina, caracterizando o perĂodo total de prevenção Ă interferĂȘncia.<br>Field trials were carried out to study the effect of weed control periods on some yield components of the peanut crop. Two experiments were carried out in Taquaritinga-SP, Brazil, one during the "dry season" (seeds sown in March), and the other during the "rainy season" (seeds sown in September). The treatments utilized were the following weed control periods: 0-17, 0-31, 0-45, 0-59, 0-73, 17-31, 17-45, 17-59, 17-73, 31-45, 31-59, 31-73, 45-59, 45-73 and 59-73 days after plant emergence. Two controls were used, one without weed control, and the other without weed interference during throughout the crop cycle. The major weed infesting both trials was Digitaria horizontalis. The infesting weed community and crop were affected by the seeding season, altering their interference relationships. In the "rainy season", the effects of the infesting weed community were more drastic, affecting peanut yield more intensely. Among the yield crop components evaluated, the number of pods per plant was the major factor in yield reduction. In the "rainy season" , control was needed only after 45 days of weed interference while in the dry season, only after 59 days, characterizing the critical times prior to interference. In both seeding seasons, weed control carried out up to 17 days after emergence was enough to maintain yield crop, being characterized as the critical weed-free period