RESUMO

This study evaluated remediation of the herbicide sulfentrazone in soils with three different mineralogies (kaolinite, hematite, and gibbsite) and three remediation sulfentrazone treatments (Canavalia ensiformis L., Crotalaria juncea L., and natural attenuation). This study was conducted in a factorial scheme, in triplicate with randomized block design. Sulfentrazone was applied at 0 and 400 g ha-1. We analyzed sulfentrazone residue in the soils by high-performance liquid chromatography and confirmed the results with bioassays of Pennisetum glaucum. Herbicide movement was greater in the kaolinitic soil without plant species. The retention of herbicide in the kaolinitic soil occurred in larger quantities in the 0-12 cm layer, with higher levels found in the treatments with plants. In the hematitic soil with C. juncea, all applied herbicides were concentrated in the 0-12 cm layer. In the other hematitic soil treatments, sulfentrazone was not detected by chemical analysis at any soil depth, although in many treatments, it was detected in the bioassay. Phytoremediation was more efficient with C. ensiformis grown in gibbsitic soil, reducing the sulfentrazone load by approximately 27%. Natural attenuation was more efficient than phytoremediation in oxidic soils due to soil pH and texture soils favored microbial degradation of the compound. Highlights The influence of soil mineralogy of herbicide sulfentrazone retention was evaluated. Canavalia ensiformis and Crotalaria juncea were evaluated as phytoremediation plants. Kaolinite soils presented great movement of sulfentrazone in the soil. Natural attenuation is more efficient in oxide soils than phytoremediation.

Assuntos

RESUMO

In anoxic environmental conditions and with a drastic reduction of the redox potential, the barium sulphate used in petroleum drilling fluids becomes a hazard to the ecosystem. A field study was conducted in Brazil in an area with a history of accidental Barium (Ba) contamination to evaluate the role of frequent plant cutting on phytoremediation. The plant species Typha domingensis and Eleocharis acutangula, cultivated in a combined plantation, were subjected to four different cut frequencies: every 90 days (four cuts), 120 days (three cuts), 180 days (two cuts), or 360 days (one cut). The total amount of Ba extracted from the soil by the plants was evaluated for each treatment and at different soil depths Overall, total Ba in the soil decreased the most dramatically for cut frequencies of 120 (37.83%) and 180 (47.73%) days at 0-0.2 m below the surface, and with cut frequencies of 120 (51.98%) and 360 (31.79%) at 0.2-0.4 m depth. Further, total Ba in the plant biomass was greatest in the 120 and 360-days frequency groups. Thus, cuts at intervals of 120 days or more are associated with high levels of Ba in the plant tissue and a decrease of soil Ba.

Assuntos

RESUMO

Given the high costs of agricultural production, especially due to the price of fertilisers, particularly nitrogen, the use of inoculants to supply nitrogen to soybean crops is a widely recommended practice. The objective of this study was to evaluate the feasibility of applying inoculants through seed and planting furrow in soil previously cultivated with soybean and Brazilian native cerrado biome soil under greenhouse conditions. Seven treatments were tested: 1) inoculation via seed (inoculant + fungicide + micronutrient), 2) treatment via seed (fungicide + micronutrient), 3) control (only seed), 4) inoculation via furrow-dose 1 (recommended dose), 5) inoculation via furrow-dose 2 (twice the recommended dose), 6) inoculation via furrow-dose 3 (three times the recommended dose) and 7) inoculation via furrow-dose 1 + seed inoculation. We evaluated plant height, fresh and dry matter weight of the aerial part and nodules, number of total, viable and non-viable nodules, number of pods per plant and grain yield. Inoculation was more effective when used in cerrado soil, but soybean performance in treatments without inoculation was higher in previously cultivated soil. Application through furrow proved to be a viable practice due to the similarity of the results obtained with the traditional application by seed.

Diante dos custos da produção agrícola, consideravelmente elevados em função do preço dos fertilizantes e, particularmente, os nitrogenados, o uso de inoculantes, visando fornecimento de nitrogênio para a cultura da soja, tem sido uma tecnologia frequentemente recomendada para viabilizar a produção. Objetivou-se com este trabalho avaliar a viabilidade da aplicação de inoculantes via semente e sulco de semeadura, em solo já cultivado e em solo de cerrado nativo com a cultura da soja. O ensaio foi realizado em casa-de-vegetação, utilizando solo de cerrado, sem cultivo anterior, e solo com histórico de cultivo de soja. Foram testados sete tratamentos: 1) inoculação via semente (inoculante + fungicida + micronutriente), 2) tratamento via semente (fungicida + micronutriente), 3) testemunha (semente pura, sem tratamento), 4) via sulco-dose1 (dose recomendada), 5) sulco-dose2 (duas vezes a dose recomendada), 6) sulco-dose3 (três vezes a dose recomendada), e 7) sulco-dose1+ inoculação via semente. Foram avaliados altura de plantas; massa de matéria fresca e seca da parte aérea e nódulos; número de nódulos totais, viáveis e não-viáveis; número de vagens por planta e rendimento de grãos. A inoculação foi mais efetiva no incremento das variáveis analisadas quando utilizada no solo de cerrado, e o desempenho da soja nos tratamentos que não receberam inoculação foi melhor no solo já cultivado. A aplicação via sulco mostrou-se uma prática viável em razão da semelhança dos resultados obtidos com a aplicação tradicional, via semente.

Assuntos

RESUMO

Given the high costs of agricultural production, especially due to the price of fertilisers, particularly nitrogen, the use of inoculants to supply nitrogen to soybean crops is a widely recommended practice. The objective of this study was to evaluate the feasibility of applying inoculants through seed and planting furrow in soil previously cultivated with soybean and Brazilian native cerrado biome soil under greenhouse conditions. Seven treatments were tested: 1) inoculation via seed (inoculant + fungicide + micronutrient), 2) treatment via seed (fungicide + micronutrient), 3) control (only seed), 4) inoculation via furrow-dose 1 (recommended dose), 5) inoculation via furrow-dose 2 (twice the recommended dose), 6) inoculation via furrow-dose 3 (three times the recommended dose) and 7) inoculation via furrow-dose 1 + seed inoculation. We evaluated plant height, fresh and dry matter weight of the aerial part and nodules, number of total, viable and non-viable nodules, number of pods per plant and grain yield. Inoculation was more effective when used in cerrado soil, but soybean performance in treatments without inoculation was higher in previously cultivated soil. Application through furrow proved to be a viable practice due to the similarity of the results obtained with the traditional application by seed.(AU)

Diante dos custos da produção agrícola, consideravelmente elevados em função do preço dos fertilizantes e, particularmente, os nitrogenados, o uso de inoculantes, visando fornecimento de nitrogênio para a cultura da soja, tem sido uma tecnologia frequentemente recomendada para viabilizar a produção. Objetivou-se com este trabalho avaliar a viabilidade da aplicação de inoculantes via semente e sulco de semeadura, em solo já cultivado e em solo de cerrado nativo com a cultura da soja. O ensaio foi realizado em casa-de-vegetação, utilizando solo de cerrado, sem cultivo anterior, e solo com histórico de cultivo de soja. Foram testados sete tratamentos: 1) inoculação via semente (inoculante + fungicida + micronutriente), 2) tratamento via semente (fungicida + micronutriente), 3) testemunha (semente pura, sem tratamento), 4) via sulco-dose1 (dose recomendada), 5) sulco-dose2 (duas vezes a dose recomendada), 6) sulco-dose3 (três vezes a dose recomendada), e 7) sulco-dose1+ inoculação via semente. Foram avaliados altura de plantas; massa de matéria fresca e seca da parte aérea e nódulos; número de nódulos totais, viáveis e não-viáveis; número de vagens por planta e rendimento de grãos. A inoculação foi mais efetiva no incremento das variáveis analisadas quando utilizada no solo de cerrado, e o desempenho da soja nos tratamentos que não receberam inoculação foi melhor no solo já cultivado. A aplicação via sulco mostrou-se uma prática viável em razão da semelhança dos resultados obtidos com a aplicação tradicional, via semente.(AU)

Assuntos