Abstract Background: Thermal weed control is a viable, cost-effective, and eco-friendly emerging alternative to highly challenged and unsustainable chemical weed control. Objective: To find out the most suitable pre-sowing soil solarization durations for effective weed control and soil fertility enhancement in sesame crop. Methods: A field study was conducted during the summer season of 2016 and 2017. Different soil solarization treatments were applied, including 0, 3, 6, 9, and 12 weeks before sowing (WBS) of sesame by spreading transparent polythene sheets. Results: The temperatures of solarized soil at 10 cm depth were 8-10 oC more than the control. The soil NPK and organic matter contents were gradually increased with increasing solarization durations. The highest soil nitrogen (0.71%), phosphorus (9.63 ppm), K (166.2 ppm), and organic matter content (1.12%) were observed with the longest soil solarization for 12 WBS. Different solarization durations provided 23 to 64% weed control efficiency and up to a 34% rise in sesame yield. Conclusions: Based on the current findings, soil solarization for 12 WBS by polythene sheets is an effective alternative to the chemical weed control method with additional positive effects on soil fertility and sesame yield.

Ag-Sn/CeO2 catalysts were synthesized by the co-precipitation method with different Ag-Sn wt.% loadings and were tested for the oxidation of CO. The catalysts were characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) techniques. UV-Vis measurements were carried out to elucidate the ionic states of the silver particles, and the temperature-programmed reduction (TPR) technique was employed to check the reduction temperature of the catalyst supported on CeO2. There are peaks for silver crystallites in the X-ray diffraction patterns and the presence of SnO was not well evidenced by the XRD technique due to sintering inside the 3D array channels of CeO2 during the calcination process. The Ag-Sn/CeO2 (4%) catalyst was the most efficient and exhibited 100% CO oxidation at 100 ºC due to small particle size and strong electronic interaction with the SnO/CeO2 support.

Avaliou-se o efeito residual de doses sub-letais de herbicidas sobre a germinação de sementes de plantas de Chenopodium album sobreviventes em uma cultura prévia de cebola (Allium cepa), que recebeu 2x, 3x, 1/4, 1/2 ou a dose recomendada de ioxynil em pré-emergência ou bentazone em pós-emergência. As sementes foram também coletadas de plantas de C. album sobreviventes de um campo de alho-porró (Allium porrum) que havia sido tratado com 1/4, 1/2 ou a dose recomendada de pendimethalin, propachlor e linuron em pré-emergência, ou ainda 2x, 3x, 1/4, 1/2 ou a dose recomendada de ioxynil ou linuron em pós-emergência. As sementes destas plantas sobreviventes foram coletadas e testadas quanto à germinação a temperaturas de 5°C, 10°C, 15°C, 20°C e 25°C. Verificou-se que o efeito das temperaturas na germinação destas sementes foi significativa. A germinação foi mínima a baixas temperaturas (5°C e 10°C). Os herbicidas não causaram nenhum efeito na germinação das sementes de C. album tendo resultado no mesmo nível daquelas das plantas controles de culturas não pulverizadas.

The carry-over effect of sub-lethal herbicides was investigated on the germination of seeds collected from surviving Chenopodium album plants, which had received 1/8, 1/8 twice, 1/8 three times, 1/4, 1/2, 1/1 doses of either pre-emergence ioxynil or post-emergence bentazone in a previous onion (Allium cepa) crop. Seeds were also collected from surviving C. album plants, which had received 1/4, 1/2, 1/1 of either pre-emergence pendimethalin, propachlor and linuron, or 1/8, 1/8 twice, 1/8 three times, 1/4, 1/2, 1/1 of post-emergence ioxynil or linuron in a previous leek (Allium porrum) crop. Seeds of surviving plants were collected and tested for germination at temperature of 5, 10, 15, 20 and 25°C. The effect of different temperatures on the total number of germinated seeds was significant. Germination was minimum at low temperatures (5°C or 10°C). Herbicides did not show any effect on germination of C. album and resulted in the same final germination percentage as seeds collected from the unsprayed control plots.