Absorption and translocation of sulfometuron-methyl in sugarcane (Saccharum officinarum L.) at different growth stages

ABSTRACT

In Brazil, weed management in sugarcane fields is mainly done with the use of selective herbicide formulations. For many years, diuron+hexazinone was one of the main herbicide mixture formulations used in sugarcane. Later, sulfometuron-methyl was included in the same mixture, which was marketed as a new herbicide formulation for residual in-season weed control in sugarcane. The mixture diuron+hexazinone+sulfometuron-methyl has been widely used in commercial sugarcane fields in Brazil. However, recent field observations have shown that sugarcane plants at different growth stages varied in their phytotoxicity levels after treatment with diuron+hexazinone+sulfometuron-methyl. Greenhouse and laboratory studies were conducted to determine ¹⁴Csulfometuron-methyl absorption and translocation, as well as ¹⁴C distribution in sugarcane at two growth stages, 2 to 3 leaves and 5 to 6 leaves. ¹⁴Csulfometuron-methyl absorption by sugarcane did not differ between the two growth stages. Different patterns of ¹⁴C accumulation were observed, which may explain variations in sulfometuron-methyl phytotoxic responses observed in the field.     

A review of dark fermentative hydrogen production from biodegradable municipal waste fractions

Hydrogen is believed to play a potentially key role in the implementation of sustainable energy production, particularly when it is produced from renewable sources and low energy-demanding processes. In the present paper an attempt was made at critically reviewing more than 80 recent publications, in order to harmonize and compare the available results from different studies on hydrogen production from FW and OFMSW through dark fermentation, and derive reliable information about process yield and stability in view of building related predictive models. The review was focused on the effect of factors, recognized as potentially affecting process evolution (including type of substrate and co-substrate and relative ratio, type of inoculum, food/microorganisms [F/M] ratio, applied pre-treatment, reactor configuration, temperature and pH), on the fermentation yield and kinetics. Statistical analysis of literature data from batch experiments was also conducted, showing that the variables affecting the H₂ production yield were ranked in the order: type of co-substrate, type of pre-treatment, operating pH, control of initial pH and fermentation temperature. However, due to the dispersion of data observed in some instances, the ambiguity about the presence of additional hidden variables cannot be resolved. The results from the analysis thus suggest that, for reliable predictive models of fermentative hydrogen production to be derived, a high level of consistency between data is strictly required, claiming for more systematic and comprehensive studies on the subject.     

The short term agronomic impact of raising canal water levels in grassland areas: A case study in the Belgian polders

This study tested the hypothesis that raising canal water levels with 30 cm beyond the growing season in intensively managed lowland grassland (2.4-3.7 m above sea level) in Belgium decreases the agronomic value of pastures The study ran 3 years before and 3 years after the water elevation. Using five pairs of plots inside and outside the wetted perimeter, it was not possible to demonstrate significant impacts of the elevated water level on dry matter yield, forage quality, botanical composition, and penetration resistance of the top soil layer of the grassland. In an ex situ lysimeter experiment, simulating the effect of a water level in canals up to 50 cm beneath the surface of the pastures indicated a significant decrease of the penetration resistance of the top soil layer.Results are discussed and confronted with the difficulties of field research addressing the elevation of water levels.     

“绿色贸易堡垒”与经济发展的“绿色通行证”

“绿色贸易堡垒”是国际贸易中非关税贸易堡垒重要的组成部分，它从保护环境的目的出发，在国际贸易中发挥着越来越重要的作用。文章通过对天津市现实状况的研究，提出克服绿色贸易堡垒，为天津市经济在入世后获得“绿色通行证”的对策建议。