Effect of Soil Type and Temperature on Persistence and Dissipation Kinetics of a New Readymix Formulation of Fomesafen + Quizalofop-ethyl.

The research portrays the fate of a new herbicide mixture of fomesafen and quizalofop-ethyl. The soil samples viz. red lateritic soil (A), coastal saline soil (B) and black soil (C) were fortified separately for fomesafen and quizalofop-ethyl at 0.5 (T1) and 1.0 mg kg-1 (T2) doses and incubated at 20, 30 and 40°C. A satisfactory mean recovery, precision and linearity proved that the methods were accurate. Both the herbicides followed first + first order kinetics. Higher persistence of fomesafen was observed in Soil C than Soil B and Soil A with 22.38-53.75 days half-life, whereas quizalofop-ethyl showed higher stability in Soil A than Soils B and C with half-life of 0.93-12.07 days. Both compounds showed faster rates of dissipation at increased temperature, irrespective of soil type. The current study will help to predict the effect of temperature on the dissipation of herbicides in different soil under real field scenario.

Profitability, energetics and GHGs emission estimation from rice-based cropping systems in the coastal saline zone of West Bengal, India.

This study compares thirteen rice-based cropping systems in the coastal part of West Bengal, India in terms of productivity, profitability, energetics, and emissions. Information on the crop management practices of these systems was collected on 60 farms through a questionnaire survey. Rice-bitter gourd system was observed to have the highest system yield (49.88 ± 4.34 tha-1yr-1) followed by rice-potato-ridge gourd (37.78 ± 2.77 tha-1yr-1) and rice-potato-pumpkin (36.84 ± 2.04 tha-1yr-1) systems. The rice-bitter gourd system also recorded the highest benefit:cost ratio (3.92 ± 0.061). The lowest system yield and economics were recorded in the rice-fallow-fallow system. Rice-sunflower system recorded highest specific energy (2.54 ± 0.102 MJkg-1), followed by rice-rice (2.14 ± 0.174 MJkg-1) and rice-fallow-fallow (1.91 ± 0.327 MJkg-1) systems, lowest being observed in the rice-bitter gourd (0.52 ± 0.290 MJkg-1) and rice-pointed gourd (0.52 ± 0.373 MJkg-1) systems. Yield-scaled GHGs (YSGHG) emission was highest (1.265 ± 0.29 t CO2eqt-1 system yield) for rice-fallow-fallow system and was lowest for rice-vegetable systems. To estimate the uncertainty of the YSGHG across different systems under study, Monte-Carlo Simulation was performed. It was observed that there was a 5% probability of recording YSGHG emission > 1.15 t CO2eqt-1 system yield from different cropping systems in the present experiment. Multiple system properties such as productivity, economics, energy, and emission from all rice-based systems taken together, the rice-vegetable system performed consistently well across parameters and may be practised for higher economic returns with judicious and sustainable utilization of resources in the coastal saline tracts of the region.