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An investigation to assess the greenhouse gases (GHG's) fluxes in rice cultivation under current and elevated temperature was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, during rabi season (November 2014 - March 2015). This experimentation was carried out with two temperature levels viz., current temperature at open environment and +2°C elevated temperature at Temperature Controlled Chamber. During the experimentation, GHG emission rate was evaluated. The nitrous oxide emission attained maximum at 15 DAT followed by 45 DAT and then decreased towards maturity. The methane emission rates increased with age of the crop, but attained maximum at harvesting stage. The methane emission rates from rice crop grown under open environment were higher than elevated temperature. The nitrous oxide emission rates from rice crop grown under +2°C elevated were higher than open environment. Methane is normally translocated through rice plants and the higher biomass generation under open environment led to higher methane translocation. The nitrous oxide emission was normally through microbial activity and the higher microbial activity was in elevated temperature led to more nitrous oxide emission. The tradeoff between CH4 and N2O emission has to be analyzed critically and developing appropriate nutrient and water management strategies and maintaining the soil redox potential at an intermediate range (-100 to +200 mV) would minimize emissions of both CH4 and N2O. Overall, the data have shown clear evidence that rice cultivation in future reduced methane emission but increase nitrous oxide emission. [ABSTRACT FROM AUTHOR]

Weeds are one of the important biotic factor, compete the crop for its resources and difficult to eliminate completely from agricultural system. Weeds respond very quickly to stress and adopt easily than crops to climatic stress. In this context, a pot culture experiment in climate control chamber with three temperature levels (0°C, +2°C and +4°C increase over the ambient) and two moisture levels (supply of moisture at 100 %, and 60 % ET of previous day) was carried out at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore during 2015 -16 to understand weeds response to future climate scenarios. The results inferred that, the problematic weed Cynodon dactylon had high acclimatization capacity and produced more growth under elevated temperature up to +4°C with sufficient moisture. The C4 pathway of bermuda grass helps that weed to utilise the moisture and temperature more efficiently even during stress and produce more growth. Moisture stress with increased temperature had negative effect on growth, but induced the early flowering and more seed production in Cynodon dactylon. It is concluded that, in near future with elevated temperature, the crop production in both dry and wet seasons would suffer from severe Cynodon dactylon menace. Hence, necessary precaution measures against Cynodon dactylon have to be included in climate change adaptation technologies. [ABSTRACT FROM AUTHOR]