Alternative Cropping Systems to Mitigate Carbon Dioxide Emission in Rice Fields under Different Nutrient Levels

The impact of different cropping systems and nutrient levels on carbon dioxide emission, soil temperature and soil moisture were studied. The experiment was carried out at Integrated Farming System Research Station, Karamana, during kharif, rabi and summer seasons of 2020-2021 in split plot design with five cropping systems as main plots (rice-rice-fallow(C1), rice-rice-sweet potato(C2), rice-sweet potato-amaranthus(C3), rice-(cassava+bush cowpea)-daincha(C4), rice-rice-daincha(C5) and three fertilizer doses as sub plots (F1:Full FYM+Full N+Full P+Full K(As per the recommendation of Kerala Agricultural University), F2:3/4 FYM+3/4 N+3/4 P+Full K and F3 :1/2 FYM+1/2 N+1/2 P + Full K) replicated thrice. Results showed that, during kharif, rabi and summer seasons, F1 (Full FYM+ full N, P, K) recorded the highest CO2 emission (321,331.4 and 322.33 ppm respectively) and the lowest CO2 emission (290.13, 291.06 and 289.20 ppm respectively) was recorded in F3 (½ FYM+ ½ N+ ½ P+ full K). Also, CO2 flux was linearly related with soil temperature.