Rice plant consumption of atmospheric nitrous oxide and temporal dynamics in paddy soil

초록

BACKGROUND Rice cultivation under submerged conditions has great potential to act as a sink rather than a source of nitric oxide (N2O) emissions under high nitrogen (N) fertilization. The study aimed to investigate whether rice plants under paddy soil conditions have the potential to influence N2O emissions and its temporal dynamics. We employed the closed static chambers with rice transplanted inside using (N2O)-N-15 injection and included five treatments, each with three replicates and (N2O)-N-15 injection: N0 (0 kg N ha(-1)), N45 (45 kg N ha(-1)), N90 (90 kg N ha(-1)), N180 (180 kg N ha(-1)) and WN90 (90 kg N ha(-1) without (N2O)-N-15 injection). RESULTS The results demonstrated that minimum N2O concentration (10.66 ppm at 30 min) was recorded at booting stage (44 days) with the treatment N90 showing 97.88% reduction in concentration compared to the initial concentration (502.02 ppm). Negative correlation (r = -0.77, P < 0.05) between N treatments and N2O reduction was reported, referring to decreased reduction at high N levels, whereas a positive correlation (r = 0.52, P < 0.05) between soil N-15 and nosZ was observed. Without added N, nosZ gene activity was low and denitrification was limited; however, plant N2O recovery was observed to be higher. CONCLUSION Overall, our results suggest that the N90 treatment is the most effective strategy for optimizing nosZ activity and enhancing N2O reduction at the same time as ensuring a balanced recovery of N2O in plant tissues. This approach also facilitates the conversion of N2O to environmentally friendly N-2, providing a sustainable strategy for rice cultivation.

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