The effect of growing soybean (Glycine max. L.) on N2O emission from soil

Abstract A pot experiment was conducted to investigate the effect of growing soybean on N 2 O emission from soil. When soybean was growing in pots, the cumulative N 2 O emission during the growing season was 2.26 mg N pot −1 , which was 5.9 times greater than that from the identical but unplanted pots (CK). However, the difference in N 2 O fluxes between the two treatments was not significant until the grain-filling stage. Of the total N 2 O emission, 94% took place during the period from grain-filling to ripening. Premature harvesting of the aerial parts of the plants at various growth stages substantially stimulated N 2 O emission from the soil. These results implied that the process of symbiotic N fixation per se does not stimulate N 2 O production or emission, but rather senescence and decomposition of the roots and nodules in the late growth stage. Therefore, additional N 2 O would be emitted from the soil after harvesting of soybean with roots, litter, and residues left in situ.