The impact of replacing chemical nitrogen fertilizer with monosodium glutamate waste liquid residue on yield, quality, and carbon emission of rice production

Abstract Replacing chemical nitrogen (N) fertilizer with monosodium glutamate waste liquid residue (MSGWLR) is beneficial for achieving clean production in both the monosodium glutamate (MSG) industry and agriculture. However, the impact of this method on rice production and environment has not yet been clear. This study adopted field experiments to clarify the rice yield, quality and carbon emissions applying conventional application of chemical N fertilizer (CF), reduction of N fertilizer by 20% (N80%), based on reduction of chemical N fertilizer by 20% and replacing 50% chemical N fertilizer with MSGWLR (MSGWLR50%), and replacing 100% chemical N fertilizer (MSGWLR100%). The results showed that compared with CF treatment, MSGWLR100% showed no significant changes in rice yield, milling quality, fatty acid value, and taste quality. The chalkiness rate of rice significantly decreased, and the protein content significantly increased. On the other hand, the carbon emissions from rice production treated with MSGWLR100% were the lowest, with a 58.5% decrease in global warming potential (GWP) compared to CF treatment. This was mainly because MSGWLR100% treatment could provide rich and balanced nutrients for rice growth, and it did not promote greenhouse gas (GHG) emissions from paddy field. At the same time, it effectively reduced the indirect carbon emissions in chemical fertilizer production by reducing chemical N fertilizer. Therefore, the MSGWLR100% fertilization treatment is beneficial for cleaner production in the MSG industry and rice cultivation. Graphical Abstract