3,4-dimethylpyrazole phosphate (DMPP) may negate the expected stimulation of elevated atmospheric CO2 and warming on fertilizer-N loss.

People have accepted the clear fact that elevated CO2 (eCO2) and climate warming are happening, but sustainable agricultural systems are still struggling to adapt. 3,4-dimethyl-1H-pyrazol phosphate (DMPP) is currently recognized as a highly effective strategy for reducing nitrogen (N) loss and related environmental impacts. There is still uncertainty, however, whether DMPP could contribute to building climate-resilient ecosystems in a future climate scenario with co-elevated CO2 and temperature. Thus, this study evaluated the responses of plant N derived from soil or fertilizer and strawberry growth to the tested climate conditions. Plants were supplied with or without DMPP, grown in controlled climate chambers under ambient CO2 and temperature (aCT; 400 ppm + 25℃), and co-elevated CO2 and temperature (eCT; 800 ppm + 27℃). The results showed that DMPP increased plant N accumulation by 9 % and 19 % under aCT and eCT conditions, respectively, compared to N treatment without DMPP. We also found a similar trend in total C content in the plants. Compared with aCT, DMPP demonstrated higher efficiency in improving N use efficiency (NUE, 51 % vs. 36 %) and reducing N loss (21 % vs. 29 %) under eCT, which could ensure higher N demand of plant, making fertilizer-N, rather than soil-N, a primary contributor to the N accumulation increment. Moreover, in terms of combating climate challenge, the combination with DMPP further strengthened the beneficial influence of eCT on the N accumulation and biomass in strawberry but reduced fertilizer-N loss. In summary, DMPP exhibits better performance under eCT, which may alleviate the potential adverse effects of co-elevated CO2 and temperature on ecosystem by reducing fertilizer-N loss and soil-N mineralization more efficiently, providing a promising approach to optimizing sustainable agricultural management under future climate change.