Quantifying the sensitivity of maize production to long-term trends in fertilization and regional climate in China

The regional climate over China has changed pronouncedly since the mid-20th, posing substantial risks and uncertainties to local crop production. The maize production has demonstrated considerable sensitivity to such changes. Observations in recent years witnessed that the use of fertilizer has been a crucial contributor to the increase in yields of global staple crops including maize. Thus, adjusting fertilizer use is a potential measure to offset the negative impacts of climate change on staple crops, while quantifying the pros and cons of such a measure for maize production has not been sufficiently performed. Based on multiple sources of observational records and statistical yield simulations, this study assesses the impacts of historical trends of regional climate and fertilizer use on maize yield over the main cultivation regions in China for the period 1981 to 2020. The results show that 1 degrees C of warming has resulted in pronounced changes in the general maize yield (-5.5 +/- 0.5 %- 21.1 +/- 1.1 %, mean +/- error standard). In comparison, a 10 % increase in fertilizer use has resulted in boosted yield by 2.4 +/- 0.2 %-4.3 +/- 0.2 %. For the mitigation effects of fertilizer, a 10 % increase in fertilizer use can offset 2-3 % of yield reductions associated with the changes in both temperature and precipitation. During the climate change period, the contribution of temperature and precipitation trends shifted from yield loss (by - 8.1 +/- 1.5 %) to yield gain (by 5.1 +/- 2 %) from north to south, while more fertilizer uses contributed to maize yield gain across the maize belt by 26.4 +/- 1.1 %. This quantified information indicates the crucial role of fertilizer use in alleviating the hazardous impacts of regional climate changes on maize production in China, which delivered a key message for optimizing strategies for climate change adaptation in maize production zones across China.