RESULTS: The FI in China increased rapidly from about 5 kg ha-1 in 1961 to the highest value of 282 kg ha-1 in 2014, then decreased to about 231 kg ha-1 in 2018. Although the fertilizer allocation efficiency (FAE) showed a slight downward trend, slight upward trend was observed for the fertilizer integrated efficiency (FIE). FIs in India, Iran and Turkey continuously rose from5 kg ha-1 in 1961to 116, 49(148 in 2006),120kg ha-1 in 2018, respectively, while FAEs showed a significant fluctuation around horizontal direction or downward trends and their FIEs showed a slight fluctuation downward. FIs of Britain, Germany and France except USA, increased rapidly from about 200-400 kg ha-1 in 1960s to peaks of 430-530 kg ha-1 in 1980s, then dropped to 150-340 kg ha-1 around 2010, and then up to current level of 200-350 kg ha-1 , while FAEs and FIEs increased rapidly.
CONCLUSION: France and Germany were found to have moderate chemical fertilizer input and the highest FIE. Thus, their experiences of ecological agricultures in both countries could provide good examples for the developing countries to follow. In short, models of FAE and FIE were easier way to reflect the fertilizer efficiencies in developed and developing countries. This article is protected by copyright. All rights reserved.
RESULTS: During 1980-2014, the FIs of NPK chemical fertilizers in China showed a significant growing trend. After reaching the highest value of 339 kg ha-1 in 2014, FIs were reduced to 303 kg ha-1 in 2019, higher than the 225 kg ha-1 maximum safe usage internationally recognized. Meanwhile, the pattern of change of FAE was one of 'decreasing to increasing', with values of 1 in 1980, 0.66 in 2003, and 0.80 in 2019. FIE basically showed an increasing trend, which could be divided into three stages: the first stage of low efficiency during 1980-2009, the second stage of medium efficiency after 2010, and the third stage of high efficiency after 2018.
CONCLUSION: From 1980 until 2019, a reduction of FAE from 1 to 0.80 with an average of 0.75 was observed in China. FIE was found between 0.65 and 0.85 and had the potential of upgrading by 15-35%. Therefore, China needs to improve the fertilizer use efficiency in order to strive for negative growth of chemical fertilizer intensity and ecological agriculture construction. © 2022 Society of Chemical Industry.