Patterns and trends in nitrogen use and nitrogen recovery efficiency in world agriculture

Abstract

[1] Worldwide increases in nitrogen (N) inputs to croplands have been and will continue to be an important contributor to growing more food. But a substantial portion of N inputs to croplands are not captured in harvested products and leave the field, contributing to air and water pollution. Whether the proportion of N inputs captured in harvest grows, shrinks, or remains unchanged will have important impacts on both food production and N pollution. We created a new global N input database (fertilizer, manure, fixation, deposition, and residues) that enables evaluation of trends in nitrogen use and recovery by country and by crop from the 1960s through 2007. These data show that despite growth in yields and increased N fertilization, differences in efficiency of N use between Organisation for Economic Co-operation and Development (OECD; http://www.oecd.org) and other countries have persisted over nearly 50 years and exhibit no sign of convergence. The high yield, high nitrogen input systems characteristic of rich countries have released large amounts of reactive N to the environment but have operated with greater efficiency-recovering a greater portion of added N in crops. Aggregate yields in OECD countries are 70% greater than in non-OECD countries on N input rates just 54% greater. Variation in recovery efficiency between countries suggests that there is scope for improvements through enhanced N delivery and capture in the world's low-yielding croplands and that increasing efficiency of N use is an important component of meeting food demand in the future.Citation: Conant, R. T., A. B. Berdanier, and P. R. Grace (2013), Patterns and trends in nitrogen use and nitrogen recovery efficiency in world agriculture, Global Biogeochem. Cycles, 27, 558-566,

Exploring the Trends in Nitrogen Input and Nitrogen Use Efficiency for Agricultural Sustainability

“…During the same period, the population of China increased by 105.6%, while the total crop production increased by 482.9% [44]. The estimated total N input from this study is similar to the estimate of Conant et al [19], but higher than the estimate of Ti et al [18]. This discrepancy is partly attributable to the exclusion of N inputs from planted seeds/tubers, irrigation water, animal manure, and recycling of crop residues by Ti et al [18].…”

“…Therefore, trend in N input appears to be moving away from animal manure and biological fixation towards synthetic N fertilizer, and synthetic N fertilizer became a dominant source of total N input to China's croplands during the 52-year period. The shift toward synthetic fertilizer in N input is in agreement with the general situation in many developed and developing countries [19,42].…”

“…We calculated the amount of various N inputs including planted seeds/tubers, atmospheric deposition, irrigation water, crop residues, animal manure, biological N fixation, and synthetic N fertilizer to the croplands and the NUE of crop production system based on 117 primary crops from 1961 to 2012 in China. Notably, compared with other studies [18][19][20], this is the first study to estimate the total N input and NUE by including all seven major N resources to croplands in China's crop production. Moreover, the Chinese government has issued a policy to reduce the use of fertilizers and pesticides in agriculture recently [22].…”

“…Generally, N inputs from planted seeds/tubers, atmospheric deposition, irrigation water, crop residues, animal manure, biological N fixation, and synthetic N fertilizer are considered the major sources of total N inputs to cropland. However, previous studies only included some of those N sources to estimate the total N input to cropland [18][19][20]. Furthermore, crop production and synthetic N fertilizer have increased substantially in China during the past decades [2], but the investigation on the partial factor productivity of applied synthetic N fertilizer (PFP N ) is limited in China.…”

Nitrogen use efficiency in rapeseed. A review

“…Moreover, mineral fertilizer production itself depends significantly on fossil energy, leading to additional greenhouse gas emissions and rising fertilizer costs. In addition, in the last 2 decades, especially in western European countries, overall crop yield increases have become partially decoupled from N fertilizer inputs (Conant et al 2013;Lassaletta et al 2014) and increases in N fertilization have led to relatively low gains in seed yield.…”