Closing the yield gap could reduce projected greenhouse gas emissions: a case study of maize production inChina

Abstract

Although the goal of doubling food demand while simultaneously reducing agricultural environmental damage has become widely accepted, the dominant agricultural paradigm still considers high yields and reduced greenhouse gas (GHG) intensity to be in conflict with one another. Here, we achieved an increase in maize yield of 70% in on-farm experiments by closing the yield gap and evaluated the trade-off between grain yield, nitrogen (N) fertilizer use, and GHG emissions. Based on two groups of N application experiments in six locations for 16 on-farm site-years, an integrated soil-crop system (HY) approach achieved 93% of the yield potential and averaged 14.8 Mg ha(-1) maize grain yield at 15.5% moisture. This is 70% higher than current crop (CC) management. More importantly, the optimal N rate for the HY system was 250 kg N ha(-1) , which is only 38% more N fertilizer input than that applied in the CC system. Both the N2 O emission intensity and GHG intensity increased exponentially as the N application rate increased, and the response curve for the CC system was always higher than that for the HY system. Although the N application rate increased by 38%, N2 O emission intensity and the GHG intensity of the HY system were reduced by 12% and 19%, respectively. These on-farm observations indicate that closing the yield gap alongside efficient N management should therefore be prominent among a portfolio of strategies to meet food demand while reducing GHG intensity at the same time.

Comparison of Asian Aquaculture Products by Use of Statistically Supported Life Cycle Assessment

“…This is well below the estimated yield potential of 16 500 kg ha -1 (Cui et al 2013), despite the fertilizer application rate is higher than in e.g. the US.…”

“…Weighted averages from: FAOStat; Wang et al 2007b;Liang et al 2009;Li et al 2010;Wang et al 2012;Zhang et al 2013 Table 97: Yield in kg per hectare, and production, imports, exports and domestic consumption (Gelfand et al 2010) (Wang et al 2007b;Liang et al 2009;Li et al 2010b;Cai et al 2011;Liang et al 2011;Zhang and Liu 2011;Zhang et al 2013;Cui et al 2013 …”

“…the US. Weighted averages from: FAOStat; (Wang et al 2007b;Liang et al 2009;Li et al 2010b;Cai et al 2011;Liang et al 2011;Zhang and Liu 2011;Zhang et al 2013;Cui et al 2013).…”

The impact of alternative cropping systems on global warming potential, grain yield and groundwater use

“…Examples include irrigated maize in central Nebraska which achieved higher grain yields (13.2 Mg ha À1 ) with lower GHG-emission intensity (231 kg CO 2 -eq Mg À1 grain) by accessing better infrastructure and appropriate agricultural inputs, technologies and equipment (Grassini and Cassman, 2012). On-farm experiments in Chinese maize production have also shown that average yields can reach 14.8 Mg ha À1 , an increase of 70% relative to the yields of current farming practice while decreasing GHGI by 19% (63 CO 2 -eq Mg À1 grain) (Cui et al, 2013a). The latest results show that if Chinese farmers can achieve 80% grain yields of the integrated soil-crop system management by 2030, the production of rice, wheat and maize can meet the future food and animal feed demand for the increased population and animal products while reducing GHG emissions .…”

Managing nutrient for both food security and environmental sustainability in China: an experiment for the world

“…The Table includes [9] fertilizer companies; (3) government-sponsored approaches with vastly improved agricultural extension systems. We believe that by engaging agricultural economists, policy experts, extension specialists and, most crucially, farmers themselves, effective programs can be developed with working solutions and guidelines to address the specific needs of various regions for the ultimate goal of food security and environmental sustainability [59].…”