The important but weakening maize yield benefit of grain filling prolongation in the US Midwest. (3rd July 2018)

• Record Type: Journal Article
• Authors: Zhu, Peng; Jin, Zhenong; Zhuang, Qianlai; Ciais, Philippe; Bernacchi, Carl; Wang, Xuhui; Makowski, David; Lobell, David
• Is Part Of: Global change biology. Volume 24:Number 10(2018)
• Page Start: 4718
• Page End: 4730
• Publication Date: 2018-07-03
• Subjects: crop growth stages -- crop model -- food security -- global warming -- Maize grain filling prolongation -- satellite data -- US Midwest -- yield benefit; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.14356
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: A better understanding of recent crop yield trends is necessary for improving the yield and maintaining food security. Several possible mechanisms have been investigated recently in order to explain the steady growth in maize yield over the US Corn‐Belt, but a substantial fraction of the increasing trend remains elusive. In this study, trends in grain filling period (GFP) were identified and their relations with maize yield increase were further analyzed. Using satellite data from 2000 to 2015, an average lengthening of GFP of 0.37 days per year was found over the region, which probably results from variety renewal. Statistical analysis suggests that longer GFP accounted for roughly one‐quarter (23%) of the yield increase trend by promoting kernel dry matter accumulation, yet had less yield benefit in hotter counties. Both official survey data and crop model simulations estimated a similar contribution of GFP trend to yield. If growing degree days that determines the GFP continues to prolong at the current rate for the next 50 years, yield reduction will be lessened with 25% and 18% longer GFP under Representative Concentration Pathway 2.6 (RCP 2.6) and RCP 6.0, respectively. However, this level of progress is insufficient to offset yield losses in future climates, because drought and heat stress during the GFP will become more prevalent and severe. This study highlights the need to devise multiple effective adaptation strategies to withstand the upcoming challenges in food security. Abstract : Satellite data was used to generate maize phenological date fields across the US Midwest. An average lengthening of GFP of 0.37 days per year was found. Analysis suggests that longer GFP accounted for 23% of the yield increase trend. If GFP continues to prolong at the current rate for the next 50 years, yield reduction will be lessened. However, this level of progress is insufficient to offset yield losses in future climates, because of more prevalent and severe drought and heat stress during the GFP. This study highlights the need to devise effective adaptation strategies to withstand the upcoming challenges in food security.