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Title: The important but weakening maize yield benefit of grain filling prolongation in the US Midwest
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 theUSCorn‐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 ofGFPof 0.37 days per year was found over the region, which probably results from variety renewal. Statistical analysis suggests that longerGFPaccounted 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 ofGFPtrend to yield. If growing degree days that determines theGFPcontinues to prolong at the current rate for the next 50 years, yield reduction will be lessened with 25% and 18% longerGFPunder Representative Concentration Pathway 2.6 (RCP2.6) andRCP6.0, respectively. However, this level of progress is insufficient to offset yield losses in future climates, because drought and heat stress during theGFPwill become more prevalent and severe. This study highlights the need to devise multiple effective adaptation strategies to withstand the upcoming challenges in food security.

 
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NSF-PAR ID:
10062994
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Global Change Biology
Volume:
24
Issue:
10
ISSN:
1354-1013
Page Range / eLocation ID:
p. 4718-4730
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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