Newer and select maize, wheat, and rice varieties can help mitigate N footprint while producing more grain.

Abstract

Sustainably feeding the growing population amid a changing climate and dwindling resources is a grand challenge facing mankind. Decades-long advancement in crop breeding has progressively elevated yield potential, markedly enhancing global food production capacity. However, relevant impact on reactive N (Nr) emissions associated with crop variety improvement has not been explicitly described. Here, we report multitiered evidence that newer and select maize, wheat, and rice varieties developed in China have the capacity to substantially lower Nr losses while producing more grain. First, we pooled studies featuring side-by-side comparison of different varieties, totaling 269 paired observations, to demonstrate that collectively, relatively newer varieties of maize, wheat, and rice had less Nr emissions (9.6%-23.5%) while yielding more grains (7.3%-11.2%) compared to older varieties under wide-ranging conditions. Next, we built an extended database (142 field studies with 833 observations) and comprehensively evaluated the Nr-loss reduction potential of newer varieties (2000 and after) versus older ones (1985-1999). We found that newer varieties had Nr emission factors (N loss as a percentage of N applied after correcting for background emissions) 18.2%-75.7% less for N2 O, 18.3%-75.7% less for , and -8.5% to 22.8% less for NH3 , while producing more grains (16.0%-24.4%). Individual varieties differed markedly in yield-emission scores. A nationwide farmer survey (2.47 million responses) indicated tremendous opportunities for a new way of management intervention. Coupling variety selection with sound N and other agronomic management can help lower N footprint while producing more grain.