"Climate-smart" crop cultivation is an approach in agriculture for implementing the Paris Agreement as part of mitigating climate change.  

Greenhouse gas (GHG) footprint is an index used to indicate the potential impact on climate change exerted by crop production. Therefore, it is crucial to accurately quantify GHG footprints of crop cultivation systems.  

However, severe problems or drawbacks in the quantification of GHG footprints still exist, limiting the applicability of GHG footprint in crop cultivation. 

Fig. 1 A "climate-smart" crop cultivation system is characterized by a low greenhouse gas (GHG) footprint, low consumption of synthetic nitrogen (i.e., new N_r), and simultaneously high crop yields. (Image by ZHENG Xunhua)  

To solve these problems or drawbacks, a research team led by Prof. ZHENG Xunhua from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences proposed a generic methodological framework to quantify the GHG footprints of crop cultivation systems free from grazing (Figure 2).  

Fig. 2 Formulas for calculating the life-cycle total net greenhouse gas emission (GHG_total), which is crucial for accurately quantifying the GHG footprint from a crop cultivation system (Image by ZHENG Xunhua)  

"The current framework can more completely take into account the direct/indirect contributors in quantifying GHG emissions and/or uptakes within a crop-production life cycle. In addition, it provides example values of some GHG emission factors while emphasizing the combination of direct measurements and model simulations in determining other key parameters," explains ZHENG. "And we hope that this methodological framework can support different studies to obtain comparable values of GHG footprints, which may be the key parameters for determining the green value added tax of foods in implementing the Paris Agreement." 

The paper entitled "A generic methodological framework for accurately quantifying greenhouse gas footprints of crop cultivation systems" was published in Atmospheric and Oceanic Science Letters.