Contributions of plant breeding to soil carbon storage: Retrospect and prospects

Abstract

There is interest in harnessing cropland C storage potential at a large scale to mitigate climate change and improve land productivity. While the effects of soil management practices on C storage have been studied extensively, opportunities to select for C sequestration traits in crop plants remain largely unexplored. This review describes how genetic improvement of major US crops may have altered soil C stocks historically and identifies potential opportunities for plant breeding to increase cropland C stocks. Through quantitative literature review, we find that breeding has led to an increase in aboveground residue C inputs to the soil for corn (Zea mays L.) and soybeans (Glycine max (L.) Merr) and a decrease in aboveground residue C inputs for wheat (Triticum aestivum L. and Triticum turgidum L.). Breeding has largely not altered the root:shoot ratio of these crops. Given that there is limited potential for further major improvements in harvest index, breeding for high grain yields may necessitate increasing aboveground biomass and residue production in the future.Crop root traits and residue quality may influence the stabilization of crop-derived C in soil, but there is uncertainty regarding historical changes in these traits due to breeding, the magnitude of their effect on soil organic C stocks, and tradeoffs or synergies with breeding for high yield. Nevertheless, root traits such as suberin content, rhizodeposition, mycorrhizal association, and depth emerge as potential targets for more efficient C stabilization. There is also a large opportunity for plant breeding to enhance the performance of cover crops, double crops, perennial grains, and perennial groundcovers, which can increase annual C inputs to the soil by occupying fallow periods. Our review reveals that there are many opportunities for plant genetic improvement to fix more C in cropping systems and enhance its stabilization in the soil to meet the goals of sustainable intensification and cropland C capture.

Salix species and varieties affect the molecular composition and diversity of soil organic matter

“…For instance, the conversion of arable land to grassland generally leads to increases in soil organic C, but affects food production (Boysen et al 2017). In view of these potential trade-offs, the breeding of plant species and varieties with traits related to the quantity and quality of the C input to soil may be a way forward (Poffenbarger et al 2023;Weih et al 2014). It has also been shown that the use of management systems with greater interspeci c plant diversity can result in, for example, greater aboveground C in forests (Huang et al 2018; Hulvey et al 2013) and greater belowground C in grasslands (Hungate et al 2017;Lange et al 2015; Prommer et al 2020).…”

“…2020). Such an effect should be considered in breeding programmes for biomass crop and multicrop systems (Moore et al 2023). The smaller differences that were seen among varieties from the same species suggest that breeding for greater soil organic C content is a viable research avenue to follow.…”

Cover crop cultivars and species differ in root traits potentially impacting their selection for ecosystem services

“…Therefore, improving winter hardiness in some species may provide enhancements to root biomass and root-related ecosystem services. As we experience more extreme cold due to climate change(Cohen et al 2021), winter hardiness may play an increased role in winter cover crop selection and breeding to improve ecosystem services(Poffenbarger et al 2023).…”