March’s CSA Paper of the Month was published in Field Crops Research and is entitled: Radiation interception and radiation use efficiency in mixtures of winter cover crops (https://doi.org/10.1016/j.fcr.2020.108034) by Ali Elhakeem, Wopke van der Werf and Lammert Bastiaans.
Winter cover crops are typically planted in the fall when temperature and solar radiation are steadily decreasing, which is reflected in the reduced potential crop photosynthetic rate, and have serious implications for crop productivity. A successful cover crop quickly covers the soil, intercepts relatively high amounts of solar radiation, and efficiently converts intercepted radiation into biomass.
Researchers investigated how dry matter accumulation in field crops can be separated in the processes of radiation interception and radiation conversion into biomass, known as radiation use efficiency. Moreover, they investigated whether and how radiation interception and radiation use efficiency differ between cover crops grown as pure stands of single species and stands of species mixtures. The overall goal was to gain insight to enhance cover crop productivity as cover crops have important ecosystem services and mitigate nitrogen leaching, enhance soil quality, and suppress pests, weeds, and diseases.
Among oats, crucifers, legumes, and a variety of forbs, oats and crucifers were the most productive species. Crucifers had rapid biomass accumulation and intercepted high amounts of radiation (517 MJ m−2), but their radiation use efficiency was relatively low (0.80 g MJ-1). Oats intercepted relatively less radiation (459 MJ m−2), but had a greater radiation use efficiency (1.15 g MJ-1) when compared to crucifers. Species belonging to other botanical families had a combination of low to intermediate radiation interception and radiation use efficiency and therefore produced less biomass when compared to oats and crucifers.