Impact of climate change stressors—temperature, CO₂, and UV-B—on early growth and development of different cover crop species

Different cover crop (CC) species may respond differently to the projected climate change scenarios. A study was carried out in a controlled environmental chamber to evaluate early season growth and development of five CC species: cereal rye (Secale cereale L.), triticale (x Triticosecale Wittmack), winter wheat (Triticum aestivum L.), crimson clover (Trifolium incarnatum L.), and mustard (Brassica juncea). Treatments consisted of two levels of carbon dioxide (CO₂) (420 and 720 ppm), ultraviolet-B (UV-B) radiation (0 and 10 kJ m⁻² day⁻¹), and temperatures (29/21°C and 19/11°C day/night), and their combinations. Root, shoot, and physiological parameters were recorded, and a combined stress response index (CSRI) was derived. Results indicated that higher CO₂ (+CO₂) had a net positive effect on all five CC species, with CSRI values ranging from 1.0 to 5.1. Conversely, higher UV-B radiation (+UV) had a net negative impact, with CSRI values ranging from −2.9 to −7.6. The most favorable environment for all CC species was the combination of increased fall temperature and elevated CO₂ (+T+ CO₂). The negative impact of +UV was mitigated in an elevated CO₂ and a high temperature environment, mimicking fall temperatures in the US Midsouth. Among the CC species, mustard was the most responsive, with a 151% increase in root and shoot combined dry weight under the +T+ CO₂ treatment and an 86% decrease under the +UV treatment. Rye and triticale were the least impacted by the imposed climatic stressors. These results are of particular interest to the agricultural and environmental science community as they offer insights into developing and selecting CC species with adaptable and desirable morphological characteristics in anticipation of a changing climate.