A new study from the University of Delaware’s Department of Plant and Soil Sciences has provided new insights into how young plants respond to different environmental conditions. The research sheds light on how specific light wavelengths and nutrient concentrations can optimize growth in controlled environment agriculture (CEA) systems.

Representative images of baby greens of Chinese cabbage ‘Tokyo Bekana’ and kale ‘Red Russian’ grown at four far-red photon flux densities (0, 25, 50, and 75 μmol⋅m−2⋅s−1) and three nitrogen concentrations in the nutrient solution (75, 125, and 175 mg⋅L−1).

Baby kale is gaining popularity in the consumer market due to its desirable flavor and leaf size. Due to its short life cycles and fast response times to environmental stimuli, baby kale is ideal for testing environmental conditions for growing crops in controlled environments on Earth and in space. In addition, far-red light has been used in research on microgreens and baby kale to increase stem elongation, leaf expansion, and biomass. However, it is still unclear how it interacts with nitrogen concentration in the nutrient solution. In a ground-based study, we investigated how far-red light and nitrogen concentrations affected the growth and morphology of baby kale from Chinese cabbage (Brassica rapa var. chinensis cv. Tokyo Bekana) and kale (Brassica oleracea var. sabellica cv. Red Russian) under continuous light and similar high CO2 levels and low relative humidity as in spaceflight.

Key findings
Far-red light: Far-red light is often overlooked in traditional horticultural practice, although recent research suggests that far-red light can promote plant growth when added to blue and red light. While maintaining the same overall light intensity, partial replacement of red light with far-red light increased stem elongation and leaf length, but had little effect on plant growth of the young green plants under the test conditions.

Nitrogen concentration: Different nitrogen concentrations elicited different responses in the young green plants. While some Chinese cabbage plants thrived with higher nitrogen concentrations, other plants responded better to lower nitrogen concentrations for optimal kale growth, indicating the need for plant-specific nutrient management.
The results of this study have significant implications for the future of the indoor and urban farming industry. By fine-tuning light spectra and nutrient concentrations, farmers can adapt their practices to the specific needs of different crops, leading to increased productivity and sustainability.

According to Dr. Meng, “This research was conducted to fill a knowledge gap in light and nutrient management to enable efficient production of leafy vegetables in controlled environments.”

Dr. Qingwu Meng is an assistant professor of controlled environment horticulture and urban agriculture in the Department of Plant and Soil Sciences at the University of Delaware.

Read the original research article at https://doi.org/10.21273/JASHS05352-23

Source: ashs.org