Influence of Ulva rigida Extracts and Bacillus thuringeinsis (S48) Treatments on Physiology, Biochemical and Mineral Composition of Triticum aestivum L. and Vicia faba in Monoculture and Intercropping Systems

Intercropping proves to be an interesting agro-ecological alternative in the biological control of biotic factors, particularly the excessive use of chemicals harmful to the environment. This study aims to evaluate the impact of individual and combined treatments of Ulva rigida extracts and PGPR S48 bacteria on the performance of Triticum aestivum and Vicia faba intercropping system. Soil results showed that the dual treatment (seaweed extract (U) + S48) resulted a significant increase in the percentage of carbon (0.99%), organic matter (1.7%), phosphorus (16.45% mg/kg) and potassium (147.93 mg/kg), particularly in intercropping systems. Regarding plant growth and development, morphological parameters revealed that the combined treatments (U + S48) favored an increase in aerial elongation (faba bean: 30.48%, wheat: 12%) and root elongation (faba bean: 35.04%, wheat: 38.78%), as well as the number of seeds per spike of wheat (22.5%). Total chlorophyll content was also improved by the dual treatment (3.12 and 3.79 mg/g of fresh weight) in both plants. Additionally, dual treatments increased protein content (faba bean: 21.09 µg/mg of fresh weight, wheat: 20.95 µg/mg of fresh weight) and sugar content (faba bean: 20.57%, wheat: 28.72%), as well as an increase in the photosynthetic performance of plants (faba bean: 6.49%, wheat: 2.6%). Regarding the mineral composition, the combined treatments resulted in a significant increase of (K), (Ca), (Na), and (P) content in the roots and leaves of intercropped wheat plants. These results reveal that the combined use of Ulva rigida algae extract and PGPR S48 bacteria can constitute a promising strategy to improve the yields and nutrients uptake of intercropped crops.