Impact of Peanut/Sorghum Intercropping on Peanut Yield and Photochemical Activity

Intercropping is a vital practice for achieving environmentally-friendly and sustainable agricultural production. The intercropping pattern of peanuts and sorghum is extensively employed in Northeast China. However, the majority of previous studies have primarily focused on analyzing the impact on soil quality as well as the composition and abundance of microbial communities. The variations among different peanut varieties under the peanut/sorghum intercropping pattern and the photoprotection mechanism to mitigate potential nutrient and light competition have received limited attention. Hence, this study aims to investigate the impact of peanut/sorghum intercropping on peanut yield and photochemical activity, consequently shedding light on its effects on yield and photochemical activity. Moreover, peanuts, being a significant oil crop, can serve as a substitute for imported soybeans. This will not only establish a theoretical basis for the selection and promotion of peanut varieties and models in peanut/dwarf sorghum intercropping but also contribute to achieving stable and high yields. This experiment employed half-erect type (L) and erect type (H) peanuts as research materials, along with the dwarf sorghum variety 'Liaonuo 10'. A two-year field experiment was conducted to examine the impact of peanut/sorghum intercropping on the yield and photochemical activity of these distinct peanut plant types. The peanut/sorghum intercropping pattern stimulated the accumulation of dry matter and net photosynthetic rate of sorghum, while simultaneously increasing the plant height of peanuts. However, it impeded the accumulation of dry matter and net photosynthetic rate of peanuts. Under the peanut/sorghum intercropping pattern, notable variations exist among different peanut varieties, reflecting their strong competitiveness and higher relative total yield. Under the peanut/sorghum intercropping pattern, intercropping hindered both the actual quantum yield and maximum quantum yield of peanuts, although significant differences were observed between the two peanut varieties. This confirms that all peanuts were at a disadvantageous position in the context of peanut/sorghum intercropping. Within the intercropping pattern, the L peanut sustained photosystem activity by augmenting cyclic electron flow (CEF), whereas the H peanut gradually acclimated to photoinhibition and enhanced CEF throughout the growth stage. Peanuts with high ΔpH display superior adaptability to intercropping-related challenges. In the intricate intercropping environment, peanuts with high ΔpH can mitigate light-induced damage and uphold the capacity for photosynthetic carbon assimilation, thereby ensuring continued growth and production. The performance of various peanut varieties differs significantly under the peanut/sorghum intercropping pattern. By inducing CEF, the stability of light response can be sustained, particularly in scenarios where sorghum demonstrates higher relative competitiveness. Cyclic electron flow plays a critical role in preserving photosynthetic capacity, as well as fostering the growth and development of intercropped crops with minimal disadvantages.