Optimizing row orientation: An effective strategy to improve yield and quality of intercropped peanut in the Huang-Huai-Hai Region of China

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In maize/peanut intercropping systems, shading from taller maize is a primary limiting factor for peanut yield. While the strip width largely constrains the shading magnitude, optimizing row orientation is crucial for improving the light environment and enhancing the yield of intercropped peanut. Field experiments were conducted during 2021–2022 to evaluate the effects of east-west (EW) and south-north (SN) orientations on peanut yield and quality in a maize/peanut strip intercropping system. The results showed that the daily photosynthetically active radiation (PAR) transmittance in EW orientation was on average 2.0 times that of the SN. Under the EW orientation, the optimized light environment suppressed main stem elongation and increased the branching number by 13.8% in during the pod-setting stage. Enhanced light capture drove superior photosynthetic performance, increasing vegetative and generative dry matter by an average of 16.9 and 18.6%, respectively, and boosted post-flowering dry matter transport to pods by 20.2%. Consequently, peanut yield in EW orientation was enhanced by an average of 17.3% without compromising maize productivity, and the land equivalent ratio (LER) increased from 1.20 in the SN orientation to 1.27 in the EW orientation, representing a 6.3% improvement. Furthermore, the EW orientation improved kernel quality, with crude fat and soluble sugar contents increasing by 4.7% and 3.3%, respectively. It also enhanced oleic acid and reduced linoleic acid, thereby maintaining a higher oleic/linoleic ratio (O/L). In conclusion, adopting an EW orientation in maize/peanut strip intercropping systems in the Huang-Huai-Hai region is a highly effective practice that simultaneously maximizes system productivity, land use efficiency, and crop quality through spatial light optimization.