Fig 3.

The photosynthetic photon flux density (PPFD) of relay-intercropped maize (a, c) and soybean (b, d) at tasseling, grain filling and maturity stage of maize corresponding to second trifoliate (V₂), fifth trifoliate (V₅) and flower initiation (R₁) stage of soybean, respectively as affected by different planting pattern from 2016 to 2017. The 2M2S (40 cm + 160 cm) and 1M1S (50 cm: 50 cm). The SM and SS refer to sole cropping system of maize and soybean, respectively. The WR and NR wide rows (WR; right side) and narrow rows (NR; left side), respectively. Means are averaged over three replicates. Bars show ± standard errors, (n = 3). Within a bar, different lowercase and same letters show a significant and non-significant difference (P < 0.05) between treatments.