Canopy heterogeneity with border-row proportion affects light interception and use efficiency in maize/peanut strip intercropping

Intercropping usually plants two or more crop species, often with different canopy architectures by row configuration, creates spatial niche differentiation, changes light distribution and affects radiation utilization and yield. In this study, we investigated how row configuration (e.g. the proportion of border rows) affected light interception (LI) and light use efficiency (LUE) in maize (Zea mays L.)/ peanut (Arachis hypogaea Linn.) strip intercropping. Field experiments were carried out for two years in 2015 and 2016. Four intercropping treatments were set as M2P2 (two rows maize and two rows peanut), M4P4, M6P6 and M8P8, with border-row proportion (BRP) of 1, 0.5, 0.33 and 0.25 under an equal land use proportion (0.5 for each crop). Two monocultures, sole maize and sole peanut (with BRP of 0), were set as controls. The LI was estimated by a light interception model developed for strip intercropping. Both light capture and light use efficiency of intercropped crops were significantly affected by strip width. The LI of intercropped high-stalk maize was 23.4 % higher while LI of shaded peanut was 32.2 % lower than the control. The LI of intercropped maize increased with the increasing of BRP. The LI of peanut decreased with BRP but did not show significant difference in low BRP treatment (i.e. in M6P6 and M8P8). The LUE differed within treatments in dry 2015 but not in wet 2016. In dry 2015, LUE of intercropped maize on average 13.6 % lower than the sole crop (2.05 g MJ⁻¹), while LUE of intercropped peanut especially in M2P2 was 23.9 % higher than the sole crop (0.73 g MJ⁻¹). The LUE varied daily and was significantly correlated with leaf area index and incident radiation intensity in both intercropping and the sole crops. Both LI and LUE responded to BRP and the responses differed between intercropped crops. The result could be used as a basis for explaining the mechanism of strip intercropping on light utilization, optimizing row configuration of intercropping design and improving light use algorithm of crop simulation model.