Effects of row spacing on yield, dry matter accumulation and partitioning of maize in maize-soybean relay strip intercropping system

Optimum planting pattern is the key to increase crop yield potential in intercropping system. In order to investigate the effects of narrow row spacing on the maize yield and dry matter accumulation and partitioning in maize-soybean relay strip intercropping system (M/S). Field experiments were conducted with 6 marrow row spacing (20, 30, 40, 50, 60, 70 cm) treatments in the 160 and 200 cm strip width, respectively in 2012 and 2013 year. The re-sults showed that row spacing had significant effect on maize grain yield and dry matter accumulation. Yield and dry matter accumulation of maize were increased with the increasing of narrow spacing. Under 160 and 200 cm strip width, soybean yield decreased with the increasing of maize narrow row spacing;Yield of M/S significantly increased with narrow row spacing increasing from 20 cm to 50 cm, and there was no significant difference between the treat-ments of 40 and 50 cm; While the narrow row spacing more than 50 cm, population yield tend to decrease. The change trend of the maximum increasing rate, dry matter accumulation of rapid increasing stage and post-anthesis as-similation were similar to maize yield. Contrary trends were observed in the maximum transportation efficiency and contribution rate of stem-sheath and leaves. The highest maximum increasing rate and post-anthesis assimilation were realized when the narrow row spacing was 50 cm under the two strip width, with the values of 320. 63, 119. 53 kg· hm-2 d-1 and 376. 92, 140. 90 g·plant-1 , respectively. In general, comprehensive results showed that optimum row spacing ( maize narrow row spacing was 40 cm to 50 cm) could significantly increase kernels per ear and improve the maximum increasing rate of dry matter accumulation, post-anthesis assimilate and plant dry mater accumulation of rapid increasing stage. So optimum row spacing was an important role for crop yield potential.