Responses of Soybean Dry Matter Production, Phosphorus Accumulation, and Seed Yield to Sowing Time under Relay Intercropping with Maize

摘要

Soybean production under maize–soybean relay-intercropping system (MSICS) is vulnerable to shading. A study was initiated to investigate the effects of three sowing-times: ST 1 , 90; ST 2 , 70; and ST 3 , 50 days of co-growth period and two phosphorus-rates: P 0 , 0; and P 60 , 60 kg P ha ?1 on soybean under MSICS. Results revealed that ST 3 significantly increased the photosynthetically active radiations, leaf area index, and photosynthetic rate by 72% and 58%, and 61% and 38%, and 6% and 8%, respectively, at full-flowering and full-pod stage of soybean than ST 1 . Treatment ST 3 , increased the total dry-matter (TDM) and the highest TDM was reached at full-seed (R 6 ) stage. Similarly, ST 3 considerably increased the dry-matter partitioning to pods and seeds, relative to ST 1 , soybean under ST 3 at R 6 had 35% and 30% higher pod and seed dry-matter, respectively. Moreover, ST 3 exhibited the maximum seed-yield (mean 1829.5 kg ha ?1 ) for both years of this study. Soybean under ST 3 with P 60 accumulated 38% higher P, and increased the P content in pods and seeds by 36% and 33%, respectively at R 6 than ST 1 . These results imply that by selecting the appropriate sowing-time and phosphorus-rate for soybean, we can increase the TDM and seed-yield of soybean under MSICS.