Abstract
The relative contribution of above- and below-ground competition to crop yield under intercropping systems is critical to understanding the mechanisms of improved yield. Changes in the content of above- and below-ground biomass, leaf photosynthetic rate (Pn), leaf area index (LAI), chlorophyll meter reading (SPAD), diffuse non interceptance (DIFN), soil water storage (SWS), crop nitrogen (N), and phosphorus (P) uptake were examined in a 2-year trial of different maize–soybean intercropping systems on the Loess Plateau, China. Compared with the sole cropping system, shoot biomass of maize was increased by 54% in M2S2 and 62% in M2S4 strip intercropping treatment. The crop N and P uptake of maize increased significantly, by 54% and 50% in M2S2 and by 63% and 52% in M2S4 compared with their respective sole crop. LAI values of maize in intercropping systems were 14% and 15% for M2S2 and M2S4 less than that in the sole crop. The DIFN of intercropped maize was increased by 41% and 48% for M2S2 and M2S4 compared to monocrop. There were no significant differences in Pn and SWS in both crops between the two cropping systems. The contribution rate of DIFN in M2S2 and crop P uptake in M2S4 on the biological yield in intercropping system was the highest among all factors. We conclude that the sowing proportion affects above- and below-ground competition in maize–soybean intercropping systems.
Highlights
The relative contribution of above- and below-ground competition to crop yield under intercropping systems is critical to understanding the mechanisms of improved yield
Compared with the sole cropping system, the shoot biomass of the intercropped maize increased 54% and 62% for M2S2 and M2S4, respectively (Fig. 1a) whereas shoot biomass of intercropped soybean was no change or decrease (Fig. 1b)
The root biomass of intercropped maize under M2S4 increased 38–178% compared with sole crop (Fig. 1c)
Summary
The relative contribution of above- and below-ground competition to crop yield under intercropping systems is critical to understanding the mechanisms of improved yield. Below-ground interspecies interactions contributed to the increased yields due to water movement in maize–pea intercropping s ystems[18] and nutrient uptake in maize–soybean intercropping systems[16] as a result of root growth[19,20] Such prior studies found that there were strong interactions between root and shoot c ompetition[21], belowground competition usually affected the balance between the competing species more than above-ground competition[16,22], and the contribution of above-ground interactions to crop growth was higher than that of below-ground interaction[13]. The objectives of this study were to (1) compare yield, above- and below-ground related parameters (Pn, LAI, SPAD, DIFN, soil water storage, nitrogen and phosphorus uptake) in different maize–soybean intercrops, and (2) quantify the relative contributions of above- and belowground competition to intercrop system performance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
