Cropping regimes affect NO3− versus NH4+ uptake by Zea mays and Glycine max
Background and aims
Intercropping cereals with legumes has been practiced for centuries. The benefits have been investigated by measuring biological N fixation and production, but have seldom been evaluated based on plant N acquisition strategies.
Zea mays and Glycine max were planted under three cropping regimes, i.e., monocropping or intercropping the two species in the same hole (sowing at the same point) or separated at a certain distance. After 50 days, an in situ 15N-labeling experiment was carried out to assess N uptake preference (NO3− or NH4+).
Intercropping in the same hole increased plant density and total biomass. Both species showed a strong preference for NO3− over NH4+. Intercropping in the same hole increased and decreased NO3− uptake by Z. mays and G. max, respectively. Z. mays significantly increased NH4+ uptake when intercropped in the same hole or at a certain distance.
Z. mays and G. max showed strong preference for NO3− over NH4+ irrespective of cropping regime. Intercropping did not influence N preference but altered uptake rates of both N forms. Thus, intercropping in the same hole is a useful practice in agricultural systems because it can increase total biomass and N uptake by Z. mays.
KeywordsInorganic N uptake Intercropping Maize Monocropping Soybean
This study was supported by the National Natural Science Foundation of China (31470560 and 41601318) and Youth Innovation Research Team Project (LENOM2016Q0004).
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