Determination of the critical soil mineral nitrogen concentration for maximizing maize grain yield
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- Peng, Y., Yu, P., Li, X. et al. Plant Soil (2013) 372: 41. doi:10.1007/s11104-013-1678-0
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Background and aims
A critical soil mineral nitrogen concentration (Nmin) for guiding fertilizer application and maximizing maize grain yield is needed.
A three-year field experiment with three N regimes, unfertilized (N0), optimized N management (Opt.) and conventional N practice (Con.) was performed in maize.
The mean soil Nmin in 0–60 cm soil profile for N0, Opt. and Con. treatments was 2.0, 6.7 and 8.9 mg kg–1 at V8–VT growth stages and 2.2, 6.1 and 11.2 mg kg–1 on average over the whole growth season, respectively. Correspondingly, the soil N supplying capacity (soil Nmin content + fertilizer N) of the three N treatments was smaller, identical or greater than the plant N accumulation at different growth stages. The Opt. treatment had significantly higher N use efficiency, N recovery efficiency and N partial factor productivity compared with the Con. treatment, while it did not cause maize yield loss.
Compared with the insensitivity of the critical shoot N dilution curve to excessive N application, soil Nmin showed strong response to all treatments. We propose a minimum of soil Nmin of 6.1 mg kg–1 at the sowing–V8, 6.7 mg kg–1 at the V8–VT, and 5.5 mg kg–1 at the VT–R6 growing stages with an average of about 6 mg kg–1 of soil Nmin in the 0–60 soil depth for maximizing maize yield and N use efficiency in northern China. To maintain this critical Nmin value over the whole growth period, N topdressing at V8 and V12 stages was recommended.