Using maize hybrids and in-season nitrogen management to improve grain yield and grain nitrogen concentrations

• We analyzed grain yield and grain N concentration associated with N management for three different maize hybrids.
• The higher yield hybrids had higher biomass and N accumulation during the grain-filling period and at harvest resulted in a higher grain yield.
• The high grain N concentration hybrid had higher apparent amount of N remobilization from stover (leaf plus stem) after silking and resulted in a higher grain N concentration.
• Using an optimal N rate based on in-season N management achieved all hybrids’ maximum grain yield and >95% of their maximum grain N concentration using less N fertilizer.
• Selection of appropriate hybrids, in combination with optimal N management can enable increasing grain yield and improving grain N concentration to be obtained in the North China Plain.

Understanding the dynamics of biomass and nitrogen (N) accumulation in maize cultivars and the relationship of these parameters to N management is essential to improve our ability to increase maize grain yield and grain N concentration (GNC). We conducted a field experiment in 2010 and 2011, using five rates of N application and three maize hybrids (YD13, ZD958, and XY335) in Quzhou County, the North China Plain, to evaluate grain yield and GNC under different N managements and with different hybrids. The maximum grain yield in 2010–2011 averaged 8.85 and 8.90 Mg ha−1 for ZD958 and XY335, respectively, which was approximately 45% higher than the yield of YD13 (6.10 Mg ha−1). GNC in XY335 was highest among the three hybrids. The maximum GNC for 2010–2011 averaged 1.62% for XY335, 1.42% for ZD958, and 1.48% for YD13. Compared to YD13, XY335 and ZD958 had higher biomass and N accumulation during the grain-filling period and at harvest, and the apparent amount of N remobilization from stover (leaf plus stem) after silking was greater in XY335 than in ZD958, which contributed to high yield and GNC in XY335. The optimal N application rate (ONR) based on in-season N management was 149 kg ha−1, and split at the 3-leaf (V3), 6-leaf (V6), and 10-leaf (V10) stages. All maize hybrids achieved their maximum grain yield and >95% of their maximum GNC with ONR treatment. Selection of appropriate hybrids such as XY335 in combination with optimal N management can increase grain yield and GNC obtained on the North China Plain.