PurposeTo clarify the key processes and leading factors affecting maize nitrogen utilization, providing a basis for improving nitrogen use efficiency and breeding of maize varieties with high nitrogen uptake efficiency.
MethodsFour main maize varieties, Weike702 (WK702), Longping206 (LP206), Nonghua101 (NH101) and Xianyu335 (XY335) were used as materials under artificial climate conditions with two nitrogen levels of 0 (CK) and 220 kg/hm2 (N), to clarify the differences of nitrogen accumulation and soil nitrogen transformation of different maize varieties.
ResultsAt both nitrogen levels, the aboveground nitrogen accumulation of WK702 and LP206 were higher than NH101 and XY335. In CK treatment, nitrification potential and denitrification capacity in the root zone of WK702 and LP206 were lower than those of NH101 and XY335; the abundance in the root zone of ammonia-oxidizing bacteria and ammonia-oxidizing archaea of WK702 and LP206 soil was significantly lower than that of NH101; the abundance of
nirK,
nirS and
nosZ genes were higher in NH101 and XY335 than in WK702 and LP206; the nitrification and denitrification gene abundance were mainly influenced by soil pH and
\rmNO_3^\rm - 
-N content. In the nitrogen treatment, the soil denitrification in the root zone of WK702 and LP206 was also lower than that of NH101 and XY335, but there was no difference in nitrification; the gene abundance of
nirK,
nirS and
nosZ in the root zone of WK702, LP206 and NH101 were significantly lower than that of XY335.
ConclusionThe high aboveground nitrogen accumulation in WK702 and LP206 depends on the low loss of nitrogen by the root zone soil nitrification and denitrification. In the future, more attentions should focus on the nitrification and denitrification losses of nitrogen under low nitrogen conditions for breeding maize with high nitrogen uptake efficiency.
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