Application of
nitrogen (N) fertilizer is one of the most important approaches on improving maize
grain yield. However, as is known to all, overuse N fertilizer not only leads
to decline of N use efficiency and maize yield, but also leads to potential
risk to environment pollution. This experiment was conducted to determine the
effects of N fertilizer applications with nine different treatments on soil physical-chemical
characters and maize grain yield using hybrid variety Zhengdan 958 in 2011 and
2012. Results indicated that the soil bulk densities of T
2 (CK) and
T
1 were the lowest compared to other treatments in 2011 and 2012,
respectively, whereas the soil bulk density of T
5 in 2011 and T
3 in 2012 were higher than other treatments. The soil porosity and field capacity
of T
5 in 2011 and T
3 in 2012 were lower than other
treatments, but those of CK in 2011 and T
1 in 2012 were higher than
other treatments. The pH values of T
3 to T
7 were lower
than other treatments. These results indicated that the soil bulk densities
were increased, whereas the soil porosity, field capacity and values pH were
decreased by N application at different stages. N application could increase
the N contents of leaf and stem, whereas less or excess N application should
not significant improve maize yield. Although the soil organic matter and total
N contents of T
3 were the highest in both 2011 and 2012, the yield
of T
4 is the highest in both 2011 and 2012. The application
amount, period and times of N fertilizer were important to maize yield.