| 其他摘要 | Reasonable application, increas fficiency, and to explicit the role of
two-
uld significantly impact crop growth, yield, and
the y
ations soil moisture profile response to the different water and N-fertilizer
Winter Wheat of the Loess Plateau
Major: Soil Science Research field: Soil Physics
ing the utilization e
way drive function between water and fertilizer is one important issue for continuing
to improve the economic and ecological benefits of the agriculture development in
semi-arid regions. In this paper, the 2-years field experiment on winter wheat was
conducted with different water and fertilizer treatments, which aimed to evaluate the yield
effect of water and fertilizer coupling on plant growth, yield, soil moisture profile and
nitrate-N transport. Targeting high yield and water use efficiency (WUE), we estimated the
optimal coupled interval of water and nutrients supplies for high yield and water use
efficiency. The mainly results as follow:
1. Water and N-fertilizer coupling co
ield components. There was a sharp positive interaction between irrigation (W) and
nitrogen application (N), which contributed to the higher plant height and grain yield. The
grain yields were increased significantly with the increase in irrigation under application
the N fertilizer from N0 to N3 treatments, while it were showed a downward trend slightly
after the first rise under N4 and N5 treatment. Meanwhile, grain yield was improved by
irrigation amount increased from W0 to W3, and then decrease slightly. The highest yield
was 9.97 t·ha -1 occurred in W5N3 treatment during 2008-2009, and was 8.62 t·ha -1 in
W3N4 treatment during 2009-2010. The similarly results occurred in biomass and leaf
areas response to different water and N-fertilizer coupling. Notably, the irrigation was
consistently produced higher LAI and the longer physiologically functional period of
winter wheat. coup
trate-N accumulation was clearly improved by N-fertilizer than by
irriga
yield significantly and there
was
ling in the harvest period. The soil moisture content was decreased with the increase
in N-fertilizer under rain-fed condition, but increased with the increase in irrigation. Base
on the interaction between irrigation and N-fertilizer application, the depth of the soil
infiltration supplement was achieved 200cm in the W0N0 treatment and more than 300cm
in W3N0 or W3N0 treatments. In the lower (W0), middle (W3), and higher (W5) irrigation
treatments, the depth of the soil infiltration supplement decreased from 200cm to 140cm
with the increase in N-fertilizer application. During 2008-2009, the highest WUE was
18.43 kg·(ha•mm) -1 occurred in W2N2 treatment, and the least WUE was 4.29
kg·(ha•mm) -1 . Similarly, the highest WUE was 16.71 kg·(ha•mm) -1 occurred in W2N5
during 2009-2010.
3. The soil ni
tion. During both growing season, crop growth needs to be consumed part of soil N
when the n application rate is less than 225 kg·ha -1 , conversely, cause of nitrate-N residual
in soil when the N application rate is greater than 225 kg·ha -1 . In application of no
N-fertilizer treatment, the soil nitrate-N have not changed much in 0-300 cm soil layer due
to the lower soil N content. In the other N-fertilizer treatments, the nitrate-N results in
waveform with the rising of soil depth from 0 to 300 cm, and the least nitrate-N occurred at
60 cm. We also found that the large number of nitrate-N residues in soil profile led to
nitrate-N leaching when the N application of 300 and 375 kg·ha -1 . Hence, blindly pursuing
high crop grain yield with higher water and N-fertilizer input will cause greater nitrate-N
residues lead to fertilizer waste and environmental pollution.
4. irrigation and/or nitrogen input can increase the final
a positive interactive term between water and nitrogen fertilizer on final yield.
However, the overuse of water and/or nitrogen led to the low yield, and met the law of
diminishing return. During 2008-2009, when the irrigation amount is 331mm and the
nitrogen fertilizer is 290 kg·ha -1 , there is the maximum yield (10.34t·ha -1 ), and the input of
nitrogen fertilizer is 243.6kg·ha -1 plus the irrigation 138 mm, which can get the maximum
value on WUE [18.96kg·(ha·mm) -1 ], While in 2009-2010, application of 283 kg·ha -1
nitrogen and 309 mm irrigation can get the highest wheat yield (9.168t·ha -1 ); and 85.9 mm
irrigation amount and 242.8kg·ha -1 nitrogen input can reach the maximum WUE [16.73
kg·(ha·mm) -1 ]. Yield and ET responses to water and nitrogen inputs followed a quadratic and a line function, respectively. The optimal-coupling domains are determined by
elasticity index (EI) and its expression in the water-nitrogen dimensions, which are the
ellipse forms with the global maximum WUE and Y corresponding to the left and right end
points on its long axis. Considering of local maximum yields, the optimal-coupling domain
was the lower half-ellipse form with the two end points of the global maximum yield and
WUE on its long axis. Total irrigation amount to winter wheat should not exceed 331mm.
The optimal-coupling domain reflects visually range of water and nitrogen inputs. It can
provide reference for the water and nitrogen inputs in agricultural applications. |
修改评论