| 其他摘要 | Field experiments were conducted to study the couple effect of water and nitrogen
on production and relevant environment factors in a tableland area of the Loess Plateau
by growing winter wheat (triticum aestivum l.) for two years. The movement
characteristics of water and nitrogen in wheat field, the physiological and
ecological responses of wheat 1canopy, the microclimate data in wheat field, and the
grain yields and protein contents under different water and nitrogen conditions were
measured in different growth stage.The main results are as follows:
1）N fertilizer rate had little effect on the increasing of water storage with the
increasing of irrigation level in wheat field. Both irrigation and appropriate N level
would significantly improve the intensity of water consumption and water use
efficiency; the effect of N level on grain water use efficiency was more important than
irrigation. Under no irrigation treatment, the water storage of 0~3 m soil in high N
fertilizer wheat field decreased through a slight dry year and an average rainfall year,
while the water storage of 0~3 m soil in middle and low N fertilizer wheat field
remained or increased a little.
2）The effect of N fertilizer was bigger than irrigation on soil nitrate. Soil nitrate
did not increase accordingly with increasing of N fertilizer level. The order of soil
nitrate content was high N fertilizer＞low N fertilizer＞middle N fertilizer. Irrigation
would reduce the accumulation of soil nitrate, and more N fertilizer was needed to lead
to the accumulation of soil nitrate with the increasing of irrigation.
3）The water content of 0~10 cm soil increased with the increasing of irrigation
level, the water content 0~50 cm soil was affected by both irrigation and N fertilizer. Irrigation decreased the soil surface temperature in daytime after jointing stage. During
filling and ripening stage, the ground temperature of wheat field in daytime decreased
with the increasing of N fertilizer, and the range among different N fertilizer reached to
5℃. The negative correlation coefficient with plant temperature and panicle temperature
of irrigation was significant high than that of N fertilizer level. The wheat population
transmittance at anthesis decreased rapidly with the increasing of nitrogen level. The
wheat population air relative humidity at anthesis increased with the increasing of
nitrogen level under irrigation treatment. The air CO2 concentration of wheat population
under proper N fertilizer and irrigation level was far greater than bare land. Winter
wheat growth duration prolonged by increasing irrigation, while N fertilizer had little
effect on wheat growth duration.
4) LAI increased with the increase of nitrogen and irrigation level during the same
growing stage. However, the greatest LAI was not observed in the highest nitrogen level.
SPAD value increased with the increase of nitrogen level, and irrigation did not
influence the change of SPAD value. Both irrigation and nitrogen treatment had higher
photosynthesis rate and transpiration rate during the grain filling stage, and nitrogen
buffered the influence of the leaf photosynthesis rate and transpiration rate for water
stress. Under N treatment, WUEleaf of irrigation was significant higher than rainfed. The
stomatal conductance in 1filling stage was increased with the increase of N and irrigation
level. After anthesis, the Ls decreased and the difference of Ls among the different of
the N fertilizer level declined, with the increase of irrigation level. The correlation index
of Pn, Tr and Cond was significantly higher in irrigation treatment than in N treatment
after booting. The correlation index of WUEleaf and Ls was lower in irrigation level than
in N fertilizer level at grain filling stage, but higher at maturity.
5) Both N and irrigation treatments significant increased the stem per plant at
recovery stage. The irrigation treatment did not influence the stem per plant after
jointing. At grain filling stage, N and irrigation treatments significant increased the plant
height and stem diameter. The 1maximum plant hight was 72% higher than the 1minimum
one, and the 1maximum stem diameter was 1.4-fold more than the 1minimum one. A
correlation analysis for the stem per plant found that, the stem per plant was
significantly correlation coefficient with N treatment, but not irrigation. The plant height, stem diameter and aboveground were markedly significantly correlation coefficient with
irrigation treatment, but there were no significant difference of correlation coefficient
with N treatment. N and irrigation treatments significant increased the accumulation of
aboveground dry matter of winter wheat. The duration of grain filling stage was longer
with the increase of irrigation level.
6) The grain yield, spike number and grain number increased and thousand kernel
weight reduced with the increase of N level. The ranking of grain yield, spike number
and thousand kernel weight was W2＞W1＞W0. The trade-off was significantly higher
in rainfed than irrigation, and the greatest trade-off was observed in 300 kgN·ha-1 in the
slight dry year. In the year of average rainfall, the the greatest trade-off was observed in
225 kgN·ha-1.
7) There was significant difference of grain protein content among different
irrigation and N treatment. The grain protein content increased with the increase of N
fertilizer level, and higher in rainfed than irrigation treatment, but did not differ among
irrigation treatment.
Keywords: Tableland area of the Loess Plateau; Winter wheat (triticum aestivum l.); N;
Soil water; Couple effect; Nitrate; Photosynthetic parameters; Microclimate; Grain
yield. |
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