| Effects of nitrogen fertilizer rates on yield formation and nitrogen utilization of winter wheat |
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| DOI：10.7606/j.issn.1000-7601.2010.05.12 |
| Key Words: nitrogen fertilizer rate winter wheat biomass grain yield N uptake distribution and transfer |
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| Abstract: |
| A field experiment was conducted to study the effect of N rate on wheat growth, yield, N accumulation and uptake and utilization efficiency with an aim to determine the differences of the transfer of dry matter and N from shoots to seeds at the late stages of winter wheat and the rational N rate. The soil used for the trial was deficient in available N and thus it had good response to N fertilizer. The experiment included four treatments: control (without N application) and addition of 80, 160 and 240 kg N per ha, respectively. During the experimental period, changes of dry matter of different organs (stem and leaf, ear chaff and seed) and N in the aboveground part were measured. The results showed that when N rate was adequate, wheat yield was remarkably increased. Application of 80 kg N per ha had the highest efficiency, and 1 kg N increased 33 kg of wheat grain, almost reaching the highest limit of N function. There was no significant effect of application of N fertilizer on N harvest index. The biomass of wheat was increased with wheat developing time, and the peak value occurred at grain filling stage. Wheat took up much higher N from N fertilizer than from soil. At the same growing stages, the N content or concentration in plants was increased with the rise of N rate while at the late stages the concentration was declined higher for the higher N rate than for the lower N rate. However, the N uptake amount was continuously increased until grain filling stage when peak values were reached. Application of N fertilizer played a great role for grain to accumulate N and a large part of N in grains was originated from the transfer of N accumulated in plants during the grain filling stage. Evaluated by N utilization efficiency and its impact on the environment, application of 80 kg N per ha was the best choice for the soil used in the trial. |
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