Effect of nitrogen management on nitrogen uptake of winter wheat in cold area

Fieldexperimentwasconductedtostudytheeffectofnitrogenmanagementonwheatyield and nitrogen use efficiency. Inorganic nitrogen(Nmin) of 0- 90 cm soil layer, and soil and plant analysis development section(SPAD) value, accumulation of dry matter, nitrogen uptake, wheat yield were measured. The experiment results showed that farmer's fertilization practice, applying excessive nitrogen fertilizer at turning green period, increased SPAD value of leaves at jointing and heading stage, enhanced the dry matter weight before jointing stage and nitrogen uptake before heading stage, but inhibited the dry matter and nitrogen accumulation after heading stage and increased residual Nmin in 0-60 cm soil layer.Optimized nitrogen management(OPT) can match wheat nitrogen demand by applying nitrogen at jointing so that 0-60 cm soil layer Nmin maintained appropriate level and improved dry matter weight and nitrogen uptake after heading. The nitrogen rate of OPT was decreased by 42.8%- 47.6% compared to farmer's fertilization practice, but the wheat yield was improved by 4.2%- 13.1% and partial factor productivity of nitrogen fertilizer was enhanced by 95.5%-98.7%(P0.05).