The rule of plant nutrient absorption can help us to take effectively measure to regulate plant growth and to increase grain yield.A research of different N-fertilization rates on dry matter accumulation and the changes of nitrogen absorption was conducted on the bases of long-term positional fertilization experiment on dry highland of the Loess Plateau

and the results showed that the dry matter accumulation changed as a "S" curve during the whole growth period

and the dry matter accumulation of winter wheat was increased with the increasing of N-fertilizer amount

the accumulation rate showed clearly a single-peak curve

the fast rate of dry matter accumulation was found in the jointing-filling stage.N content of wheat plant and the accumulation of N nutrient were increasing with the increasing of N-fertilizer amount

two key periods of N accumulation were found in the before winter-jointing stage and the flowering-filling stage.