THE MOVEMENT AND LEACHING LOSS OF NO3-N IN PROFILE OF CHAO SOIL IN BEIJING

In lysimeters the NO3-N change in Chao soil profile was observed during spring wheat and summer corn growing period in Beijing. The results of common chemical analysis indicated that the NO3-N movement was coresponded with the water condition. During spring wheat growth period the marked movement occrued only from 0-20cm to 20-40cm with certain experimental treatments. However, NO3-N moved down in the profile like a wave during summer corn period, thus it brought up leaching loss of NO3-N out of 130cm soil body. With 15N stable istope techenlque the directed movement of NH4-N and/or (NH2)2CO-N was observed in short distance in early stage of spring wheat growth period, and NO3-N derived from fertilizers might moved down to deeper horizon expecially during later stage and in the treatment with NH4NO3.During summer corn period the residual labelled N could moved down in increasing rate with urea treatment or to much dooper with NH4NO3 treatment.