STUDY ON THE EFFECT OF NITROGEN FERTILIER UNDER RIDGE CULTURE CONDITION ON WHEAT GROWTH AND N EFFICIENCY

A experiment on the effect of nitrogen fertilizer on growth of wheat under ridge culture(20cm ridge height) condition with different depth fertilization 11～2cm. 25cm and 45cm under ridge) and soil surface fertilization without ridge (normal culture) as control were conducted in field. Tracer N was used. The resulte showed that the deeper fertilization. the higher effect of N fertilizer in ridge culture treatments. The recovery rate which N fertilizer applied in 1～2cm layer under ridge was 14.52%, In the 25cm was 16. 53% and in the 45cm was 20. 56%. The recovery rate of N fethilizer wa8 23. 78% in surface fertilization without ridge.Leaf area index and biomass of shoot and root of wheat at different growth stuge of wheat while the N applied in 5cm under ridge or in surface non-ridge werc better than other treatinents. Therefore. under ridge culture condition. the N fertilizer application with a suitable depth of soil should be considered.