• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.185-194
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• 1995

The prevention of excessive use of nitrogen fertilizer get an attention in Korea not only for minimizing $NO_3^-$ contamination of groundwater but also for establishment of environmental friendly sustainable agriculture. In order to find out the dynamics of $NO_3^-$ in barley rhizosphere and its suitability for nitrogen fertilization strategies and for environmental control, the accumulation of $NO_3^-$ in 3 layer, 0~30cm, 30~60cm, 60~90cm of soil profile has been detected in winter barley pro-duction system. It showed the recommended N fertilization rate for winter barley cause the $NO_3^-$ contamination of groundwater through $NO_3^-$ leaching during winter. The $NO_3^-$ content of 0~90cm soil depth have directly reflected the amount of basal N fertilization in the early spring, but not 0~30cm and 0~60cm soil depth. The contents of $NO_3^-$ measured to 0~30cm, 0~60cm soil depth were not significanly correlated with yield but the contents of $NO_3^-$ measured to 90cm soil depth was highly correlated with yield. Nitrogen fertilizer requirement could be estimated accurately by soil test and it provides field specific N rate recommendation for spring N application to winter barley. It was concluded that $N_{min}$ method could be applied to korean climatic and soil condition for optimal fertilizer application rate.