| NO-3-N deep migration in loess layer of non-saturated zone under irrigation condition |
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| DOI：10.7606/j.issn.1000-7601.2006.06.33 |
| Key Words: irrigation Loess layer non-saturated zone NO-3-N deep migration |
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| Abstract: |
| Soil NO-3-N was measured in Weibei Loess soil under irrigation condition.The deep irrigation of NO-3-N concentration was measured in 10m scope in the ultra root level with time changing.It quantitatively analyzed and discussed the migration flux and velocity.The result showed that the scale of soil water migration velocity in the minipore permeation is 44～65 mm/d,the velocity in preferential flow is up to more than 450 mm/d. NO-3-N concentration is accumulated as a peak strip influenced by irrigation,fertilizer and crop absorption.The peak strip moves on and its average velocity is 56.3 mm/d.Under higher irrigation quota in the winter,the crops cannot absorb extra urea.The NO-3-N absorbed in upper layer leaches largely,and the 50% urea moves to the lower root zone with the pore water.Consequently it becomes the source of deep soil and ground water pollution. |
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