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Leaching of15N‐labeled fertilizer nitrate in undisturbed soil columns after simulated heavy rainfall

 

作者: Martti Esala,   Aku Leppänen,  

 

期刊: Communications in Soil Science and Plant Analysis  (Taylor Available online 1998)
卷期: Volume 29, issue 9-10  

页码: 1221-1238

 

ISSN:0010-3624

 

年代: 1998

 

DOI:10.1080/00103629809370022

 

出版商: Taylor & Francis Group

 

数据来源: Taylor

 

摘要:

A laboratory experiment was conducted at +5°C with undisturbed columns (0.19 m i.d., 0.60 m long) of fine sand, heavy clay, and peat to determine the effect of soil and timing of the rainfall event on the amount of fertilizer nitrogen (N) that might be leached after fertilizer application. The15N‐labeled calcium nitrate [Ca(NO3)2] equal to 120 kg N ha‐1was applied 13 or 1 days before adding a total of 70 mm of water. Drainage water was collected through an inlet attached to the bottom of each column until drainage had ceased nine days later. From the sand columns, 27 and 19% of the fertilizer nitrate‐nitrogen (NO3‐N) applied was leached out when the columns were irrigated 1 and 13 days after fertilizer application, respectively. From the three water‐permeable clay columns containing earth worm burrows, 23 and 53% of the fertilizer NO3applied was leached out when irrigation took place 1 and 13 days later, respectively; the other five clay columns were impermeable. Less than 0.1% of fertilizer NO3was leached out from the peat columns with either incubation treatment. After the experiment, the content of fertilizer N was highest at a depth of 0.12–0.24 m in the peat and clay columns, and at a depth 0.24–0.33 m in the sand columns. In the sand and peat columns, less fertilizer N moved down in the column when soil and fertilizer were incubated before irrigation. It is concluded that in a rainy and cool spring, substantial amounts of fertilizer N can be leached beyond the reach of plant roots and out of the soil profile. The time passing between fertilizer application and rain may reduce the risk of leaching of applied N at low temperatures by diffusion into smaller soil pores rather than by biological immobilization. With the intensity of irrigation applied here, fertilizer N moved down in the sand and clay columns as bypass flow and hydrodynamic dispersion, whereas in peat columns it tended to move more as a front.

 

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