Measurement of water and nitrogen fluxes in soil profiles planted to maize
A field experiment to study the flux of water and nitrogen from the root zone of maize during growth and the following fallow period is described. The experiment includes four rates of fertilizer applied as $sup 14$N in $sup 15$N- depleted NH$sub 4$SO$sub 4$, and three irrigation regimes. Tensiometers for measuring soil water pressure, neutron probes for measuring soil water content and suction probes to obtain soil solution samples are located in the experimental area. Water is supplied by sprinkler irrigation. Results demonstrate the responsiveness of the instruments and the wide differences in water movement out of the root zone. Nitrogen losses are largest under the wettest treatment although very little of the N lost appears to have been derived from the fertilizer applied at the beginning of the experiment. The fate of nitrogen in the Soil-Water-Plant system is partially controlled by the behaviour of the water in the soil. Previous work has shown that the soil water content and the soil water flux must be considered when accounting for microbial transformations, movement of nitrogen in the soluble and gaseous forms, mixing of solutes in homogeneous and non-homogeneous soil profiles and transport of this nitrogen out of the root zone and the extraction of nitrogen by plants. (auth)
- Research Organization:
- Univ. of California, Davis
- NSA Number:
- NSA-33-007651
- OSTI ID:
- 4146872
- Country of Publication:
- IAEA
- Language:
- English
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