Kissel, D.E. and Smith, S.J. and Dillow, D.W. (1976) Disposition of fertilizer nitrate applied to a swelling clay soil in the field. Journal of Environmental Quality, 5 (1). pp. 66-71.
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Abstract
This study was prompted by the present controversy over the role that N-fertilizer use may have in reducing water quality. The objective was to determine the disposition of N fertilizer (enriched with 15N) applied to level (<2% slope) Houston Black clay near the economic optimum application rate (112 kg N/ha) for grain sorghum. Particular emphasis was placed on determining the amount of applied N which leached below the root zone at different times during and after the growing season. A large, undisturbed, field-drainage lysimeter was used to measure leaching of NO3--N below the root zone.During spring 1973 94 mm of drainage water containing a mean concentration of 2.4 ppm fertilizer-derived NO3--N percolated through the soil profile. At crop maturity, only 55% of the N applied the previous spring was recovered by the crop or was present in drainage water. Large amounts of N not recovered by the crop were either measured as immobilized N (20% of the applied N) or were unrecovered and assumed denitrified (17%). During the fall and winter approximately 120 mm of drainage water containing 0.5 ppm or less fertilizer-derived NO3--N percolated through the soil profile. These results indicate that for rainfall conditions observed in this study (minimal crop water deficit), the application of N fertilizer to grain sorghum at the near-optimum economic rate probably will not seriously reduce ground-water quality on a swelling clay soil, even though crop recovery of applied N may be low
| Item Type: | Article |
|---|---|
| Author Affiliation: | Texas Agricultural Experiment Station, Texas A & M University, College Station, Texas, USA |
| Subjects: | Social Sciences |
| Divisions: | Sorghum |
| Depositing User: | Ms K Syamalamba |
| Date Deposited: | 18 Jul 2012 09:28 |
| Last Modified: | 18 Jul 2012 09:28 |
| Official URL: | http://dx.doi.org/10.2134/jeq1976.0047242500050001... |
| URI: | http://eprints.icrisat.ac.in/id/eprint/6857 |
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