Premium
Disposition of Fertilizer Nitrate Applied to a Swelling Clay Soil in the Field
Author(s) -
Kissel D. E.,
Smith S. J.,
Dillow D. W.
Publication year - 1976
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1976.00472425000500010015x
Subject(s) - fertilizer , lysimeter , leaching (pedology) , sorghum , drainage , environmental science , soil water , agronomy , irrigation , nitrate , dns root zone , chemistry , soil science , ecology , organic chemistry , biology
This study was prompted by the present controversy over the role that N‐fertilizer use may have in reducing water quality. Our objective was to determine the disposition of N fertilizer (enriched with 15 N) applied to level (< 2% slope) Houston Black clay near the economic optimum application rate (112 kg N/ha) for grain sorghum ( Sorghum bicolor [L.] Moench). 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 NO 3 − ‐N below the root zone. During spring 1973 94 mm of drainage water containing a mean concentration of 2.4 ppm fertilizer‐derived NO 3 − ‐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 fall and winter approximately 120 mm of drainage water containing 0.5 ppm or less fertilizer‐derived NO 3 − ‐N percolated through the soil profile. These results indicate that for rainfall conditions observed in this study (minimal crop water deficit), the application 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.