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Tracing Nitrogen Movement in Corn Production Systems in the North Carolina Piedmont: A Nitrogen‐15 Study
Author(s) -
Crozier Carl R.,
King Larry D.,
Volk Richard J.
Publication year - 1998
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1998.00021962009000020009x
Subject(s) - agronomy , legume , mineralization (soil science) , nitrogen , red clover , fertilizer , growing season , nitrogen cycle , nitrification , leaching (pedology) , chemistry , biology , soil water , ecology , organic chemistry
Legume cover crops have been studied in the southeastern USA, but there have been no 15 N tracer studies comparing movement of legume N and fertilizer N for this region. Our study used l5 N‐enriched crimson clover ( Trifolium incarnatum L.) (135 kg N ha −1 ) and either 15 NH 4 NO 3 or NH 15 4 NO 3 (70 kg total N ha −1 ) to quantify N movement through soil inorganic and organic N pools and into corn ( Zea mays L.). Clover N mineralized rapidly, with 45% of the initially applied N detectable as inorganic N at 18 d following incorporation. Rapid nitrification of enriched NH + 4 occurred, but, since the soil NO ‐ 3 pool was larger in this treatment than in the enriched NO ‐ 3 treatment (presumably due to chance), the relative enrichment of the soil NO ‐ 3 pool was less than with the application of enriched NO ‐ 3 . At anthesis, 25% of the N in corn had been derived from the NO ‐ 3 source, while only 11% had been derived from the NH + 4 source (P < 0.05). At physiological maturity in 1990, the first growing season, 38 to 44% of each enriched source could be accounted for. By physiological maturity in 1991, 60% of the clover source but only 28 to 36% of the fertilizer sources could be accounted for. This study demonstrates the substantial amounts of endogenous soil N mineralization, inorganic N immobilization, and legume N persistence in these cropping systems.