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Nitrate Leaching from Grassed Lysimeters Treated with Ammonium Nitrate or Slow‐Release Nitrogen Fertilizer
Author(s) -
Owens L. B.,
Edwards W. M.,
Van Keuren R. W.
Publication year - 1999
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/jeq1999.00472425002800060017x
Subject(s) - lysimeter , leaching (pedology) , nitrate , fertilizer , nitrogen , ammonium nitrate , ammonium , chemistry , zoology , volatilisation , agronomy , environmental chemistry , environmental science , soil water , soil science , biology , organic chemistry
Nitrate leaching is a potential in humid regions when crops and forages are fertilized. This study was conducted to compare NO 3 leaching with two different N fertilizer formulations applied to forages. For 11 yr, ammonium nitrate (AN) was applied to a large (8.1 m 2 surface area), undisturbed, monolithic lysimeter Y101B at an annual rate of 168 kg N ha −1 , and methylene urea (MU), a slow‐release fertilizer, was applied to a similar lysimeter (Y101D) at the same rate. Nitrate‐N concentrations in the percolate from these 2.4 m‐deep lysimeters were measured weekly. Even though NO 3 ‐N levels increased steadily with the AN applications, the greatest increases occurred during the eighth year of treatment and reached levels above 20 mg L −1 . With the MU, NO 3 ‐N concentrations remained relatively constant until after 8 yr of treatment, reaching concentrations of 6 mg L −1 . The highest rates of annual NO 3 ‐N transport in percolate were 42.3 and 12.1 kg ha −1 from lysimeters treated with AN and MU, respectively. (Losses from NH 3 volatilization were measured at 12.0 and 44.8 kg N ha −1 for AN and MU, respectively.) Nitrate‐N transport in percolate varied seasonally with the greatest amounts being moved during the late winter‐early spring. Following 11 yr, the NO 3 ‐N concentrations in each lysimeter declined to approximately 1 mg L −1 . Based on this study with a 168 kg N ha −1 annual application rate, less NO 3 ‐N leaching will occur when a slow‐release N fertilizer, such as MU, is applied to forages than when AN is applied.