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ARS Home » Research » Publications at this Location » Publication #72698
Title: NITRATE LEACHING FROM LYSIMETERS TREATED WITH AMMONIUM NITRATE OR SLOW RELEASE NITROGEN FERTILIZER

Author
item Owens, Lloyd

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Large, undisturbed, monolithic lysimeters (8.1 m**2 surface area) were used in a multi-year study of NO3 leaching under forages. For 5 years, 56 kg N/ha was annually applied (as NH4NO3). During each of the next 11 years, methylene urea, a slow release fertilizer, was applied to a lysimeter (Y101B) and NH4NO3 was applied to another lysimeter (Y101D) at an annual rate of 168 kg N/ha. Nitrate-N concentrations in the percolate from these 2.4 m-deep lysimeters were measured weekly. The soil is a well-drained silt loam on a 23 percent slope. Nitrate transport varied seasonally with the greatest amounts being moved during the late winter/early spring. Nitrate-N concentrations were below 3 mg/L during the first 5 years. Even though NO3-N levels increased steadily with the high NH4NO3 treatment, the greatest increases occurred after 8 years of treatment, and reached levels above 20 mg/L. With the methylene urea, NO3-N concentrations remained relatively constant until after 8 years of the higher treatment, reaching concentrations of 7 mg/L. Following high fertilizer treatments, no N fertilizer was applied. Within 2 years, the NO3-N concentrations in each lysimeter fell to approximately 1 mg/L.