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Disposal of Feedlot‐Lagoon Water by Irrigating Bromegrass: II. Soil Accumulation and Leaching of Nitrogen
Author(s) -
Olson R. V.,
Terry R. V.,
Powers W. L.,
Swallow C. W.,
Kanemasu E. T.
Publication year - 1982
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/jeq1982.00472425001100030016x
Subject(s) - leaching (pedology) , irrigation , feedlot , nitrogen , agronomy , environmental science , lysimeter , soil water , drainage , zoology , chemistry , soil science , biology , ecology , organic chemistry
This field experiment measured the role of soil accumulation and leaching of N when bromegrass ( Bromus inermis ) was irrigated with beef‐feedlot‐lagoon water. The 4‐year study included three replications at irrigation rates of 0, 2.5, 5.1, 7.6, and 10.2 cm irrigation −1 . The heaviest irrigation added 1,890 kg N ha − during the 4 years. Microplots encased in steel pipes in the main plots received 5.1‐ and 10.2‐cm irrigations with lagoon water enriched with ( 15 NH 4 ) 2 SO 4 . With the main plots, there were no significant differences in total or inorganic soil N due to treatments. Profile contents of total N in the microplots increased during the experiment with 10.2‐cm irrigations, and decreased with 5.1 cm. Amounts of leaching were small and were related to drainage from the profile rather than quantities of N added. Leaching did not constitute a significant hazard to underground water supplies. The linear relationship between amounts of labeled NH 4 + ‐N added and labeled N found in the soil to 70 cm deep was highly significant. Most of the labeled N was in the 0‐ to 10‐cm soil layer with 88–94% of it immobilized in organic forms. The N balance after 4 years for the 5.1‐cm treatment showed 28% of the labeled N applied as NH 4 + was in the soil profile, 41% used by the crop, 31% lost as a gas, and 0.7% leached below 105 cm. With the 10.2‐cm treatment, 20% was in the soil, 38% used by the crop, 40% lost as gas, and 1.3% leached.