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Nitrate‐nitrogen Removal from Soil Profiles by Alfalfa
Author(s) -
Mathers A. C.,
Stewart B. A.,
Blair Betty
Publication year - 1975
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/jeq1975.00472425000400030026x
Subject(s) - medicago sativa , sowing , nitrogen , nitrate , agronomy , manure , yield (engineering) , tonne , crop , environmental science , zoology , chemistry , biology , materials science , organic chemistry , metallurgy
Alfalfa ( Medicago sativa L. ‘Cody’) was established in the fall of 1971 on plots previously treated with 0, 22, 45, 112, or 224 metric tons/ha of manure annually for 3 years. Additional plots had received 224 kg N/ha (as NH 4 NO 3 ) annually for 3 years. Nitrate‐nitrogen and water contents of the soil profile were determined by 30‐cm increments to 6 m prior to planting. Nitrate‐nitrogen was found to 6 m, but the largest concentrations were in the top 1.8 m, where amounts of NO 3 − ‐N varied from 100 to 2,400 kg/ha. Additional profile samples were taken in 1972 and 1973 after the final cutting of alfalfa. The data showed that alfalfa removed water and NO 3 − ‐N to a 1.8‐m depth the first year and to 3.6 m the second year. These results indicate that alfalfa could remove NO 3 − ‐N from the lower depth of soil profiles where annual crops were not effective. Yield, NO 3 − ‐N, and P contents of alfalfa were increased by manure. Total N taken up by the crop was directly related to the yield.