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The Effect of Ammoniacal Nitrogen on Lettuce (Lactuca sativa) and Radish (Raphanus sativus) Plants
Author(s) -
Weir B. L.,
Paulson K. N.,
Lorenz O. A.
Publication year - 1972
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1972.03615995003600030028x
Subject(s) - lactuca , raphanus , nitrogen , chemistry , dry matter , ammoniacal nitrogen , nutrient , horticulture , botany , biology , organic chemistry
Abstract The relationship of the growth of radish and lettuce plants to pH, NH 3 , and NH 4 + concentration of the nutrient solution was determined by the use of stepwise multiple regression. Data were collected from plants grown in nutrient solutions with a factorial arrangement of pH (6, 7, and 8) and ammonical nitrogen (0, 10, 20, 30, 40, 60, and 90 ppm of N). The equations obtained for radish and lettuce, respectively, were: Y = 0.479 + 0.00242 X 1 3 + 0.0207 X 2 − 0.605 X 3 + 0.0133 X 3 3 + 0.0200 X 4 − 0.000746 X 4 2 + 0.551 X 4 3 and Y = 5.571 − 0.551 X 1 − 0.00111 X 2 3 − 0.605 X 3 + 0.0171 X 3 3 + 0.0428 X 4 − 0.000753 X 4 2 + 0.327 X 4 3 where Y was grams of dry matter/plant, X 1 was pH, X 2 was H + cone x 10 7 , X 3 was NH 3 conc. (ppm of N) and X 4 was NH 4 + conc. (ppm of N). Both equations were significant at the 0.5% level and had R 2 's of 0.575 and 0.646, respectively. The response of the two species to pH and H + differed, with radish having its optimum growth at pH 8 and lettuce at pH 7. Their responses to NH 3 and NH 4 + were very similar. Growth was reduced as the NH 3 conc. increased and was increased as the NH 4 + conc. increased to an optimum level of 17 ppm of NH 4 + ‐N for radish and 36 ppm for lettuce.