Acidity produced by leguminous plants through symbiotic dinitrogen fixation

Journal Article · · Journal of Environmental Quality; (United States)

DOI:https://doi.org/10.2134/jeq1989.00472425001800040025x· OSTI ID:5946323

Liu, Wencheh; Lund, L J; Page, A L ^[1]

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1. Univ. of California, Riverside (United States)

Red clover (Trifolium prateuse L.), sweet clover (Meliotus alba Medik.), alfalfa (Medicago sativa L.), and crown vetch (Vica villosa Roth) were grown in nitrogen-free Hoagland's solution in a declining nutrient condition. Increases in acidity of the nutrient solutions were recorded over the experimental period. In general, the excess bases and the excess bases/nitrogen ratio varied considerably among harvests. Significant positive relationships between total N and proton efflux, excess bases and H+ excretion, and dry weight and H+ efflux were observed. The milligrams H+ produced per gram N fixed for the four legumes were 49 for red clover, 43 for crown vetch, 42 for alfalfa, and 37 for sweet clover. By extrapolating the protons produced per gram dry weight in this study to yields commonly observed in the field, annual hydrogen production per hectare would amount to 9.7 kg for red clover, 4.6 kg for sweet clover, 15.2 kg for alfalfa, and 4.5 kg for crown vetch. The amounts of acidity produced per hectare per year calculated from the values of N{sub 2} fixation were 5.2 to 14 kg by alfalfa, 4.2 to 9.4 kg by red clover, 3.2 to 7.1 kg by sweet clover, and 3.9 to 6.8 kg by crown vetch. The study demonstrates that production of H+ through symbiotic fixation by legumes is an important source of acidity in agricultural ecosystems. The acidifying effect of legumes could, in the long-term, result in acidification of the bulk soil causing the downward leaching of exchangeable cations and a decrease in base saturation.

• OSTI ID: 5946323
• Journal Information: Journal of Environmental Quality; (United States), Vol. 18:4; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALFALFA
NITROGEN FIXATION
CLOVER
SOILS
ACIDIFICATION
VICIA
AGRICULTURE
HYDROPONIC CULTURE
LEACHING
PLANT GROWTH
SYMBIOSIS
DISSOLUTION
GROWTH
INDUSTRY
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
PLANTS
SEPARATION PROCESSES
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology