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Journal of Environmental Quality Abstract - Waste Management

Growth of Alfalfa in Sludge-Amended Soils and Inoculated with Rhizobia Produced in Sludge


This article in JEQ

  1. Vol. 31 No. 4, p. 1339-1348
    Received: July 6, 2001

    * Corresponding author(s): tyagi@inrs-eau.uquebec.ca
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  1. F. Ben Rebaha,
  2. D. Prévostb and
  3. R.D. Tyagi *a
  1. a Université du Québec, Institut national de la recherche scientifique (INRS-Eau), 2700 rue Einstein, Sainte Foy, QC, Canada G1V 4C7
    b Centre de recherche et de dévolppement sur les sols et les grandes culture, Agriculture et Agraoalimentaire Canada, Sainte Foy, QC, Canda G1V 2J3


The efficiency of rhizobial inoculants produced in wastewater sludge used as a growth medium and as a carrier was compared with that of inoculants produced in yeast mannitol broth (YMB) medium and by using peat as a carrier. Alfalfa (Medicago sativa L.) plants were inoculated with solid and liquid Sinorhizobium meliloti inoculants and grown in pots containing two soil types (Kamouraska clay soil and Saint-André sandy soil). The effect of various levels of sludge amendment (60 and 120 kg N/ha) and nitrogen fertilizer (60 kg N/ha) was also studied. The sludge-based inoculants showed the same symbiotic efficiency (nodulation and plant yield) as YMB-based inoculants. The inoculation increased the nodulation indexes from 4–6 to 8–12, and the rhizobial number from 103 (uninoculated soils) to 106–107 cells/g in inoculated soils. However, the shoot dry weights and the nitrogen contents were not increased significantly by the inoculation. Applying sludge as an amendment enhanced the rhizobial number in soils from 103 to 104 cells/g and improved significantly the plant growth (shoot dry weights and nitrogen contents). This improvement increased with sludge rate and with the cut (three cuts). Compared with sludge, N fertilizer gave lower plant yields. The nodulation was not affected by sludge and N-fertilizer application. The texture and physico–chemical properties of soil were found to affect the yield and nitrogen content of the plants. In this study, macroelements and heavy metals were at acceptable levels and were not considered to be negative factors.

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Copyright © 2002. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.31:1339–1348.