Effects of Tillage and Bradyrhizobium Inoculation in Soybean/Maize Intercrop on Microbial Biomass and Water-Soluble Carbon in Samaru, Nigeria

  • K. C. Uzoma
  • J. O. Omeke
  • J. F. Akpan
  • G. O. Chukwu
Keywords: Tillage, Rhizobium inoculation, Soybean/Maize intercrop, Microbial Biomass and Water-soluble carbon


A field study was conducted during 2011 cropping season to investigate the effect of tillage practices and bradyrhizobium inoculation of soybean on microbial biomass carbon (Cmic), microbial biomass nitrogen (Nmic) and water-soluble carbon (WSC) in maize-soybean intercropping systems. Treatments comprised of two tillage practices (conventional tillage (CT) and reduced tillage (RT)) as the main plot and bradyrhizobium inoculation at four levels (inoculated soybean sole, inoculated soybean/maize intercrop, un-inoculated soybean sole and un-inoculated soybean/maize intercrop) as sub-plot. The treatments were laid in a split-plot under a randomized complete block design with three replications. Results showed that Cmic and Nmic were significantly higher under RT than CT by 31.97% and 17.28% respectively. The WSC was consistently higher in maize-soybean intercropping system with soybean inoculated with bradyrhizobium than in the un-inoculated plots. Values of WSC was 22% higher in inoculated sole soybean and 38% higher in inoculated maize-soybean intercrop than the un-inoculated sole and intercropping system respectively. Similarly, Cmic was 39.20% higher in the inoculated sole soybean than the un-inoculated sole and 24.43% higher in inoculated soybean/maize intercrop than in the un-inoculated soybean/maize intercrop. Also results of Nmic obtained under inoculated sole soybean and inoculated soybean/maize intercrop, respectively, were significantly higher than in un-inoculated sole soybean and soybean/maize intercrop by 45.13 and 56.78% rrespectively. The results demonstrated that inclusion of bradyrhizobium inoculants in soybean-maize intercropping systems under tillage practices will improve microbial biomass and water-soluble carbon, thereby enhancing the productivity of Alfisols of Northern Guinea Savanna of Nigeria.


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eISSN: 0300-368X