VIEWS: 0 PAGES: 2 POSTED ON: 2/16/2012
Title Activities of Rhizosphere Microorganisms as Affected by Application of Organic Amendments in a Calcareous Loamy Soil. 1. Carbon Assimilation Author/s F. N. Barakah, S. H. Salem, A.M. Heggo and M. A. Bin-Shiha Journal of Contact Info. Department Major Year of Publication 1995 Publisher Arid Soil Research and Rehabilitation Type of Publication Full Text (Yes, No) No Key Words Abstract The activities of soil microorganisms in the rhizosphere ( R ) and nonorhizosphere ( S ) regions of alfalfa and wheat plants, growing in calcareous loamy soil of Saudi Arabia, as influenced by application of organic amendments such as sludge and wheat straw, were studied in pot experiment for 7 weeks. The study showed that counts of aerobic heterotrophic bacteria in the rhizosphere soil of both alfalfa and wheat plants significantly increased due to application of organic amendments accompanied by a high decomposition rate for carbonaceous materials. Application of sludge to the soil enhanced the rhizosphere microorganisms during all experimental periods as compared with those treated with straw. Strow manure clearly enhanced the aerobic cellulose decopmosing bacteria, especially in the rhizosphere region. The total microbial counts in the rhizosphere of alfalfa were generally higher than those of the wheat plants in the first and second weeks and at the end of the period,especially when sludge was applied as an amendment . The densities of the total fungi, actinomycetes, and sporeformers were slightly affected by the rhizosphere soils, and the R/S ratios rarley exceeded 2.0. Soil treatment with either sludge or straw significantly increased the organic carbon and consequently, the organic matter of the soil, especially in the rhizosphere region with relatively higher values for those amended with straw.A high carbon-to- nitrogen ratio of the amendment to the soil was associated with slow decay of the organic matter. Ammendement of loamy soil with sludge at the common rate(2%) enhanced the microbial flora with no harmful effects to plant growth or soil fertility and can be used safely on agricultural land.
Pages to are hidden for
"227"Please download to view full document