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Measurement of microbial numbers, activity, biomass and diversity as a response to different methods of treatment of Tanzanian soil

Grimsby, Lars Kåre (2005) Measurement of microbial numbers, activity, biomass and diversity as a response to different methods of treatment of Tanzanian soil. Thesis, Norwegian University of Life Sciences, Department of Chemistry, Biotechnology and Food sciences. . [Unpublished]

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Summary

Microbial biomass, numbers, activity and diversity were measured in tropical agricultural soil in Tanzania throughout the growth season of maize (Zea maize). Four farmers each had three plots that were subject to three different methods of treatment to improve soil fertility: 1) Removal of plant residues and other organic material, tilling to 10 cm, and adding nitrogen (60 kg pr ha) and phosphorus (40 kg pr ha). 2) Tilling organic plant material, such as maize residues, 10 cm into the soil, without adding fertilizer. 3) Collecting residues in heaps and burning them. No added fertilizer and no tillage. During the growth season, the total biomass and activity of the microflora increased as a response to higher soil water levels due to the rainy season. The microflora was also investigated to see whether there was any difference between the four farmers’ soil types, and it was found that the total microbial biomass were in correlation with the organic carbon content in each of the four soil types. It was also found that the ratio between fungi, actinomycetes and bacteria was the same for all the four soils. The measurement of microbial activity by soil respiration was influenced by the different soil types’ texture. When comparing the three different methods of treatment, it was found that burning organic material on the soil without tilling gave the greatest numbers and biomass. The combination of removing residues, tilling and fertilizing with inorganic fertilizer decreased the soil microflora most. And tilling and incorporating plant residues gave numbers and biomass between the two extremes.

Summary translation

One of the treatments (2) was close to an organic farming practice.

EPrint Type:Thesis
Thesis Type:Master thesis
Keywords:Microbial biomass, Microbial numbers, Microbial activity, Microbial response, Tanzania, Small scale farming, Soil Organic Matter, Tropical soils, Rhodic ferrasol, Maize residues, Soil texture
Subjects: Crop husbandry > Weed management
Soil > Soil quality > Soil biology
Crop husbandry > Soil tillage
Research affiliation: Norway > UMB - Norwegian University of Life Sciences
Deposited By: Grimsby, Lars Kåre
ID Code:10378
Deposited On:03 Apr 2007
Last Modified:12 Apr 2010 07:34
Document Language:English
Status:Unpublished
Refereed:Not peer-reviewed

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