Sokoine University of Agriculture

Organic matter and humus characteristics of some volcanic ash soils of South western Tanzania

Show simple item record Msanya, B. M. Otsuka, H. Araki, S. Fujitake, N. 2017-12-18T10:53:35Z 2017-12-18T10:53:35Z 2010
dc.description Enhancing Dissemination of Soil and Water Research Outputs of SADC Universities en_US
dc.description.abstract This study was done on soils developed from volcanic parent materials including pumice and ashes originating from various volcanoes in and around the Rift Valley of South Western Tanzania. The soil moisture and temperature regimes in the area are udic and isothermic respectively. One pedon close to Lake Nyasa (Mwaya) had aquic SMR and isohyperthermic STR. Soil OC content varied widely among and within pedons, with surface horizons generally having higher values (high to very high). N levels also varied similarly and correlated very well with OC. C:N ratios were very variable and increased with increasing OC. Based on the distribution of OC, N, C:N ratios and the relationship among these parameters, the Tanzanian volcanic ash soils compare quite well with known Japanese volcanic ash soils, although the absolute values of OC were much higher for Japanese than for Tanzanian soils. Results on humic acid studies indicate that the soils predominantly contain A type humic acids particularly in the surface A horizon, buried A, AB and BA horizons. These horizons are characteristically humusrich with intense dark colors. UV-VIS absorption spectra revealed in some soils the presence of Pg fraction with absorption bands around (280), 450, 570 and 615 nm, which are normally associated with the presence of dihydroxyperylenequinone (DHPQ) nuclei responsible for the absorption bands at those wavelengths. On the basis of ∆log K, RF, HE, PQ values and the UVVIS absorption spectra, the characteristics of HAs of the Tanzanian volcanic ash soils compare very well with Japanese volcanic soils en_US
dc.language.iso en en_US
dc.publisher SADC Project en_US
dc.subject Organic matter en_US
dc.subject Humus characteristics en_US
dc.subject Volcanic ash soils en_US
dc.subject Tanzania en_US
dc.title Organic matter and humus characteristics of some volcanic ash soils of South western Tanzania en_US
dc.type Workshop Presentation en_US
dc.url en_US

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