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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comparative studies of selected semi-arid soils near Mosul, Iraq

Al-Juburi, Kadhim Daud January 1973 (has links)
No description available.
2

The decomposition of organic matter in relation to soil fertility in arid and semi-arid regions

Oberholzer, Obie January 1936 (has links)
No description available.
3

Fixation of nitrogen by algae and associated organisms in semi- arid soils; identification and characterization of soil organisms

Cameron, R. E. (Roy E.) January 1958 (has links)
No description available.
4

Dispersion and permeability of arid soils as affected by salt concentration and exchangeable cations

Abu-Fakhr, Mahmud Suleiman Sayyid Ahmad, January 1956 (has links) (PDF)
Thesis (M.S. - Agricultural Chemistry & Soils)--University of Arizona. / Bibliography: leaves 53-55.
5

Fixation of nitrogen by algae and associated organisms in semi- arid soils: identification and characterization of soil organisms /

Cameron, R. E. January 1958 (has links) (PDF)
Thesis (M.S. - Agricultural Chemistry and Soils)--University of Arizona. / Bibliography: leaves 106-129.
6

Characteristics and sorption properties of charcoal in soil with a specific study of the charcoal in an arid region soil of Western Australia /

McMahon, Claire Louise. January 2006 (has links)
Thesis (M.Sc.)--University of Western Australia, 2006.
7

The Productive Capacity of Semiarid Soils and the Present Emergency

McGeorge, W. T. 03 1900 (has links)
No description available.
8

Nitrogen Fixation, Ammonification, Denitrification in Great Basin Arid Soils

Klubek, Brian Paul 01 May 1977 (has links)
The inputs and losses of nitrogen from Great Basin arid soils were studied using the acetylene reduction and 15N techniques. Filamentous blue-green algae were observed to be the predominant algal group in the soil crusts. The bacterial association with this group of algae suggest a phycosphere-like effect, thus allowing heterotrophic nitrogen fixation and denitrification to occur. Up to 17.5 mg N/100 g soil was found to have been fixed in surface soils (0 to 3 em) during a three week incubation period, while 45.9 mg N/100 g soil was fixed in a five week incubation period. Ammonium sulfate and ammonium sulfate plus plant material amendments reduced the gain in nitrogen by 41 to 100 percent. 15 + 15 - Fifty to sixty percent of the applied NH4-N and N0 3-N was denitrified during the first week of incubation while 70 to 80 percent of the NH 4-N was lost in a three- to five-week incubation period. These data suggest that a potential for heterotrophic nitrogen fixation exists, and under optimal conditions, significant gains in soil nitrogen may be achieved. However, in the presence of allelochemic agents, the potential gain in soil nitrogen may be reduced or inhibited. In addition, the denitrification potentials of these soils may also limit the input of nitrogen. The application of protein ( casein) to these soils resulted in an ammonification rate of 50 to 60 percent. 15 Fixed N2 indicated a 21 to 48.8 percent ammonification rate, thus suggesting that the mineraliztion of NH 4 was the rate limiting step for nitrogen loss. Ammonia volatilization accounted for less than a five percent nitrogen loss, regardless of experimental conditions. The inhibitory effects of plant material and litter extracts, and ''N-Serve" on heterotrophic nitrogen fixation has been assessed. The data suggest that the nitrogen fixing population is sensitive to the inhibitory effects of such agents .
9

Artificial revegetation of sandy semidesert lands of southern New Mexico

Cassady, John Tom, 1909- January 1937 (has links)
No description available.
10

Characteristics and sorption properties of charcoal in soil with a specific study of the charcoal in an arid region soil of Western Australia

McMahon, Claire Louise January 2006 (has links)
[Truncated abstract] Fire creates charcoal from the partial burning of biomass which results in a biologically inert form of carbonaceous (non-living) organic matter that, once integrated into soil and sediments, can persist for long periods of time. Charcoal has a large surface area with a high sorptive capacity for organic and inorganic substances. As a repository for metal and non-metal elements charcoal has been given little, if any, attention in the fields of geochemistry, agriculture and environmental monitoring . . . Despite the differences in charcoal surface area, soil charcoal achieved nearly 100% sorption of 0.5 and 5 μg/g Au from 0.03 M NaCl and 0.01M Ca(NO3)2 solution, almost independent of solution pH. At low pH, charcoal sorbed between 10 and 60% of Cu with initial additions of 2 and 20 μg Cu/g. Similarly, between 15 and 40% of Zn was sorbed by charcoal with initial additions of 5 and 40 μg Zn/g. The role of surface area in sorption of elements by charcoal is clearly only one factor that is important. Charcoal aromatic and aliphatic chemical functional groups, which can be distinguished from other forms of organic matter through spectroscopic determination, are also important in charcoal’s capacity to sorb elements. Accumulation of Be, B, Na, Mg, Al, Si, K, Ca, Ti, Mn, Co, Ni, Cu, Se, Mo, Ba, Au and Pb (out of a range of 29 elements) in soil charcoal, above the concentrations in the matrix soil and plant reference charcoal, was confirmed by ICP-MS analysis. Concentrations of V, Mn, Co, Ni, Cu, Mo, Ba, Au, Pb and Bi were higher in soil charcoal than in values quoted for gossans and pisolites in the field area region (Smith and Perdrix, 1983). Higher values of Au in soil charcoal were associated with considerable amounts of included clay minerals and higher values of other elements including Mo, Mn and Fe.

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