الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
The effect of farmyard manure, town refuse compost
and sewage sludge on the chemical and biological properties
of alluvial and calcareous soils was investigated.
A weight of 60 g of each manure was added to 3 kg of
each soil in 4 replicates pot experiment. Soil samples
were taken at 0, 1, 2, 4, 6, 8, 10 and 12 weeks intervals
for microbial and chemical analyses.
Microbiological determinations comprised the counts
of total microbial flora, actinomycetes, fungi, aerobic
nitrogen fixers, CI. Easteuria~, nitrifiers and aerobic
cellulose decomposers. Soil samples were analysed for
total organic carbon content, total nitrogen, C/N ratio,
total available nitrogen, water soluble phosphorus,
available P and soil pH.
The obtained results were as follows:
1. The sOils under experimentation were clay and clay loam
textured for the alluvial and calcareous sails, respectively.
2. The application of organic manures slightly increased
the total microbial counts. Tbe sewage sludge was the
most effective in this respect in both alluvial and
calcareous soils. Similar results were noticed also
in the case of actinomycetes count.3. The numbers of the fungal colonies appearing on the
count plates showed lower densities in the treated
samples than the control of alluvial soil and the
lowest numbers were observed in the sewage sludge
treatment. This was attributed to the competition
between the bacterial and fungal population. However
the counts of fungi in calcareous soil treated with
organic manures were remarkably higher than those in
the control treatment.
4. The growth of aerobic nitrogen fixers represented by
azotobacter was enhanced by the application of organic
manures in both soils.
5. The used organic manures enhanced the growth of
Cl. pasteurianum when they were applied to the alluvial
soil~ while in the calcareous soil the counts were
almost similar to those of the control.
6. The addition of different organic manures enhanced
the nitrification process as indicated by the increase
of the nitrifying organisms. Also~ the counts of
aerobic cellulose decomposers were enhanced by the
application of organic manures.
7. The application of different organic manures clearly
increased the organic matter content of the two. soils
in the order: Sewage sludge ) Town refuse compost ”/
Fa rmya rd manu re •
8. The total ni~rogen content of the two tested soils
was increased as a result of the addition of organic
manures and also during the course of experiment.
9. The C/N ratio of the soil treated with sewage sludge
showed the lowest value followed by farmyard manure then
town refuse compost which showed also lower value than
control.
10. The application of sewage sludge to the alluvial soil
was more effective than either farmyard manure or town
refuse compost in regard to their enhancing effect on
nitrogen availability. The results of available nitrogen
in the calcareous soil showed decreasing amounts, sewage
sludge showing the sharpest decrease in this concern.
11. The level of soluble P fraction in both allUVial and
calcareous soils was not significantly affected by organic
manu ring. At certa in inte rvals ~ 0 rganic manu ring reduced
the soluble fraction of soil P as compared with the control
treatment. Such trend can be attributed to a decrease
in P potential because of P adsorption on effective
organic compounds.
12. The application of different organic manures increased P
availability in both alluvial and calcareous soils~
especially in the first intervals. Sewage sludge was more
effective in this respect then both _anures on- b~th types
of .soils.13. The application of sewage sludge to the alluvial
soil lowered its pH than did farmyard manure or town
refuse compost, while manuring the calcareous soil
exerted, in general, slightly higher figures of pH
values as compared with the control treatment through
most of the sod L samples removed.