الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
The current work aims at throwing some light on the effect of some organic wastes on the availability of phosphorus in calcareous soils as
well as its uptake by barley plants grown thereon. To fulfill these
purposes, surface soil samples (0-30 em) differing mainly in their
contents of CaC03 were collected from three locations along Cairo-
Alexandria desert road. The first location is about 100 Km from Cairo,
the second is adjacent to EI-Noubaria Seed Company and the third
location is El-Noubaria Agricultural Research Station. The organic
wastes used in this study were sewage sludge taken from Waste-Water
Treatment Plant, El-Gabal EI-Asfar and town refuse taken from Organic
Manure Plant (Shoubra).
The experimental work involved two experiments, i.e., an
incubation experiment and a greenhouse one.
In the incubation experiment, 200g portions of the investigated soils
were mixed with either of the tested organic wastes at a rate of 2% the
organic material Phosphorus was also added as KHZP04at a rate of 0,
50, 100 or 200 uglg. The aforementioned-treated soil samples were
incubated at two moisture levels, i.e., 60% and 100% of the saturation
percentage. Periodically, sub-samples from each treatment were taken
after 0, 1, 2, 4, 6 and 8 weeks of incubation, oven dried and divided into
two parts, the first was extracted with NaHC03 solution pH 8.5 (Oleson
- 76-
et al. 1954) to determine the available P content while the second part was
suspended in distilled water (l : 2.5 soil : water ratio) to be used for
measuring soil pH.
In the greenhouse experiment, plastic pots were uniformly packed
with 1 Kg portions of the investigated soils. The packed pots were
grouped in nine sets corresponding to the following treatments:
1. Control (untreated soil).
2. Soil mixed with sewage.
3. Soil mixed with sewage sludge + 50 p.gPIg.
4. Soil mixed with sewage sludge + 100 p.gPig.
5. Soil mixed with sewage sludge + 200 p.gPIg.
6. Soil mixed with town refuse.
7. Soil mixed with town refuse + 50 p.gPIg.
8. Soil mixed with town refuse + 100 p.gPIg.
9. Soil mixed with town refuse + 200 p.g PIg.
Twenty-five seeds of barley (Hordium vulgare, Giza 124) were
sown per pot, then thinned to 15 plants after the complete germination.
Throughout the period of experiment, moisture content at the desired
level of 60% of SP was maintained by daily addition of distilled water.
After 60 days, the upper parts of plants (2cm. above soil surface) were
cut, oven dried at 700C, dry matter yield was recorded, crushed and subsamples were wet digested for P determination.