الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Two pot experiments were carried out in Plant Nutrition Greenhouse, Agriculture Research Center, by using sorghum plants grown on sandy and calcareous soils to study the effect of different sources of organic manures alone or in combination with rock phosphate on the rya:lability of N and Pin the sc,:],s anti their uptake by plants. The first experiment (incubation) was performed to
ifivestigate the effect of adding manure treatments on the
chemical availability of N and P in the two studied soils.
The second experiment (cultivation) was conducted to study
the effect of different manures on the availability and uptake
of N and P by sorghum plants.
Three sources of organic manures namely: Qattamia, Biogreen and Nile manures were added with two rates of 2 °A) and 4%, while rock phosphate was added by 2%. The obtained results could be summarized as follows:
1- Application of Nile compost 4% in combined with rock phosphate treatments increased organic matter content for both two soils a.td was r.-ore effective than that of Qattamia
and Biogreen manures.
S., I NI N: A in1
2-Application 4. different organic manure treatments to soils alone or in combination with rock phosphate decreased
soil pH values in the two studied soils.
3-The highest decrease of soil pH was obtained when organic manures ..were applied at highest rate (4%) in
combination with rock phosphate.
4-Generally, application of Nile compost was more effective in decreasing soil pH than Qattamia and Biogreen
manures in both two soils.
5-The values of available N and P increased by the application of various treatments, while Nile compost was more effective in increasing the availability of N and P than Qattamia and Biogreen manures for both two soils.
6-Application of either organic manures alone or in combination with rock phosphate to soils increased available content of Fe, Mn, Zn, and Cu in the studied soils. -
7-Application of different organic manure treatments to soil alone or in combination with rock phosphate increased various nitrogen forms (Nri4 and NG3) in the sandy soil.
8-Application of different orgailic manure treatments to the • calcareous soil alone or in combination, with rock phosphate
increased nitrogen in form (N- NO3), while nitrogen (N -NH4 ) decreased in all treatments.
9-Application of organic manure treatments to the studied soils combined with or without rock phosphate increased available phosphorus released in the two studied soils for all treatments.
10-The highest values of plant height were achieved due to the treatments of Nile compost 4% in sandy and calcareous soils. Same trend was obtained with addition rock phosphate.
11-The relative increase percent of plant height in response to organic manures was more obvious in sandy soil than in the calcareous one, although the values of plant height were higher in calcareous soil.
12-Application of organic manure treatments to the studied soils combined with or without rock phosphate increased the sorghum plant dry weights over the control treatments.
13-The greatest growth value was recorded in Nile compost 4% in combined with rock phosphate treatment. However, Nile compost 4% in combined with rock phosphate treatment was more effective in increasing sorghum growth
than Qattamia and Biogreen manures.
14-The dry weights of the sorghum plants grown on the calcareous soil were generally higher than the obtained of the sorghum plants grown on sandy soil.
15-Application of different organic manure treatments to the studied soils alone or in combination with rock phosphate increased N-uptake by sorghum plants in all treatments as compared to the control treatment.
16-Addition of different organic manure treatments to the soils alone or in combination with rock phosphate increased P - uptake by sorghum plants in all treatments as compared to the control treatment.