الفهرس 
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Abstract
The conducted work included two main parts Le. i), the recycling of
some organic residues through compost processing, and ii), investigating the
impacts of using such produced composts for inducing the safe agricultural
production.
The two parts of the work i.e. the composting trial and the biological
experiment as well as the main results and conclusions of both of them are
briefly presented as follows:
1- Composting experiment-
This experimental included the production of three compost mixtures
(co-composts) that were produced from the materials, Bagasse (8), Beet tops
(BT), rice straw (R8) and sewage sludge (88).
These residues were mixed at weight ratios of:
Compost Mix. I
Compost Mix. II
Compost Mix. II
3 (B): 1(BT): 2 (88)
5 (B) : 4 (88)
4 (R8) : 2(BT) : 1 (88)
The used residues were mixed at the above mentioned ratios to attian
comparable initial CIN ratios of about 30: 1 through all the tested heaps,
before composting.
The composting process was conducted for 16 weeks Le. 112 days
whereas the final CIN ratios were 12.4, 13.0 and 14.2 for the three types of
produced co- compost, respectively.
Physical and chemical analysis were determined during the
composting process, including bulk density, moisture content, dry matter,
organic matter, total nitrogen ammoniacal nitrogen (NH4+-N), nitrate (N03
” _ N)
pH, EC, CEC and C/N ratio, at the periods of 0, 1, 2, 4, 6, 8, 12 and 16
weeks.
The changes in temperature degrees were recorded daily at three
different depths (20, 40 and 60 em). Total bacterial counts, actinomycetes,
Fungi (mesophilic and thermophilic) and Pathogenic bacteria (Total and
faecal coliform), Salmonella and Shigella were determined during
composting at the periods of 0, 1, 2, 4, 8, 12 and 16 weeks.
The produced co-composts were subjected to physical and chemical
analysis as well as to counting of different microbial types at specific intervals
of composting where the results obtained revealed mainly the followings:
A- Physical and chemical changes:
1) Through the thermophilic stage (1.0 to ~ 40-45 days) the temperature was
raised particularly at the depths of 60 and 40 cm to reach maximum
range of 70-78 °C after a range of 2-10 days from composting start.
The initial mesophilic stage did not exceed about one day after
composting start thereafter occurred again as the thermophilic stage was
faded where its duration extended for about 40-45 days with temperature less
than 45°C and higher than 30 DC. However the cooling down and, maturation
stage, i.e, of temperature less than 30°C occurred after about 80 days from
composting beginning. Thereafter, the composting materials for three heaps
were approximately at the same temperature of the surrounding air (~25 DC)
and until the end of the experimental period.
2) Values of bulk density of the different materials recorded through the
composting process showed a gradual increase with composting
development ranging from 367 to 705, from 429 to 644 and from 457 to
791 kg/m3
for co- camp I, II and III, respectively.
3) The pH values of the piles showed initial reduction to reach minimum pH
values of about 6.75- 6.90 after three weeks of compost processing,
thereafter tended to be increased to reach maximum values of 7.80, 7.44
and 8.20 after 8t 8 and 16 weeks of composting for co- composts It II and
Ill, respectively.
4) The EC values of the different compost mixtures tended to be slightly and
gradually increased during the initial four weeks of composting. The EC
values, in general ranged between of minimum and maximum values of
5.42 - 6.82,2.22 - 4.78 and 7.25 - 9.0 dSm-1 for the three compost Mix. I,
II and III respectively. Such variation could be explained on the net
nutrient ions release and immobilization phenomena taking place through
wastes decomposition.
5) Results showed that the decomposition rates of the organic matter was
slowly increased during the first week of the composting period, then
rapidly increased to show maximum value in the third week for piles Mix. I
and Mix. II and fourth week for pile Mix. Ill. Thereafter it decreased
rapidly towards the end of the composting per.iQdas a result of microbial
activities.
6) Results showed that the losses in organic matter and compost dry weights
were 74.57 and 61.11 % for pile mix 1,73.47 and 59.37 % for pile Mix II
and 70.46 and 52.52 % for pile Mix III after 16 weeks of the compost
beginning respectively. Also, the initial percentage of the oryanic matter
decreased from 81.94 to 53.57 %, from 80.82 to 52.79 % and from 74.55
to 46.39 %for the compost Mix. I. II and III respectively after 16 week.
7) As a result of the higher bio-oxidation of the easily decomposable
,~ carbonaceous substrates, the initial percentage of total nitrogen increased
gradually throughout the composting period from 1.60 to 2.51 % for pile
Mix. I, from 1.53 to 2.35 % for pile Mix. III and from 1.46 to 1.90 % for pile
Mix. HI, respectively. While the nitrogen content showed maximal losses
of 39.31 and 39.97% for piles Mix. 1 and Mix II of after 8 weeks of
composting, while this maximum for pile Mix. III was 41.12 % after 12
weeks of the composting period.
8) Ammoniacal nitrogen showed gradual increases during the first four weeks
to reached maximal concentrations of 1060, .980 and 679 mg/kg fresh
weight for the piles Mix. 1, II and HI respectively: ’Thereafter, the
concentration of ammonia decreased rapidly until the end of the
composting period to reach minimal values of 23, 15 and 26 mg/kg fresh
weight for the piles Mix. 1, II and III respectively. While the nitrate
showed gradual decreases during the first four weeks of composting.
Thereafter all ecorded three piles increasing towards the end of
composting peri
9) The values of e N ratio showed higher reduction during the first four
weeks of camp sting process, little decreases towards the end of
composting peri were observed. This is true for all compost mixtures,
where the C/N r tio narrowed from initial values of 29.7,30.6 and 29.6 to
final values of 12.4,13.0 and 14.2 for compost products of Mix. I, II and III
respectively.
10) The cation e change capacity (CEC) for all piles showed gradual
increase throughout the composting. The CEe values increased from
31.3, 34.6 and 29.4 me/100g TS compost at initial time to 66.4, 71.8 and
58.9 rne/100 g compost after 16 weeks of the composting process for the
piles Mix., 1, II and 11Irespectively. Thus, there is a highly significant
negative correlation between the data of GEG and GIN ratio collected from
the three pile mixtures during composting.
8- Changes in the microbial population:
1) The numbers of mesophilic total viable bacteria actinomycetes and fungi,
in general were slightly higher than those of thermophilic ones at the
initial of composting.
By composting development and temperature inducing, the numbers of
the thermophilic types tended to be higher, showing a maximum peak at the
third and four weeks as compared with the mesophilic microbes which were
minimized.
As result of temperature decreased the mesophilic microbial Counts
proliferated rabidly and their number increased and reached maximum at 81t1
to 12l!Jweeks of composting in all piles.
However after about 6 weeks of composting both types showed almost
comparable values whereas this tend was upset later on and till the end of
the composting process where the mesophilic types serious.ly exceeded the
thermophilic ones.
2) As for the pathogenic bacteria were gradually decreases with composting
development where the numbers of total coliform bacteria were not
detected at dilution 10.1 after the alb week for co-compost piles I. If and
for co-compost piles III after 121b weeks of composting. However the fecal
coliform tended to be more persistent at the eighth week, they were not
detected dilution 10-1 after 12 weeks of composting. While salmonella &
shigella disappeared after the a!!:l week of composting in the three pile
mixtures.
II. Greenhouse Experiment:
This experiment was conducted to investigate the reliability of
”4ft
substituting either partly or entirely, the previously produced composts
instead of mineral N fertilizer as a source of N for growing plants.
Wheat (Sakha 69 Var.) was grown in pots packed with light textured
soils of lower lime content and higher lime content.
The tested control treatment received the recommended rate of N
requirements of wheat in the area as a mineral source (120 kg N/fad as
NH4N03). The other treatments included increasing rates of compost N that
were added on the expense of the mineral source i.e. 30, 60, 90 and 120 kg
organic N per fed combined with 90, 60, 30’ and zeio’-kg mineral N,
respectively. In all cases the pots received the recommended dozes of P and
K.
Plants were grown for five months, removed and subjected to
recording the different yield parameters as well as to the analysis of macro
and micro nutrients in plants and also study in their effect of the tested
treatments on the count of soil microflora (bacteria, actinomycetes, fungi and
pathogenic. bacteria) were estimated at the periods of 0, 15, 3D, 60, 90, 120
and 150 days from wheat seeding.
The obtained results could be briefly summarized in the following:
A- Yield of wheat grain and straw:
1- The wheat grain yield from the soil of the higher CaC03 content (Soil II),
significantly surpassed that of lower CaC03 content (Soil).
The highest yield of wheat grain as well as straw in both soils was
achieved with the combined treatment consisted of 90 kg mineral N source
and 30 kg N from organic compost. However, the different rates of mixing the
mineral and organic sources all of these combinations showed a more
positive effect over the single application of either N form. Accordingly it may
be concluded that substituting the nature organic N source (compost N) for
more than 25%, up to about 75% of the total N requirement could be
recommended as a safe treatment leading at the same time to higher grain
and straw yield of wheat.
2) The productivity of both wheat grain and straw was higher in soil II, of
heavier texture and higher lime content as compared with soil I.
B· Nutrients concentration and uptake:
1) Effect of soli:
- Although the plants grown on soil I (of lower lime content) contained higher
values (concentrations) of N (and hence protein), K, Fe and Mn in grain,
the total content (up take) of all nutrients except K and Fe where higher for
plants grown on soil II (of higher lime content) as compared with soil I.
- On contrast, soil II, of higher lime content, produced wheat straw of
higher N, K, Mn, Zn and Cu but lower in P and Fe content
(concentration) as compared with soil I.
- In general soil 11,of higher lime content, favoured soil I respect to the
total uptake of all the tested elements
2) Effect of compost type:
- In general compost of pile 1 showed significant positive effect over the other
types with respect to the total uptake of wheat grain from P and Cu, the
second for Zn & Fe while compost III showed superiority for N, K and Mn.
- Concentration (content) of all the tested nutrients (except Nand P)
either in wheat grains or wheat straw were increased with increasing
the rate of manures application (compost) to both soils while for P and
N a decreasing trend was obvious.
3) Effect of treatments:
- The highest (significant) effect the different treatments showed different
effects on total content (uptake) of wheat grains from the different nutrients,
according to the following sequence:
- Treatment No. 2 (30 kg camp. N + 90 kg Min. N), was favoured for all the
macro nutrients as well as Mn. Treatments NO.4 (90 kg camp N + 30 Kg
Min. N), was favoured for Fe, Zn and Cu.
- Soil II, of higher lime content as well as compost III showed the highest
values of total contents uptake of all the tested nutrients in wheat straw.
Also treatments No 2 (30 kg camp N + 90 kg Min N) showed the same
trend of superiority with respect to all nutrients except for Nand P.
c. Microbial activity:
1) The numbers of total bacteria, actinomycetes and fungi in general were
increased with manuring. Increasing the rate of added compost in both soils.
Where, Soil 11, of higher CaC03 content show apparently contained higher
microbial group counts than soil I, of lower CaC03 content
The peak of maximum numbers appeared after 15 and 30 days from
sowing and gradually decreased WI the end of the experimental period. The
compost type were greatly effective on the microbial counts in the soil Iand
soil II according to the order:
Compost Mix. III > compost Mix. II > compost Mix. I for bacteria and fungi
Compost Mix. II > compost Mix. I > compost Mix. III for actinomycetes .
2) Also the numbers of coliform group increased with increasing the applied
compost rate such inducing effect was maximized after 1S’days from seed
sowing. Thereafter, gradually decreased to be completely disappeared
after 90 days.
3) Also there was neither colony of Salmonella sp. nor Shigella sp. in the
control treated of both soils. While treated soils by composts, there were
some colonies at the beginning and then disappeared rapidly.