الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
String bean, PhaseollIS vulgaris, L. is a new cultivar has a good
potential to be exported and there is a great demand on it especially from the
European comunity. These new variety alone produce a high percentage of
straight pods in the Extra and Fine categories which enjoy the best market
prices. Thus export of this variety becomes very important to increase the
national revenue.
The aim of this investigation was to study:
1) The response of Pbaseolus vulgaris plants to inoculation under
sterilized condition as well as the effect of N application to inoculated
and uninoculated plants on nodulation and plant growth.
2) The ability of Phaseolus vulgaris plants to form nodules under natural
soil condition and their ability to utilize the atmospheric nitrogen.
3) The effect of N source, rate and method of application on the commercial
exportable yield of the Extra and Fine categories.
4) The efficacy of ammonium nitrate fertilizer when applied through drip or
as surface continuous band under submersion irrigation conditions.
To accomplish the first and second objectives, laboratory and
greenhouse experiments were conducted.
I. LABORATORY EXPERI •••ENT
Seeds of Puseolu, vulgaris were pl~ted in sterilized sand culture
(Leanard Jar system), inoculated or uninoculated with the appropriate
Rhizobium culture (strain No. 3612). Nitrogen was applied at the rate of
0,165 and 33 mg N/kg sand to the inoculated and uninoculated treatments.
The results obtained from this experiment can be briefly summarized as
follows:
1. The plants fallled to form any nodules when planted in sterilized soil free
from Rhizobium bacteria, but the nodules were formed after
inoculation with effective strain of Rhizobium phaseoU.
2. Inoculated treatments without N application exhibited a relatively high
plant growth with highest nodulation i.e, number and weight of nodules.
Nitrogen addition to inoculated treatments decreased not only number of
nodules/plant but also the total and individual weight of nodules. The
number of nodules/plant was reduced from 136 in absence of nitrogen to
38 with the rate of 16.5 mgN/kg and to 6 with the highest rate of nitrogen
(33 mgN/kg).
3. The root dry weight was increased significantly with increasing N rate.
However, the effect of inoculation on dry weight of root was negative.
4. The shoot dry weight was increased significantly with increasing N
application to inoculated and uninoculated plants. At the rate of 0 and
16.5 mg N/kg, the inoculated plants produced high shoot dry weight
comparing with uninoculated ones.
5. Total N and N03-N in blade were increased significantly as a result of
increasing the applied nitrogen and the increase. was higher in the
inoculated plants provided that the rate of nitrogen did not exceed 16.5
mgN/kg.
II. GREENHOUSE EXPERIMENT
Natural and fumigated sandy soil was used in this experiment. Nitrogen
was applied to the pots before sowing at the rate of 0, 16.5 and 33 mgNlkg.
Phaseoills vulgaris seeds were planted in soil inoculated or uninoculated
with the appropriate Rhizobium culture (strain No. 3612).
The following is a brief summary of the results obtained:
1. Plulseolus vulgaris plants in all investigated treatments failed to form
any nodules.
2. Soil organisms and antagonistic factors had no inhibitive effect on the
Rhizobium phaseoli indicating that such a failure could be
undoubtedly attributed to the high content of available native soil-N, or
pH effects.
3. It is worthy to conclude that Phaseolu, vulgaris pants is not able to use
the atmospheric nitrogen as a result of its failure to form any nodules
under common natural soil condition. Thus the addition of N to
Phaseolu, vulgaris plants is very important to increase the
productivity than other leguminous crops.
To achieve the third and fourth objectives two field experiments were
executed.
III. FIELD EXPERIMENTS
A) Submersion Irrigation experiment:
The aim of this study was to detrnnine the most effective N source, rate
and method of application on plaat growth, yielding ability and physical and
chemical characteristics of pods. The N sources (ammonium nitrate,
ammonium sulphate and urea) were applied at rates of 33 and 66 kg N/fed
through the two application methods namely surface continuous band (SCB)
and surface localized band (SLB).
The results obtained from this experiment can be summarized in the
following:
a) Plant growth:
1. Plant height was not affected significantly by N source, rate and method of
application in the two growing seasons.
2. Plants fertilized with ammonium nitrate had the highest number of
leaves/plant, followed by those received ammonium sulphate, while the
other treated with urea had the lowest number of leaves, in both seasons.
Furthermore, increasing N rate resulted in significant increase in number
of leaves/plant in both seasons with all N treatments.
3. The effect of N source on leaf area was followed this order: urea >
ammonium sulphate > ammonium nitrate. Nitrogen rate showed a
significant effect on leaf area only in the second season.
4. The highest dry weight of plant was obtained with ammonium nitrate and
ammonium sulphate which significantly did not exhibit any difference
compared each other in the first season. The lowest dry weight of plant
was recorded when N was applied as urea fertilizer with significant
difference in both seasons compared to the other two sources. Increasing
N fertilization dose resulted in a significant increase in dry matter
production with all N sources dwing the two seasons.
5. Application of N through surface continuous band method significantly
increased the dry weight of plant comparing with surface localized band
method.
b) Yielding ability:
1. The yield of Extra pods was affected positively and significantly by N
source. Ammonium nitrate was the superior and urea was the inferior.
The yield was increased as the rate of N application increased except with
urea, whereasethe yield was decreased by increasing the rate. This was
true in both growing seasons.
2. The effect of N source on Fine pods yield was followed the following
order: ammonium nitrate>urea> ammonium sulphate with significant
difference compared to each other, in both growing seasons. The highest
values of Fine pods yield, in both seasons, were concomitant with the
highest level of applied nitrogen except with urea the high dose of
nitrogen significantly retarded the pods production.
3. The highest yield of Bobby pods was concomitant with ammonium
sulphate source, while the lowest was recorded with ammonium nitrate.
Concerning the effect of rate, there is a significant decrease in the yield
of Bobby pods as a result of increasing the rate of ammonium nitrate and
ammonium sulphate. However, the yield was increased sharply with
increasing the rate of mea. Similar effects of ammonium nitrate and urea
on the yield were obtained in the second season, but increasing the rate of
ammonium sulphate increased the production of Bobby pods.
c) Physical and chemical characteristics of pods:
* Physical characteristics of pods:
1. The lowest average length of pods was recorded when N was applied as
ammonium nitrate with significant difference compared to the other two
sources (ammonium sulphate and urea) which significantly did not exhibit
any difference compared to each other, in both seasons. The pods length
of Extra category was not affected significantly by N rate in the two
growing seasons.
2. The least values of length trait were obtained after anunonium sulphate
application with significant difference compared to the other two sources.
Nitrogen rates did not induce any significant effect on length of Fine
pods, in both seasons.
3. The effect of N source on Extra pod diameter was followed this order:
ammonium nitrate> ammonium sulphate> urea.
4. The most effective N source on Fine pod diameter was ammonium nitrate
followed by urea and the least effective was ammonium sulphate.
5. In both growing seasons, the higher values of Extra and Fine pods
diameter were significantly concomitant with the highest level of the
applied nitrogen.
6. The effect of N source on Extra pod dry weight was followed this order:
ammonium nitrate > ammonium sulphate> mea. Increasing the dose of
applied nitrogen was accompained by significant incIcase of about 7.4%
in dry weight of Extra category.
7. The following order describes the effect of N source on Fine pod dry
weight: ammonium nitrate > urea > ammonium sulphate. Increasing N
fertilization dose resulted in a significant increase in dry matter
production during the two seasons.
** Chemical characteristics of pods:
1. The fibers content in Extra pods was ranged from 0.01 to 0.04%. Neither
N source and rate nor method of application had a marked effect on
fibers content in Extra pods, in both growing seasons, indicating that this
category is free from fibers.
2. The fibers content in Fine pods was ranged from 3.9 to 5.8%. The effect
of N source on fibers content of Fine category was followed this order:
ammonium sulphate> urea> ammonium nitrate with significant
difference compared to each other during the two growing seasons.
Concerning the effect of N rate, there is a significant decrease in the
fibers content of Fme· pods as a result of increasing the rate of N in both
seasons. Moreover, the surface localized band method gave a relatively
high effect on fibers trait, in the two growing seasons.
3. The fibers content in Bobby pods ranged from 29.9 to 60%. Therefore
this category is practically unexportable because the fibers content was
too high .
4. The effect of N source on fibers content of Bobby category was followed
this order: ammonium sulphate > urea > ammonium nitrate. Increasing
the nitrogen rate resulted in a significant decrease in the fibers bootent of
this category in both seasons.
5. The effect of N source on protein content of Extra pods was followed this
order: ammonium nitrate > ammonium sulphate > mea. Nitrogen rates
did not induce any significant effect on protein content of Extra pods, in
both seasons.
6. The surface continuous band method gave the superior results with
significant effect compared with the other method of application in both
seasons.
7. The effect of N source on protein content of Fine pods was followed this
order: ammonium nitrate > urea > ammonium sulphate with significant
effect in both seasons.
8. The protein content in Fine pods was decreased significantly with
increasing N rate, in the first season. However, a poor relationship
between protein content and N rate was found in the second one.
9. The protein content was affected significantly by the methods of
application, only in the first season. Furthermore, the surface continuous
band method gave a relatively high effect on protein content of Fine
category, in both growing seasons.
Generally, application of ammonium nitrate fertelizer at a rate of 66 kg
N/fed through surface continuous band method was commercially the best of
all fertelization treatments. Such a treatment gave the highest commercial
exportable yield with quite excellent pod characteristics during the two
growing seasons.
B) Drip Irrigation experiment:
This investigation aimed at studing the efficacy of anunonium nitrate
fertilizer when applied through drip irrigation or as surface continuous band
under submersion irrigation systems. The ammonium nitrate was applied at
the rate of 0, 33 and 66 kgN/feddan.
The results of this experiment could be summarized as follows:
a) Plant growth:
1. Plant height was increased significantly as the rate of N increased from 0
to 33 kgN/fed under the two irrigation methods. Increasing N rate from
33 to 66 kgN/fed resulted in a slight decrease in-plant height when the N
was applied through the drip irrigation system.
2. The plant heights in the drip irrigated plots were increased over the
submerged ones by about 7.5, 15.6 and 6.4% for the 0,33 and 66 kg
N/fed, respectively.
3. The leaf area was increased significantly with increasing N rate and the
highest leaf area was obtained with the highest Nrate (66 kg N/fed) under
the two irrigation regimes.
4. The dry weight of plant exhibited a positive response towards drip
irrigation system of about 7.5 and 10.0% for the 33 and 66 N dose,
respectively, as compared with those irrigated by the other one.
5. The number of leaves/plant was increased significantly with increasing the
application rate and the highest number was obtained with the highest N
rate (66 kgN/fed) with the two irrigation systems.
b) Yielding ability:
The drip irrigation system exhibited a positive effect on the yield of
Extra and Fme categories showing an incIeasc of about 24.8 and 21.3% for
the 33 kgNlfed and 13.8 and 26.2., for 66 kgN/fed over the plants ferti1iz.ed
with the same doses of N fertilizer under submersion irrigation regime.
However, the total yield of submerged plants was higher than that of drip
irrigated ones because of the occurrance of undesirable Bobby category.
c) Physical and chemical characteristics of pods:
* Physical characteristics of pods:
1. Regarding the drip irrigation system, application of N fertilizer to plants
did not induce any significant effect on the average length of Extra pods
in all treatments. However, significant increase was observed with
increasing N rate in case of using the submersion irrigation regime.
2. The pod length of the Fine category was increased significantly with
increasing N rate under drip and submersion irrigation conditions.
3. The 33 kg N/fed was the best N dose affecting the length and diameter of
Extra pods through drip irrigation system which accompained with the
highest length (10.0 em) and quite good diameter character (6.5 rom).
However, 66 kgN/fed was the most effective dose on diameter and length
of Extra pods under submersion irrigation system as wll as on the same
character of the Fine pods under both regimes.
4. There were a continuous increaments in dry matter of Extra and Fine
pods with increasing N rate from 0 to 66 kgN/fed under both irrigation
conditions. However, pod dry weight of drip irrigated plants was higher
than that of submerged ones.
** Chemical characteristics of pods:
1. There is a gradual decrease in fibers content of Extra and Fine with
increasing N rate under both irrigation systems. Fine category produced
more fibrous pods, while those of Extra grade contained the least amount
of fibers. This was true under the two irrigation systems.
2. Extra pods was the richest category in their protein content The protein
content in pods was increased significantly with increasing N dose and the
highest value was obtained with the highest N rate (66 kgN/fed) with the
two irrigation systems. Moreover, the superiority was recorded for the
drip irrigation regime.
3. Extra pods was the richest category in the chlorophyll content. There
were a significant increase in chlorophyll content in Extra and Fme pods
with increasing the level of the applied nitrogen under both irrigation
systems.
4. The carbohydrate content in Extra. pods of drip irrigated plants were
increased over submerged ones by about 3.6, 8.5 and 12.2% for 0, 33 and
66 kgN/fed, respectively. However, Fine pods produced under drip
irrigation regime was lower in their carbohydrate content than that of
submerged ones by about 1.9. 7.9 and 16.5% for 0,33 and 66 kgN/fed.
respectively.
d) Nutrient content of Phaseolus VUlgarIs plant:
The results indicated that blades were the best representative organ for
the nutritional status in plants. Blades analysis showed that the 66 kgN/fed
treatment was the best one which increased the concentration of N,P. Ca and
Mg; but decreased K concentration.