The effects of salinity with different (Cl-) / (So42-) ratios and nitrogen (N) levels on wheat
Hojat Emami1, Alireza Astaraei2
1.
Soil science Dep. Agriculture Faculty of Tehran University, Karaj – Iran.
2.
The professor of Soil Science Dep., Agriculture Faculty of Ferdowsi University, Mashhad –
Iran.
Po. Box: 31587-11167
Fax: 00982612231787
E-mail: hojatemami@yahoo.com
Abstract
In order to evaluate the effects of Cl- / So42- ionic ratios at different salinities and N amounts on wheat, a greanhouse
experiment was conducted. A factorial experiment based on a completely randomized design with three replications was
carried out. The factors were including three Cl-/So42- ratios [ R1(Cl-/So42- =1/2), R2(Cl-/So42- =1/1) and R3(Cl-/So42=2/1)], two levels of Nitrogen [N1(100KgN/ha) and N2(200KgN/ha)] and three levels of salinity [S1(2dS/m), and S2(4dS/m)
S3(8dS/m)]. Germination percentage, height and dry matter weight of the plants were used for evaluation the tolerance of
wheat against salinity, Cl- / So42- ratios and also the effect of N fertilizer. Comparison of the interaction effects between N
fertilizer and Cl- / So42- ionic ratios showed that an increasing in N fertilizer amounts in soils had R 1 and R2 ratios could
engender positive effects on dry matter weight , while in R3 increase of N fertilizer in reaction to disruptive effects of
excessive Cl- didn’t show significant effect on dry matter weight. Regarding to interaction effects between N , Cl - / So42ratios and salinity it seems that use of more N in order to stimulate plant growth and it’s development and to prevent of
salinity stresses can be more useful in saline soils which their main anionic type is So4 2- and their anionic varieties are
including the Cl-/So42- ratios of 1/1 and 1/2.
Keyword: salinity, Cl-/So42- ratios, N fertilizer, yield, interaction effects.
Introduction
Saline media are distinguished by two main characteristics; these characteristics are low osmotic potential
and high concentration of salts potentially toxic for plants (Patel, P. et al.1975). Crop in this media encounter to
growth decreasing and disorders in metabolic activities (Flowers et. Al.; 1977 and Levit. J. 1980).
Relationships between ionic uptake and growth are complex and in general, high concentration of many ions
in plant root medium is caused limitation of some nutrient uptake. Ionic toxicity intensity for crops depends on
dominant salt type, growth medium and plant species. Mozafar and Goodin (1989) by considering the effects of
various salts on two sensitive and tolerant genotypes of wheat found that not only genotype sensitivities to
various salts are different, growth stages show different reactions to salt type.
Antagonisms between Cl- and No3- ions are observed in sugar beet (Geortz, S.H. and J.M. Cons. 1991),
potato(Jackson, T.L. and R.E. Mc Bride.1986), pea(Astaraei A.R. 1990), cotton(Siliberabush, M. and J. BenAsher.1987), wheat(Tanji, Kenneth, K. 1990), bean and soy bean(Weigel. R.C. et al.1973) and many other
plants (Astaraei A.R.1990) and in some cases were been severe that Bernstein(1965) decreasing of crop yield in
result of salinity attributes to Nitrogen deficiency. Weigle et al (1973) reported this competition is decreased in
bean with Nitrogen increasing. Glass and Siddiqui(1985) also observed the effect of Nitrogen amounts on Cluptake in barely.
These evidences show that antagonism between Cl- and So42- is interactive. The mechanism of this
competition is not exactly clear, but seems that it is been the result of Na+ preventative effects (Siliberabush, M.
and J. Ben- Asher;1987), because No3- ion moves from roots to leaves by xylem and K has a stimulator effect in
this process. Whenever excessive Na+ and Cl- ions enter into the vesicular system, Na+ ion prevents of K+
uptake. Decreasing of K+ decreases the transferring of No3 and as a result of this activity Cl- anion transfers
instead of No3- into the leaves and concentrates there (Mass , E. V. and G. Y. Haffman;1997; Siliberabush, M.
and J. Ben- Asher;1987).
The aim of this study is to evaluate the effect of different levels of salinity on wheat injurious because Cland So42- anions are the salinity factors in most places and Cl- importance on injury appearance in relation to
other ions present in saline condition is considerable , more notice has been focused on this anions and on the
effect of Nitrogen fertilizer too.
Material and methods
Laboratory studies
The soil sampled from 0-15 Cm, then air dried and passed a 2 mm sieve. (Silt Clay Loam EC=0.5dS/m.
Regarding to treatment and replications, soil sample as equal content had put on polyethelene culvert pipes with
inner diameter 12 Cm and length of 60 Cm. In this study, solutions included 2 , 4 and 8 dS/m salinity levels and
1/2 , 1/1 and 2/1 Cl-/So42- ratios was prepered via dissolving certain amounts of Calcium Chloride(CaCl2) and
Calcium Solphate (CaSo4) in distilled water. These solutions were used to leach the soil. Soil leaching was
conducting twice a week for two month. After every leaching, the leachate of soil was collected and the
hydroulic conductivity (EC) of its was measured. When the EC of leachate was equaled to solutions, the
leaching activity was stoped. Soil columns after air drying was grinded and passed a 2 mm seive.
Greenhouse studies
In this stage the effect of salinity stress, Cl-/So42- ionic ratios and probable effects of Nitrogen on germination
percentage, heigth and dry matter weigth of wheat was studied in pot and greenhouse condition. In addition to
three levels of salinity and three ionic ratio of Cl-/So42- , two levels of Nitrogen(100 and 200 Kg N/ha)was
applied. We had 18 treatment (3 salinity level * 3 Cl-/So42- ratios * 2 N levels) and 3 replications was added, so
the number of pot was 54. In order to apply treatments we used of plastic pots. 1000 gr soil was added in each
pot and phosphate di-amonium fertilizer (100 Kg N/ha) was applied to each pot. 6 wheat seeds put on in each
pot, then they was covered with sand in 2 Cm thickness and irrigated by natural water for 56 days. After 25
days, remainder Nitrogen fertilizer was applied to treatment that included 200 Kg N/ha , so that oureas 46%
(110.4 mg/pot) was used. The seeds germinated were counted and after 56 days the height of plants was
measured, and the plant were harvested. Plant samples were dried oven at 60 oC , then dry matter weigth was
measured.
Germination percentage, height and dry matter weight was used to evaluate the plant tolerance to
salinity, Cl-/So42- ratios and Nitrogen fertilizer. MS-TATC soft ware and Duncan test was used for
statistic analysis.
Results and discussion
1- The interaction effects between salinity and nitrogen on germination percentage, height and yield of
wheat
The results obtained from interaction effects between salinity and nitrogen in relation to germination
percentage didn’t show any significant different in each treatment when N amount increased from N1 to N2.
Also in each salinity level when N amounts increased, height and yield of wheat increased, but they were not
significant (=5%). Increasing of yield in all salinity level probably in due to competitive effects of N as No3form with Cl- or So42- that established as a result of N increasing in a root medium.
In N1 when salinity increased from S1 to S2 and S2 to S3, height and yield of wheat decreased, but they were
not significant (=5%). In reverse in N2 when salinity increased from S1 to S2 yield of wheat decreased (20%)
significantly, but it was not significant when salinity increased from S2 to S3. These comparisons showed that in
high salinity level N could decrease undesirable effects of salinity (table 1).
Table 1) The interaction effects between salinity and nitrogen on germination percentage, height and yield of
wheat
Treatment
S1N1
S1N2
S2N1
S2N2
S3N1
S3N2
Germination
Percentage
98.14a
96.30a
92.58ab
92.58ab
81.48b
83.33b
Yield (mg/pot)
Height (mm)
684.3ab
770.7a
607.8bcd
642.2bc
530.7d
567.3cd
50.88a
52.94a
50.11a
51.58a
46.99a
50.16a
2- The interaction effects between Cl-/So42- ratios and nitrogen on germination percentage, height and
yield of wheat
In general in various Cl-/So42- ratios when N amount increased, germination percentage didn’t show any
significant different. Also in both N1 and N2 when Cl-/So42- ratios changed from R1 to R3, it was not show
any significant different on germination percentage (table 2). In each Cl-/So42- ratios when N increased,
height and yield of wheat increased, that they were not significant (=5%).
Comparison of experimental treatment showed that in N1 when Cl-/So42- ratios changed from R1 to R2
and from R2 to R3, the yield of wheat decreased that it was not significant. But in this N amount when Cl/So42- ratios changed from R1 to R3, decreasing of yield was not significant. In reverse, in spite of in N2
amount when Cl-/So42- ratio changed R1 to R2, the yield of wheat didn’t show any significant decreasing, but
when Cl-/So42- ratio changed from R2 to R3, it decreased (10%) significantly. These results showed that
increasing of N fertilizer in soils included R1 and R2 could induce positive effects on yield, whereas in R3
increasing of N against to undesirable effects of excessive Cl- didn’t have perceptible influence on yield
(table 2).
Table 2) the interaction effects between Cl-/So42- ratios and nitrogen on germination percentage, height and yield
of wheat
Treatment
R1N1
R1N2
Germination
Percentage
90.73a
96.29a
Yield
(mg/pot)
632.1ab
683.5a
Height (mm)
50.29a
52.23a
R2N1
R2N2
R3N1
R3N2
88.89a
90.74a
92.58a
85.19a
624.4ab
682.3a
566.3b
614.4bc
47.54a
49.16a
49.23a
54.2a
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