Basic HTML Version
Molecular Soil Biology (online), 2011, Vol. 2 No.1, 1
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8
ISSN1925-2005
http://msb.sophiapublisher.com
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Table 3 Fruit vitamin C (VC), soluble sugar content (TSC), total titratable acid (TTA) and sugar-acid ratio (TSC/TTA) in the ck and
treatments (n=6, means ± SD)
Property
Samples
ck
T1
T2
T3
VC (mg/100g)
3.33±0.09
3.11±0.07
2.98±0.22
2.83±0.08
TSC (g/100g)
1.86±0.11
1.99±0.02
2.15±0.0.7
2.36±0.13
TSP (g/kg)
1.26±0.08
1.29±0.04
1.31±0.08
1.35±0.10
CF (g/100g)
15.6±1.25
16.3±2.29
16.9±2.01
17.5±1.18
Table 4 The relationships between electrical conductivity (EC) and NO
3
-
contents in 0~8 cm horizon of the control (ck) and
treatments (T)
Item
Linear regression equation
r
p
ck
NO
3
-
= 0.008 39 EC + 0.132 31
0.986
0.010
T1
NO
3
-
= 0.004 65 EC + 1.232 49
0.981
0.020
T2
NO
3
-
= 0.002 71 EC + 1.983 89
0.997
0.004
T3
NO
3
-
= 0.002 53 EC + 2.070 91
0.996
0.005
T4
NO
3
-
= 0.002 70 EC + 2.059 06
0.984
0.020
should result from the difference in nitrate content and
could be characterized as NO
3
-
type SSS. This finding
is consistent with previous studies (Albiach et al.,
2000; Shi et al., 2009).
The soil is considered to be saline if the electrical
conductivity of a solution, extracted from a saturated
soil paste, reaches to a value of 4 mmhos/cm (equal to
2.56 g/L dissolved salt). (Maas and Hoffman, 1977;
Nele et al., 2011). According to this threshold, the
soils in the T2 was very closer to the secondarily
saline, T3 and T4 were definitely secondary saline,
which then defined as NO
3
-
type SSS in this study.
2.2 Relationships among soil EC and plant height
and yield of Cucumber
During the experimental period, from the whole trend
line, the plant height of cucumber in the T1, T2and T3
decreased with the increase of EC in soils. There was
a significant relationship between EC in soil and plant
height of cucumber (Height =
-
12.23EC + 122.31, r =
-
0.975,
p
= 0.025). When the plant height decreased
by 15%, 30% and 60%, the corresponding soil EC
were 2.33 ds/m, 3.69 ds/m, 6.39 ds/m, respectively.
The correlation between Y/P of cucumber and the soil
EC (ds/m) was negative, following the linear equation:
Y/P =
-
0.214 EC + 2.017 (R =
-
0.964,
p
= 0.0036).
When Y/P decreased by 10%, 30%, 50% and 70%, the
corresponding soil EC were 2.03 ds/m, 3.67 ds/m,
5.32 ds/m and 6.97 ds/m, respectively. Number of
fruits per plant (NF) was not obviously affected by the
different concentrations of soil salinity (Table 3).
There was a linear relationship between the weight of
single fruit (WSF) and soil EC [WSF =
-
25.099EC +
250.02 (R =
-
0.954,
p
= 0.046)]. When WSF decreased
by 10%, 30%, 50% and 70%, the soil EC values were
2.09 ds/m, 3.83 ds/m, 5.59 ds/m and 7.34 ds/m,
respectively.
2.3 Relationships between EC and cucumber quality
Salt treatment can slightly affect cucumber fruit
quality. In our study total soluble sugar contents
(TSC), total soluble protein (TSP) and crude fiber (CF)
were linearly increased by varying degrees with the
increasing soil EC (TSC = 0.130 EC + 1.702, r =
0.961,
p
= 0.039; TSP = 0.023EC + 1.233, r = 0.972,
p
= 0.028; CF = 0.503 EC + 15.07, r = 0.989,
p
= 0.011).
While fruit VC contents linearly decreased with the
increasing soil EC. (VC =
-
0.132 EC + 3.458, r =
-
0.998,
p
= 0.002).
2.4 The proposed classification of NO
3
-
type SSS
It is noticeable that the height of harvested fruits per
plant decreased with salinity that was a contributing
factor to loss fruit yield. This result was consistent
with the previous studies (Adams and Ho, 1989;
Kareem and Taiwo, 2007). So it might be potential