Agriculture Reference
In-Depth Information
day, on particular days, the leaf-water potential and stomatal conductance were
simultaneously measured each hour.
4- Growth and Yield
Leaf area, plant height and dry matter were determined at the successive phenological
stages on two plants per lysimeter.
At harvest, the yield of grain and straw and the yield components (number of pods per
plant, number of grains per pod, 1000-grain weight) were measured from all plants per
lysimeter.
5 - Statistical Analysis
For the statistical analysis, each of the 5 lysimeters was treated as a replicate. In order to
analyse the effect of texture, comparisons were made between the two control treatments
irrigated with fresh water in clay and in loam soil. In order to analyse the effect of the salinity,
the treatments C (control), 15 and 30 were compared separately in loam and in clay soils.
Each comparison between the two soil types, or among the three water qualities, affecting
plant water-status, crop growth, evapotranspiration and yield was statistically analysed with
the general linear model (SAS, 1999). Treatments were further compared by calculating the
least significant difference (LSD; P < 0.05).
III-
R
ESULTS AND
D
ISCUSSION
1- Soil Salinity
Table 3 shows the values of ECe, determined, after each irrigation, with the Salt Balance
method. The values of ECe observed in the three treatments on the loam soil were slightly
superior to the same treatments on the clay soil. However the differences (0.4 - 0.7 dS/m)
between the mean values observed during the whole crop cycle are not higher than 10%.
Table 3. Values of ECe (dS/m) determined during the soybean crop cycle observed on
loam and clay soils.
Soil
loam
clay
D.A.S.
C
15
30
C
15
30
11
0.8
4.08
6.96
0.8
3.71
6.29
25
0.8
4.11
6.92
0.8
3.73
6.25
44
0.8
4.14
6.96
0.8
3.85
6.30
61
0.8
4.22
7.03
0.8
3.81
6.29
91
0.8
4.39
7.14
0.8
3.83
6.27
0.8
4.19
7.00
0.8
3.79
6.28
mean
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