Agriculture Reference
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Table 5. Yield, yield components, seasonal evapotranspiration (ET), and water use
efficiency (WUE) observed on loam and clay soils for three irrigation water-qualities
(control C, 15 and 30 meq/l).
soil
loam
clay
water quality
C
15
30
C
15
30
plant/m
2
18 a
18 a
18 a
18 a
18 a
18 a
n° pod/plant
44 a
43 a
32 b
41 a
34 b
25 c
n° grain/pod
2.6 a
2.5 b
2.5 b
2.7 a
2.5 ab
2.4 b
1000-grain weight (g)
164 a 154 a
130 b 161 a 148 b
100 c
grain yield (g/m
2
)
334 a 294 a
180 b 311 a 221 b
106 c
straw (g/m
2
)
261 a 269 a
169 b 257 a 253 a
251 a
seasonal ET (mm)
410 a 376 a
306 b 430 a 361 b
300 c
WUE (kg/m
3
)
0.81 a 0.78 a 0.59 b 0.72 a 0.61 b
0.35 c
The yields of straw and grain are reduced in loam and clay soils with the increase of soil
salinity. However, in the case of loam soil the differences in yield between the control
treatment and the 15 meq/l treatment are not significant. Additionally, these two treatments
do not present differences in the level of water use efficiency. Moreover, the reduction in
straw and grain yield observed for the 30 meq Cl/l treatment is significant.
In the case of the clay soil, the reductions in yield (straw and grain) and in water use
efficiency observed, on the one hand, between the control and the 15 meq/l treatments and, on
the other hand, between the 15 meq/l and the 30 meq Cl/l treatments were significant.
The reductions observed for the grain yield of the treatments irrigated with the saline
waters are due to the simultaneous reductions of three parameters: the number of pods/plant,
the number of grains/pod and the 1000-grain weight.
100
75
50
25
loam
clay
0
0
2
4
6
8
ECe (dS / m)
Figure 7. Relation between relative yield of soybean and soil salinity, observed on loam and clay soil.
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