Agriculture Reference
In-Depth Information
District (latitude 30.13° N, altitude 31.25° E, and 41.9 m high above sea level), Qalu-
bia Governorate, Egypt.
TABLE 1
Soil physical properties of the experimental site.
*
FC
*
PWP
*
AW
**
HC
(cm/
h)
Soil
sample
Depth
(cm)
Particle size distribution (%)
BD
(g/
cm 3 )
Texture
class
Coarse
sand
Fine
sand
Silt
Clay
w %
0-15
15-30
30-45
45-60
0.8
0.7
0.6
0.6
27.8
27.5
27.9
28.7
41.6
41.2
38.5
37.0
29.8
30.6
33.0
33.7
SCL
SCL
CL
CL
35.46
35.21
34.72
34.78
19.10
19.24
19.76
20.10
16.36
15.97
14.96
14.68
1.25
1.28
1.28
1.29
3.12
2.36
1.74
1.56
*Determined as percentage in weight basis; **HC: Hydraulic conductivity;
SCL: Silty clay loam and CL: Clay loam.
Field experiments were carried out through two successive growing seasons
(2002/2003 and 2003/2004) under three irrigation systems drip, low-head bubbler and
the modifi ed surface by using gated pipes that considered as control. Soil of experi-
mental fi eld represents the (Nile alluvial) silty clay loam.
Soil particle size distribution was carried out using pipette method after Gee and
Bauder [26] as shown in Table 1. Soil bulk density (B.D.) was measured according to
Black and Hartge [13].
Soil moisture content at fi eld capacity (F.C) and permanent wilting point (P.W.P)
were measured according to Walter and Gardener [81] as shown Table 1. The available
water (AW) was calculated from the following equation:
AW = F.C - P.W.P
(1)
where: AW = available water ( w %), F.C = field capacity ( w %) and P.W.P = perma-
nent wilting point ( w %).
Soil aggregate stability aggregation percentage (Agg.%) and mean weight diam-
eter (MWD) was carried out using wet sieving technique without using a dispression
agent after Kemper and Rosenau [48]. Soil hydraulic conductivity (HC) was deter-
mined under a constant head technique [48]. HC was calculating using the following
formula:
HC = (QL)/(A.t .H)
(2)
where: Q = volume of water flowing through the sample per unit time (L 3 /T), A = cross
sectional flow area (L 2 ), L = length of the sample (L), and H = differences in hydraulic
head across the sample (L). Soil intake rate was determined with double wall ring
infiltrometer technique [50]. Kostikove equation was used to represent the infiltration
process:
 
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