Abstract:
This study characterizes the spati
al distribution of Gravimetric soil Water Content
(GWC), soil saturation extract Electrical Conductivity (ECe) and Root Length Density
(RLD) in the wetted area by the emitter in a drip irrigated nectarine orchard cultivated in
bare and plastic
-
mulched soil
s. To this aim, 150 soil cores were sampled in a 0.25 m by
0.25 m grid spacing at three soil depths in one m
2
area with an emitter located in the
center and a tree in a corner of the area in the bare and plastic
-
mulched soils. The 0
-
60
cm soil profile mean
GWC
was 15% higher and the mean
ECe
42% lower in the mulched
than in the bare soil, whereas the mean
RLD
was similar in both treatments. Root growth
was preponderant at the 0
-
20 cm soil depth, where
RLD
accounted for 66% of the total
RLD
. The root weighed
GWC
(GWC
rw
) was somewhat higher and the root weighed
ECe
(ECe
rw
) somewhat lower than their arithmetic means, indicating that root growth was
preponderant in regions with higher moisture and lower salinity. This conclusion was
supported by the positive
RLD
-
GWC
correlation, and the
RLD
-
ECe
upper boundary line
analysis showed that root growth decreased above a threshold ECe of about 4 dS m
-
1
.
Overall, plastic mulching benefited water conservation and soil salinity control, but did
not promote nectarine root g
rowth.
Keywords:
Contour maps, Drip irrigation, Root growth, Soil mulching.
