Agriculture Reference
In-Depth Information
Time
Depth
(cm)
Surface area
(cm
2
)
Average diameter
(mm)
Root length density
(cm/dm
3
)
Weight (g)
May
0-10
65.4±19.4 b
0.8± 0.2 b
466.3± 52.6 b
1.3± 0.4 ab
10-20
103.0± 17.9 a
1.0± 0.2 a
541.7± 93.6 a
2.3± 1.1 a
20-30
121.3± 11.6 a
1.0± 0.2 a
257.3± 26.5 c
1.8± 0.5 ab
30-40
61.1± 16.5 b
0.8± 0.2 ab
201.9± 61.2 cd
1.2± 0.6 b
40-50
54.0± 14.5 b
0.8± 0.1 b
179.0± 61.4 cd
0.8± 0.3 bc
50-60
39.9± 3.8 c
0.7± 0.1 b
152.6± 24.8 d
0.6± 0.1 c
60-70
23.7± 3.3 d
0.6± 0.1 bc
112.7± 27.4 de
0.3± 0.1 d
70-80
13.5 ±1.8 e
0.4± 0.1 c
81.0 ±18.0 e
0.2 ± 0.1 d
October
0-10
82.1± 32.6 b
0.7± 0.2 c
539.9± 78.6 b
2.3± 0.7 ab
10-20
142.6± 53.3 a
0.8± 0.2 bc
720.7± 82.5 a
2.9± 0.7 a
20-30
131.8± 35.1 a
1.3± 0.4 a
408.7± 52.9 c
3.6± 1.3 a
30-40
76.1± 20.4 b
1.0± 0.4 ab
344.9± 39.5 cd
2.0± 1.1 ab
40-50
60.7± 15.9 bc
1.0± 0.3 b
230.2± 25.4 e
1.3± 0.7 b
50-60
40.5± 12.0 c
0.8 ±0.2 bc
190.2± 31.4 e
0.7± 0.5 bc
60-70
37.5 ±13.5 cd
0.9± 0.2 bc
171.3± 22.1 e
0.5± 0.3 c
70-80
25.0± 9.3 d
0.8± 0.2 c
120.5± 20.9 f
0.2± 0.2 d
Table 1.
Vertical root distribution in different soil layers. Roots from four different distances (50, 100, 150 and 200 cm)
from the tree trunk in the same soil layer from each sampling location were pooled. Three sampling locations were
used. Means and SD are shown (n= 3). Different letters refer to significant difference at the P ≤ 0.05 level within the
same sampling time [Courtesy Sun et al., 2011].
Angle between main stem and lateral branches, lateral branches and petioles of leafs are the
most suitable morphological markers for cultivar screening in walnut [213]. Under stress, the
angle between the main stem and lateral branches and especially angle between lateral
branches and petioles of leaves showed significant decreases [213].
Drought during the year of bud formation decreases the number of new leaves formed in the
bud and the number of new stem segments (internodes) present. These phenomena were
observed for several walnut varieties during the first and second years of growth [212].
Drought then influences the number of leaves, leaf surface area, and twig extension the
following year when those buds expand [212]. Summer droughts can greatly reduce shoot
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