Macadamia Nuts in Hawaii: History and Production - ctahr ...
Macadamia Nuts in Hawaii: History and Production - ctahr ...
Macadamia Nuts in Hawaii: History and Production - ctahr ...
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due to lack of chlorophyll formation, a complete<br />
yellow<strong>in</strong>g at the term<strong>in</strong>als <strong>in</strong>dicat<strong>in</strong>g Fe deficiency.<br />
In recent tests yet unreported, Shigeura<br />
(73), us<strong>in</strong>g leaves <strong>and</strong> stems as <strong>in</strong>dex tissues, has<br />
been able to show that manganese (Mn) can also<br />
become a problem on lava l<strong>and</strong> where excessive<br />
phosphate has been applied. In another test on<br />
soil order Inceptisols (suborder Andepts) at Honokaa<br />
(72), Shigeura demonstrated that a reduction<br />
<strong>in</strong> leaf concentrations of Mn, Ca, <strong>and</strong> Mg is associated<br />
with an <strong>in</strong>crease <strong>in</strong> P concentration beyond<br />
0.10 percent <strong>in</strong> the leaf <strong>in</strong>dex tissue, suggest<strong>in</strong>g<br />
three possibilities: (l) that phosphate causes a big<br />
flush of growth <strong>and</strong> "dilutes" other nutrients;<br />
(2) tha t phospha te <strong>in</strong>creases soil cation exchange<br />
capacity <strong>and</strong> thus leads to lower solubility of<br />
other nutrients; or (3) that cation fixation by<br />
phosphate <strong>in</strong> the soil occurs with macadamia <strong>in</strong><br />
<strong>Hawaii</strong>an soils.<br />
On the basis of a "recently matured term<strong>in</strong>al"<br />
sampl<strong>in</strong>g, Shigeura et a1. (74) presented data suggest<strong>in</strong>g<br />
the optimum Ca level is 0.55 percent (Fig.<br />
66). This value is not applicable us<strong>in</strong>g Cooil's<br />
physiologically older leaves s<strong>in</strong>ce older leaves<br />
analyze at a higher level of Ca.<br />
Workers <strong>in</strong> <strong>Hawaii</strong> on sugarcane, papaya, <strong>and</strong><br />
p<strong>in</strong>eapple used recently matured leaves <strong>in</strong> their<br />
foliar diagnostic work. Jones (31) <strong>and</strong> Jones <strong>and</strong><br />
Embleton (32), <strong>in</strong> their work on M. <strong>in</strong>tegrifolia <strong>in</strong><br />
California, used "matured spr<strong>in</strong>g growth" leaves,<br />
which are essentially comparable to "recently<br />
matured term<strong>in</strong>al" <strong>in</strong> <strong>Hawaii</strong>. Although the<br />
advantage of the "recently matured term<strong>in</strong>al"<br />
sampl<strong>in</strong>g is very real, onedanger with this method<br />
is that sampl<strong>in</strong>g done by an <strong>in</strong>experienced person<br />
can <strong>in</strong>clude term<strong>in</strong>als not yet fully matured.<br />
Immature leaves are dist<strong>in</strong>ctly softer to the touch.<br />
However, with proper tra<strong>in</strong><strong>in</strong>g <strong>and</strong> care <strong>in</strong><br />
sampl<strong>in</strong>g, this procedure is very easy to learn.<br />
Boron (B) deficiency (24) is quite prevalent <strong>in</strong><br />
the Isl<strong>and</strong>s. On macadamia it manifests itself <strong>in</strong><br />
term<strong>in</strong>al dieback as <strong>in</strong> P deficiency; but unlike P,<br />
B-deficiency symptoms show clusters of small,<br />
leafy heads on the dy<strong>in</strong>g term<strong>in</strong>als. When a Bdeficient<br />
tree is sprayed with soluble B, regrowth<br />
takes place throughout the defoliated area <strong>and</strong> at<br />
the very term<strong>in</strong>al branches (Fig. 67); regrowth<br />
term<strong>in</strong>als appear lighter <strong>in</strong> color. Further work on<br />
m<strong>in</strong>or elements such as z<strong>in</strong>c, manganese, copper,<br />
<strong>and</strong> iron is <strong>in</strong>dicated.<br />
The suggested leaf analyses values by the various<br />
workers are given <strong>in</strong> Table 3.<br />
100.0<br />
8<br />
93. 0<br />
89.<br />
18<br />
A<br />
f<br />
. - .<br />
. . .. . . . .<br />
.1<br />
. 3<br />
. . -. .<br />
.8<br />
- ...-<br />
.0 .<br />
. .<br />
( . :<br />
3<br />
.<br />
14.<br />
105<br />
66.8<br />
CALCIUM YS. QUALITY<br />
(COMBINEDl<br />
0.150 D.225 D.3OO 0.315 0.450 0.525 D.6OO 0.615 0.150 D.825<br />
% CAlCIUM<br />
Figure 66. No. I nuts as affected by percentage of leaf Ca. Except for<br />
the stray po<strong>in</strong>t, the chart shows a widespread distribution<br />
of po<strong>in</strong>ts for No. I nuts below 0.4 percent Ca, <strong>and</strong> a relatively<br />
conf<strong>in</strong>ed distribution above 0.4 percent, becom<strong>in</strong>g<br />
beller conf<strong>in</strong>ed at po<strong>in</strong>ts above 0.55 percent.<br />
Figure 67. Boron-deficiency symptoms show<strong>in</strong>g regrowth (lighter<br />
colored) on defoliated branches after B application.<br />
I<br />
51