The cracking quality of the nuts from the trees in this study was tested
on a random sample of nuts from each crop that was collected and brought
back to Norris. The nuts of each sample were weighed and the average nut
weight computed. The nuts were then cracked in a hand-cracking machine,
and kernels that could be extracted with the fingers were removed and
weighed.[13] From this weight was computed the first-crack marketable
kernel percentage. The nuts that still contained kernels were recracked
and the remaining kernel removed. All kernels, including crumbs, were
then weighed in order to compute the total kernel weight and kernel
percentage. Finally, all of the quarters extracted were counted, and the
average number of quarters was computed. Kernels recovered at first
crack and the average number of quarters extracted indicate the relative
ease of extraction of kernels.

Cracking quality of walnuts for individual sample trees averaged by crop
years are presented in Table 1. Nuts of all crops collected from four
trees, 57, 58, 60, and 139, were shriveled or abnormal, and afforded no
test of nut quality during the six-year period. Thus, nut quality data,
based on 440 nut crop samples, are complete for 128 of the 132 sample
trees. From this study, the average common black walnut in the Tennessee
Valley has a nut weight of 17 grams, a kernel weight of 3.3 grams, a
total kernel content of 20 per cent, a marketable kernel recovery at
first crack of 17 per cent, and a quarter recovery of unbroken quarters
averaging 1.8.

[Footnote 13: The kernels were extracted over a 6-mesh wire screen. In
commercial cracking, kernel pieces passing through this type of screen
are not marketable as kernels.]

Table I--Yield of Nuts and Kernels, and Cracking Quality of Nuts from
132 Sample Trees of Common Black Walnut in the Tennessee Valley

_________________________________________________________________________

Tree
_____________________

Diameter
at 4-1/2 ______________________________________________________
Sample ft.
number av. yr. 1940 1941 1942 1943 1944 1945 Av. yr.
_________________________________________________________________________

inches pounds pounds pounds pounds pounds pounds pounds
1 20.4 27 16 2 95 5 3 25
2 14.9 43 43 26 45 42