The investigation has been extended to include, besides black walnuts, pecans, hickories, hazel nuts, chinkapins and chestnuts. With each of these nuts our object is to determine better varieties for Missouri conditions, more profitable and economical methods of production and more satisfactory methods of culture, as well as to stimulate an interest in the marketing and larger use of these products.
The improved varieties of seedling black walnut have been found to be exceedingly easy to propagate by cleft grafting the native or common seedlings. The cleft graft has been used successfully upon seedling trees ranging in diameter from 1-1/2 inches to as much as 8 or 10 inches. In general, however, it has been found best to cleft graft branches or limbs of no greater diameter than from 4 to 6 inches. Such wounds, if properly handled, usually heal over completely within 3 or 4 years. When larger branches are used, decay is much more apt to develop in the wound before healing over is accomplished.
The cleft grafting work is accomplished in the usual way. The limb or branch is removed by sawing it off. The end of the branch is then split with a regular grafting implement used for this purpose; or the work may be accomplished with an axe. If the branch is large a wedge is driven in the center to hold the split cavity apart and to relieve the pressure upon the scions which are to be inserted. Wood of the last season's growth is procured from the variety which it is desired to propagate and the lower end of the scion, which is made about 4 inches long, is whittled to a wedge shape, after which it is inserted in the slit made upon the stock. Where the stock is more than 2 inches in diameter, it is usually advisable to place 2 scions; and where the stock is as large as 4 to 6 inches or more in diameter 4 scions should generally be used. After the placing of the scions all the cut surfaces should be carefully covered with grafting wax. Paper sacks are often used in our experimental work to cover the grafts and cut surfaces for a week or 10 days. It has been found that the inclosing of the grafted branches in paper sacks for this period lessens greatly the evaporation, and more of the inserted scions are apt to grow.
The scions may grow very rapidly, in which case it is usually necessary to brace them by tying a stick or branch to the stock and allowing it to extend for 2 or 3 feet above the point at which the grafting work was done. The inserted scions are then tied to this support. It is very important that the grower examine grafts after wind storms in order to repair damage which may have been done.
Investigations at this station have shown that grafts usually bear fruit in 4 years after the grafting operation. We receive some fruit, occasionally, in 3 years after the work is performed. It is also interesting to note that when seedling walnuts of the same size are selected, some topworked and others untreated, the grafted trees after 5 years' growth generally grow tops equally as large as the tops of the ungrafted trees.
The principal improved varieties of black walnut which are being used at this Station are as follows: Stabler, Ohio, Thomas and Ten Eyck.
(Note by the editor.—The cleft graft described by Prof. Talbert has been superseded in the East by other methods, chiefly the bark and the modified cleft grafts).
CARE AND PREPARATION OF NUTS FOR SEED PURPOSES
By Prof. E. R. Lake, U. S. Department of Agriculture
A nut is a seed, and a seed, normally, is an embryo plant asleep. To keep a nut-seed asleep and safely resting against the favorable time when it may awake, arise and go forth, as a vigorous seedling bent upon a career of earth conquest, requires no great or unusual attention and care save that which is necessary to maintain such conditions as will insure the complete maturing, ripening and curing of the seed, its protection against the ravages of rodents or other nut-eating animals, undue moisture and an unfavorably high temperature. In other words harvest the nuts as soon after they are mature as is possible, insure their complete curing, store them where they will be kept constantly so cool that germination cannot take place, and some nuts, as the black walnut and butternut, may germinate at a temperature just above zero (centigrade(?) Ed.) and keep them moist enough to prevent undue hardening of the tissues or enclosing structures (shell), at the same time prevent them from becoming saturated with moisture and thus rotting. Summarized, these conditions are: (a) a temperature just too low for vegetative activity. (b) A moisture content of the nut just below turgidity. (c) An immunity against ants, rats, mice and squirrels.