The Almond in California

Part 1

UNIVERSITY OF CALIFORNIA PUBLICATIONS

COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA

THE ALMOND IN CALIFORNIA

BY R. H. TAYLOR

BULLETIN No. 297 AUGUST, 1918

UNIVERSITY OF CALIFORNIA PRESS BERKELEY 1918

BENJAMIN IDE WHEELER, President of the University.

EXPERIMENT STATION STAFF

HEADS OF DIVISIONS

THOMAS FORSYTH HUNT, Director. EDWARD J. WICKSON, Horticulture (Emeritus). HERBERT J. WEBBER, Director Citrus Experiment Station; Plant Breeding. HUBERT E. VAN NORMAN, Vice-Director; Dairy Management. WILLIAM A. SETCHELL, Botany. MYER E. JAFFA, Nutrition. CHARLES W. WOODWORTH, Entomology. RALPH E. SMITH, Plant Pathology. J. ELIOT COIT, Citriculture. JOHN W. GILMORE, Agronomy. CHARLES F. SHAW, Soil Technology. JOHN W. GREGG, Landscape Gardening and Floriculture. FREDERIC T. BIOLETTI, Viticulture and Enology. WARREN T. CLARKE, Agricultural Extension. JOHN S. BURD, Agricultural Chemistry. CHARLES B. LIPMAN, Soil Chemistry and Bacteriology. ‡CLARENCE M. HARING, Veterinary Science and Bacteriology. ERNEST B. BABCOCK, Genetics. GORDON H. TRUE, Animal Husbandry. JAMES T. BARRETT, Plant Pathology. FRITZ W. WOLL, Animal Nutrition. WALTER MULFORD, Forestry. W. P. KELLEY, Agricultural Chemistry. H. J. QUAYLE, Entomology. J. B. DAVIDSON, Agricultural Engineering. ELWOOD MEAD, Rural Institutions. H. S. REED, Plant Physiology. W. L. HOWARD, Pomology. †FRANK ADAMS, Irrigation Investigations. C. L. ROADHOUSE, Dairy Industry. O. J. KERN, Agricultural Education. JOHN E. DOUGHERTY, Poultry Husbandry. S. S. ROGERS, Olericulture. J. G. MOODEY, Assistant to the Director. Mrs. D. L. BUNNELL, Librarian.

DIVISION OF POMOLOGY

W. L. HOWARD R. H. TAYLOR A. H. HENDRICKSON *E. L. OVERHOLSER W. P. TUFTS W. L. SWEET G. L. PHILP ‡V. W. HOFFMAN M. N. WOOD

‡ In military service.

† In co-operation with office of Public Roads and Rural Engineering, U. S. Department of Agriculture.

* Exchange professor from Cornell University for 1918-19.

THE ALMOND IN CALIFORNIA

BY R. H. TAYLOR

INTRODUCTION

The almond (Prunus communis) is supposed to be native to the countries around the Mediterranean and at present the bulk of the world’s supply is produced in that region. It resembles the peach somewhat in manner of growth and character of blossoms and leaves, but the wood is much harder and the tree is longer-lived under equally favorable conditions. The fruit, instead of having a thick, fleshy pericarp as in the case of the peach, has a thin, leathery pericarp or hull, which splits on ripening and generally opens when dry, exposing the nut inside.

California produces over 98 per cent of the entire American crop and has done so for many years. During the period from 1900 to 1913 the number of bearing trees remained approximately the same, new plantings having replaced old orchards that were being pulled out. The variation in California production from year to year prior to 1915, as shown in figure 1, is due to seasonal variations rather than to change in acreage.

Imports into the United States from the Mediterranean countries are also shown in figure 1, the top line representing the total imports, the other lines, as indicated, showing the proportion of that total originating in the three principal countries exporting to the United States. Previous to 1912 the records of shelled and unshelled almonds were not kept separate. Since the records have been segregated, the percentages of shelled almonds imported each year have been approximately as follows:

Per cent 1912-13 83 1913-14 70 1914-15 71 1915-16 82 1916-17 79 --- Average 77

With the 1915 crop the production in California entered upon what appears to be a long prospective increase. The large acreage of almonds set out in the last four or five years is the result of greatly improved market conditions due to the successful work of the California Almond Growers’ Exchange. The first of these new plantings are now coming into bearing, and each year for many years in the future will continue to see increased yields. Large acreages are still being planted so that the almond production in California bids fair to continue to grow.

Within the next few years California growers will, in all probability, be forced to accept lower prices for their almonds than they are now receiving. The American markets are fully supplied at present prices, yet constantly increasing acreage will inevitably result in a greatly increased tonnage. European almonds are being produced at a lower net cost and can be laid down on the Atlantic Coast more cheaply than is possible with the California product. This brings the grower face to face with the necessity of becoming more thoroughly familiar with the most economical methods of production and marketing if they are to continue to make a profit. It is essential, therefore, that a careful study be made of all the factors concerned in the growth, production and final disposition of the almond crop.

HABITS

The almond is the first of the deciduous fruit trees to start growth and come into bloom in the spring, and normally the last one to shed its leaves in the fall. In other words, it has a very short period of rest. When the trees are forced into premature dormancy by mites or lack of moisture, they soon reach the end of their normal rest period before the winter season is over. Then the first warm weather in spring will bring the trees into blossom. In some cases where moisture and temperature conditions are favorable late in the fall, they may actually blossom before the winter season. In young trees that have become dormant unusually early, the rest period may terminate and then the tips of the branches resume growth and continue to slowly develop new leaves at the terminals throughout the winter. Trees which have been kept growing thriftily until the leaves have been forced to fall by the cold weather and frosts of winter, do not tend to blossom as early in the spring, nor do they open under the influence of a few days of warm weather in late winter or early spring.

Young trees blossom somewhat later than the older trees, and buds on sucker growth blossom later than the more mature portions of the same tree. The difference may amount to three or four days or almost a week. Well-grown trees carry large numbers of blossoms over the entire tree, as shown in figure 2.

Crops of 1899 to 1917.]

Part 2

The wood of the almond is very hard and strong, enabling the tree to bear the weight of heavy crops where pruning has been given proper attention during the formative period of the young tree. As with other fruit trees, the almond is subject to heart-rot and care should always be exercised to prevent the checking and cracking of large wounds and consequent infection with decay organisms. The hardness of the wood makes it the finest kind of fuel, and when old orchards are being dug up the returns from the sale of wood often more than pay for the expense of digging and cutting up the trees and burning the brush.

The nuts are of two general classes—sweet and bitter almonds. The former is primarily the almond of commerce, though the latter is used largely in the manufacture of almond oil and almond flavoring, as well as in the manufacture of prussic acid. The bitter almond is also used largely in nurseries as a rootstock upon which to bud the almond and some other fruits.

For a long time there has been considerable evidence to show that some varieties are always self-sterile while a few are sometimes self-fertile. Work done in 1916 and 1917 by Tufts shows that practically all varieties are self-sterile and that some of the self-sterile varieties are also inter-sterile. In these tests the principal commercial varieties were used. Blossoms of each variety were pollenized with pollen from its own blossoms and from each of the others. Checks were for natural pollination with each variety. The important results of this work are briefly summarized as follows:

The Nonpareil and I.X.L. are inter-sterile, although both are inter-fertile with the Ne Plus Ultra.

The Languedoc and Texas are inter-sterile.

The I.X.L. and Peerless are practically inter-sterile.

The California has proved the best pollenizer thus far tested, for all varieties that bloom near it.

The Drake is inter-fertile with the Nonpareil, I.X.L., Ne Plus Ultra, Peerless and Jordan, the only ones tested.

The I.X.L. is inter-fertile with the Drake, Jordan, California, Languedoc, Ne Plus Ultra and Texas.

The Ne Plus Ultra is inter-fertile with the California, Drake, I.X.L., Languedoc and Nonpareil.

REQUIREMENTS

While the almond is in many ways an easy tree to grow where conditions are favorable, it is more particular in its requirements than most common orchard fruits, and the grower may find it difficult to produce a good, thrifty tree unless he chooses the proper location. Very often it will grow well and make a fine healthy tree, but owing to unfavorable conditions, will not bear regularly, if it all.

CLIMATE

Heat.—Where the conditions of soil and moisture are favorable the almond will endure the intense heat of the interior valleys and even of the Imperial Valley, provided it is pruned properly to shade the main branches so as to prevent sunburn. Where trees, by severe pruning, are opened up suddenly to the intense heat of the summer sun, almonds will sunburn, but if the necessary opening up is done gradually, the bark will become inured to the new conditions without danger. The nuts grow and ripen more satisfactorily in the greater heat of the interior than along the coast.

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