HOW TO PREVENT INJURY FROM

FROST.

BY F. C. BARKER, NEW MEXICO.

N studying methods of preventing injury from frost it is necessary to have a clear knowledge of how and why the temperature falls and frost is produced.

The surface of the earth is continually losing heat by radiation into space, but during the day it usually receives heat from the sun more rapidly than it loses it by radiation, and therefore it grows warmer. Radiation, and consequent loss of heat, takes place most rapidly when there is nothing to obscure the sky. Clouds or any other obstruction act as a screen in retarding it.

The escaping rays of heat strike the obstruction and are driven back to the earth. This is why frost is more likely to occur on a clear night than when the sky is cloudy. It also explains why smudge fires, by forming a screen of smoke over the orchards, are a protection against frosts.

Cold air is heavier than warm air, and this principle causes the air on slopes, as it becomes chilled by radiation, to flow down into the valleys, where it accumulates and becomes injurious. We thus understand why trees on the foot hills often escape injury from frost, while those in the adjoining valleys are damaged. Smudge fires are only effective on broad, flat expanses of land. In narrow valleys

the cold air comes down from the hillsides and gets underneath the smoke. On windy nights the danger from frost is lessened by the warmer air above getting mixed with the colder air below.

The above theories of the radiation of heat and the falling of the colder air are tolerably well recognized by all orchardists, but there is another and perhaps more important law of nature, which is but little understood, and this is the "dew-point " theory.

Every one knows that the atmosphere holds a very considerable amount of water

in the form of vapor, and that this invisible vapor, which is invariably present in greater or less quantities, can always be condensed into water if the temperature of the atmosphere be sufficiently lowered. If the condensation takes place at temperatures above the freezing point of water, the moisture is deposited as dew; if below the freezing point, the condensation is in the form of frost. To fully comprehend what follows, it must be understood that the temperature at which condensation begins is called the dew-point, and this varies with the amount of moisture or vapor in the air. The greater the proportion of moisture the less the fall of temperature required to condense it into dew or frost. When the air is saturated with moisture the dew-point will be reached at a higher temperature than when the air is dry. For instance, in a dry atmosphere the dew-point may not be reached until the thermometer falls to 28 degrees Fahrenheit, when frost forms. At this point peach buds are seriously injured.

If, however, you can artificially add to the amount of vapor in the air by keeping the land moist by means of recent irrigations, then you raise the dew-point and frost may be formed at a higher degree of temperature, or say at over 30 degrees Fahrenheit, which is the amount of cold necessary to injure peach blossoms. If, therefore, you can prevent the temperature of the atmosphere from falling to 30 degrees, you are safe. At first sight it may appear that if the vapor in the air freezes at 30 degrees and the indication of heat still continues, the temperature will continue to fall until injury results. But here a very wonderful natural law comes into play.

Of course it is well understood that an enormous amount of heat has been required to convert water into atmospheric vapor. This heat is latent in the vapor, and when the latter is condensed into frost

rated and again condensed in the surrounding air is sufficient to raise the temperature ten degrees throughout a space eighty feet square and deep.

FERTILIZING ORANGE ORCHARDS.

אן

BY W. C. FITZSIMMONS.

N no department of soil tillage does a knowledge of "book farming" pay better than in the production of fruits of various kinds. The question of fertilizing the soil in order to reach the best results in fruit production is one which few understand fully, and none can wholly comprehend without study and thought along the lines which science has traced as a guide to the intelligent horticulturist. Chemical analysis alone can properly determine the composition of fruits or other products of the soil, and it is by a study of results reached in the laboratory, that the orchardist is enabled to apply to his soil the proper ingredients in right proportions to produce a crop. The chief and most expensive substances entering into the necessary food for fruit crops of nearly all kinds are nitrogen, phosphoric acid and potash. Without definite amounts of these substances to feed upon, a full crop of perfectly formed fruit is impossible. It should be understood by all orchardists that Nature is inexorable in her demands, and when she asks for bread she will not be satisfied with a stone. other words, her call for nitrogen, phosphoric acid and potash must be heeded, or no crop. There is no appeal from this, and no orchardist should delude himself with the hope of deceiving her by substituting carbon, soda and magnesia or any other combination of ingredients, however captivating the name or small the

cost.

In

Take an orange grove for example: At twenty-four feet apart the trees would stand at the rate of about seventy-five to the acre. At ten or twelve years of age many trees will yield, say, seven boxes of fruit per tree, weighing about 500 pounds. Let us see then the amount and cost of the chemical ingredients which must enter into that 500 pounds of fruit, and without which it will be impossible to produce that amount on one tree. The principal chemical substances to be found in the orange and derived from the soil are: Nitrogen, potash, phosphoric acid, soda, lime, mag

nesia, and oxides of iron, alumina and manganese, also sulphuric acid, silica and chlorine. All save the three at the head of the list may generally be disregarded, since repeated analyses have shown most soils in which orange trees are planted in the United States to be fully supplied with the small amounts required save perBut lime is abundant almost haps lime. everywhere and cheap, hence we shall confine this discussion to the three chief substances required. According to analysis made at the laboratory of the California Experiment Station, 500 pounds of seedless oranges contain 1.6 pounds of potash, .27 pound phosphoric acid and .92 pound nitrogen. With the prices of 5 cents a pound for potash, 6 cents for phosphoric acid and 15 cents for nitrogen these ingredients entering into 500 pounds of seedless oranges (presumably the product of one tree) would cost 23.6 cents; or, if lime be required, say 25 cents per tree. At the prices given, the absolute requirements of the fruit in the way of plant food would cost at the rate of $18.75 per acre. If the soil already contains all or any part of these substances, it would, of course, lessen the cost of the annual fertilization. And right here is where many orchardists-in fact most of them-neglect an opportunity if not a duty. should have their soils analyzed for the chief ingredients here mentioned, and thus learn what they lack or how long the present supply will last. In fact, without some such guide, the orchardist is at a great disadvantage and must in a certain sense grope his way in the dark to reach results. But this is the requirement of the seedless fruit only, and takes no account of the growth of the tree itself and of the perfecting of the seed growth. For these purposes a further supply of each of the ingredients would be required, bringing the probable cost to 15 cents more for a tree large enough to bear 500 pounds of fruit. It is probable, therefore, that an orange tree producing as above stated uses each year some 40 cents' worth of fertilizing material. This must be already in the soil or must be put there by artificial means, else a crop to meet reasonable expectations cannot be produced. It is useless to attempt to replace one of these essential ingredients with some other substance. That is, the lack of potash cannot be supplied by an excess

They

of nitrogen, and vice versa. A chain is only as strong as its weakest link, and a fruit crop will be measured by the product due to the smallest amount of any needed ingredient which may be present in the soil. It is, therefore, of the greatest importance that a well-balanced ration of fertilizer be used so that the best results and no waste shall follow its application. If the soil be deficient in any one ingredient, putting on the others in excess will not bring a fruit crop. Most of these things are fairly understood by the foremost orange growers in Florida, but in California, owing to a richer soil, growers do not generally comprehend the science of fertilization. It is a common custom to apply nitrogenous fertilizers, such as sheep manure and that of dairies and horse stables, without much regard to other substances which a proper orchard fertilizer should contain. These things will all be learned in time, no doubt, but the object of this article is to call present attention to the great need of intelligent action along the line of fertilizing orchards, and if greater interest in the subject shall have been aroused the purpose of the writer will have been accomplished.

THE EASTERN STOCK FARMER SHOULD GO TO THE IRRIGATED WEST.

THE

'HE more I see of farming in the irrigated West the more I am convinced that our Eastern farmers have failed to appreciate the great advantages which irrigation offers to the producer of butter, cheese and pork, writes F. C. Barker, of New Mexico. In the first place, more milk and pork can be raised from an acre of irrigated alfalfa than from an acre of any other crop and at less expense. In the second place, dairy products and pork invariably sell for more money out West than they do in the East. For instance, in the town where I live fresh ranch butter is never worth less than 30 cents, and, although doubtless pure, will fall when we have a better supply, yet throughout New Mexico large quantities are still imported from Kansas, and it will be a long time before butter will sell for less than Kansas prices plus cost of express. Enterprising Eastern farmers who understand dairy farming ought to take advantage of this state of affairs and make their butter where it

sells for the most money. That butter, cheese, pork, poultry and eggs sell for more money in the irrigated West than in the East requires no proof at my hands. The immense shipments from points farther east prove this beyond any doubt.

The question which will naturally be asked by the farmer is, whether butter and pork can be raised as cheaply on an irrigated farm as in States like Illinois, Iowa, etc. Personally, I feel more certainty upon this point than I do upon the question of prices. The latter are liable to fluctuation and beyond the farmer's control, whereas the only variation in the cost will be in the direction of further economy as the farmer gains experience. Enough has already been done to show that no crop is so suitable for dairy cows and pigs as alfalfa. Under irrigation it produces at least three and often four or five cuttings, making a total of three to five tons of hay for the year, the feeding value of which is at least equal to the best timothy hay, indeed it is considered superior by every one who has had experience with both alfalfa and timothy. I give the estimates in hay because they are more easily compared, and after all hay must be the basis of all stock feeding. But alfalfa is not the only stock food raised here. Corn, sorghum and cattle beet can be raised with the greatest ease and under very favorable circumstances to the stock feeder, and bran is always obtainable at reasonable prices. And last, but not least, the open winters make stables quite superAnous.