SOILS.
General Remarks.
—No one certain variety of soil can be said to be the best for raisin purposes, and both in different countries, as well as in the same district, various varieties of soils are valued equally. Every raisin district has, however, its favorite soil, which is supposed to have some peculiar advantages for the raisin grapes, but upon closer investigation we generally find other varieties of soils which are not inferior. Growers who have succeeded with raisin grapes on one variety of soil are only too apt to consider this kind preferable to any other. This is especially the case in California, where soils vary so much and where in some districts it is difficult to find forty acres with a uniform soil. Whether the soil is black, red or gray, it makes but very little difference, as long as it is rich and susceptible of the highest state of cultivation and has the faculty of retaining moisture. The deeper and richer the soil the better the Muscatel grape will thrive and produce, and as such soils are most generally found along the banks of creeks and rivers, or in their bottoms and sinks, we might conclude that in such localities the best soils for the Muscat grape may be found. Other varieties of raisin grapes, such as the Malaga (California) and the Sultana, do well in less rich soil; indeed, they bear profitably in places where the Muscat would be a failure. It is therefore important for every vineyardist to carefully select his soil and then plant on it the proper variety of vine.
Malaga.
—The soils of Malaga are of various kinds. The best is a reddish loam containing much gravel, both coarse and fine. This soil is very stiff and hard, and when dry is as solid as a brick. The red color is derived from oxide of iron or other iron compounds, which many of the best vineyardists consider a most desirable element in any raisin soil. The upland vineyards, or those on the slope of the hills, contain soils of decomposed clay and slate mixed with more or less gravel and sand. The Dehesa lands contain alluvial deposits of a black or gray color.
Valencia and Denia.
—In this district we find soils of many different grades and colors. The sandy and gravelly soils are considered as producing the finest flavored raisins, and those having the best keeping qualities, while the rich, loamy soils of the valleys produce raisins of inferior flavor and keeping qualities, but of larger size and more per acre. For economical reasons, the latter soils are preferred, as they alone can be irrigated and made to produce large crops. Some of the best vineyards in this district contain a gray, ashy soil, quite similar to the white ash of the Kings river lands, while others are growing on a red clayey loam similar to the California red soil.
Smyrna.
—The raisin-grapes of Smyrna in Asia Minor are almost exclusively grown on a white limestone soil, which consists of decomposed white rocks mixed with a stiff ocher-colored loam. This soil is so rocky that it must first be cleared, and the large rocks are carried away and used for boundary walls. This is the soil in the coast districts. In the interior the Sultana vines, as well as the Muscats, are replaced by fig orchards and other trees which delight in sandy soil,—too sandy to produce profitable raisin crops.
Zante.
—The soils of Zante, the home of the Currant grape, are of various kinds. The heavy marl of the plains, which contains a large percentage of gypsum or sulphate of lime, is considered the best; indeed the gypsum is by many considered indispensable, or at least highly beneficial, to the above variety of grape. Other soils are red clay, gray marl and gravelly loam, all containing an abundance of lime. The Currant grape grows well and produces well on all these different soils, but does the best on the gypsum soil, which is therefore the most valued. On other soils the bunches are less solid, and the quantity of grapes produced is somewhat less, while their quality is inferior.
Scene in a Fresno Raisin Vineyard: Raisin Trays Exposed for Drying.
Chile.
—The Huasco grape grows in the valley of Huasco, on the coast of Chile, in a soil that is very light and red, containing a great quantity of sand. While very light in weight, this soil is said to be very rich in plant food, and yields good crops.
Fresno.
—The Fresno soils are of several kinds, but the three principal varieties are red or chocolate-colored loam, white or gray ashy soil, and a light, very sandy, loam. To this may be added the deeper gray bottom soils or alluvial deposits of the Kings river. Each one of these varieties have different grades more or less suitable to the Muscatel grape. The best grades of each are equally valuable, while again the poorer grades are not to be recommended. The deep chocolate-colored loam is by many preferred, and the largest and most successful raisin vineyards are now located on this soil. But even in the best districts the soil varies to such an extent, that while one twenty-acre field will yield 250 boxes of raisins to the acre, the adjoining field, with only a slight change in the soil, will yield only seventy-five boxes to the acre. The best grades of the white ashy soil are also very good, and almost identical with the gray bottom-land deposits of Kings river. The light sandy soil should be avoided for Muscat grapes, but may do for Malaga and Sultanas, especially if judiciously fertilized.
Other Soils in San Joaquin Valley.
—In Merced the best soil is heavy chocolate-colored loam, in places redder, in others darker, almost blackish. It is generally mixed with some gravel. As a rule, all the red soil in the San Joaquin valley is of the same characteristics, and well suited to the Muscat grape, provided the ground is sufficiently level. In Tulare county the proper soil for the Muscat is found to be the bottom lands of Kings and Kaweah rivers, as well as the deposits of the smaller creeks. This variety of gray alluvial loam is exceedingly fertile, and there is none superior for the Muscat grape. But an admixture of alkali often spoils soils which otherwise would be considered the very best. A similar soil is found in Kern county, especially near Kern Lake, and which must be rated among the best in the State, its color being a deep bluish gray. The vineyards of Yolo and Solano counties are located on a very similar soil, rich in humus, lime and phosphates, but more yellowish or pale chocolate colored.
Orange County.
—A similar rich alluvial deposit is found in Orange county in the fertile district known as Santa Ana valley. The soil around Anaheim, Santa Ana, Orange and Tustin consists of a more or less dark alluvial loam of unsurpassed fertility, and especially adapted to the Muscat grape. It varies as to the percentage of sand and gravel. The sandiest soil in this district, while less rich, brings the earliest grapes, which come to perfect ripeness several weeks before those grown on the heavier soils, but the latter produce the best raisins.
Redlands and Riverside.
—The Redlands soil of the mesa lands is reddish, rather darker than the same quality of soil in Riverside and Fresno. It is mixed with sand and gravel, and partakes strongly of the nature of the red or chocolate-colored loams of the State. The Lugonia bottom soil consists of a very sandy loam, on which the Muscat grape has proved a failure. The best Riverside soil is red or chocolate-colored sandy loam, so often spoken of. Towards Rincon we find alluvial bottom soils producing grapes of superb quality and size. The soil of the San Bernardino district resemble the red Fresno soils, while the white ashy soil is not found there.
El Cajon.
—The El Cajon valley soils are of three or more kinds: Rich red clay mixed with gravel, with the color changing from lighter chocolate to deeper reddish. This is a very desirable soil,—a steel gray or slate gray adobe with much gravel of a coarse nature; a black adobe with some gravel; an alluvial sandy loam consisting of decomposed granite mixed with much vegetable matter and humus. The El Cajon soils, while sandy and gravelly, produce exceedingly sweet and highly flavored grapes but comparatively small crops.
Subsoils.
—The subsoil in a raisin vineyard is of great importance. Properly irrigated soils, if they are sufficiently rich, need not necessarily be very deep, as the raisin grapes, especially the Muscat, seldom extend deeper than eight feet below the surface. Even from four to five feet of rich soil may be considered as enough in irrigated vineyards, where the water is abundant. In poorer soils, or in districts with less irrigation, the roots of the vines penetrate much deeper, and the importance of the subsoil in such cases is apparent. Any rich subsoil will serve our purpose. It is always best to thoroughly investigate the subsoil before the vineyard is planted, and in doing this the following points must be considered: The subsoil should be as rich as possible, and there should, in no instance, be less than four feet of rich top soil. Very sandy soil or pure sand is not a proper subsoil for raisin grapes. Such soil will cause the top soil to dry too quickly after each irrigation, and will cause the top soil to leach out, while it besides gives no nourishment to the vines. Hardpan is not desirable, not even admissible, except in places that are or will become subirrigated. Alkali or salty subsoils will soon spoil the quality of even the best top soil. This especially is the case in irrigated districts, where the salts of the subsoil are carried to the top by the rising waters or by the continued irrigation. Hardpan which readily dissolves when wet is not injurious.
Hardpan Soils.
—While I have alluded to them already, a few more remarks on these soils are here in place. The hardpan consists of a stratum of hard soil or hard rocky substance below the top soil. The depth at which the hardpan is found varies. In places where it is situated eight or ten feet below the top surface it does but very little harm, and may even prove beneficial in localities where water for irrigation is scarce, as it checks too rapid drainage. If the hardpan is situated closer to the top soil, it may seriously interfere with the vines, and if too close, or say within two or three feet from the top, it makes such soils entirely unfit for raisin grapes. If situated somewhat lower down, say from four to six feet, the hardpan does no great harm in subirrigated districts, while, in places where irrigation is not used, it leaves the top soil too shallow and too dry. But allowance must always be made as to the nature of the hardpan. Some varieties of hardpan are so hard that they can best be compared to regular stratified rocks, impenetrable to the roots of the vines, and impervious to water. Other hardpans again are softer, and allow the vine roots to penetrate more or less readily, while some again are so soft that they dissolve in water and make good soil for the vines. If the hardpan is very shallow, it may pay to blast holes through it, in order to allow the roots of the vines to penetrate to lower soils. But if the hardpan is thick and hard, and if there is no immediate prospect of subirrigation, it is better to use such land for some other purpose than for raisin-vines, which will only pay properly if grown under the most favorable circumstances, and on the best and deepest soils.
As to the nature of the hardpan, a few remarks may prove of interest. The hardpan can best be compared to a stalactite formation similar to those found in various caves. It has been formed very much in the same way as they were. In caves the rainwater, that seeps down from the top surface, dissolves various substances, especially carbonates (and silicates even) which again are deposited on the underside of the cave roof. This precipitation of hard material is caused both by evaporation of the water, as well as by attraction and adhesion. Such redeposition of dissolved minerals is seen for instance if solutions of salt in water are passed through tasteless and clean sand. The water will come through sweet and tasteless, the salt having adhered to the surface of the sand grains. Similarly, if a hole is dug near the seashore in the sand, the salt water will seep through, and form a well of more or less tasteless drinking water. In the formation of hardpan, this is exactly what has taken place. The rainwater has dissolved certain elements, such as carbonates of lime, or carbonates of sodium and various other salts, and in its way through the lower strata of the soil these dissolved elements have again been taken up by the sand and cemented it together. Thus it is explained why hardpan upon examination is so often found to resemble sand or sandstone: the lower sandy strata of the soil have been especially effective in causing the lime in the water to adhere to the numerous surfaces of every individual grain of sand. In hog-wallow districts the hardpan is found principally between the individual hog-wallows, but rarely in or under them. The rainwater has here carried the minerals in the soil to the deeper places between the hog-wallows, in which it has accumulated to a greater extent than anywhere else, and thus formed a heavier hardpan. In flooding the hog-wallows, the top of every hog-wallow is seen to settle and fall in, there being no hardpan below it, if the sides of the hog-wallow are steep. Where the hardpan consists principally of lime compounds, its chemical composition is not detrimental to the vines. But where the hardpan is cemented by alkalies more or less soluble in water, these deleterious substances will dissolve and rise to the surface to the great detriment or even to the total destruction of the vineyard.
Comparative Value of Soils.
—The river bottom soils, or soils formed by the deposit of creeks, are with few exceptions rich and deep, and contain in abundance all the elements necessary to produce a superior Muscat grape. Such soils are, however, often injured by subsoils containing mineral deposits, which will injure the vines, or by hardpans, which will cause the soil to dry out. Poor soils will not prove profitable, and rather than plant vines on such soils it would be better to plant no vines at all. The rich soils are not only the heaviest producers, but the vines grown on them are stronger and healthier and in every way better able to resist the attacks of insects and fungi and the ravages of other inexplicable diseases. But regardless of these advantages the various soils leave their effects on the grapes, some of them producing sweet and very keeping raisins, while others cause large berries and bunches, which bring the highest market price. Thus the lighter and drier soils produce richer flavored and sweeter raisins than the wet and rich soils, which again produce the largest and handsomest grapes. On the latter soils the raisins when cured will be found to be dark and covered with a heavy bloom, while the raisins from the sandier or gravelly soils are lighter in color and with less pronounced bloom. The keeping quality of the raisins from gravelly soils is well known. In California the keeping quality of the raisins is seldom inquired into, as our raisins keep remarkably well and are in this respect superior to those grown in Spain. This may be from the effect of our drier climate more than from any certain quality in our soils.
As a rule it may be said that poor soil causes the raisins to mature earlier than the rich, heavy loams, and on this account the latter are to be greatly preferred, as the earliest raisins in any district are never as good as the bulk of the crop, and are in demand rather as a curiosity, and for the purpose of supplying an early market, than through any superior qualities. In some districts there is such a great difference in the time of ripening upon the various soils that the grapes grown on the earliest soils are used only as table grapes fresh. In planting a raisin vineyard, the future profits depend upon the choice of land, and it is far better to pay a high price for the best land than to take the inferior land as a gift. Few of those who now enter upon raisin culture take the proper care in selecting the land, neither do they sufficiently, if at all, realize the advantages of the rich soil, nor the disadvantages of the poor land.
Alkali Soils.
—While nothing but first-class land is to be recommended for raisin vineyards, and alkali lands are of all soils those least suitable for our purpose, still a consideration of these lands will interest many raisin-grape growers. The best lands for raisin purposes in California are often contiguous to alkali lands, or to land containing more or less traces of alkali. A vineyard on the best soil contains often spots charged with alkali, and it may be inconvenient for the grower to allow these spots to lie idle, and he would prefer to fill them up with vines. The first work must then be to get rid of the alkali or reduce it to such an extent that it will not prove injurious. The general alkali lands are classed in three kinds, according to the quality of the alkali.
1st. Alkali salts, such as carbonates and borates. These are greatly detrimental to the vines, and no vines could be expected to do well in such soils, as even the smallest percentage of this alkali is injurious or even ruinous to the crop. In clayey soils these alkalies cause the clay to harden in such a way that no good tilth can be obtained. The land may be plowed ever so much, it will only turn up in chunks and never become properly pulverized. These true alkali salts consist principally of carbonate of sodium (sal-soda) or of carbonate of potassium (saleratus). Remedies: Gypsum, land-plaster or leaching with water.
2d. A second class of alkalies are the sulphates and chlorides, all soluble in water. Such salts are: Magnesium chloride (bittern), magnesium sulphate (Epsom salt), calcium chloride, etc. These salts, when not present in too large quantities, are easily counteracted by lime.
3d. A third class of alkalies is composed of neutral salts, such as chloride of sodium (common salt), sulphate of sodium (Glauber salt), sulphate of potassium, all soluble in water, but not convertible into less injurious substances by lime or gypsum. These salts do not bake the soil, but rather contribute towards keeping it loose and mellow.
The remedies which are practical and not too expensive may be divided into several classes, which, if used in combination, may prove effective, while each one of them used separately would fail.
1st. Leaching with water. All soluble salts may be leached with water. The alkali land should be checked and so ditched that the water from each check can be drained into a waste ditch. But, besides these waste ditches, drain ditches should be made for the purpose of draining off the water, say to a depth of four feet below the surface. The modus operandi consists in first flooding the soil, and while the check is yet full the floodgates are opened and the water drawn off into the waste ditch, when the water will carry off the salts which have been dissolved in it. A second or third flooding should be allowed to settle in the soil and be drained off below into the drain ditches. The drawback to common leaching is that under certain circumstances the water may deposit its alkali in lower strata, especially if they are sandy, and there form hardpan or alkali accumulations. A much better method is under-drainage by means of pipes or gravel drains constructed all through the tract at certain regular distances. This under-drainage, if properly constructed under conditions favorable for its perfect working, is by far the best method of freeing alkali soils from their superfluous salts. To what extent this system is practical depends upon circumstances. To reclaim large districts by this method may not prove economical as long as good land is plentiful and cheap, but where smaller alkali tracts are surrounded by soil, and where it is of importance to get a uniform plantation, under-drainage by pipes or common drains is both the surest and most practical solution of the alkali problem. Under-drainage is strongly recommended by Prof. E. W. Hilgard, who has repeatedly pointed out its value, and who has called the author’s special attention to this as yet little understood remedy.
2d. Deep and constant plowing. Deep and frequent plowing acts in various ways. By being mixed with a larger quantity of soil, the alkali is diluted sufficiently to not cause any serious injury to the crops, the damage generally being done near the surface. Constant plowing also prevents evaporation, which carries the alkali to the surface and deposits it there. This method can only be successful when the alkali salts are limited in quantity, and no one need expect to be able to rid badly charged lands from their alkali by plowing it under.
3d. By plowing under green or dry crops. If grain can be made to grow on the alkali land at all the turning under of it, either green or dry, will in course of time greatly reduce the alkali. The turned-under stubble or straw forms in decaying an acid, which in many instances will combine with and counteract the effects of the alkali. Similarly, straw stacks spread on alkali spots and plowed under will considerably reduce the alkali. But manure containing ammonia and other salts should not be used, as it will, on the contrary, only increase the alkali by adding other or similar salts to those already in the soil.
4th. Cropping. If water, either in the form of sufficient rain or as irrigation can be had, alkali lands can be reclaimed by cropping. It is amply proved that beets and carrots, as well as other plants, such as salt-bush (Chenopodium), take up large quantities of alkali salts, and in the course of a few years render alkali soils available for grain. Wheat also extracts alkalies, and repeated croppings with grain will in the course of time prepare the soil for vines and trees. Bermuda grass will completely remove the alkali from soils to the depth at which the roots can penetrate, and must be recommended for the worst places. Afterwards, cropping with annual crops may be advisable before vines are finally planted on such reclaimed lands. The Australian salt-bushes, or Chenopodium, extract alkalies, and are besides liked by stock. They should be introduced to alkali lands and take the place of the California native salt-bushes, which are not eaten by stock. While being real desert plants, they yet require some moisture in the soil, but they could probably be grown anywhere on the alkali lands in this State where the rainfall is over three or four inches.
5th. By chemicals. The use of chemicals of various kinds in counteracting the alkali is not resorted to by our farmers as it should be. The principle upon which chemicals can be used is that obnoxious or greatly injurious alkalies may be changed into less obnoxious and less injurious salts, or even into fertilizers. The most available of these chemical compounds are gypsum (sulphate of lime) and lime (carbonate of lime). When the alkali consists mainly of carbonates, such as carbonate of sodium (sal-soda) or potassium carbonate (saleratus), in other words of the class which we have designated as class number one, the most dangerous and worst class of alkalies to combat, gypsum may be used as an antidote or rather as a means to convert these alkalies into alkalies of the second class, or the sulphates. The principle upon which this is done is to displace the sulphate in the gypsum and force it to combine with the alkali (sodium carbonate) and form sulphate of sodium (Glauber salt), an alkali belonging to the third class of alkalies, and which is twenty times less injurious to vegetation than is class number one. The change is made on the following principle, and might be thus illustrated: To the alkali in the soil (carbonate of sodium), add sulphate of lime. As soon as the mixture is made with sufficient water, a change will take place, and the substances (carbonate of sodium and sulphate of lime) will form new compounds. Thus we will get, out of those two substances, two new compounds, viz., carbonate of lime and sulphate of sodium. Of these, carbonate of lime is not injurious to vegetable life, and sulphate of sodium (Glauber salt) is only injurious when present in large quantities. The carbonate of lime is not soluble in water, but the sulphate of sodium is, and can consequently be eliminated by underdraining or by flooding, as we have previously described.
To know when gypsum can be used is not necessarily a scientific matter. Mix some of the alkali in a tumbler with water, and allow the mixture to settle. In another tumbler mix some gypsum and water, and allow it to settle. Then mix the two clear liquids, which, if gypsum is an antidote and the proper thing to use, will be turbid or milky through the chemical combinations which take place. If the water remains clear, gypsum will not prove an antidote to the alkali under consideration. The use of lime is based very much on the same principle. If the second class of alkalies are present, and lime is added, the changes that take place may be illustrated as follows: Epsom salt (magnesium sulphate) combined with calcium carbonate, will form two new compounds, viz., gypsum (calcium sulphate) and magnesium carbonate, both of which substances are less injurious to crops. But, as I have already stated, raisin-vines prefer soils which are naturally free from alkali, and should never be planted on soils which cannot readily be reclaimed. Chemical antidotes may do where the alkali occurs in a few spots mixed in among tracts of good soil, but where the whole field must be reclaimed some other crop than vines had better be first attempted. There is too much good and suitable soil in California, and until all this is occupied the alkali soils had better be given up to other crops than vines.
Fertilizing.
—To this date but few grape-growers manure their soil. California has not yet been engaged in the raisin business twenty years, and her vineyards are comparatively virgin. The first raisin vineyards were planted on the deepest and richest soil, the soil which would naturally hold out the longest, but the croppings of a raisin vineyard are enormous, and when from eight to ten tons of green grapes have been taken from the soil year after year, it is but natural that the land should become gradually exhausted. In Spain it is considered that even the richest soils require manuring after ten years of constant cropping with Muscats, and the same experience is likely to become ours in California. So far, I know of not one vineyard which has yielded Muscat grapes for ten continuous years and still keeps yielding as much as formerly. Yearly the crop must become less, and finally will not be large enough to pay. The manuring of the Muscatel vines is fully understood in Spain, where all kinds of manures are used. When home manures fail in supply, the Spaniards use imported fertilizers, such as Mexican phosphates, etc. This fertilizer brings in Spain sixty-five dollars per ton, and is brought there from our very doors,—the Gulf of Lower California. It could be laid down here for, and is actually sold here now at, forty dollars per ton, or twenty-five dollars less than in Spain; still to my knowledge only very few raisin-growers in Fresno use it for their vines. In one year one of these succeeded, with the aid of this phosphate, in raising the crop of an acre of Sultana grapes from a very poor yield to over eight tons. The grapes were grown on a piece of sandy soil of the kind well known to Fresno vine-growers, and which is generally considered as less suited to raisins, lacking in fact in more than one of the necessary qualities of a good raisin soil.
It is certainly a wrong policy to crop the soil until the grape crops begin to fail. The soil will then be so exhausted of several of its ingredients, that it will take the most scientific treatment to bring it back again to what it was formerly, and it is even questionable if this could be done in a way that would prove profitable. Experience in Spain teaches that vineyards which formerly used to yield from eight to ten tons of green grapes to the acre now, after years of neglect, only yield two tons to the acre, and even with expensive manuring can in no way be brought back to their former fertility. On the other hand, we know that vineyards which have been fertilized from the beginning have for fifty years been kept up in apparently as good condition as at first; it is accordingly this method that must be recommended. The manure or fertilizer must be varied occasionally. In rotation, phosphates, bone dust, guano, stable manure, sheep manure, lime and plaster of Paris or gypsum may be used, but it is best to have every variety of soil in the vineyard analyzed, and to apply from year to year that kind of fertilizer which is particularly needed. The phosphates are those which will first give out in our California soils. Phosphates must therefore be considered as the best fertilizers we can use, but the quantity to be used must always be determined by a practical chemist. Of these chemical fertilizers, it is dangerous to use too much, as they might injure the vines, and from fifty to a few hundred pounds to the acre may in some instances suffice and produce better crops than would four or five times as much. But, regardless of chemical fertilizers, the cautious raisin-grower should endeavor to return to the soil as much as he possibly can out of the wastes of his crop. The refuse of stems and berries, which are wasted at the stemmer and in the packing-house, should not be burned, as is generally the case, but returned to the vineyard, and applied one year on one piece of ground, and another year on some other piece. If, however, these wastes must be used as fuel in the dryer, etc., the ashes should be carefully collected and spread over the soil, and kept dry and shaded until thus used.
Another most valuable fertilizer generally wasted is the trimmings. In our careless California farming, these trimmings of the vines are put in piles on the roads, outside of the vineyards, and there burned. Thus the ground loses the most powerful soluble salt, which would greatly increase the yield of grapes and the profits to the farmer. Where the vines are planted far enough apart, the trimmings may be burned between the rows of the vines without injury to them, but, when the vines are set close, there is no other way than to carefully collect the ashes and spread them evenly over the soil. Some vineyardists use large troughs made of galvanized iron and perforated with holes. These vats are drawn through the vineyard by a team, and scatter the ashes evenly over the soil. The vats may be so constructed that the cuttings are burned in them directly as they are being pulled along, thus saving much labor as well as ashes. Such contrivances will probably only prove profitable in large vineyards, where there are long rows and few turnings for the teams. Even the stable manure in our State is not used as it should be. It is hardly possible to understand how vineyardists can be thoughtless enough to haul loads upon loads of stable manure on their roads or in holes and waste places, while their vines adjoining are suffering from the want of sufficient nourishment. In the irrigated districts, this is a very common sight, and the wet places on the road are often deep with manure and strongly smelling of ammonia. If the manure had been placed around the vines, the increase in crops would probably have been sufficient to enable the owner to macadamize or otherwise permanently fix the roads.