STORING IN THE BARN
The barn is the best place for alfalfa if all conditions are right. Cases of spontaneous combustion in stack and mow make farmers fearful of using the barn, especially for the first cutting, which is always most difficult to cure. There are certain conditions that must be observed if this hay is to complete its curing properly and safely in the mow. The bottom of the mow should be elevated at least a foot from the ground, floored with poles or joists, and they should be about two-thirds covered with boards or other material in such a way as to provide numerous openings or air spaces of considerable size. If the mow already has a tight floor, a part of the flooring should be removed before the hay is put in. Then a box or barrel should be placed in the center of the space and lifted up as the filling proceeds. If the mow is over thirty feet long, a second barrel should be used; that is, an air shaft should be left in about each fifteen to twenty feet. A layer of dry hay or straw sandwiched in about every four of five feet, as the mow fills, can be used to much advantage. If the mow is large enough in length and width, an excellent, safe plan is to spread the first cutting over the entire bottom, filling up to a height of four or five feet. The second cutting may be placed over this, on top of a layer of straw, and the third cutting over this. There is virtually no danger from spontaneous combustion or from mold if this is done, and the hay will be as bright and green and almost as rich in protein in January as when harvested.
J. W. Berry of Jewell county, Kansas, member of the board of regents of the state agricultural college, uses this method and bales his hay in October for the city markets, finding it in perfect condition. He puts his hay into the mow green but not wet, direct from the cocks, or windrows the day it is cut, in layers about four feet deep, with the slightest possible loss of leaves, no bleaching and no injury by dew. In 1905 he cut his alfalfa four times and stored the fourth cutting on top of the three preceding. He says that having an open floor and plenty of air from the outside, the hay can be put in the barn as described; that it should not be tramped, and it will settle and cure perfectly. The bottom layer or first cutting may show some dust when taken out if handled loose, but the color will be good and it will bale in with the other cuttings and all grade well. Hay cured in this way in 1904 graded “choice” in the St. Louis market.
Spontaneous combustion does not occur very often, but it is a possibility, and it is well to bear in mind that hay may be put in the barn too green. Observation teaches that it never takes place unless the hay has been put in the barn while containing a large amount of moisture, and piled too deep. Alfalfa and other clover hays may safely be put in the barn when they contain not to exceed 30 per cent of water. If, however, they contain much more than this there is considerable danger, especially where large quantities are put together, as is the case in large, deep mows and sometimes in large stacks. A practical test which may be safely followed is to take a handful of hay, twist it as hard as possible, and if no juice can be wrung out of its stems, it is dry enough to be put in the mow. Bunches of wet hay mixed with dry hay have often caused combustion. Such should always be discarded. It is poor policy to haul clover hays into a barn after sundown, as at that time it absorbs moisture from the atmosphere very rapidly.
It is a good plan for the haymaker to go into his mow every morning while the hay is curing and observe the conditions, but he should not, however, become alarmed if he finds that the top of his hay is very damp. This will always be the case, even if it was comparatively dry when put in; considerable heat develops during the night, which in turn evaporates moisture. The following morning, when the air is cool, a large percentage of this, especially if the mow is not well ventilated, is condensed and settles back on the hay. If the moisture, however, is excessive, it is a good plan to scatter a load of dry straw over the top. This will absorb the moisture in part, after which filling may be continued. In case a load has been put in the barn too wet, it should be spread to the outer edges, as there is much less danger of combustion at these places than in the center. In fact, the greatest heat is always developed in the center, where the so-called craters form, and from which moisture and gases are given off as a result of heating and oxidation below.
From the fact that spontaneous combustion cannot take place until the water has all been evaporated, there is no danger until three to four weeks after the hay has been stored. During the first week or so, if the hay heats to such an extent that there is danger of combustion, it is well to open up the center as much as possible and allow some of the heat to escape. If, however, the heating has continued much longer, it is dangerous practice to open the hay at all, because all that is needed, after the water has been evaporated, is air, or oxygen to support combustion, and the mass will at once burst into flames. Sometimes combustion takes place without flames, in which case the center of the mow gradually chars, leaving the hay there as black as charcoal, and without value.
Professor Cottrell, discussing spontaneous combustion (Kansas Bul. No. 114), says that all cases observed by him have occurred in hay of the season’s first cutting—cut at a time when the growth was rank and the curing most difficult. A period of wet, muggy weather in July or August increases the danger, which in dry weather seems much less. On account of previous trouble from heating in the barn, he had four years prior to writing stacked the first cutting out of doors and put only the later cuttings in the barn.