“Satisfactory inoculations have been obtained by transferring soil from old fields on which the legume has been grown, but experience has shown that there are dangers incident to such methods of soil transfer which it is wise to avoid.
“The source of supply of such soil should be definitely known, and in no case should soil be used from fields which have previously borne any crop affected with a fungous disease, a bacterial disease, or with nematodes. Where a rotation of crops is practiced, it is often difficult to make sure of this factor, so that the method of soil transfer is, under average circumstances, open to suspicion, if not to positive objection. Numerous animal and plant parasites live in the soil for years, and are already established in so many localities that it is manifestly unwise to ship soil indiscriminately from one portion of the country to another.
“The bacterial diseases of the tomato, potato, and egg plant, and the club-root, brown rot, and wilt disease of the cabbage, all more or less widely distributed, are readily transmitted in the soil; while in the South and West there are the wilt diseases of cotton, melons, sweet potatoes, cowpeas, and flax, and various nematoid and root-rot diseases which might easily become a serious menace over areas much larger than they now occupy if deliberately spread by the careless use of soil for inoculation purposes. There are several insects and fungous diseases of clover to be avoided, and various diseases of beans and peas. There is also a disease of alfalfa, the ‘leaf spot,’ which is causing damage in some regions. These are only a few of many diseases liable to be transmitted in soils. The farmer should therefore be on his guard. The danger from such sources is by no means imaginary. The Department of Agriculture has had specific cases of such accidental distribution reported, and if the business of selling soil for inoculation is made to flourish by farmers purchasing without question ‘alfalfa soil,’ ‘cowpea soil,’ etc., there is every reason to believe that experience will demonstrate the folly of such haphazard methods.
“Of scarcely less importance is the danger of disseminating noxious weeds and insect pests through this plan of inoculation by means of soils. Even though weeds may not have been serious in the field, the great number of dormant seeds, requiring but a slight change in surroundings to produce germination, is always a menace. The enormous damage to crops caused by introduced insects and weeds should convey a warning and lead to caution. It is not the part of good judgment to view the risk as a slight one.”
OTHER METHODS OF INOCULATION
There are two or three better ways of inoculating land than by using a neighbor’s soil. Some alfalfa raisers recommend the sowing of alfalfa meal with the seed. Another plan which appears reasonable and practicable is for the farmer who wishes to introduce alfalfa to buy alfalfa hay the year before and feed it to his live stock; then haul the manure to the fields and plow it under for the crop to precede alfalfa. It is claimed by those who have done this that a satisfactory stand is well-nigh certain, other conditions being met. It can be said, however, that some high authorities on this crop, men who have experimented on many different kinds of soil and who have succeeded under varying conditions, declare that neither soil nor seed inoculation is necessary. It is altogether probable that if a field has been well farmed for a few years previous to the alfalfa-sowing, with unusually good cultivation the preceding year, a heavy application of stable manure plowed under at least five months before, then given the proper preparation and seeding, using seed raised in about the same latitude and under similar conditions in which the new crop must grow, and with seed testing ninety per cent germinable, there should be little anxiety about the need of inoculation. Of course old, worn-out land may require more fertilizers, restoring to the soil not only necessary nitrogen that has been exhausted by other crops, but also the potash and phosphorus. In eastern states it has been found advantageous also to apply a very light top-dressing of stable manure just before sowing the seed. If lime is deficient, that must be applied. An examination of any particular soil will usually be made without charge by the state chemists, and the farmer may thus approximately ascertain just what the soil will need for alfalfa, corn, or any other crop he may desire to raise.
KEEP ON TRYING
It is important to say to the eastern farmers, especially, that there is little difference between successful alfalfa-growing and the successful growing of other crops. Poor farming never brings big crops, nor will poor land produce as big yields as the more fertile. Failure to restore to the soil the necessary elements of which it has been robbed means the same in New York, Kansas, Virginia, or anywhere else. Every farm plant, to prosper, must find in the soil, readily available, the elements needed for its development. If a farmer finds the soil lacking in elements needed for certain crops, he should either apply the deficiency or not attempt their raising. This is true of corn or wheat, cotton, or tobacco, no less than alfalfa.
Alfalfa needs especially nitrogen, potash and phosphorus. The average virgin soil in the United States contains enough of these to last several hundred years. If there had been at all times an intelligent rotation of crops, these chemical elements would be found in just as large proportions in the soil that has been farmed a hundred years as in the soil never cultivated. Hence, if after trying alfalfa a man meets with failure, he should not stop, and say, “Alfalfa won’t grow ‘here’,” but try it again immediately. If he discovers a seeming failure in March or April, he should disk and harrow and as early as possible sow about ten pounds of seed to the acre; in many instances he will have to clip his alfalfa in about six or eight weeks and can mow a crop of hay in September, or possibly two hay crops in the season. There have been various cases reported where three hay crops were secured the first season after such cultivation, when the fields had been pronounced a failure in March. Alfalfa may be sown on such ground as late as the first of June if the weeds have been thoroughly subdued. Or, if it has been sown in the spring and the weeds seem to be overtopping it in July, mow close to the ground, rake into windrows and burn. Then disk and harrow thoroughly and sow again. In all probability there will be something of a crop to mow early in September, with a considerable autumn growth to follow. If it is not desired to sow alfalfa in midsummer, disk this ground and sow to rye or oats for pasture; then late in August disk and put in readiness for September sowing. The failure may have been because the soil had not enough bacteria, or favorable environment for the bacteria. Some of the seed sowed at first undoubtedly germinated and some bacteria were developed; enough certainly to prepare the soil for the second sowing. It is unwise after such a failure to go to another field or to wait for another year. It is wiser to meet the conditions at once, and vigorously persevere.
In reference to the application of lime, mentioned on a preceding page, it should be noted that the later experiments seem to indicate that it is better to apply smaller quantities at shorter intervals than larger quantities at longer intervals; also that air-slacked lime is less caustic than the quicklime, and not so liable, when recently applied, to harm the young plants which may come in contact with it, hence more of the former may be used and with greater safety. Ordinarily quicklime is considered the most beneficial.