The Principles of Practical Agriculture pp. 398-399 (1856)

By Albrecht Daniel Thaer

Many persons consider a frequent change or renewal of the seed as an indispensable condition to the production of a fine crop. The necessity of this change is insisted on both by theorists and practical men, especially in extensive agricultural undertakings, where the great object is to produce, the largest possible amount of matter. But, according to my own conviction, the strength of which has been rather increased than diminished, in proportion as I have acquired new data, the advantage derived from the use of seeds procured from foreign sources arises solely from this cause, viz. that farmers are not in general sufficiently careful in the choice and preservation of the seeds which they have gathered themselves. It may occasionally depend upon locality, or upon the nature of the soil and climate not being favorable to the perfect formation of certain kinds of grain; and. in that case, recourse must be had to seed procured elsewhere. But it more frequently happens that the amount of labor required by the farm or agricultural undertaking does not admit of the farmer's being able lo devote the necessary care and attention to the grain in tend ed for seed; hence it is often injudiciously selected, and suffered to experience fermentation, which deteriorates from its value and healthfulness. In all countries there are some districts and some particular farms which are famous for producing certain kinds of grain, and where the whole harvest is frequently sold for seed at very high prices. In such localities we generally find that this advantage arises not less from the nature and properties of the soil being favorable to the production of one particular kind of grain, than to the infinitely greater care and attention which is paid to the crop; and we shall also find, even among the farmers themselves, a conviction that they owe the reputation their seeds enjoy as much to the latter as to the former circumstance.

In places where one or both of these advantages are not attainable, it may undoubtedly be advantageous to procure the seed elsewhere, even though this can only be done at great expense; but I am by no means an advocate for the absolute necessity of this mode of proceeding, for I am convinced that if the soil be in other respects favorable, any kind of seed which is at first imperfect will gradually improve in quality, and, with care and attention, eventually be rendered perfect.

Persons who maintain that a renewal or change of seed is absolutely necessary, inquire whether it ought to be taken from a richer or poorer, a stronger or lighter soil, and from a milder or colder climate. My reply is, procure it from that place where it is most perfect and healthy. This is not always where the soil is richest, or the climate the mildest; as in such places the corn is often too thick on the ground, and consequently not sufficiently exposed to the influence of air and light to allow the grain to acquire absolute perfection; besides, the seed or grain is often too large, and there is more husk than farina in its component parts, the latter of which is alone capable of affording nutriment to the young plants. In those places, on the other hand, where the soil is so weak that it is incapable of furnishing sufficient nourishment to effect the complete formation of the grain, that grain will be equally improper for the reproduction of other plants; for wheat grown upon a soil which only produces stunted grain will always bear an imperfect seed, and will require to be replaced by seed derived from really good wheat land.

It is a well known fact that, in plants as in animals, strength and weakness, health or disease, are transmitted not only to the first generation, but through several succeeding ones; and that these dispositions can only be gradually eradicated by the help of other influences.

A change of seed is never entirely successful unless managed with great circumspection. Great care must be taken to see that the grain which is to be sown is perfectly free from the seeds of weeds, otherwise we shall incur the danger of introducing into our fields some useless or even injurious plant which had not previously existed there—as, for example, the golden daisy or corn chrysanthemum (chrysanthemum segetum).

If there be no means of separating the grain from certain seeds of weeds, that may be considered as a motive for procuring the former from some other place where these pernicious seeds do not exist Thus, in my neighborhood, they often change the barley and oats grown on the hills for those raised on the low lands; because, in the latter, those kinds of grain are found mixed with field mustard, which weed does not thrive on high lands; while, on the higher grounds, the oats and barley are found intermingled with wild horse-radish, which weed can easily be extirpated from the low grounds.

Some seeds retain their germinating power for a considerable period, provided only that they are carefully preserved; while others, on the contrary, lose it quickly, and can hardly retain it for the space of a year. If we come to examine which are the seeds that retain their vitality for the greatest length of time, we shall find it is always the most perfect ones, and that the imperfect and sickly ones lose their power of germinating first. To this fact is to be principally attributed the advantage of old seed over new in several kinds of plants. Vegetables and plants can only be procreated by perfect and healthful germs, which have not been deprived of their necessary space and nourishment during their growth by abortive plants which will never come to maturity, and which come from a crop free from those diseases the germ of which lies in the grain, as is the case with smut mildew, &c. But, if we would fully understand this point, we must make ourselves perfectly acquainted with the nature of each particular kind of plant or vegetable. Grain which has become perfectly matured may be preserved for a very long time. Stores of grain are known to have been preserved from time immemorial in caves hewn in solid rocks, which have been discovered by chance, and the contents of which have still proved to be good for seed. This could not, however, in all probability, have been the case had not the grain been totally secluded from the influence of light, air, and moisture. In general, grain does not keep for any great length of time; some persons, however, assert that they have found wheat that had been kept five years, and rye three years old, to be fit for vegetation. Wheat of only one or two years old is almost universally preferred, as being less liable to disease. Most agriculturists are of a different opinion as regards rye, and prefer quite new grain; for, when it is more than a year old, they consider it necessary to sow it more thickly than they would in the former case; and, consequently, an equal measure of seed would sow a smaller extent of ground in the former than in the latter case.

Change of Stock/Seed/Conditions