Science and Practice in Farm Cultivation Part 20

We distinctly recollect when the lias clays of the Vale of Gloucester could scarcely be made to grow a good crop of even the hardier sorts of red wheat, the common cone being the sort generally grown. This was succeeded by many sorts of red wheat, and now only the best-cultivated farms produce white wheats. These, however, are facts which will be more strongly brought out when we consider the subject of cultivation; for the present we would be content with the expression of a belief that wheat, as a cereal grain, is derived by cultivation from a wild gra.s.s, and it is due to the effects of cultivation that we have so many sorts, with such variable adaptability.

CHAPTER XXVI.

THE WILD OAT AS THE ORIGIN OF THE CULTIVATED VARIETIES.

Crop oats, like wheat, have ever been considered as a direct gift from Ceres, and few, indeed, amongst scientific men were willing to believe that they were derived from a wild and weed species. Still, the farmer had long maintained that oats, when cultivated, often left behind them weed oats; and in some districts of Worcester, Gloucester, and Warwick, we have known men refuse to grow oats as a crop from their fear of producing the terrible weed, which, indeed, the wild oat is on all hands admitted to be.

Now, although we by no means wish to advance the theory of trans.m.u.tation, and cannot believe that by any plan barley can be converted into oats, or oats into barley, we are yet confident that what has been termed _enn.o.bling_, or the producing of a cultivated plant from a wild one, is oftentimes comparatively easy, and in none more so than in the production of crop oats from the wild species, _Avena fatua_.

Professor Lindley, in the article "Avena," in Morton's _Cyclopaedia of Agriculture_, suggests that the cultivated oat "is a domesticated variety of some wild species, and may be not improbably referred to _Avena strigosa_, bristle-pointed oat;" but our experiments would show that the _Avena fatua_ is the form from which at least the domestic sorts in general cultivation seem to have sprung.

The _Avena fatua_ (wild oat) is an annual gra.s.s which almost universally accompanies agrarian circ.u.mstances; that is to say, it seldom, if ever, occurs in a truly wild aboriginal state, and is therefore not found in uncultivated tracts, but is the common attendant on tillage, and in some soils is a most common and disagreeable weed in various agricultural crops, but more especially amid grain, whether of wheat, barley, or oats. Sometimes it is found with beans, peas, and vetches, and, indeed, it may be said to be a common weed in some districts in any crop from which it has not been eradicated by the hoe-an operation almost impossible in grain, as its growth is so much like that of the crop itself.

It is a tall gra.s.s, rivalling the height of the finest cultivated oat crop, from some forms of which, and especially those with a lax panicle, it is at first not easily distinguished; however, a more careful examination and comparison with the so-called _Avena sativa_ (cultivated oat) enables us to make out the following differences:-

_Avena fatua, L._ _Avena fatua_, var. _sativa_.

The valves of the inner pales, The valves of the inner pales not which adhere to the seeds, thick, not so coa.r.s.e as in _A. fatua_, and covered with stiff hairs, and quite devoid of hairs. The especially towards the base. The outer valve with or without an external valve has a long stiff awn, which when present is not so awn, which in the ripe seed is stiff as in the wild plant, usually twisted at the lower part, sometimes twisted at the base, and bent at nearly right angles but seldom bent. Seeds large and at about the middle. The grain- full, forming the grain for which seed very small and worthless. the crop is cultivated.

The experiments about to be detailed were performed with the _Avena fatua_.

In 1851, a quant.i.ty of this plant was noticed by the author on the farm of C. Lawrence, Esq., near Cirencester. It was mixed with a patch of mangel-wurzel which had been planted for seed; and from these specimens sufficient seeds were preserved wherewith to sow one of our experimental plots.

It should be noticed that the substratum was forest marble, and no doubt the seeds of the oat were brought with the manure by which the mangold patch was dressed.

In the spring of 1852 a plot of two and a half yards square was sown with seed which had been kept during the winter-a fact which should be carefully noted, as it forms a first and most important link in the chain of evidence, and const.i.tuting what we term a cultivative process, inasmuch as in wild growth the seeds are sown as soon as they become ripe.

The seeds of the first crop came up well, and on ripening, towards autumn, the plants were tall and robust; the grains presented a scarcely appreciable difference from the wild examples; if any, there may have been a slight tendency to an increased plumpness of grain.

The seeds of crop No. 1 were again collected and preserved throughout the winter, and sown in a patch of similar size, but in a different part of the garden, in the spring of 1853, repeating the process with the successive crops in 1854 and 1855, with slight alterations from year to year, though in some examples the following tendencies seemed from the first to be gaining strength in some few of the specimens:-

1st. A gradual decrease in the quant.i.ty of hairs on the pales.

2nd. A more tumid grain, in which the pales were less coa.r.s.e and the awn not so strong and rigid, and less black than in the wild example.

3rd. A gradual increased development of kernel or flower.

The seeds of 1855 crop, without selection, were treated in the same manner during the winter, and were sown in the spring of 1856, the resulting crop in August of the same year presenting the following curious circ.u.mstances:-

1st. _Avena fatua_ (typical wild oat), with large loose panicles of flowers,[10] thin hairy florets, with a bent awn twisted at the base.

Five parts of crop.

[10] Some examples of this plant, gathered at Framilode, in the Vale of Gloucester, in the past autumn, gave as many as 750 seeds to a root, from which its rate of increase as a weed may be imagined.

2nd. _Avena fatua_, var. _sativa_, with loose panicles of flowers, florets quite smooth, tumid, with or without straight awns, some few examples slightly hairy towards the base. This is the potato-oat type.

Six parts of crop.

3rd. _Avena fatua_, var. _sativa_-Panicles more compact, flowers inclining to one side, grains more tumid than 2nd, quite devoid of hairs, awn straight. These present the type of the white Tartarian oat.

Twelve parts of crop. Fig. 2. See plate.

Having now procured a crop of separate types of oat from the same seed, we preserved them distinct, and this year carried on our experiments by cultivating a patch of each, whilst the plot of 1856 was left with self-sown seeds, in order that it should again become wild by degeneracy.

From these experiments, then, we may conclude that different types of crop oats are derived from the _Avena fatua_, or wild oat; but, besides this, they open out a subject for inquiry of great practical interest and importance, which may be clearly stated as follows:-

If by cultivation the wild oat a.s.sumes the cultivated form, then by degeneracy cultivated oats may become wild ones.

Those who know what a detestable weed is the wild oat wherever it occurs, and how difficult it is to eradicate,[11] will at once see the cogency of the question involved.

[11] The author once went with a rector of a parish in Gloucesters.h.i.+re to examine the glebe allotments of the poor people, when, catching sight of an apparent crop of oats, the landlord threatened to dispossess the tenant, "because he had carelessly left his crop without gathering."

However, the matter was explained when it was pointed out that the land was planted with wheat, which the oats had quite smothered.

Farmers in some districts, and more especially on stiff clay soils, have ever objected to the cultivation of oats, as they had always maintained that they left behind a crop of weed oats. This, which was never a favourite idea with the botanist, who is generally too much inclined to species-making, seems now to have a basis of truth, for not only is it confirmed by the experiments described, but observation of an independent kind points to the same truth.

On examining the produce of shed, or accidentally scattered oat seeds, the first crop will often present the wild tendency in a partial reversion to the hairy state, an elongation and thickening of the awn, and a lessening of the size of the kernel; and this more particularly on heavy soils. It was, indeed, an observation of this change in oats scattered on forest marble clay which induced us to try the experiments above detailed; and as the subsoil of our botanical garden is the same clay, we are, perhaps, indebted to this cause for arriving so soon at such signal results.

Again, it is known in farming that some clay lands will never produce heavy oats; a sample, however good, is sure to degenerate upon such soils. Hence, then, the foregoing experiments and observations lead to the following conclusions:-

1st. The wild oat is perhaps not a native of Britain, but derived through the degeneracy of the cereal crop; and hence its occurrence only as an agrarian.

2nd. The cereal oat, on the contrary, is the result of the impress of cultivative processes upon the wild form, and as such liable to lapse into the wild state with greater or less celerity, according to the circ.u.mstances of soil and situation.

These conclusions are of practical value, as they show the direction in which experiments should be conducted in order to attain to varieties, it being a well-known fact that one variety is suitable for one soil, and another for a different kind of land. And again, as some forms of plants would seem to have the tendency of wearing out by long cultivation, so we have the means of applying to the original source of their production, and thus of commencing a new generation.

They teach us, too, the necessity of avoiding the growth of the oat crop in some situations, and which in the case before us is not the result of the "pigheadedness" with which the farmer is often so thoughtlessly accused, but a conclusion founded in reason; and if we consider how robust is the growth of the wild oat, and that its support is secured by robbing the grain crop with which it occurs as a weed-the difficulty of separating it from the crop where it has gained a footing-and, above all, that its succession is secured by its seeds universally ripening a few days before that of the crop with which it is mixed, and the moment they are ripe they fall and become self-sown,[12]-we can see abundant reason for wholesome fear as to the introduction of cereal oats in districts liable to their degeneracy.

[12] The wild forms shed their seeds much more readily than the cultivated ones, and are, besides, earlier in ripening, and thus much of our wild seed had dropped before the other forms were fully ripe; and it much a.s.sists experiments in trans.m.u.tation not to let the seeds with which they are to be carried on become dead ripe. This is another cultivative process.

The annexed enlarged figure of a bunch of wild oat seeds will sufficiently ill.u.s.trate the changes necessary to produce the cultivated form.

Under cultivation, which supposes the _selection, saving up, and sowing in a prepared_ bed of our seed, the wild oat seed gradually becomes smooth externally, and its awn less coa.r.s.e, while internally the grain becomes larger and heavier; so that while the seed of the wild oat would weigh about 15 lb. per bushel, that of a fine sample of white cultivated oat sown on our farm this year weighed as much as 48 lb. per bushel.

Now, the proof of this theory consists in the facts-

1st. That heavy oats degenerate by being _cultivated_ in poor soil.

2nd. By _being let go wild_, they sink still lower, and gradually a.s.sume the external hairs, stiff awns, and poor grain of the wild oat.

[Ill.u.s.tration: _Spikelet of the Wild Oat._[13]]

[13] From _Popular Science Review_, vol. i. p. 10.