Part 31

The Second sort of Blight, viz. from light Ears, is that which is most frequent, and more general: This brings the greatest Scarcity of Wheat. The Cause is plainly Want of Nourishment to perfect the Grain, by whatever means that Want is occasioned.

Several Accidents kill the Plants, or injure their Health, and then the Grains are not filled; as Lightning, the Effects whereof may be observed by the blackish Spots and Patches in Fields of Wheat, especially in such Years as have more of it than usual. Against this there is no Defence.

The other Causes of the Blight, which are most general, and do the most Damage, may, in some measure, be prevented.

One Cause is the lodging or falling of Corn; for then the Stalks are broken near the Ground, whereby many of the Vessels are so pressed, that the Juices cannot pass them; and then the free Circulation is hindered; the Chyle cannot mount in sufficient Quantity to be purified, and turned into Sap; the Defect whereof makes the Plants become languid, and only just able to live; they have Strength enough to linger on to the time of their Period, as in very old Age, but not to bring their Fruit, which is the Grain, to its natural Bulk, nor to fill it with Flour: and the sooner the Stalks fall, the less and thinner the Grain will be.

Hence it often happens, that when Tillage, Dung, and good Land have brought a Crop of Wheat, that in the Months of April and May promise to yield the Owner Five or Six Quarters on an Acre, then in June it falls down, and scarce affords Five or Six Bushels; and that perhaps is so thin and lank, that the Expence of reaping and threshing it may overbalance its Value.

That the falling down of Wheat does cause the Ruin of the Crop, is well known; but what causes it to fall, is not so plain.

And, without knowing the true Causes, ’tis not likely that a Remedy should be found against the Disease.

I take this Weakness of the Stalks, which occasions their falling, to proceed from want of Nourishment, want of Air, want of the Sun’s Rays, or of all Three.

One Argument, that it lodges for want of Nourishment, is, that a rich Acre has maintain’d a Crop of Five Quarters standing, when another poorer Acre was not able to support a Crop from falling, which was but large enough to have brought Three Quarters, if it had stood: and this in the same Year, and on the same Situation. And ’tis very plain, that if one Acre was twice as rich as the other, it must be able to nourish Five Quarters better than the other could nourish Three Quarters.

Air is necessary to the Life and Health of all Plants, tho’ in very different Degrees: Aquatics, which live under Water, are content with as little Air, as their Companions the Fishes.

But Wheat, being a terrestrial Plant, (tho’ in Winter it will live many Days under Water, whilst the slow Motion of its Sap gives it little or no Increase), requires a free open Air, and does not succeed so well in low sheltery Places, as upon higher and opener Situations; where the Air has a greater Motion, and can more easily carry off the Recrements from the Leaves, after it has shaken off the Dews and Rains, which would otherwise suffocate the Plants; and therefore the Leaves are made so susceptible of Motion from the Air, which frees them from the Dews, that would stop in the Recrements at the Vesiculæ of the Leaves, but shaken down will nourish the Plants at the Roots: The want of this Motion weakening the Wheat, ’tis (as Animals in the like sickly Case are) the more unable to stand, and the more liable to be press’d down by the Weight of Rain-water, and more unable to rise up again when down: All which Evils are remov’d by the free Motion of the Air, which shakes off both Dews and Rains, and thus contributes to prevent the falling (or lodging) of Wheat.

A great Quantity also of the Sun’s Rays is necessary to keep Wheat strong, and in Health; and in Egypt, and other hot Countries, it is not so apt to fall, as it is when sown in Northern Climates, tho’ the Produce of the South be the greatest.

This proves that the Crop doth not lodge on account of its Bigness.

It may be observ’d, that every Leaf is inserted into a Sort of Knot, which probably delivers the Sap to be depurated at the Vesiculæ of the Leaves, and then receives it back again for the Nourishment of the Plant, doing for that Purpose the Office of an Heart: But the Sun with his Rays supplies the Part of Pulse, to keep the Sap in Motion, and carry on its Circulation, instead of the Heart’s Systole and Diastole. Wheat, being doubtless originally a Native of a hot Country, requires by its Constitution a considerable Degree of Heat to bring it to Perfection; and if much of that Degree be wanting, the Wheat will be the weaker; and when the Solar Rays cannot reach the lower Parts of the Stalks, the lowest Leaves and Knots cannot do their Office; for which Reason the Chyle must mount higher before it be made into Sap, and there must be then a greater Mixture of crude Chyle next to the Ground, as by the white Colour it appears. By this Means that Part, which, if it had a due Share of the Sun’s Influence, would be harden’d like a Bone or Spring, for the Support of the Stalks, for lack of that, becomes more like to a Cartilage, soft and weak, unable to sustain the Weight of the bending Ear, which, having its greatest Impetus against this Part, which is most feeble to resist it, it yields, and lets it fall to the Ground; and then the Grain will be blighted.

But now I suspect this to be a Mistake, it being more likely, that the white Colour of the Rind is owing to the Absence of the Sun and free Air, than to the Chyle, as the Skin of those Parts of our own Bodies that are concealed from them, is whiter than of those which are exposed to them, though no Chyle-vessel comes near our Skin.

There is also another Cause of the Blight; and that is, the Wheat’s coming too late into Blossom. The usual Time is the Beginning of June; and if it be later, the Days shorten so fast after the Solstice, that the Autumn of the Year hastening the Autumn of the Wheat’s Life, the full Time of its Pregnancy is not accomplish’d; and then its Fruit, which is the Grain, becomes as it were abortive, and not full-grown. This Time betwixt the Generation, Blossoming, and the Maturity of the Grain, is, or ought to be, about Two Months.

Ut enim Mulieres habent ad Partum Dies certos, sic Arbores ac Fruges. Varro, Lib. 1. Cap. 44.

Mense Maio florent; sic Frumenta, & Ordeum, & quæ sunt Seminis singularis, Octo diebus florebunt, & deinde per Dies 40. grandescunt Flore deposito usque ad Maturitatis Eventum. Palladius, Pag. 114, 115.

Quindecim Diebus esse in Vaginis, Quindecim florere, Quindecim exarescere, cum sit maturum Frumentum. Varro, Lib. 1. Cap. 32.

But the different Heat that there is in different Climates, may alter both the Time that Plants continue in Blossom, and the Time betwixt the Blossoming and the Ripening.

Therefore ’tis advantageous to hasten, what we can, the Time of Blossoming, and to protract the Time of Ripening: And ’tis observ’d, that the earliest sown Wheat generally escapes the Blight the best, because it comes first into Blossom.

Feeding down the Wheat with Sheep prevents the Blight, by doing what the Blight wou’d do, if the Wheat fell down, i. e. causes the Ears to be light.

Heavy Ears never fall. If they did, that would not make them light. Wheat falls sometimes whilst ’tis in Grass, and before it comes into Ear; so far are the Ears from causing it to fall. This was proved by my whole Crop the last Harvest, and particularly by the Measured Acre, the Ears of which, tho’ prodigious large and heavy, were none of them lodg’d, when those of sown Wheat on the other Side of the Hedge were fallen down flat, and lodg’d on the Ground.

And we find, that those who practise this Method of feeding their Wheat with Sheep in the Spring, to prevent the lodging of it, have most commonly their Straw weak, and Ears light.

These, instead of making the Stalks strong enough to support heavy Ears, make the Ears light enough to be supported by weak Stalks. They know that heavy Ears make the greatest Crop; and yet they still hope to have it from light ones.

They cause the Blight by the very means they make use of to cure it.

This feeding of Wheat much retards the Time of its blossoming; and that it may blossom early, is one chief End of sowing it early, to prevent the Blight. But when it is fed, what the Plants send up next is but a Sort of second or latter Crop, which has longer to stand than the first would have required, and is always weaker than the first Crop would have been; and the longer time it has to continue on the Ground, the more Nourishment is required to maintain it; and yet, as has been shewn, the longer it has been sown, the more the Earth has lost of its Nourishment; and consequently, the Crop will be yet weaker, and in more Danger of the starving Blight.

I am sure, that whenever Sheep break into my drill’d Wheat in the Spring, it lessens my Crop half, just as far as they eat the Rows. There are several Reasons why Sheep are more injurious to drilled Wheat than sown; I would not therefore be understood to decry the Practice of seeding sown Wheat, when the Thickness and Irregularity of its Plants make it necessary: I have only endeavoured to shew, that that Practice is founded upon a false Theory. For, if Wheat fell down by reason of the Luxuriance of it; a Plant of it would be more likely to fall when single, and at a great Distance from every other Plant, than when near to other Plants, because such a single Plant is (cæteris paribus) always the most luxuriant; and I have not seen such a one fall (except Birds pull down the Ears), but have observed the contrary, though its Ears are the largest.