96 CULTIVATION OF PLANTS. 



these blow off the soil in many situations, and, by leaving the roots of wheat 

 exposed, occasion their destruction. Another cause is the heaving of the soil, 

 occasioned by the alternations of cold and warm weather. The water in the 

 soil, in the act of freezing, expands and raises up the earth, and also the roots of 

 the wheat-plants which the earth embraces; when a thaw succeeds, the earth 

 being heaviest, falls down first and leaves the roots of wheat a little elevated, 

 and by repeated changes of the weather, the roots are so far thrown out as to 

 perish. 



Farmers, when convenient, usually sow their winter grain early in Septem- 

 ber, upon a supposition which guides their common practice, that grain thus 

 early sown withstands best the action of unfavourable seasons. This supposi- 

 tion is founded upon the very plausible theory, that, as the oldest roots will be 

 longer and more numerous and take a firmer hold of the soil than those which 

 are younger, they will be the least exposed to be thrown above it, and at the 

 same time, from 'their greater strength, be more tenacious of life. But expe- 

 rience informs us, that wheat, sown as laie as the first or even the second week 

 in October, very often survives with less injury than that which is sown in the 

 early part of September. Indeed farmers very generally admit, as the result 

 of their experience, that rye, who selaws of vegetation must be nearly the 

 same as those of wheat, sown so late in the season as barely to come up, is 

 most likely to withstand an unfavourable winter. Still the very plausible 

 theory which has been mentioned very generally induces them to sow rye 

 early as well as wheat, in direct opposition to conclusions which have been 

 drawn from actual observation. 



An experiment was made last autumn for the purpose of collecting some 

 further information on this subject. On the first day of September last I ex- 

 cavated a spot of ground six feet square. On the one side, the excavation was 

 about six inches deep, on the opposite side, its depth did not exceed one inch. 

 Seed wheat was placed over the bottom, so that the kernels were about four 

 inches distant from each other, the excavation was then filled up. The soil 

 was a suitable mixture of gravel, sand and clay, for wheat, and of ordinary 

 fertility. This was the latter part of the extreme drought which prevailed 

 last summer, and the soil was dry, warm and finely pulverized before it was 

 thrown on the wheat. These circumstances, except the extreme dryness of 

 the soil, were highly favourable to the vegetation of seed at the greatest depth 

 in the earth. On the fourth of the month there was a heavy shower, which 

 not only wet the soil, but beat it down close and hard. On the ninth of the 

 month the plants began to show themselves; but none came up from a greater 

 depth than about three and one-half inches. Two or three days after the 

 second leaf had displayed itself, some of the roots were taken up and examin- 

 ed. It now appeared that nearly an inch below the surface of the ground, a 

 new joint was formed which was the basis of the second leaf, and also of a new 

 system of roots. There were now two tiers of roots; the seed or knot adjoin- 

 ing it, had generated the lower tier, and the new joint the upper one. Those 

 two tiers or systems of roots were connected together by a root resembling a 

 cord or thread, and, in one instance, I cut off this connecting thread and trans- 

 planted the upper part. This grew with little apparent check from its cur- 

 tailment; but the under part died, although the soil above it was opened so as 

 to afford it the advantages of air and solar heat. On the 20th day of Sep- 

 tember, I examined another plant, which had its two regular formations as 

 expected, and, what was not expected, a blade was discovered about an inch 

 long, which had started from the lower system of roots, and would doubtless 

 have found its way to the surface, had it not been disturbed. It is to be re- 

 marked, that this plant sprung from seed placed under cover of nearly four 

 inches of soil, which was about an inch deeper than any of the other plants 

 examined, and that some of the tops of the wheat plants had been eaten off 

 and trodden down by accidental intrusion; a fact unregarded at the time. On 

 the 26th day of September I examined another root, expecting to see the blade 

 from below more perfectly developed, none, however, was discovered; but a 

 third tier of roots was found at the surface of the ground, which proceeded 

 from the second as that had from the first system of roots. On the 16th day of 

 October I placed some seed wheat about two inches in the ground; their delay 



