“I wish,” writes a distinguished New York gentleman, who has a farm of barren sand, “you would tell us whether it is best to let clover ripen and rot on the surface, or plow it under when in blossom? I have heard that it gave more nitrogen to the land to let it ripen and rot on it, but as I am no chemist, I do not know.”
If, instead of plowing under the clover—say the last of June, it was left to grow a month longer, it is quite possible that the clover-roots and seed would contain more nitrogen than they did a month earlier. It was formerly thought that there was a loss of nitrogen during the ripening process, but the evidence is not altogether conclusive on the point. Still, if I had a piece of sandy land that I wished to enrich by clover, I do not think I should plow it under in June, on the one hand, or let it grow until maturity, and rot down, on the other. I should rather prefer to mow the crop just as it commenced to blossom, and let the clover lie, spread out on the land, as left by the machine. There would, I think, be no loss of fertilizing elements by evaporation, while the clover-hay would act as a mulch, and the second growth of clover would be encouraged by it. Mow this second crop again, about the first week in August. Then, unless it was desirable to continue the process another year, the land might be plowed up in two or three weeks, turning under the two previous crops of clover that are on the surface, together with the green-clover still growing. I believe this would be better than to let the clover exhaust itself by running to seed.
[ CHAPTER XXV.]
DR. VŒLCKER’S EXPERIMENTS ON CLOVER.
In the Journal of the Royal Agricultural Society of England, for 1868, Dr. Vœlcker, the able chemist of the Society, and formerly Professor of Agricultural Chemistry, at the Royal Agricultural College at Cirencester, England, has given us a paper “On the Causes of the Benefits of Clover, as a preparatory Crop for Wheat.” The paper has been repeatedly and extensively quoted in this country, but has not been as critically studied as the importance of the subject demands.
“Never mind all that,” said the Deacon, “tell us what Dr. Vœlcker says.”
“Here is the paper,” said I, “and Charley will read it to us.” Charley read as follows:
“Agricultural chemists inform us, that in order to maintain the productive powers of the land unimpaired, we must restore to it the phosphoric acid, potash, nitrogen, and other substances, which enter into the composition of our farm crops; the constant removal of organic and inorganic soil constituents, by the crops usually sold off the farm, leading, as is well known, to more or less rapid deterioration and gradual exhaustion of the land. Even the best wheat soils of this and other countries, become more and more impoverished, and sustain a loss of wheat-yielding power, when corn-crops are grown in too rapid succession without manure. Hence, the universal practice of manuring, and that also of consuming oil-cake, corn, and similar purchased food on land naturally poor, or partially exhausted by previous cropping.
“Whilst, however, it holds good as a general rule, that no soil can be cropped for any length of time, without gradually becoming more and more infertile, if no manure be applied to it, or if the fertilizing elements removed by the crops grown thereon, be not by some means or other restored, it is, nevertheless, a fact, that after a heavy crop of clover carried off as hay, the land, far from being less fertile than before, is peculiarly well adapted, even without the addition of manure, to bear a good crop of wheat in the following year, provided the season be favorable to its growth. This fact, indeed, is so well known, that many farmers justly regard the growth of clover as one of the best preparatory operations which the land can undergo, in order to its producing an abundant crop of wheat in the following year. It has further been noticed, that clover mown twice, leaves the land in a better condition, as regards its wheat-producing capabilities, than when mown once only for hay, and the second crop fed off on the land by sheep; for, notwithstanding that in the latter instance the fertilizing elements in the clover-crop are in part restored in the sheep excrements, yet, contrary to expectation, this partial restoration of the elements of fertility to the land has not the effect of producing more or better wheat in the following year, than is reaped on land from off which the whole clover-crop has been carried, and to which no manure whatever has been applied.