PROF. JOHNSON. Do they cut the clover entirely off?

MR. GOULD. They do, one year. They generally have a pretty good crop before they plow it in. They plow it in, usually, about the first of August.

DR. RIGGS. They take off the first crop, and plow in the second.

PROF. JOHNSON. There are some further facts in regard to clover which are very interesting. Dr. Voelcker, who has been Chemist to the Royal Agricultural Society of England for the last twelve years, when he was formerly in the Royal Agricultural College at Cirencester, found that some of the farmers in the vicinity not only thought that clover was an excellent preparation for wheat, but asserted that the wheat did better when, instead of plowing in the second crop, they took it off. The doctor we may suppose was rather incredulous; but he found other farmers who said, "Our wheat does best when we let the clover ripen, and save the seed and put the wheat in after that." These opinions were put to him in such a way that he could but candidly say, "It would be folly to deny such statements on my knowledge of what is probable; I will look into the matter, and satisfy myself by my own trials. I am living here on the ground, and I can make the experiments, and if it be true, that taking off two crops of clover leaves the soil in better condition for wheat than when one crop is taken off, if I examine the soil when one crop has been taken off and when two crops have been taken off, I ought to find more available nitrogen and more available phosphoric acid in a given quantity of soil in the latter case than in the first case; and if it be true, that where the plant has been allowed to go to seed, the preparation for wheat is still better than in the other two cases, I ought to find still more of those materials." He made the investigation, and actually found that the quantity of those nutritive materials left in the surface soil after the clover seed had been taken off was greater than when two crops of clover hay had been cut,

and greater when two hay crops had been removed than when only one had been taken off. That is due to the fact, which I have already insisted upon, that the clover plant, after producing its seed, is still able, when the character of the soil is adapted to it, to continue its growth and bring up to the surface-soil those materials which the wheat crop cannot reach. We cannot, from cases of this sort deduce rules of universal application, and this English experience may not apply to the Genesee valley or to the lands of this vicinity, because of differences of soil, but these results of Dr. Voelcker are of very great importance. They enable us to make the experience of those Cotswold farmers of general value, by showing us the reason of their result. They furnish us a grand contribution to our knowledge of the capacities of the clover plant. If the farmers of Genesee do not find the rule to hold good with them, we shall find, by study, the reason for it.

- QUESTION. It is often asked, What is to be done with our side-hill pastures in New England, that are too rough and hard or too steep to plow and get manure on? I have a pasture of this kind. It is naturally moist land, pretty stony, and it has begun to be covered with moss. Forty years ago, one acre of it produced more feed than two do now. What shall I do with that land? It is considerably steep, and it would be very unprofitable to undertake to plow, manure, and cultivate it. I have been thinking of putting on a heavy harrow, well sharpened, with a strong team, in the month of March, when the ground is thawed say three or four inches deep, and harrow it severely, and then sowing clover. Can we not in that way resuscitate these old pastures, so that they will produce something again? If I can get some information on that point, it will be valuable to me, and I think I have neighbors who would receive benefit from it. We have immense quantities here in Windham county of moist side-hill land, too rough to plow and cultivate. What is to become of these pastures? Are they to become a loss to us?

MR. Low. Travellers in the northern portion of this county will find a great many acres of that kind of land which are producing most luxuriant grass, the result of the application of plaster and ashes. You do not need clover seed if you put on ashes and plaster.

PROF. JOHNSON. There is one question to which Mr. Gold referred in a letter to me written previous to the one which I read yesterday, and that is, the waste of manure, which seems to belong to the production of some crops and not to others. Any man who for twenty-five years will cultivate a number of plots of land with different crops and different fertilizers, will get hold of a great many facts and find a great many questions coming up which it would be exceedingly interesting to discuss. This is what Mr. Lawes has done. He has shown that on his land, in order to get a large crop of wheat, he must use a great deal of one kind of manure. I mentioned, yesterday, that he got 16 bushels of wheat to the acre, for twentyseven years, in unbroken succession, on land to which he applied no manure whatever; that by the use of 14 tons of stable manure per acre, applied annually, he was able to get 36 bushels of wheat. By using all the elements of our fertilizers, with the single exception of nitrogen, applying phosphates, sulphates, and carbonates of lime, magnesia, potash, and soda, all the fertilizing matters which are found in ashes, in guano, or in stable dung, nitrogen compounds excepted, he raised the crop to barely 25 bushels; but when, to one good dose of these materials, he added annually 400 lbs. of salts of ammonia, or nitrate of soda, the yield went up to 36 bushels and held at that point for years. This difference between 25 and 36 was unquestionably due to the nitrogen of the nitrate of soda or salts of ammonia. If the facts admit of any other inference, I do not understand the logic which can make it.

Let us compare the quantities of nitrogen in those two applications. In the salts of ammonia, there were about 80 lbs. of nitrogen; in the barn-yard manure, Mr. Lawes says 200 lbs. ;

but there are usually nearer 300 lbs. of nitrogen in strong stable manure. It would thus appear that there must be a great loss of nitrogen, and the wheat crop has got the repute, among some writers, of wasting a great deal of nitrogen in its growth.

On another plot of land, where Mr. Lawes raised barley, he applied 200 lbs. of ammonia-salts, which contained 40 lbs. of nitrogen, and raised 40 bushels to the acre. When he doubled his dose, and put on 80 lbs. of nitrogen, his grain was so heavy that it lodged and failed to ripen, and the crop was spoiled. Without the addition of any fertilizer, the soil gave him considerably less than half that amount.

I will mention some other experiments which may give us light on this subject, made by Dr. Hellriegel, who has been studying agricultural problems for some twenty years, having been all this time employed in one of the Experiment Stations kept up in Germany, partly by government and partly by associations of individuals, for the purpose of making agricultural investigations, by the help of chemistry and physiology, and whatever aids can be brought to bear on these questions. Dr. Hellriegel proposed to himself to ascertain what quantities of the different materials which plants require for their growth must be furnished to them in order to get a crop. We have for some years known that phosphates and sulphates of potash, lime and magnesia, and nitrogen must be given, but we need to know how much of each of these various substances is necessary. In order to arrive at accurate results, Dr. Hellriegel had to experiment under artificial conditions. So he took for soil a perfectly pure sand, or one as nearly free from everything that would furnish plant-food as possible. In a large series of experiments, he mixed the soil with a sufficient quantity of all the materials necessary for the support of a crop, with, in each case, one single and different exception. These excepted substances he added in graduated quantities, putting one quantity in one box of soil and a larger in another, and so on through a sub-series of

eight or nine boxes, in order to ascertain by the growth of the plant, in which case he had hit the best proportion of these ingredients. His trials have been extended to the whole list of the elements of the plant. In regard to water, for example, he found that the growth was greatly influenced by the quantity of this substance with which the crop was supplied. There was a certain quantity of water in the soil necessary to a maximum crop, other things being equal. In the sandy soil which he experimented with, the largest yield of rye, wheat, or oats was obtained when the soil held steadily ten: or fifteen per cent of its weight of water. On increasing this. proportion, the straw in some cases was heavier, but the grain was reduced in quantity. Thus the very fact that the amount of rain fall is unequal in absolute quantity, and unequal in distribution from year to year, is of itself a reason why you get different crops, everything else remaining perfectly the same. That is a matter always to be taken into consideration in judging of the value or effects of a fertilizer. But it is the effect of nitrogen I am coming at. Dr. Hellriegel experimented with various quantities of nitrogen (in the form of nitrates), applied also to cereals. The plants grew in the arti ficial soil, consisting of pure sand, with an admixture of ash ingredients in such proportions as previous trials had demonstrated to be appropriate. All the conditions of the experiments were made as nearly alike as possible, except as regards the amount of nitrogen, which, in a series of eight trials, ranged from nothing to eighty-four parts in a million parts of soil. The following table gives the results: *