On a portion of the same impoverished field upon which the potato trials alluded to were made, the effects of a dressing of 150 lbs. to the acre of nitrate of soda on corn were plainly visible 50 feet away three days after the application in the darker color of the leaves as compared with the rest of the field which had received potash and phosphoric acid only.

Our great authority, Sir ]. B. Lawes, grew potatoes on the same plots for nine consecutive years, from 1876 to 1884 inclusive. The average yield from the use of 400 lbs. of ammonia salts alone was 103 bushels per acre; that from 550 lbs. of nitrate of soda was 104 bushels. The same amount of ammonia salts with the ash elements added (complete) produced an average for the nine years of 325 bushels per acre. Nitrate of soda (550 lbs.) with the ash elements added, gave 300 bushels per acre. Farmyard manure (16 tons) - an average of six years - gave a yield of 253 bushels per acre.

Mr. Harris remarks that the 200 lbs. of nitrate of soda, used in several of our experiments to form complete fertilizers, can be bought for $5. Three and a-half per cent. of nitrogen equals 70 lbs. in a ton. Seventy lbs. of nitrogen are contained in 368 lbs. of nitrate of soda, which at 2½ cents per lb. (Mr. Harris's figures), would cost $8.70, and not $5, as he states. Still we agree with him that for potatoes it is an ill-balanced fertilizer in most cases, not, however, because it contains too little nitrogen necessarily, but because it does not exist in varied forms and also because the potash is too low by half for soils deficient in potash. Where a large crop is anticipated it is always safer to use an excess of food constituents, particularly of those that do not waste by leaching. Phosphoric acid is, next to nitrogen, the in" gradient oftenest deficient in soils. Nine-tenths of the fertilizers used in England and America are mainly phosphoric acid. Potash in many soils, however, is present in liberal quantities, and it would be unwise to supply it in full rations unless a known deficit exists.

If you err at all, gardeners and farmers, it is better to err on the side of economy. Phosphoric acid will remain with you to feed subsequent crops. So will potash. Know that your soil needs more nitrogen before you apply it in liberal doses. Nitrogen costs a lot of money, and the higher the price of experiment ingredients, the less the farmer should apply it without due discrimination. We say give the soil all the phosphoric acid you choose. You will rarely overdo it. Give it potash according to its needs, as nearly as you may. But be gentle and conservative in the use of nitrogen, unless you are positive it will give you full returns. It is a ruinous luxury.

We may every one of us bear in mind that if phosphates materially increase our crops, we have evidence, to a certain extent, that nitrates are the less needed at present; if potash increase the crop, here is evidence that nitrates are the less needed. If both phosphates and potash fail, then let the experimenter add nitrates in varying quantities from 100 to 300 pounds to the acre, and thus in a safe, inexpensive way find out approximately what his land needs.

Readers of The American Garden may be pleased to know that a somewhat extended series of experiments are being carried on at the Rural grounds (now substantially controlled by The Rural Publishing Company) in the hopes of throwing some additional light upon the nitrogen problem as it may affect the potato crop grown upon an impoverished soil. An epitome of these experiments is show in the following table.

Then, other plots receive varying amounts of a fertilizer strong in nitrogen (ammonia 7.50), supplied in many different forms, and a lower per cent. of phosphoric acid (4.50) and 10.50 per cent. of potash.

E. S. Carman.