respects. It must not be supposed that all manure has such value, or that any manure will retain such value under careless treatment.

Green Manuring.—The system of green manuring, as formerly understood and practiced, had two purposes in view. One was to supply the soil with needed humus; the other to furnish winter protection and prevent washing. The practice is a very old one and has much to commend it. Not only do plant roots draw up fertility from considerable depths, to be afterward deposited in the superficial soil when the growing crop is turned down by the plow, but the process favors chemical changes in the soil by the admission of air and sunlight and by the decomposition of leaves, stems and roots. But nothing whatever in the way of new fertility is added by turning down a rye crop, for instance.

Crimson or Scarlet Clover, a Nitrogen Gatherer.

Cultivating the Legumes.—The present system of green manuring contemplates something in addition to what was formerly gained, for agricultural sciences now recognizes the fact that nitrogen, the most expensive element of fertility, can be taken from the air and added to the plant food in the soil by means of certain plants which have the peculiar habit of regularly forming little tubercles or lumps on their feeding roots. These lumps are to be found on plants in perfect health, and are not parasitical in any hostile sense. The lumps are filled with small living organisms called bacteria, and, hence, have been called bacteroid tubercles. The minute tenants slowly but surely secrete nitrogen, and put it in a form adapted to plant growth.

The plants which bear these root lumps belong to a group called legumes, of which clover, peas, beans, vetches, etc., are familiar examples.

Curiously enough, nearly all the leguminous plants are thus fitted by nature by means of the root lumps to act as soil enrichers, and these plants have, therefore, assumed the highest agricultural significance.

It is well known that such crops as cowpeas, crimson or scarlet clover, common red and pea vine or sapling clover, Soja beans, vetches, etc., can be used to add nitrogen to the soil in commercial quantities. The gain of new material, expressed in money, has been estimated as high as $25 per acre. This, therefore, is the avenue through which the farmer can most economically supply nitrogen to his land. If he will exercise all the economy heretofore suggested in the care of natural manures, and will grow legumes, he will not have much occasion to buy nitrogen in the market.

Grass vs. Clover.—An idea of the great fertilizing value of the leguminous plants as compared with grasses may be obtained by a study of the following analyses from U. S. Farmers' Bulletin No. 16, by Dr. E. W. Allen, on "Leguminous Plants for Green Manuring and for Feeding":

Nitrogen, Phosphoric Acid, Potash.—We have just noted the cheapest source of nitrogen. It can be collected by root tubercles at less than the commercial rate of 14 to 17 cents per pound.

Phosphoric acid can be best secured, if a new supply becomes necessary, in the form of ground bone or in the form of acid phosphate. Either of these articles, if bought from a reliable dealer, is a good and economical thing to use.

Potash is to be had most cheaply, perhaps, in the manner suggested heretofore: by the use of kainit as a preserver of stable manure. The kainit performs a double purpose if used in that way, and thus gets upon the land in a cheap manner.

Muriate of potash and sulphate of potash are high-priced articles, but when bought from good houses are fully worth the money they cost. Except for the use of kainit, just mentioned, the muriate or sulphate would be the more economical form.

Potash or phosphoric acid (or both), as may be determined by circumstances, are needed to aid crimson clover in its growth, and with the clover form a perfect manure.

Barnyard manure is a perfect fertilizer, especially when preserved with kainit or acid phosphate; and a leguminous crop, if stimulated with phosphoric acid and potash, leaves the land in fine cropping condition.

Value of Green Manures.—The cash value of green manuring is somewhat a matter of location. On light, sandy soils it will be found wise to turn the whole crop under with the plow, while on heavy loams this plan is of doubtful benefit. On the latter land it is conceded to be better practice to harvest the crop and feed it to stock, and return the resulting manure to the land.

Maximum Amounts of Manures.—Nobody has yet ventured to fix the maximum amounts of natural or artificial manures that soils will bear, but these amounts are great. Reference has already been made to the number of tons of stable manure per acre used respectively by market gardeners and farmers in America. As to commercial fertilizers, the quantity has been pushed up to two tons per acre, with enormous crops in consequence, and with no bad results where the constituent of the fertilizer were well balanced and where the water-supply was ample. It is quite easy, however, to scorch or burn the foliage of growing plants by the improper use of acid fertilizers in dry weather. Of course, no such amount as two tons per acre would be used in ordinary farming or farm gardening, but only in certain intense cultural operations.

CHAPTER II.

CHOICE OF LOCATION.

Almost every farm has a choice spot for a garden, some favored location where the soil is warm and mellow, and where, perhaps, shelter is afforded by hill or woodland. Such a spot, especially if it can be artificially irrigated, is capable of great things in the way of growing truck.

The place of all others, if it can be had, is a rich meadow bank, on ground low enough for