There are fourteen different chemical elements that are necessary for plant growth—carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, chlorine, silicon, calcium, iron, potassium, sodium, magnesium and manganese; the first four are derived directly or indirectly from the air, the remainder from the soil. Virgin soil contains all these soil-derived elements in available form and in sufficient quantities for plant growth, and it has the power to absorb the elements which are derived from the air, but our short sighted methods of soil cultivation, or robbery, deplete the soil of some of its elements faster than it can convert them into available food for the plants. Liberal applications of manure replace the loss more quickly and economically than any other treatment and if this is supplemented with such chemical elements as the soil may seem to be particularly in need of the fertility of the soil will be assured.
The most economical and practical treatment of the soil would be through the analysis of the soil by a soil chemist; this can readily be done by sending a sample of the soil to your state agricultural college which will analyze and advise as to its requirements, or a sample can be given to your county agent who will attend to it and advise you. In this way one works intelligently and wastes neither time nor money in experiments with no definite aim.
Not all of the fourteen different chemical elements required for plant food need to be artificially supplied; there are but three important elements which we need to consider in this connection—nitrogen, phosphoric acid and potash and only one of these may be lacking; a soil analysis will indicate which one. Nitrogen is the most expensive of the three; it is available, commercially, in three forms—organic nitrogen, ammonia and nitrates. The organic nitrogen is commonly and most economically derived from tankage and dried blood—by-products of slaughter-houses—dried fish, and refuse from fish canneries and cottonseed meal; they contain, approximately—in dried blood, ten to fifteen per cent.; tankage, seven to nine; dried fish, seven to eight; cottonseed meal, six to seven per cent. These decay rapidly when added to the soil and are particularly valuable when applied to light soils, where nitrates or ammonia leach too rapidly and should not be applied until the crops are up and growing. They make available during their processes of fermentation the phosphoric acid and potash already present in the soil. Sulphate of ammonia, containing about twenty per cent. of nitrogen is a valuable chemical form in which to secure nitrogen as it does not leach from the soil as nitrate of soda does and so can be made available by the plant without loss.
Phosphoric acid is found commercially in the form of superphosphates; these come from phosphate rocks and are first ground, then treated with sulphuric acid. Bone is rich in phosphoric acid and is a very excellent form in which to supply this element to the garden, as it is obtained in several forms—raw bone, coarsely ground, fine ground and bone meal. One may by applying two or more grades secure the fertility of the garden for several years as raw bone decays slowly and will give results for a period of four years while bone meal is immediately available. Potash is most economically supplied by applications of wood ashes. But it must be borne in mind that the use of commercial fertilizers is not intended to replace that of barnyard manure, but rather to supplement it until the soil has regained what it has lost by poor management. Commercial fertilizers will of themselves produce a crop, but it is at the expense of the after-fertility of the land, just as the application of the whip will spur a jaded horse to one more final effort. Liberal applications of manure, leaf mould or muck and bone meal will bring any land that has soil at all, up to a satisfactory condition of fertility in a very few years.
Nor is it necessary to go far afield for the humus for so small a piece of land as a kitchen garden for the material for the finest kind of mould lies right at hand in every bit of outdoors. What nature does in a field and woods she will do in one's dooryard if one will only watch her methods and co-operate with her. In the woods, for instance, she shakes down the ripe leaves from the trees, cuts with frost and age the undergrowth and sends the wind to drift them into piles where she waters and compacts them until in process of time they lose their identity as leaves and plants and become a fine, black mould, fine and warm to the touch and blended with a clean, sharp, white sand, or silicate. To imitate her methods successfully we have only to collect the dead leaves in the fall instead of wastefully burning them, pile them in a heap in some convenient place; surround them with a frame to keep them from being distributed about the premises by fowls or wind and to the nucleus thus formed add any waste matter—animal or vegetable—that will decay, about the place—the weeds from the garden, the wastings from the house and laundry. It is amazing, once one has started to conserve fertility, how much one can find to add to this compost heap; I recall that one spring, from a well-tended compost heap and one horse stable, I had hauled on to the garden ten large, two-horse loads of fertilizer, and put the garden in excellent shape, and not only this,—it had kept the premises tidy as nothing else would have done. The gatherings of the summer and fall will, by spring, have rotted down into available form and the action of the soil, sun and rain will complete the process.
The growing of pet stock on a place adds so greatly to the upkeep of the land that it constitutes an object in itself. Poultry is an abundant source of manure which may be composted in barrels with alternate layers of soil, of lime or of any absorbent material or may be piled on the compost heap and mixed with the vegetable matter. To this will be added the litter from the hen house floors which is rich in droppings and full of earth and ground up leaves and straw. But another source of manure, not enough considered, is found in the droppings from the rabbit hutches. If one raises Belgian hares, as every one who wishes to conserve meat, should, one will find that, in addition to a supply of delicious meat, one has also produced a valuable garden asset in the form of a highly concentrated manure; one will also find that one has practically done away with all waste from the garden as the hares will have consumed all the unusable parts of the vegetables—all such early things that run to seed, as lettuce, endive, swiss chard and the like. A large part of the weeds incident to a garden will also be consumed if pulled and offered them, thus minimizing the weed growth for the coming year, as every weed consumed means just so many less to appear the following year. It will be many years before the lesson of the home garden so insistently brought before us by the war will be lost, but we shall not have gained the full measure of its lesson if we do not realize that the critical shortage of meat is not up to the farmer and stockman altogether, but is a matter for each individual householder to adjust by producing, as far as his environment will permit, his own meat supply, by raising chickens and hares if only room for small stock is available, and pork if it is possible to find room and feed for a pig—and a pig does not require a great amount of room—a six by eight pen will do and a paddock, with grass and fresh water, which need not be more than two rods square, and reasonable attention to sanitation will render him a contented and unobjectionable member of the family and a very savory and profitable member, too, come butchering time. These three things should go hand in hand;—A garden to produce vegetables for the family; live stock to consume the waste from the garden and live stock to furnish fertility for the garden; these three spell fertility for the soil and prosperity for the family.
Where the supply of manure is limited so that the entire garden area cannot be covered, quite as good returns may be secured by following the plough with a load of any manure available, and dropping it in the furrow that will correspond with the planting row—if for corn, every three feet of furrows, setting stakes to indicate the fertilised strips. In a small garden fertiliser may be trundled along in a wheelbarrow and shovelled in with fork or spade. This is an excellent plan in preparing ground for peas.