The knowledge that chemical manures have been used with highly successful results in vegetable growing, and may be in other cases if a proper system is adopted, cannot fail to prove of interest to large numbers of people. Except to those who keep stock, or are in a position to make a contract for a large supply of yard or stable manure, the article is difficult to get of good quality at a reasonable price; moreover, it is bulky, and awkward and expensive to handle. There is an idea that country gardeners have no trouble in the matter, but this is erroneous. Farmers and stockkeepers have manure, professional gardeners can often command a supply, but the majority of other cultivators are often driven to extremities from the want of the wherewithal to fertilise the ground.
Chemical manures are inferior to yard manure in some respects, and superior in others. In some soils yard manure is valuable from its mechanical action, and because in its decay warmth is given out. On the other hand, chemicals are easily accessible, cheap, portable, cleanly, and of concentrated power.
The two great nitrogenous manures are nitrate of soda and sulphate of ammonia. After several years of experimenting I have come to the conclusion that all others may be dispensed with. It is troublesome to stock many kinds. Taking one year with another, these fertilisers cost me ten shillings per hundredweight. The average quantity used (generally in conjunction with other fertilisers) is 1 1/2 lb. per square rod.
The most generally useful all-round manure in this section is superphosphate of lime; average price per hundredweight, five shillings; average quantity per square rod, 3 to 4 lb. Steamed bone flour is valuable to use in conjunction with superphosphate, for the reason that sulphuric acid is used in the manufacture of superphosphate, and at times a modicum of free acid is left, which acts injuriously, unless absorbed by a little bone flour. Steamed bone flour is insoluble in water, and therefore it cannot be turned to account, as superphosphate can be, for liquid manure; moreover, owing to the very fine state to which it is reduced, it requires to be handled with great care, otherwise clouds of disagreeable dust will arise; but it is quick-acting, and altogether an exceedingly valuable manure. The average price is six to seven shillings per hundredweight, and the average quantity to use per rod (in conjunction with other manures) is 1 lb. Basic slag is another phosphatic manure which may be mentioned. It is not so valuable as superphosphate for most vegetables, and being rather slower in its action requires to be applied earlier, but it is very good for Grass. Average price, three to four shillings per hundredweight. Average quantity to apply, 4 lb. per square rod.
The most common of these is kainit; average price, three to four shillings per hundredweight; average quantity to use, 2 to 3 lb. per square rod. It is a good fertiliser. Sulphate of potash and muriate of potash; average price of each, seven to nine shillings per hundredweight; average quantity, 1 1/2 lb. per square rod; are both much superior to kainit, the former for vegetables, the latter for fruit, but they are not so easy to get.
There are several other fertilisers besides those mentioned, and perhaps the best of them is nitrate of potash (saltpetre). It is, however, expensive, often costing fifteen to eighteen shillings per hundredweight. A large quantity is not required, 1 1/2 lb. per square rod sufficing. Like superphosphate, it is valuable for making liquid manure. Half an ounce of each to 2 gallons of water will make a good fertiliser for most things.
With the fertilisers here named, any vegetable grower who knows how to till his soil, and is not afraid to do it, may grow good crops of all vegetables; indeed, he may do exceedingly well with four only, namely superphosphate, kainit, steamed bone flour, and nitrate of soda. The prices quoted are the prices I have myself paid for hundredweights and half-hundredweights. The quantities advised are those which I have found to be the best in a fairly considerable practical experience.
Speaking broadly, they are best applied two or three months prior to cropping. In the case of Potatoes and green vegetables, I have found applying at cropping quite suitable. In the case of Kidney Beans I have found it do great harm.
The following is the most generally useful chemical mixture that I know, and may be taken as a standard :-
4 superphosphate of lime
2 nitrate of soda
1 steamed bone flour
The figures give the proportions of each to make up the perfect mixture; 10 lb. may be used per square rod.
Fig. 13. Till Well, Manure Intelligently, And Your Potatoes Will Be Sound And Clean