A Controlling Principle. The chief purpose of liming land is to provide a base with which acid may combine, so that the soil may be friendly to plant life. Lime has little power to distribute itself through a soil, and harmful acid may remain only a few inches distant from the point where lime has been placed. In a general way, the tendency of lime is downward, especially when the application at the surface is heavy. Economical use demands even distribution through the soil so that a sufficient amount is in every part. Means to that end are good means of distribution.

Spreading on Grass. Where lime is burned on the farm, and little account of labor is taken, it has been a common custom to spread the lime on grass sods the year previous to breaking the sod for corn, using 100 to 300 bushels per acre. Rains carried some of the lime through the soil, and the increased yields for a few years were due to the improved physical condition of a stiff soil that a heavy application of caustic lime produces, and to the disintegration of organic matter and to change in compounds of mineral plant food. The practice is rightly going into disrepute, being wasteful and harmful.

The smaller application of any form of lime to correct soil acidity may be made on grass land that should not be plowed, but the full effectiveness of an application is not secured in top-dressings. If the land is under a crop rotation, it is better practice not to apply the lime on grass, but to defer application until the sod has been broken, when the lime can be intimately mixed with the soil by use of harrows. It is the rule that it should go on plowed land, and should be mixed with the soil before rain puddles it. In no case should it be plowed down.

When clover or alfalfa shows a lime deficiency, it is advisable to make an application, either in the spring or after a cutting, obtaining whatever degree of effectiveness may be possible to this way, but the fact remains that full return from an application is secured only after intimate mixture with the soil particles. On the other hand, if land needs lime, and there is not time or labor for the application when the soil can be stirred, it is far better to apply on the surface during any idle time than to leave the soil deficient in lime.

Distributors. The most satisfactory means of distribution is a machine made for the purpose. A number of good distributors are on the market. They are designed to handle a large quantity of material after the fashion of a fertilizer distributor ordinarily attached to a grain drill. A V-shaped box, with openings at the bottom, and a device to regulate the quantity per acre, enables the workman to cover the surface of the ground with an even coat, and the mixing with the soil is done by harrows.

Light applications can be made with a drill having a fertilizer attachment. Some makes of drill have much more capacity than others. Granular lime, such as limestone, is handled more satisfactorily than a floury slaked lime.

Farm-Slaked Lime. Lime slaked on the farm must continue to be a leading source of supply to land. If there is stone on the farm, and labor in the winter is available, it is not a costly source of supply. The chief drawback to the use of farm-slaked lime is the difficulty in securing even distribution. The loss from spreading with shovels from small piles slaked in the field is heavy. The quantity per acre must be large to insure sufficient material for every square foot of surface. The lime slaked in a large heap can be put through distributors only after screening to remove pieces of stone, unless they are made with a screening device, and the caustic character and floury condition make handling disagreeable, but no other method is as economical when lime is high in price.

Use of the Manure Spreader. The next best device is the manure spreader. The makes on the market vary in ability to do satisfactory work with lime, and none does even work with a small quantity per acre. An addition to the bulk to be handled by placing a layer of other material in the spreader before filling with lime helps, but some spreaders do fair work in spreading as little as 3000 pounds of slaked lime per acre, and certainly far better work than usually is done with shovels from a wagon.