Time of Application.--The use of lime on land should be associated in the land-owner's thoughts with the growing of clover. It does help soil conditions so that more grain can be produced, but if it is permitted to displace the use of fertilizers, and does not lead to the growth of organic matter, harm will result in the end. Lime should be applied to secure clover, and therefore it should be mixed with the soil before the clover is sown. The application may be made when fitting the seed-bed for the grain with which clover usually is seeded, or may be given a year or two years previous to that time. The important point is to have the soil friendly to plant life when a sod is to be made. Lime should be put on ground always after the plowing, and it should be well mixed with the surface soil. Even distribution is just as important in its case as in that of fertilizers. A good practice is to break a sod for corn, harrowing and rolling once, and then to put on the lime. A cut-away or disk harrow should be used to mix the lime with the soil before any moisture causes it to cake. When large crumbs form, immediate efficiency is lost. If the application is light, and may barely be equal to immediate demand, it is better practice to put on the lime when preparing the seed-bed for the wheat or other small grain in which the clover will be sown. It should never be mixed with the fertilizer nor applied with the seed. The lime should go into the soil a few days, or more, prior to the seeding. The soil having been put into a condition favorable to plant life, the seeding and the use of commercial fertilizers should proceed as usual. Lime should never be mixed with manure in the open air, but it is good practice to plow manure down, and then to use lime as indicated above, if needed. If manure and lime must be used after the land has been plowed, the lime should be disked well into the soil before the manure is applied, and it is advisable that the interval between the two applications be made as long as possible. CHAPTER IV ORGANIC MATTER Office of Organic Matter.--The restoration of an impoverished soil to a productive state usually is a simple matter so far as method is concerned. It may be a difficult problem for the individual owner on account of expense or time involved, but he has only a few factors in his problem. Assuming that there is good drainage, and that the lime requirement has been met, the most important consideration is organic matter. A profitable agriculture is dependent upon a high percentage of humus in the soil. Average yields of crops are low in this country chiefly because the humus-content has been greatly reduced by bad farming methods. [Illustration: Turning down organic matter with a gang plow.] Nature uses organic matter in the following ways: