=Lime.=--Lime is used on the land not for its direct results as a fertilizer, but because it has the ability to break up combinations already existing in the soil and set free the plant food that previously was in an insoluble form. Lime sometimes produces almost marvelous results; at other times no visible effects whatever. Hence, it is not a fertilizer, though in actual practice it is sometimes a fertilizing agent of great value. Land that has been much manured or long in sod is likely to be benefited by lime. Artificial manures, on the other hand, furnish real plant food in soluble form, and may be expected to produce crops invariably, year after year, if the soil be sufficiently moist. When a fertilizer contains nitrogen, phosphoric acid and potash it is said to be complete. When any element is missing the fertilizer is said to be incomplete. Ground bone, wood ashes, South Carolina rock, kainit, etc., are examples of incomplete fertilizers. =Barnyard Manure.=--Barnyard manure is the best of all known fertilizers. Not only is it complete in character, but it has the highly valuable property of bulk. It is rich in humus or humus-forming materials. It opens and ventilates the soil, and improves its mechanical condition to a remarkable degree. Humus is a name for decaying organic matter. American market gardeners deem it entirely safe to use fifty to seventy-five tons of barnyard manure to the acre of ground in their intensive cultural operations. American farmers seldom apply more than ten or fifteen tons of such manure to the acre in the open field. The manufacture of artificial fertilizers had its origin in the fact that cultivators could not get enough manure from natural sources, and, hence, were compelled to go into the market and buy nitrogen, phosphoric acid and potash in other forms. =Closer Economy.=--With the increase of competition and consequent fall of prices a closer economy in cost of production is necessary. Prices have fallen most in respect to commodities that will bear long-distance freight transit and less in respect to the more perishable products of the soil. Hence, farmers have widely turned attention to small fruits and vegetables for money crops, instead of grains, and are now studying how to fertilize these crops in the most effective and economical manner. It is very evident that while great quantities of fertility are demanded by the new crops, there is no such margin of profit in their culture as to warrant wasteful methods, and no losses of home-produced fertility can be tolerated. =As to Saving Manure.=--A penny saved is a penny earned. A half ton of manure saved is a dollar earned; and, conversely, a half ton of manure wasted is a dollar wasted. In many American barnyards much of the manure is lost, partly by leaching and partly by escape of ammonia. It is estimated that as much as a third of the natural manure produced in this country is practically thrown away.