SOILS AND FERTILIZERS 439 



nitrates to the drain. In very compact soils the depth should not 

 exceed 4 inches. In light soils this depth may be considerably in- 

 creased, although in such soils there is more danger of loss by drain- 

 age than with heavy clay soils. 



Application in the hill or drill is useful where the supply of 

 manure is limited and the full immediate effect is desired. For forc- 

 ing truck crops this method is especially valuable. Well-rotted ma- 

 nure is best suited to this method of application. It has been claimed, 

 however, that manure applied in this way sometimes injures the 

 appearance of root crops, especially potatoes, by increasing the 

 amount of scab. 



The so-called parking system, or feeding animals on the land, 

 is a method of application which has many advantages; but the 

 distribution of the manure by this system is irregular and subject 

 to the same objection as broadcasting. 



The application of liquid manure has certain obvious advan- 

 tages and is largely practiced, especially in Europe. Manure leach- 

 ings is a quick-acting, forcing manure, and is especially valuable 

 for grass. The expense of cisterns for collecting the leachings and 

 the trouble of hauling and distributing, together with the care 

 which must be exercised to prevent loss of nitrogen from the read- 

 ily fermentable liquid when it stands for any length of time, ren- 

 der it doubtful, however, whether this method is practicable ex- 

 cept for special purposes and under peculiar conditions. 



Authorities. N. J. E. S. B. 150; Univ. Wis. B. 180; Bu. Pit. 

 Ind. B. 692; Colo. Ag. Col. B. 168; W. Va. E. S. B. 140; La. E. 

 S. B. 31; Tex. E. S. B. 112; Md. E. S. Bs. 122, 128; N. H. E. S. 

 B. 21; Fla. E. S. B. 20; F. Bs. 56, 192, 245; Tex. E. S. B. 138; 

 Ky. Univ. B. 140; Mass. Ag. Col. B. 81; O. E. 6. Bs. 134, 183, 

 184; R. I. Ag. Col. Bs. 142. 143; Penn. Col. Bs. 54, 63; F. B. 

 44; Univ. Miss. B. 34; Cornell Univ. B. 56; Univ. Wis. B. 174; 

 F. B. 192; Colo. Ag. Col. B. 99. 



NEED OF COMMERCIAL FERTILIZERS. 



A careful study of the present condition of farming in the 

 United States indicates, that as a rule the manure produced on 

 the farm is not sufficient to maintain its fertility, and that the 

 need for artificial supplies is real, though the amount required may 

 be considerably reduced by careful management. 



Effects of Grain Farming. In the system of so-called "grain 

 farming," which has obtained over large areas of this country for 

 a long time, and is still practiced, the live stock is often limited 

 to a number sufficient only to the needs of the farm for labor and 

 food; the grain is sold, and the manure is made up chiefly of the 

 natural wastes or unsalable material, such as straw, stalks, etc. The 

 grain contains proportionately greater amounts of nitrogen and 

 mineral constituents than these wastes; hence the practice con- 

 tinued for a long time results not only in a deficiency in the soil 

 of organic substances containing nitrogen, but also in an exhaus- 

 tion of the mineral substances. The original character of the soil 

 and its treatment measure the rate of exhaustion. The less fertile 



