KINDS OF FERTILIZERS 99 



a portion of the plant foods removed by the growing crop is 

 replaced occasionally, for the production and removal of flesh, 

 bone, milk, and wool will sooner or later reduce the supply of 

 plant food in the soil. 



If the soil is acid, this condition must first of all be corrected 

 by the addition of lime; otherwise fertilizers will do little good. 

 Acid soils are comjnon in the Northern States, and in Penn- 

 sylvania and Ohio. If the rest of the farm needs liming, so do 

 the pasture and other grass areas — possibly more than do the 

 cultivated fields. But before applying lime one should be sure 

 that he is making no mistake. Do the clovers grow well there? 

 If so, there is already enough or nearly enough lime. Is moss or 

 other vegetation common to acid soils appearing? If so, lime 

 is needed. Invariably the famous pasture regions of the world 

 are on soils that contain an abundance of lime. Good results 

 from the application of fertilizers and manure presuppose a 

 dense grass growth, an abundance of feeding roots, and a sweet 

 soil. 



Kinds of Fertilizers and Amounts to Apply. — Nitrogen and 

 phosphate are the essential ingredients of fertilizers for grass- 

 lands. Of less importance generally is potash. 



The need for nitrogen in the soil is indicated by the leaf blades 

 taking on a yellow-green cast. Phosphate is often required on 

 pasture lands and in soils that have long been cultivated. Lands 

 east of the Mississippi, in the South, and in the middle West 

 are often quite as deficient in phosphate as in nitrogen. Pot- 

 ash, on the other hand, is abundant in most soils; but because 

 of its being only slightly soluble the application of it does not 

 always appreciably increase the yield. 



In correcting acidity and improving the tilth of the soil, 

 common ground limestone, unburned, is used. From 2 to 10 

 or more tons to the acre is applied. In Europe basic slag, which 

 is rich in lime and phosphate, is popular. Along the Atlantic 

 seaboard basic slag is used to advantage, but for the interior 

 States its use is impracticable because of the high transportation 

 charges. 



For top-dressing, a fertilizer must be readily soluble, or it 



