11 



the atmosphere. 25 bushels of stone lime per acre, every 

 4 or 5 years, is recommended for average soils which 

 are used for the frequent growth of legumes. 



Root and Tuber Crops require an abundance of all the 

 fertilizing constituents in readily available forms, bu*^^ they 

 differ widely as to their special needs. In one group may 

 be placed beets ^ carrots and mangels. They require a lib- 

 eral supply of readily soluble phosphoric acid and nitro- 

 gen, and in light, sandy soils the addition of a little pot- 

 ash is advisable. In clay soils they seem to be able to 

 get most of the potash they require from the soil. 

 Turnips respond most liberally to applications of avail- 

 able phosphoric acid, while they seem able to extract 

 this constituent from sources not readily accessible to 

 other plants. A liberal supply of nitrogen, also, espe- 

 cially during early growth, is desirable. While the 

 turnip is a voracious feeder on potash compounds, it 

 seems able to obtain this constituent from the natural 

 soil supply, though it should not be required to depend 

 solely on this supply. Potatoes, both Irish and sweet, 

 require a large amount of potash, which should be in the 

 form of sulphate rather than of muriate. The nitrogen 

 may be mostly in organic forms, though the nitrate of 

 soda or sulphate of ammonia is recommended for the 

 early irish potato. The phosphoric acid in moderate 

 amount should be available. 



Fruit Crops differ from the others that we have con- 

 sidered in that they are produced by perennial plants 

 instead of by annuals, and hence they require a differ- 

 ent sort of fertilization. As the plants grow slowly, fer- 

 tilizing materials which give up their constituents 

 slowly are better, perhaps, than those vhose constituents 

 are more readily available. Fertilizers of the latter 

 class, however, may supplement those of the former 

 with advantage at such times as there is a rapid devel 



