

70 DEPARTMENT OF AGRICULTURE GEORGIA. [356] 



growth about one month, by causing the plant to mature 

 its fruit about a month earlier than that cultivated without 

 manure in the drill. A similar advantage is realized in 

 the original cotton belt, in enabling the planter to gather 

 his crop in better condition, and before the weather grows 

 too cold for expedition in the tedious process of cotton 

 picking. Indeed, before the present system was adopted, 

 more cotton was picked in January than is gathered now 

 in December. 



The organic constituents of plants, with the exception 

 of nitrogen, are supplied in sufficient quantity from the 

 atmosphere, which is beyond the control of man. It is 

 now universally agreed by scientists who have investigated 

 the matter, that carbon, which forms so large a part of 

 vegetation, is derived from the air, in combination with 

 oxygen, as carbonic acid, and hence it is not necessary 

 for the farmer to apply carbon to the soil as plant food. 

 There are elements of plant-food, however, which the 

 farmer not only may, but in many instances must, apply 

 to the soil to secure remunerative crops. The principal of 

 these are nitrogen, phosphoric acid and potash, and on 

 some soils, and for some plants, lime, magnesia and soda ; 

 the last three being generally present in sufficient quantity 

 in the soil for most plants. The fact, however, that some 

 of these elements are more important to man, on account 

 of the necessity of their artificial supply, does not imply 

 that one is more important in plant nutrition than another. 

 Each is equally important to the plant to the extent to 

 which it enters into its composition, since the plant can- 

 not be perfectly developed without the proper combination 

 of its chemical constituents. In the entire absence of 

 phosphoric acid, perfect seed cannot be formed ; without 

 carbon, neither woody fibre, starch, nor sugar can be pro- 

 duced. 



The analysis of an entire plant shows the percentage 

 and ratio in which each constituent enters into its compo- 



