PRINCIPLES OF AGRICULTURAL CHEMISTRY 



largely in excess of the requirements of the crop, is not advisable. 

 Such an application is likely to lead to loss of plant food, either 

 by percolation or by fixation. 



4. The Fertilizer is Applied to the Money Crop in a Rotation. 

 In this system, the money crop is supplied with an abundance of 

 plant food, so as to insure continuous feeding and maximum pro- 

 duction. The remaining crops, or those immediately succeeding 

 in the rotation, are nourished by the residues, with small applica- 

 tions of fertilizer, if necessary. If, for example, the rotation is 

 cotton, corn, and cowpeas, the cotton would be liberally fertilized, 

 the corn and cowpeas being allowed to feed on the residues. 



Use of Nitrate of Soda. Nitrate of soda is easily soluble in 

 water, and distributes itself through the soil, and as the nitrogen 

 can be easily taken up by plants, it is quickly effective. On the 

 other hand, it is so soluble in water that it is easily washed from 

 the soil by rains, and there may be loss from leaching when 

 applied previous to the growth of the plant, or in too large 

 quantities at the wrong time, or when heavy rains occur im- 

 mediately after its application. 



The best use of nitrate of soda 1 is secured when an abundant 

 supply of potash and phosphoric acid is present. We have al- 

 ready seen that the size of a crop is controlled by the most un- 

 favorable condition, and if potash or phosphoric acid are deficient, 

 this deficiency cannot be overcome by the use of nitrate of soda. 



The best use of nitrate of soda is also secured when it is applied 

 to soils in good condition rather than to poor or worn out soils. 

 Larger quantities may profitably be applied to good soils than to 

 poor soils. Clods and lumps prevent a proper distribution of the 

 material as well as a ready absorption of plant food, which are 

 also necessary for good results. The application of nitrate of 

 soda is especially advantageous for quick growing vegetable crops, 

 where market quality is measured by rapid and continuous 

 growth, and for those field crops which make their greatest 

 development in spring, before the conditions are favorable for the 

 change of the nitrogen in the soil into forms usable by plants. 

 1 Bulletin 172, New Jersey Station. 



