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2. For the nitrogen consumers the requisite amount of nitrogen 



should be secured from the cheapest possible source, the 

 atmosphere. Extensive cultivation of leguminous plants, 

 fertilized by potash (kali) phosphates, and their use as 

 nitrogen-fertilizers effects this. 



3. As far as nitrogen, procured without cost from the air does 



not suffice, the nitrogen-consumers should be supplied with 

 the requisite amount of nitrogen, sufficient for the pro- 

 duction of a maximum crop. , 



4. Whatever nitrogen has been secured from the air by green 



cattle food, and passes on into their manure, should be pre- 

 served from losses. This is effected by spreading potash 

 (kali) salts, containing magnesia, either in the stable or the 

 dunghill. 



5. Whatever nitrogen has been secured to the soil by way of 



stubbles, roots, etc., of leguminous plants, should also be 

 protected from loss, which is done by planting after fruits, 

 or leguminosae, for fertilization alone, properly fertilized 

 with potash (kali) phosphates. 



6. All nitrogen furnished to the crop by the soil, by the stable 



manure, or by commercial fertilizers, should be induced 

 to produce the highest effect, which again is effected 

 by liberal fertilization with potash (kali) phosphates. 



7. Wherever lime is deficient, the soil should be supplied with 



it, so that the potash (kali) salts may develop their whole 



efficacy. 



These are the theses Prof. Wagner extracted from his inves- 

 tigations and experiments, and they carry within themselves a 

 convincing power. They all aim at preservation of the most 

 expensive element of plant-food on one side, and on the other 

 at obtaining and utilizing it to the fullest extent at the least 

 expense to the farmer. 



