TO IMPROVE A SOIL. 123 



takes years of hard toil to correct the mistakes of former 

 generations. They had some excuse ; we have none. 



As the increase of active plant-food in our farm-lands ought 

 to be one of the prominent objects of every system of farm- 

 ing, we ask quite properly here, By what economical means 

 can this result be secured as far as the nitrogen plant-food is 

 concerned ? 



To answer this question necessitates a few general remarks 

 concerning the customary modes of increasing our crops. A 

 soil may be improved, physically and chemically, or in both 

 directions ; its latent resources may be rendered merely in a 

 higher degree available ; or a direct addition of plant-food 

 may be made. Those modes of treatment which aim at the 

 last-named result only can enrich the soil ; the others virtu- 

 ally tend to hasten on its early exhaustion. 



Superior mechanical treatment, subsoiling and drainage, 

 aid in improving the physical condition of the soil, and ren- 

 der the latent resources more active; without the support of 

 a rotation of crops or manuring, they tend to exhaust it. 



Fallow causes an accumulation of general plant-food at 

 the expense of time. Its merits regarding the accumula- 

 tion of organic nitrogen plant-food are frequently more than 

 doubtful. 



Wherever the surftice soil is left unshaded ajjainst the stim- 

 ulating action of the direct sunlight, a wasteful decomposition 

 of its stored-up organic matter must result. Irrigation aids 

 mainly in a uniform distribution of the latent plant-food of the 

 soil, and increases its amount only in exceptional cases. 



Rotation of crops and direct manuring alone, can really en- 

 rich our lands with nitrogen plant-food, and at the same time 

 improve, to some extent at'least, their physical condition. 



I do not intend to discuss here in detail the special merits 

 of these various modes of improving our farm-lands, and to 

 state from the stand-point of an agricultural chemist, imder 

 what circumstances and in what connection they ought to be 

 turned to account, to secure the best possible results ; but 

 will confine myself to a short exposition of some of the prin- 

 cipal means by which, in an economical way, an efficient sup- 

 ply of nitrogen plant-food for a general farm management 

 may be obtained. 



