182 BOARD OF AGRICULTURE. 



active form the materials which tbe soil contains in abundant 

 quantity, but in an inert state. 



To go back and review, in a couple of statements : Exhaustion 

 is the reduction of the producing capacity of the soil below the 

 point of profitable cultivation, and depends either upon the abso- 

 lute removal of certain materials, or their removal to such a point 

 that the suppty is below the demand of the crop, and such re- 

 moval of materials must be compensated either by suitable fertil- 

 izing applications or by making the unavailable materials still 

 present in the soil available by fallow, tillage, &c. 



Mr. Lawes, of England, a gentleman who has devoted a great 

 deal of attention to agriculture, and spent a great deal of money 

 in its study, and who has arranged the most beautiful and elabo- 

 rate field. experiments that have ever been made in any country, 

 has brought out in a recent publication the distinction between the 

 " natural strength " of the soil and what he designates its " con- 

 dition ;" and as this distinction is an extremely important one, I 

 will devote a few moments to its consideration. The natural 

 strength of a soil is its feeding power aud adaptedness to crops in 

 all those respects which belong to the soil by its original nature. 

 This standard fertility or productive power is something character- 

 istic of the soil, something you cannot separate from it, something 

 belonging to its entire mass and dependent upon its original com- 

 position, texture, and properties. It is a thing which lasts a long 

 time, and perhaps has scarcely any limit in the matter of duration, 

 whatever may be its limit in the quantity of crop which the soil 

 will produce. Every soil has its natural strength, greater or less, 

 the degrees covering a very wide range. You have all heard of 

 soils which are remarkable for their productiveness, or for their 

 want of productiveness. The valley of the Nile, for instance, is a 

 region which has been cultivated for a period longer than history 

 can define with any accuracy, and produces large crops annually 

 of the most exhausting kinds. Wheat and similar grains are 

 grown there continuously, year after year, without any attention, 

 except digging in the seed, watering and taking the crop oil'. We 

 find in Hungary and Southern Russia large tracts of country, 

 where, every other year, or every third year, large wheat crops 

 are harvested. The land is cleared, the seed put in, and after the 

 crop is gathered the land is allowed to rest one or two years, then 

 another crop is put in, and so on. This process has beeu going 

 on for centuries. Black Sea wheat is famous all over the world. 



