No. 4.] SOIL EXHAUSTION. 281 



while the heavier inland soils possess sixty to seventy per 

 cent. A soil, for example, that is adapted to onions is not 

 adapted to lettuce, and one Avhich will grow potatoes will 

 not necessarily grow tobacco. The influence of the physi- 

 cal properties of the soil can best be seen on our native 

 species of plants. Every farmer has noticed the fondness 

 of the white birch, pitch pine and scrub oak to dry, sand}^ 

 or gravelly soils ; and these plants are seldom seen on the 

 heavier clay soils. There are, in fact, a considerable num- 

 ber of native plants in our State which are so particular 

 about the physical condition of the soil that they can only 

 be found in those localities where soil of a certain texture 

 abounds. The peculiarities in the distribution of the wild 

 plants would scarcely be noticeal)le except to a botanist, 

 who has paid some attention to the physical conformity of 

 our flora ; and a knowledge of the hal>itats enables one to 

 form a reliable conception of the nature of the soil upon 

 which they are found growing. The rattle-box ( Orotalaria 

 sagiUalis) and the barberry are types of such plants, as, 

 to a less extent, is the red cedar ; the latter species seems 

 to delight in the presence of numerous cobble-stones as a 

 soil condition. 



It is our intention to consider the chemical and physical 

 changes which have taken place in our Massachusetts soils 

 during the past two hundred and fifty years, and to ascertain 

 whether the common methods of cultivation which have 

 been in vogue are well adapted to produce crops of the same 

 magnitude as those formerly produced. During the last 

 decade we have heard much of abandoned farms and worn- 

 out soils. Yet it is well known that these farms were not 

 always in a sterile condition, but that they contained at one 

 time a considerable quantity of plant food. 



Inasmuch as the predominance or scarcity of our wild 

 l)lants in certain localities gives us a clue to the soil condi- 

 tions under which they are growing, we may consider their 

 adaptation as a means of determining the changes w^hich 

 have taken place in our soils. There are also many scatter- 

 ing historical records which show us that plants Avhich were 

 once common have greatly decreased in numbers in certain 

 localities during the last fifty or one hundred years. It is 



