314 



SOILS. 



by the observation of the native grow'th, especially the tree 

 growth; and where this consists of familiar species, normally 

 developed, such estimates on the part of experienced men, 

 based on previous cultural experience, are generally very ac- 

 curate; so much so that in many of the newer states they have 

 been adopted in determining not only the market value, but 

 also the tax rate upon such lands, their productiveness, and 

 probable durability being a matter of common note. 



Thus in the long-leaf pine uplands of the Cotton States, the scattered 

 settlements have fully demonstrated that after two or three years crop- 

 ping with corn, ranging from as much as 25 bushels per acre the first 

 year to ten and less the third, fertilization is absolutely necessary to 

 farther paying cultivation. Should the short-leaved pine mingle with 

 the long-leaved, production may hold out for from five to seven years. 

 If oaks and hickory are superadded, as many as twelve years of good 

 production without fertilization may be looked for by the farmer ; and 

 should the long-leaved pine disappear altogether, the mingled growth 

 of oaks and short-leaved pine will encourage him to hope for from 

 twelve to fifteen years of fair production without fertilization. 



Corresponding estimates based upon the tree growth and in 

 part also upon minor vegetation, are current in the richer lands 

 also. The "black-oak and hickory uplands," the "post-oak 

 flats," " hickory bottoms," " gum bottoms," " hackberry ham- 

 mocks," " post-oak prairie," " red-cedar prairie," and scores 

 of other similar designations, possess a very definite meaning 

 in the minds of farmers and are constantly used as a trust- 

 worthy basis for bargain and sale, and for crop estimates. 

 Moreover, experienced men will even after many years' cul- 

 tivation be able to distinguish these various kinds of lands 

 from one another. 



Cogency of Conclusions based upon Xatirc Growth. Since 

 the native vegetation normally represents the results of 

 secular or even millennial adaptation of plants to climatic and 

 soil-conditions, this use of the native flora seems eminently 

 rational. Moreover, it is obvious that if we were able to in- 

 terpret correctly the meaning of such vegetation with respect 

 not only to cultural conditions and crops, but also as regards 

 the exact physical and chemical nature of the soil, so as to 



