FERTILITY AND HOW TO MAINTAIN 63 



good soils. The character of growth of this plant will suggest whether 

 or not the soil is good or poor. On good soil it will have a rank and 

 vigorous growth. The same may be true with other plants, but where 

 nature is allowed to run her course and the law of "the survival of the 

 fittest" has free sway, those plants naturally best adapted to the region 

 are the ones which will ultimately predominate. 



It should not be understood that any one species of plant should be 

 relied upon to indicate whether or not a soil is good or poor, but when 

 one takes into consideration all the vegetation present, one can then judge 

 quite accurately as to the relative strength or fertility of the soil. 



Drainage Reflected in Character of Vegetation. — The condition of 

 the soil with reference to drainage is, of course, a modifying factor. Swamp 

 soils, for example, are adapted only to those plants that can grow in the 

 presence of an excess of moisture. So long as soils are in a swampy con- 

 dition they are unsuited to agricultural crops, and in that condition may 

 be considered unproductive. A good system of artificial drainage may 

 change the whole aspect and cause them to be transformed into highly 

 productive farm soils. Indeed, the establishment of a drainage system 

 under such conditions would ultimately cause the disappearance of the 

 native vegetation and encourage the encroachment of an entirely dif- 

 ferent set of plants. Then, again, climate is a modifying factor, and 

 certain plants are found in regions of continuous warm climate that are 

 not found where cold winters prevail. 



Lime Content and Acidity Related to Plants. — The predominance of 

 chestnut trees as above indicated suggests a poor soil and one low in lime 

 content. Chestnut trees are not found on limestone soils, and the lime- 

 stone soils in general are considered among the most fertile. Such plants 

 as the huckleberry, blueberry, cranberry and wintergreen are seldom found 

 on soils well supplied with lime. Redtop, while often indicative of a poor 

 soil, will grow luxuriantly on a fertile soil. It is also very tolerant of soil 

 acidity and an excess of moisture. It has a wide adaptation and is often 

 grown as a hay crop on poor soils. 



The presence of an abundance of sorrel, plantain and moss in culti- 

 vated fields is indicative of the condition of the soil, although it may have 

 no relation to the soluble plant food present. Such plants generally indi- 

 cate an acid soil, and call for the application of lime to encourage the 

 growth of clover. Sorrel, like clover, is generally benefited by lime, but 

 it is more tolerant of soil acidity than clover, and on an acid soil the clover 

 disappears and the sorrel fcakes its place. Red clover is less tolerant of 

 soil acidity than alsike clover. Many farmers make it a practice to mix 

 these two species of clover. On neutral soils the red clover wall always 

 dominate and the alsike will scarcely be noticeable. But if the acidity 

 of the soil approaches the limit for red clover, then the alsike will pre- 

 dominate, and this predomination is very noticeable when the crop comes 

 into blossom. 



