CHAPTER 3 



Fertility and How to Maintain 



Fertility Defined. — The fertility of a soil is measured by its capacity 

 to produce an abundant growth of the crops to which the soil and climate 

 of the region are adapted. Fertility is not dependent upon a single factor, 

 but requires the presence and co-ordination of a number of factors acting 

 in unison. The fertility of the soil is, therefore, dependent, first, upon 

 the presence of a sufficient supply of the necessary plant-food elements 

 in an available form; second, upon an adequate water supply to convey 

 these elements in solution to the roots of the plants; third, upon suf- 

 ficient warmth to promote plant growth; fourth, upon the presence of 

 sufficient air to meet the needs of the roots for oxygen. A fertile soil 

 will, therefore, generally consist of the ordinary soil minerals reduced to 

 a fine state of subdivision, incorporated with more or less organic matter, 

 and containing a sufficient supply of air, water and soil bacteria. 



Vegetation an Index to Fertility. — The best index to soil fertility is 

 the growth and condition of plants produced by the soil. On a virgin 

 soil, either in timbered regions or on the prairies, the species of plants 

 and their conditions of growth have long been recognized as indications 

 of the character and value of the soil. In general, such trees as apple, 

 ash, basswood, black walnut, burr oak, crab-apple, hard maple, hickory 

 and wild plum, are indicative of good soil. On the other hand, where 

 beech, chestnut, hemlock, pine or spruce dominates the forest growth, the 

 soils are likely to be comparatively poor. White oak and beech are fre- 

 quently found growing together in considerable abundance. If the white 

 oak predominates the soil may be considered fairly good, but if beech 

 predominates it may be looked upon with suspicion, and will probably 

 prove to be a poor soil. 



Herbaceous plants in the same manner are a good indication of the 

 fertility of the soil. For example, in regions where alfalfa, Canada thistle, 

 bindweed, clover, corn, cockle-burr, Kentucky blue grass, quack grass, 

 ragweed and wheat grow well, the soils are generally found to be fertile. 

 On the other hand, the predominance of buckwheat, Canada blue grass, 

 the daisy, five-finger, oats, paint-brush, potatoes, redtop, rye, sorrel and 

 wild carrot, indicate soils relatively poor. 



In general, legumes indicate a good soil, although in case of the wild 

 legumes there are some exceptions to this. Soils on which the grasses 

 predominate are generally better than those given over largely to the 

 growth of sedges. The sedges in general indicate wet soils. Golden-rod 

 is a common weed having a wide habitat. It grows on both poor and 



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