The Problem of Impoverished Lands. 97 



deeper and mellower. Well-drained soil is drier in wet weather and 

 nioister in dry weather than soil which is underlaid with a high and 

 hard subsoil. Most of the cold, wet and so-called " sour " lands need 

 draining to make them productive. Even though they are not too 

 wet for tillage, they may need the drainage for the purjjose of deep- 

 ening the soil and causing it to hold more air and moisture. Deep- 

 rooting plants, as clover, tend to make soils deeper. Subsoiling has 

 a similar tendency, but its effect usually is not permanent. Consult 

 Part II, paragraph 9, page 103. 



•1. Ths soil may become acid. — There are some cases in which 

 the soil becomes sour to a degree that is injurious to many plants. 

 This is true of some sandy uplands and sometimes is indicated by 

 growths of sorrel, daisies and golden rod. The acid in soil can be 

 detected by its reddening blue litmus paper (to be had at drug stores 

 or at this Station). This over-acid condition often accompanies a 

 lack of humus, and sometimes may be corrected by adding humus. 

 It is also relieved by the use of ashes or lime, which have the power 

 of neutralizing or sweetening acids. The ashes or lime should not 

 be ploughed in, but harrowed in after ploughing, as lime tends to 

 work downward. When experimenting with humus (see next page), 

 an application of ashes on an adjoining plat may help solve the 

 problem. 



5. The soil may lack in useful plant-food. — Some of the leading 

 plant-food elements may be nearly or quite exhausted ; or, as is 

 more usually the case, they may be in an unavailable condition or 

 locked up. The chemist can tell if the soil which he analyzes lacks 

 plant-food ; but another sample of soil from the same field may be 

 very different in composition. There is very little uniform soil in 

 New York, for nearly all of it is mixed glacial soil. But the chemist 

 cannot tell how much of the plant-food is available to plants. Food 

 which is nearly unavailable when he analyzes it, may be made avail- 

 able by a change in conditions or by better tillage ; and that which 

 is clearly available may become unavailable the same season. In 

 certain very pronounced cases of depleted lands, the chemist may 

 render much direct aid ; but in general he can only suggest and 

 advise, not prescribe. The only sure way to find out whether more 

 plant-food is needed is to experiment on the land in question. 

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