pactness unfavorable to crops should be handled with implements 

 that tend to keep it in the loosest possible condition. 



A second condition of importance in soil control is the content and 

 character of the organic matter. As a general rule soils respond to 

 applications of organic matter whether in the form of stable manure 

 or of plant remains; or, to state it in another way, soils to do their 

 best require that a constant supply of organic matter be fed to them, 

 and that this organic matter be of such character as to be easily 

 digested by the soil. No standard can be fixed as to the quantity of 

 organic matter a soil should contain, but it is essential for its most 

 effective use that it should at all times contain readily digestible 

 organic matter. 



A soil is most efficient when crops are grown upon it in certain 

 order of rotation. It is not to be expected that a soil will produce 

 as large a crop of corn immediately following potatoes as it would 

 if the corn followed sod; nor is it to be expected that the soil will 

 produce as large a crop of wheat following wheat as it would if a 

 crop of clover had intervened between the two wheat crops. The 

 general principle in a rotation should be a sod followed by corn, then 

 by a small grain, and then by sod again. This is a safe general guide 

 where such crops are well adapted to a soil type, but the soil types 

 differ so markedly in their adaptations and in their peculiarities that 

 no general rotation can be expected to be successful on all types of 

 soil; and yet, as stated above, the soil will maintain its maximum 

 capacity only if crops are rotated in certain orders, depending upon 

 the soil material, the soil class, and the crop adaptations. 



Drainage is another factor upon which the efficiency of the soil 

 depends. There is an optimum water content for each type and 

 grade of soil with which the highest efficiency of the soil may be 

 expected. If the soil is so situated as to have excessive or deficient 

 drainage, the highest efficiency of the soil can not be expected until 

 these conditions are alleviated. 



The presence of certain weeds, and in general an abundance of 

 weeds, lowers the efficiency of the soil for all cultivated crops, and 

 weeds are often indicators of soil conditions which make the soil 

 poorly adapted to certain crops. 



These factors of miscontrol do not leave as a rule sufficient evi- 

 dence in the soil to be determined by a laboratory examination of a 

 sample, and where failure to maintain the soil in its highest state of 

 efficiency results through such mismanagement, it is the part of the 

 expert farmer or soil scientist, skilled in handling soil material in 

 the field, rather than that of the soil chemist, confined to laboratory 

 examination, to determine the cause of failure and the remedial 

 measures. 



[Clr. 26] 



