transportation, do not apply. It is only in the absence of these 

 limiting conditions that such results are of value. 



It, thus, is essential to the proper investigation of a sample of soil 

 by the bureau that the purpose for which the examination is required 

 be stated, and that information be given which will enable the bureau 

 to identify the material, the agencies which have led to its formation, 

 and those that have influenced the present condition of the soil. The 

 general purposes for which such examinations may be requested may 

 be briefly stated : 



1. Adaptation of the soil for crops. 



2. Fertilizer and manurial requirements. 



3. Alkali determination. 



4. Special chemical and mineralogical examination. 



5. Investigations to reveal the presence of deleterious substances suspected to 

 be of organic nature. 



The purpose for which the soil is to be used should be stated that 

 is, whether for greenhouse, garden, or field crops, and the kind of 

 crops it is intended to grow. 



The general topography and elevation of the field should be stated 

 and its relative position with respect to surrounding fields. If the 

 soil occurs as prairie or not, this fact should be stated, together with 

 the nature and species of the native plants, whether weeds, grass, or 

 trees. 



The occurrence of concretionary formations such as ferruginous 

 or calcareous hardpan or nodules will often aid in the identification 

 of material and in the consideration of the problem of adaptation 

 and yield. If the soil is of recent alluvium, it should be stated 

 whether of first bottom or of second bottom, and a note should be 

 made of the drainage conditions. Any unusual phenomena or ab- 

 normal growth or death of crop should be stated, and general infor- 

 mation as to the crops previously grown and the character and 

 efficiency of cultivation. 



It is advisable always to have a sufficiently large sample to serve 

 for the different kinds of examinations that will be required. For 

 this purpose there should be submitted at least 10 pounds of the top 

 soil taken down to a change of color or of texture marking the sub- 

 soil ; or if there is no particular difference between the soil and sub- 

 soil, the sample should be taken to a depth of at least 8 or 9 inches. 

 There should also be submitted a sample of about 5 pounds of the 

 subsoil immediately underlying; and if there is a gravel substratum 

 below this, the fact should be stated. Care should be exercised in 

 securing the sample to select a spot representing as accurately as 

 possible the conditions that are to be investigated. If the examina- 



[Cir. 26] 



