1^4 



no easy matter to come at once to a common understanding so 

 that a o-iven statement means the same thing to all of iis. So to- 

 day I am going to talk hrst about soils in general leaving the mat- 

 ter of type adaptation until later. 



In studying soils, a- in other things, we begin by making a 

 few large groups. Thi- is commonly done by classif}"ing the rocks 

 from which the soils have been derived. Thus we have limestone 

 soils, sandstone soil^. shale soils, granitic soils, etc.. and in that 

 part of the South Alountain district in this immediate vicinity you 

 have manv liner divi-ions. even, -uch as white hint." "gray hint."" 

 ■"copperstone."" "mountain -tone."" etc. A p"roup of soils is desig- 

 nated by the soil series name. Thus the vallev limestone soils were 

 named the Hagerstown series because thev were hrst mapped in the 

 vicinitv of Hagerstown, Md. And in similar manner other names 

 have been selected to designate main o-i-oup> or series of soils. 



Leavm.o; the stone content and the gravel content out of con- 

 sideration we are accustomed to speak of soih as clays, sands and 

 loams, or some combinatiijn the-e terms such as sandy loams, 

 clay loams, etc. Adiat d'^ thc-e term- mean? Analvsis of a true 

 clay will alwavs sh^jw that the per cent, of exceedingly hue particles 

 is relatively high and where the amoimt is as much as 35 per cent, 

 of the soil ma-s it eives to the soil a dehnite character, in fact 

 seems the determinirg factrir in the wav the soil behave^- vdien 

 worked. If plowed or cultivateil when wet such a soil will cV"\ 

 badly. Soils are sometime- found which analyze as much as 50 

 per cent, of clav. btit I know of none so heavy in this state. A soil 

 that would be maoDcd as a -and. on the other hand, is compo-ed 

 principally of particles much c^r^arser than the grains of clay. 

 Through such a S'jil water r'erc'jlate- rapidly and we think of it as 

 a drouthv soil. Ilctween the-e twc extreme-, then, of sand and 

 clay, the coarsest soil particles and the hne-t there is a wide range 

 of sizes. A trtie loam is a mixture of a large number of ditterent 

 sized particles. It is a medium mixture in which clay, medium 

 and fine sands and silt are well balanced. AMien there is a little 

 too much sand for this medium mixture of loam the soil is called 

 a sandv loam, but where there is a little tc>o nuich cla_\y for the 

 same classification the soil is called a clav loam. This phase of 

 classification, as von will note, i- based solely on the size of the 

 . soil .grains, and determines the so-called texture of the soil. 



But there are also stifi:' soils, mellow soils, mealv S':als. and so 

 on. This is brought about bv a difir'erence in the jrrajijcijiciit of 

 the various sizes of soil particle-. Tw- -'T:- mav analyze practi- 

 cally the same. /. c, their textures mav show no material ditter- 

 ences and vet after a rain the nr.e has to be dried out much more 

 thoroughly than the other before it can be w^rtrked without cl':'d- 

 ding. This is due to the difir'erences in the -oil structure. Supp^r^-e 

 we reduce this to fractions having a common denominator, as we 

 used to do in school. Some of vou have tried packing apples in 

 boxes, and until experience has been acquired it is not easv to come 

 out even. If all apples were of the same size it would be an ea-y 

 matter. But there are all sorts of variations in size, and it takes 

 patience to work out the best combination. Apples of difi"erent 



