332 



EXPERIMENT STATION RECORD. 



hygroscopic moisture, organic matter, humus, and mineral constituents 

 of 71 samples of soils from the different sections of the State are 

 reported. The averages for the main divisions of the State, as well as 

 for the State as a whole, are given in the following table: 



Average composition of Oregon soils. 



Analysis of lint- darfch. 



Willamette 

 Valley. 



/'//• cent. 



Insoluble matter 65. 18 



Soluble silica 5. 02 



Potassium oxid -23 



Sodium oxid .18 



Calcium oxid I .83 



Magnesium oxid .79 



Marigano-manganic oxid .08 



Ferric oxid... 1 16 45 



Aluminium oxid I 



Sulphuric acid | .03 



Phosphoric acid -21 



Water and organic matter 10. 77 



Total 99. 77 



Humus 1. 03 



Southei ii 

 Oregon. 



/'. /■ cent. 



62. 45 



8.74 



.34 



.21 



2.22 



30 



.25 



.01 



.13 



9.52 



Eastern 



Oregon. 



Per 



cent. 

 66. 59 

 13. 12 



.43 

 .22 

 1. 22 

 . 7") 

 .10 



.04 



.14 



6.21 



\ .rr-|_]' 



for whole 



State. 



Per 



cent. 

 05.08 

 7.69 

 .32 

 .29 

 .97 

 .82 

 .16 



12.68 



.70 



.26 



10.05 



100. 02 

 2.25 



99.51 



1.44 



99.02 

 2.42 



The bottom lands of the Willamette Valley as a rule " have a tend- 

 ency toward clay loams with clay subsoils forming a hardpan." The 

 soils are divided into dark loam and gray loam, the latter running into 

 the so-called ''white lands." They are all, however, of about the same 

 chemical composition. They are rich in phosphoric acid and humus, 

 well supplied with lime, but deficient in potash. 



"That these soils should be fairly well supplied with lime would be expected from 

 a priori reasons on account of the basaltic origin of a large part of them. The lime 

 in the valley soils is not altogether in the form of a carbonate — indeed, it is rare that 

 sufficient carbonate is present to cause evident effervescence with acid — but even a 

 casual examination shows a A T ery common occurrence of easily decomposable zeo- 

 lites, principally mesolite, from which, by weathering, the lime may be constantly 

 supplied." 



In the hill country surrounding the Willamette Valley, in its north- 

 ern part, are found the so called " shot lands," which contain consider- 

 able amounts of iron oxid, together with quartz, feldspar, and some 

 hornblende, the iron oxid cementing the particles of clay together into 

 small nodules which to some extent resemble shot, but which wear 

 away in cultivation. These soils are usually well drained and easily 

 worked, but wash badly in heavy rains. They contain as a rule a fair 

 amount of potash, a limited amount of lime, and are well supplied with 

 phosphoric acid. 



The soils of southern Oregon -'are stronger than the Willamette 

 Valley soils not only in lime but also in potash, but weaker in phos- 

 phoric acid." The soils of eastern Oregon contain more lime than 

 those of the humid or western area. They also contain a larger supply 

 of potash, which is more available than that in the soils of the Willa- 

 mette Valley. The amount of phosphoric acid, however, is smaller 

 than that of the western soils. 



