1919] 



Pendleton : A Study of Soil Types 



433 



two croppings, while one crop was grown on the San Joaquin sandy 

 loam soils. The infertility of the San Joaquin soils, in some cases 

 extreme, greatly retarded crop growth. 



Diablo clay adobe. First crop. — Due to the presence of wild oat 

 seed in all the four samples of this soil, and the inability to distin- 

 guish the young wild oat plants from the planted oats, wheat, or 

 barley when thinning, the value of the results of the grain crops in 

 this series is much decreased. The averages plotted include the total 



.OqVs 

 ~*/ and 



Bur Clover 

 Bur Clover 



Z5 



20 



*\5 



E 

 o 



u 



O 

 10 



Oa\s 



Barle_y 



Wheat 



J--Phase'oluS 



5 < 



Soils 



Fig. 27. Graph showing the total dry matter produced by wheat, barley, 

 oats, Phaseolus, bur clover, and oats and bur clover on the four samples of 

 Diablo clay adobe. First crop. 



crop, whether pure or with a greater or less quantity of the wild oats, 

 though the number of plants harvested was usually six or less. 

 Planting the oats and bur clover together was not a success. In three 

 of the soils the crop of bur clover alone was greater than that of the 

 six bur clover plants plus the six oat plants. Plate 44 shows how, in 

 some cases, the oats dominated, and in others the bur clover was 

 superior. On the soils of this type bur clover was the most satisfactory 

 crop, while the white beans were the most unsatisfactory of all. 



Comparing the total crops (see fig. 27 and tables 45-50), it will 

 be seen that 1, 5, 2, 6 is the order for bur clover, soil no. 1 giving the 



