222 University of California Publications in Agricultural Sciences [Vol. 1 



twelve feet and more. Two columns were obtained by INIr. F. 

 E. Johnson, one near the town of Arroyo Grande, the other from 

 the farm of the Routzahn Seed Company, a few miles to the 

 westward, the only apparent difference being a darker color in 

 the surface foot of the seed-farm soil. 



The soil from the Routzahn seed-farm in the Arroyo Grande 

 Valley is certainly remarkably rich in humus for an arid soil ; 

 for not only does each foot of the upper five feet and also the 

 seventh contain more than 1 per cent, but the twelfth foot has 

 1.20 per cent and the tenth nearly 1 per cent. The soil from 

 near the town of Arroyo Grande is even richer than that of the 

 seed-farm, for it contains not only more than 1.50 per cent of 

 humus in each of the upper seven feet, but each of the lower 

 five feet lacks but little of having 1 per cent. 



The percentages of humus-nitrogen in these soils are also very 

 high, especially in the upper few feet of each column, that of 



Table 26. — Humus in Soil Columns op Santa Maria and Lompoc Valleys, 



Santa Barbara County 



Santa Maria Valley 



SANTA BARBARA COUNTY 

 West of Santa Maria 



Soil 

 Clay 10.25 



Ft. 



1 Dark loam ... 



2 Dark loam ... 



3 Dark loam .. 



4 Light loam .. 



5 Light loam .. 



6 Light loam .. 



7 Light loam .. 



8 Gray loam.... 



Humus- 

 Nitrogen in 



r \ 



Humus Humus Soil 



1.44 9.57 .11 



1.11 4.81 .05 



.84 5.52 .05 



.26 9.72 .03 



.46 7.76 .04 



.32 8.97 .03 



.24 9.36 .02 



.21 11.36 .02 



9 Gray loam 21 12.03 .03 



10 Gray loam 23 9.77 .02 



11 Gray loam 09 18.72 .02 



12 Gray loam 16 17.15 .03 



Lompoc Valley 

 santa barbara county 



Burpee Seed-Farm 



Soil 

 Clay 33.40 



Humus- 

 Nitrogen in 



' -^ N 



Humus Humus Soil 



Dark clay 2.50 5.28 .13 



Dark clay 1.56 4.62 .07 



Dark clay 1.51 4.90 .07 



Dark clay 1.93 6.12 .12 



Dark clay 1.07 5.32 .06 



Dark clay 1.18 7.28 .09 



Dark clay 1.33 5.94 .08 



Dark clay 80 6.13 .05 



Dark clay 43 6.27 .03 



Dark clay 21 8.58 .02 



Dark clay 24 8.75 .02 



Dark clay 27 8.53 .02 



Sum of per cents 5.57 



Average per foot .46 10.40 .04 



Upper 3 feet :* 

 Sum of per cents 3.39 

 Average per foot 1.13 6.67 .07 



* Range of most annual plant roots. 



13.03 

 1.09 



5.57 

 1.86 



6.50 .05 



4.93 .09 



