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



Table 35. — Humus in Soil Columns op San Oabriel 



Orange County 

 FcLLERTOx Anaheim 



EivER Alluvial Plain, 



Ft. 



1 

 2 



3 

 4 



8 



9 



10 



11 

 12 



Soil 

 Clay 7.94 



Humus- 

 Xitrogen in 



Humus Humus Soil 



Loam 51 



Loam 64 



Loam 25 



Loam 22 



Loam 22 



Loam 26 



Loam 33 



Loam 29 



Loam 29 



Loam 29 



Sum of per cents 3.30 

 Average per foot .33 



Upper 3 feet :* 

 Sum of per cents 1.40 

 Average per foot .47 



10.89 

 7.82 

 18.40 

 15.45 

 20.45 

 10.77 

 15.15 

 19.31 

 12.41 

 19.31 



.06 

 .05 

 .05 

 .03 

 .05 

 .03 

 .05 

 .06 

 .04 

 .06 



15.00 .05 



12.40 .05 



Soil 

 Clay 5.78 



Humus 



Sandy 88 



Sandy 83 



Sandy 68 



Sandy 49 



Sandy 41 



Sandy 33 



Sandy 33 



Sandy .25 



Sandy 22 



Sandy 24 



Humus- 

 Xitrogen in 



f -^ N 



Humus Soil 

 8.00 .07 

 6.46 

 6.91 

 8.00 

 6.09 

 6.06 

 4.58 

 4.40 



.38 



.28 



.05 

 .05 

 .04 

 .03 

 .02 

 .02 

 .01 

 .01 

 .01 



4.66 

 .46 5.12 .03 



2.39 



.79 7.12 .06 



COMPTON 



Soil 

 Clay 7.45 



Humus 



Dark loam.... 1.50 



Dark loam 91 



Dark loam 51 



Light loam 60 



Dark loam 49 



Light loam 53 



Light loam 64 



Light loam 52 



Fine sand 38 



Fine sand 42 



Dark loam 49 



Dark loam 32 



7.31 

 .61 



2.92 

 .97 



Humus- 

 Xitrogen in 



> '^ ^ 



Humus Soil 

 6.77 .08 

 9.16 

 6.50 

 7.47 

 5.18 

 7.25 

 5.17 

 7.00 

 12.30 

 5.80 

 4.15 

 3.18 



.05 



.04 

 .03 

 .09 

 .04 

 .02 

 .02 

 .02 

 .02 

 .03 

 .01 



6.66 .04 



7.50 .06 



Range of most annual plant roots. 



localities, as around Comptou. the soil is of a dark sandy loam 

 nature, quite micaceous and contains more humus than elsewhere. 

 The Compton column is fairly well supplied with humus and 

 nitrogen throughout the depth of twelve feet, and conditions 

 seem to be especially favorable for deep rooting of plants. In 

 other localities there are heavy sandy deposits from old river 

 overflows, the soil of which while quite fertile needs humus to 

 give it a stronger texture. 



The Anaheim column was taken from a walnut orchard whose 

 owner had practiced a system of green-manuring for a number 

 of years with good results. While the percentage of humus is 

 still rather low, yet it contains much nitrogen in the upper por- 

 tion of the column. The sandy loam soils along the border of 

 this allu^^al plain near Fullerton. represented by a column a 

 short distance south of town, are surprisingly low in their humus 

 content, but the humus is remarkablv rich in nitrosren. not in 



