34 



BULLETIN 1105, U. S. DEPARTMENT OF AGRICULTURE. 



Table 10. — Seedling soil survey — Continued. 

 2. Sample plot 3b (September, 1920). 



Plot. 1 



Vegetation in order of abun- 

 dance. 



Num- 

 ber of 

 seed- 

 lings . 2 



Plot.* 



Vegetation in order of abun- 

 dance. 



Num- 

 ber of 

 seed- 

 lings. i 



H 5 



Soil No. 12, rock outcrop: 

 Lot, M, C, F, And . 



49 

 31 



E 10 



F3 



G9 



J9 



K9 



L7 



L8 



L9 



L10 



1.1 acre... 



A3 



A 10 



C2 



D2 



E 1 



E2 



Fl 



0.7 acre... 



Soil No. 24, stony clay— Cont'd. 



M, Lot, Vic, Sit, F, Er 



F, M, Vic 



37 



II 6.. . 



Lot, M, C, Vic, Lup 



Total 



8 





Vic Lot M F 



11 





80 

 400 





13 





Per acre 



M, Vic, Sit, Lot, F 



53 





Soil No. 6, very stony clay: 

 M,F,Lot 



F, M, Lot, Vic, Sit . 



45 





26 

 62 

 18 

 54 

 47 

 81 

 78 

 68 

 10 



M, Lot, Vic, F,Sit 



21 



D 6 



M, F, Lot, Vic 



14 



H3 





Lot, M, Vic . 



34 



13 



M Lot Sit 



Total 





17... 



M^ Vic, Sit 



287 



J6 



Sit, M, F, Vic, Lot 





261 



J 7 



Vic M Lot 



Soil No. 20, fine clay: 



F, Vic, Lup, Sit 





L 1 . 



Lot, M 





L 2 



M, Vic, Lot 







J4 



M, Sit, Vic 



F, Vic 



6 





Total 





5 





444 

 493 



F (almost pure), Vic, Lup. . 

 F,M, Vic 



8 







4 





Soil No. 24, stony clay: 

 F, Vic, M 



F (very rank), Ann, Vic — 

 F, M, Lot 





 2 





22 

 29 



D 4 



Total 





E 4 



F, Sit, Vic, Ann. . 



25 









36 









Summary of sample plots 3a and 3b. 



Soil. 



No. 12, rock outcrop . . . 

 No. 6, very stony clay. 



No. 24, stony clay 



No. 9, gravelly clay 



No. 20, fine clay (deep) 

 No. 28, shallow clay . . . 



Acres. 



0.48 



.9 

 1.5 



.7 

 1.0 



.5 



Number of seedlings. 



Total. 



176 

 414 

 3:..-. 



Per acre. 



367 

 493 

 237 

 137 



Reproduction in various types of soil. — It should be noted that 

 the groups of plots in Table 10 are arranged in the order of the rela- 

 tive amounts of stone or gravel contained. A possible exception may- 

 occur in the case of Nos. 20 and 28, the latter of which is usually 

 somewhat the more gravelly. It should also be borne in mind that 

 all of these soils are distinctly clayey. The varying degrees of 

 loaminess referred to in the descriptions apply only to a surface 

 layer varying from 2 to 12 inches deep, or in rare cases slightly 

 deeper. The seedling counts leave no doubt as to the favorable 

 influence of rock or gravel. Since practically all of the seedlings 

 were over 3 years old and the majority over 5 years old at the time 

 of the examination, the data should furnish a reliable index as to 

 ultimate survival on the various soils. 



There also seems to be a definite relation between soil, reproduc- 

 tion, and herbaceous vegetation. Where Festuca arizonica is dis- 



