1 1 2 Journal of Agricultural Research voi. m. No. i 



The figures in Table IV show two important facts: (i) In the finer 

 soils a higher percentage of water is required to maintain the life of a 

 seedling than in soils of coarser texture; and (2) mountain bunch-grass 

 requires but little more available water than western porcupine grass, 

 one of the deepest rooted species, to become established in a given soil. 

 Mountain bunch-grass, moreover, will thrive on a soil containing less 

 water than would be required for short-awned brome-grass. To judge 

 from the nature of the situations invaded by mountain bunch-grass, 

 the plant may safely be classed among the drought-resistant native 

 species. 



Numerous observ-ations in 1909, supplemented by many counts on 

 small unit areas in different range types and on different soils, showed 

 that nearly the entire loss of seedlings occurred before August 1 . After 

 that date loss was prevented by cooler temperatures and by an increase 

 in soil moisture resulting from precipitation. However, the loss before 

 August I had been rather severe, varying from 20 to 70 per cent, accord- 

 ing to the situation, with a general average of about 50 per cent. 



In 1 9 10 the seedling loss in the fore part of the season was approxi- 

 mately the same as in 1909, but the loss in the latter part was much 

 greater, and only 25 per cent of the original stand remained vigorous 

 and active in the autumn. This extensive loss was due to continued 

 dry weather and high temperatures. 



LOSS OP FORAGE SEEDLINGS DURING DORMANT PERIOD FOLLOWING FIRST YEAR 



Table V shows that, in general, the loss of forage seedlings due to 

 physical conditions from October i, 1909, to July i, 1910, approximately, 

 was practically negligible. It will be seen that the heaviest seedling 

 loss occurred on steep slopes, particularly on those where the soil was 

 coarse and gravelly and the vegetation sparse. Quadrats 14 and 16 

 show this strikingly. The soil in quadrat 14, whose slope is 28.5° to 

 the west, is very coarse and gravelly, and only one-tenth of the ground 

 was covered with vegetation. In quadrat 16, with a slope of 3° to the 

 south, the soil is mainly of clay loam, with a small amount of gravel, 

 and three-tenths of the ground was covered with the same kind of 

 vegetation as quadrat 14. The loss of seedlings on the two quadrats 

 was 28.4 and 1.4 per cent, respectively. These losses were not due to 

 severe temperatures, but primarily to heaving of the soil and erosion 

 before growth began. Additional contrasts can be seen in quadrats 3 

 and 5, and 31 and 55. 



