ABSTRACT 



In a community of widely spaced perennials, mostly shrubs, in the 

 cold desert of western Utah, total accumulated organic mass (excluding 

 the small amount of humus) is about 1,770 g./m.^ . Of this total, 240 g. 

 are above the ground and 1,530 g. below. Of the latter, 295 g. is under- 

 ground litter. About half of the 1,235 g. of roots are in the surface 30 cm. 

 of the soil, about 0. 3 of them in the second 30 cm. , 0. 15 in the third, 0. 03 

 in the fourth, and 0.01 of them occur below 120 cm. to about 135 cm. 

 Coarse roots C>2 mm. in diameter) are found only in the immediate vicin- 

 ity of plants and are unimportant below the 15-cm. depth. Fine (< 0. 5 mm. 

 in diameter) and medium size roots have a much more even horizontal 

 distribution at all depths. A gross estimate of net primary productivity 

 for this desert site (average annual precipitation = 154 mm.) is 258 g. / 

 m. ^ , 28 g. above the ground (probably a good estimate) and 230 g. below 

 the ground (a calculation based on some necessary assumptions). 



