The Microflora 



283 



BASIN 



TROUGH 



RIM 



5 2000 



■o 



c 



01 



Q 



o 



c 



3 



'6 



o 



E 

 o 



CD 



800 

 600 

 400 

 200 



r=0.92 



2.0 

 1.6 

 1.2 



0.8 



^ 0.4- 



r=0.77 



J I L 



J I L_ 



4 8 



12 16 20 



Labile P, mg m ^ cm ' 



FIGURE 8-11. 77?^ density and bio mass of soil fungi in relation to 

 available phosphorus 10 days earlier. An r value of 0.81 is statistically 

 significant at the 0.05 level. (Barel, Laursen and Miller, unpubl.) 



do appear to be related to amounts of resin-extractable phosphorus pres- 

 ent ten days earlier (Figure 8-11). Correlation coefflcients for phos- 

 phorus with density and biomass were 0.77 and 0.92 for the basins of 

 low-centered polygons where concentrations of phosphorus are generally 

 low. The correlations were poorest for polygon troughs, where concen- 

 trations of phosphorus are much higher than in basins. Low concentra- 

 tions of phosphorus may reduce fungal biomass below the levels that can 

 be supported by the amounts of organic substrate present. In the 

 phosphorus-rich troughs fungal density and biomass appear limited by 

 either the reduced amount of organic matter or other conditions 

 associated with high bulk densities. 



Regressions of resin-extractable phosphorus against levels of fungal 

 biomass or density 5 or 10 days earlier reveal no significant relationships. 

 Thus, low concentrations of phosphorus do not appear to be a function 

 of low densities of fungi. It is impossible to evaluate the role bacterial 



