Skip to main content

Table 3 Regression model results for microbial nutrient limitation

From: C:N:P stoichiometry and nutrient limitation of the soil microbial biomass in a grazed grassland site under experimental P limitation or excess

Explanatory variable Estimate Std. Error T value P value
C-limitation     
(Intercept) 1.898 0.184 10.33 <0.0001***
C:Psoil −0.392 0.074 −5.27 <0.0001***
N:Pmic 1.088 0.30 3.63 0.0011**
C:Psoil × Cmic:DOC 0.021 0.005 4.0 0.0004***
N:Pmic × Cmic:DOC −0.092 0.023 −4.03 0.0004***
CP-limitation     
(Intercept) 0.622 0.071 8.74 <0.0001***
CNlmt × N:Pmic × C:Nmic 0.013 0.003 3.79 0.0003***
CN-limitation     
(Intercept) 13.239 3.534 3.75 0.0009***
N:Psoil −1.048 0.339 −3.09 0.0047**
Clmt −6.749 2.306 −2.93 0.007*
Clmt × N:Psoil 0.491 0.192 2.565 0.0164*
N:Pmic −1.748 0.635 −2.753 0.0106*
N:Pmic × Clmt 0.728 0.304 2.395 0.0241*
N:Pmic × N:Psoil 0.122 0.055 2.223 0.0351*
CNP-limitation     
(Intercept) 0.842 0.129 6.56 <0.0001***
CNlmt 0.573 0.079 7.26 <0.0001***
  1. Minimum adequate model of a multiple regression on microbial C-, CP-, CN- and CNP-limitation as dependent variables respectively. Explanatory variables are as follows: for C-limitation: soil C:P ratio (C:Psoil), microbial N:P ratio (N:Pmic), interactions of these with the ratio of microbial C to dissolved organic C (Cmic:DOC) (r² = 0.671, F[4,29] = 17.83, P < 0.0001); for CP-limitation: interaction of microbial CN-limitation (CNlmt) × N:Pmic × microbial C:N ratio (C:Nmic) (r² = 0.164, F[1,67] = 14.3, P = 0.0003); for CN-limitation: soil N:P ratio (N:Psoil), microbial C-limitation (Clmt), N:Pmic, and interactions between these variables (r² = 0.78, F[6,26] = 19.58, P < 0.0001); for CNP-limitation: microbial CN-limitation (CNlmt) (r² = 0.429, F[1,68] = 52.8, P < 0.0001).