Table 1.
Regression equations for physiological efficiency (PE), N use efficiency (NUE), apparent fertilizer recovery (AFR), biomass straw production, grain yield, shoot and root biomass, N shoot accumulation and leaf chlorophyll index (LCI) at flowering, as a function of N rates at each inoculation treatment
| Treatment | PE (kg grain kg N accumulated−1) | NUE (kg grain kg N applied−1) |
|---|---|---|
| Control | Ŷ = 127.788–0.681x + 0.001 × 2 (R2 = 0.99**) | Ŷ = 24.027–0.061x (R2 = 0.78**) |
| Azo | Ŷ = 127.206–0.811x + 0.001 × 2 (R2 = 0.99**) | Ŷ = 55.073–0.209x (R2 = 0.86**) |
| Bac | Ŷ = 162.735–1.169x + 0.002 × 2 (R2 = 0.92**) | Ŷ = 36.429–0.113x (R2 = 0.97**) |
| Azo + Bac | Ŷ = 89.366–0.482x + 0.001 × 2 (R2 = 0.85**) | Ŷ = 48.238–0.158x (R2 = 0.90**) |
| Treatment | AFR (%) | Biomass straw (kg ha−1) |
| Control | ns | Ŷ = 6820.383 + 27.498x − 0.078 × 2 (R2 = 0.99**, P.M. = 176 kg N ha−1) |
| Azo | Ŷ = 63.887–0.174x (R2 = 0.96**) | Ŷ = 8260.360 + 15.089x − 0.050 × 2 (R2 = 0.94**, P.M. = 151 kg N ha−1) |
| Bac | Ŷ = 18.786 + 0.355x − 0.001 × 2 (R2 = 0.76**, P.M. = 178 kg N ha−1) | Ŷ = 8189.974 + 21.751x − 0.065 × 2 (R2 = 0.97**, P.M. = 167 kg N ha−1) |
| Azo + Bac | Ŷ = 67.825–0.158x (R2 = 0.97**) | Ŷ = 8354.989 + 20.693x − 0.066 × 2 (R2 = 0.89**, P.M. = 157 kg N ha−1) |
| Treatment | Grain yield (kg ha−1) | Shoot biomass (kg ha−1) |
| Control | Ŷ = 6838.649 + 10.141x (R2 = 0.92**) | Ŷ = 8350.770 + 14.818x − 0.040 × 2 (R2 = 0.94**, P.M. = 185 kg N ha−1) |
| Azo | Ŷ = 7784.245 + 19.991x − 0.067 × 2 (R2 = 0.86**, P.M. = 148 kg N ha−1) | Ŷ = 9043.568 + 14.631x − 0.045 × 2 (R2 = 0.99**, P.M. = 161 kg N ha−1) |
| Bac | Ŷ = 7772.477 + 17.476x − 0.053 × 2 (R2 = 0.79**, P.M. = 164 kg N ha−1) | Ŷ = 8835.659 + 24.406x − 0.078 × 2 (R2 = 0.96**, P.M. = 156 kg N ha−1) |
| Azo + Bac | Ŷ = 8052.723 + 19.374x − 0.055 × 2 (R2 = 0.90**, P.M. = 175 kg N ha−1) | Ŷ = 8981.098 + 22.565x − 0.070 × 2 (R2 = 0.95**, P.M. = 161 kg N ha−1) |
| Treatment | Root biomass (kg ha−1) | N shoot accumulation (kg ha−1) |
| Control | Ŷ = 561.259 + 3.559x − 0.009 × 2 (R2 = 0.97**, P.M. = 197 kg N ha−1) | Ŷ = 97.039 + 0.492x − 0.001 × 2 (R2 = 0.94**, P.M. = 189 kg N ha−1) |
| Azo | Ŷ = 741.384 + 4.250x − 0.015 × 2 (R2 = 0.96**, P.M. = 140 kg N ha−1) | Ŷ = 106.263 + 0.683x − 0.002 × 2 (R2 = 0.99**, P.M. = 171 kg N ha−1) |
| Bac | Ŷ = 626.585 + 4.447x − 0.012 × 2 (R2 = 0.97**, P.M. = 181 kg N ha−1) | Ŷ = 106.694 + 0.760x − 0.002 × 2 (R2 = 0.96**, P.M. = 158 kg N ha−1) |
| Azo + Bac | Ŷ = 820.312 + 4.575x − 0.017 × 2 (R2 = 0.96**, P.M. = 133 kg N ha−1) | Ŷ = 112.809 + 0.791x − 0.002 × 2 (R2 = 0.93**, P.M. = 152 kg N ha−1) |
| Treatment | LCI | |
| Control | Ŷ = 63.697 + 0.026x (R2 = 0.87**) | |
| Azo | Ŷ = 68.291 + 0.057x − 0.0001 × 2 (R2 = 0.95*, P.M. = 143 kg N ha−1) | |
| Bac | Ŷ = 65.450 + 0.085x − 0.0002 × 2 (R2 = 0.91**, P.M. = 143 kg N ha−1) | |
| Azo + Bac | Ŷ = 68.251 + 0.080x − 0.0002 × 2 (R2 = 0.96**, P.M. = 135 kg N ha−1) |
Ctl Control, Azo Single inoculation with A. brasilense, Bac Single inoculation with B. subtilis and Azo + Bac = co-inoculation with A. brasilense and B. subtilis; ns Not significant, P.M. the calculated point of maximum in equation (plateau)
** and *: significant at p < 0.01 and p < 0.05, respectively