Table 1. Location, physicochemical characteristics and rhizobial abundance of the soil samples used in this study.
| Soil character | Sample site | |||||
|---|---|---|---|---|---|---|
|
| ||||||
| Xochimilco, Mexico City | Ocozocuautla, Chiapas | General Cepeda, Coahuila | Parras de la Fuente, Coahuila | Acaxochitlán, Hidalgo | ||
| Texture | Sandy loam | Sandy loam | Silty clay loam | Silty clay | Loam | |
| Field capacity (g kg−1) | 750.0 | 225.0 | 232.5 | 337.5 | 517.5 | |
| Electric conductivity (dS m−1) | 4.193 | 0.883 | 0.420 | 0.629 | 1.059 | |
| Organic material (g kg−1) | 157.70 | 17.40 | 7.50 | 9.50 | 77.90 | |
| Total nitrogen (mg kg−1) | 1068.10 | 39.44 | 10.57 | 39.62 | 204.89 | |
| Total phosphor Olsen (mg kg−1) | 258.74 | 28.59 | 12.90 | 6.85 | 16.28 | |
| Total phosphor Bray (mg kg−1) | 239.26 | 58.06 | 10.46 | 7.63 | 8.00 | |
| Potassium (mg kg−1) | 2345.79 | 175.20 | 194.80 | 288.41 | 598.54 | |
| Calcium (mgkg−1) | 4513.85 | 1400.95 | 4807.15 | 5108.19 | 2377.13 | |
| Magnesium (mg kg−1) | 2784.10 | 109.89 | 5.26 | 229.61 | 127.19 | |
| Sodium (mgkg−1) | 782.58 | 105.46 | 60.65 | 94.57 | 81.47 | |
| Iron (mgkg−1) | 26.26 | 247.66 | 0.87 | 0 | 58.87 | |
| Zinc (mgkg−1) | 8.01 | 1.40 | 0.17 | 0 | 0.42 | |
| Manganese (mg kg−1) | 0 | 16.84 | 0 | 0 | 4.83 | |
| Copper (mgkg−1) | 0.86 | 0.85 | 0.73 | 0.74 | 1.25 | |
| Boron (mgkg−1) | 17.42 | 1.00 | 1.00 | 1.34 | 0.80 | |
| Sulfur (mgkg−1) | 293.88 | 139.20 | 61.25 | 77.84 | 33.54 | |
| pH | Value | 8.72 | 4.25 | 7.84 | 7.86 | 4.92 |
| Definitiona | Strong alkaline | Strong acid | Intermediate alkaline | Intermediate alkaline | Strong acid | |
|
| ||||||
| MPN of rhizobiab | Flor de Mayo | 0 | 0 | 1.1 ×104 | 82 | 320 |
| Negro Querétaro | 0 | 0 | >1.8×104 | 620 | 450 | |
a
According to official Mexican standard NOM-021-RECNAT-2000.
b
Most probable number of rhizobia was estimated by the plant trapping method using the two cultivars, respectively.