Table 3. Effect of long-term fertilization on P balance, grain yield, soil pH, SOM, total P and Olsen P concentrations.
| Sitesa | Treatmentsb | pH | SOM | Total P | Olsen P | P balance | Grain yield |
|---|---|---|---|---|---|---|---|
| (H2O) | (g kg-1) | (g kg-1) | (mg kg-1) | (kg ha-1) | (kg ha-1) | ||
| NC | CK | 5.65 ± 0.10 Ab | 29.27 ± 0.20 Ca | 0.36 ± 0.04 Cb | 7.28 ± 0.24 Ca | -7.7 ± 1.02 Cb | 1844 ± 143.2 Ca |
| NPK | 5.20 ± 0.08 Bb | 41.08 ± 0.06 Ba | 0.54 ± 0.03 Bb | 61.13 ± 1.40 Ba | 6.8 ± 0.98 Ab | 4129 ± 144.7 Ba | |
| NPKM | 5.71 ± 0.13 Ab | 48.44 ± 1.33 Aa | 1.63 ± 0.06 Ac | 81.50 ± 2.18 Ab | -1.9 ± 3.19 Bc | 4615 ± 181.2 Aa | |
| JX | CK | 5.59 ± 0.14 ABb | 22.85 ± 0.52 Cb | 0.49 ± 0.01 Ca | 6.52 ± 0.53 Ca | -4.8 ± 0.45 Ca | 1608 ± 352.4 Ca |
| NPK | 5.45 ± 0.08 Bb | 32.54 ± 0.99 Bb | 0.93 ± 0.02 Ba | 30.07 ± 1.39 Bb | 9.9 ± 0.81 Ba | 2510 ± 105.8 Bc | |
| NPKM | 5.91 ± 0.14 Ab | 37.53 ± 1.59 Ab | 1.63 ± 0.13 Ab | 64.69 ± 1.64 Ac | 21.3 ± 1.02 Aa | 4533 ± 108.1 Aa | |
| NX | CK | 6.30 ± 0.05 Ba | 20.89 ± 0.65 Cc | 0.45 ± 0.07 Ca | 4.53 ± 0.33 Cb | -5.4 ± 0.11 Ca | 1631 ± 35.5 Ca |
| NPK | 6.54 ± 0.15 Aa | 24.74 ± 1.39 Bc | 0.96 ± 0.10 Ba | 14.97 ± 0.16 Bc | 8.5 ± 0.93 Aab | 3337 ± 79.6 Bb | |
| NPKM | 6.73 ± 0.04 Aa | 37.32 ± 1.43 Ab | 2.21 ± 0.15 Aa | 90.80 ± 2.86 Aa | 2.2 ± 0.85 Bb | 4047 ± 76.1 Ab | |
| ANOVA | |||||||
| Soil type | *** | *** | *** | *** | *** | *** | |
| Fertilization | *** | *** | *** | *** | *** | *** | |
| S*F | *** | *** | *** | *** | *** | *** |
a Sites: NC: Nanchang, JX: Jinxian, NX: Ningxiang
b Treatments: CK: unfertilized control; NPK: inorganic nitrogen, phosphorus and potassium; NPKM: inorganic NPK plus manure
Data followed different uppercase letters denote significant differences (P ≤ 0.05) between fertilization treatments at the same site (A, B, C) and lowercase letters between sites for the same fertilization treatment (a, b, c).
Significance levels
*** represents P<0.01