TABLE 2.
Nitrate and ammonium concentrations in rhizosphere soil in different treatments at three different plant development stages
| Sample | Mean concn (mg of N kg of soil−1) ± SDa
|
|||||
|---|---|---|---|---|---|---|
| NO3+-N
|
NH4+-N
|
|||||
| EC30c | EC60 | EC90 | EC30 | EC60 | EC90 | |
| Control | 6.4 ± 3.6A1 | 5.4 ± 1.5A1 | 68.7 ± 36.9B1 | 1.9 ± 1.6A1 | 3.9 ± 2.7A1 | 1.1 ± 0.7A1 |
| C+U | 18.4 ± 13.2A1 | 7.9 ± 3.4A1 | 84.6 ± 42.5B1 | 4.2 ± 3.5A1 | 3.8 ± 2.1A1 | 1.6 ± 1.1A1 |
| Straw | 5.3 ± 3.5A1 | 6.2 ± 1.7A1 | 82.5 ± 44.9B1 | 1.5 ± 1.0A1 | 5.1 ± 1.9B1 | 3.7 ± 6.1AB1 |
| S+U | 19.2 ± 13.8A1 | 8.9 ± 3.0A1 | 136.9 ± 70.6B1 | 1.7 ± 1.0A1 | 5.8 ± 1.9B1 | 5.7 ± 6.2AB1 |
| Manure | 17.4 ± 15.9A1 | 6.6 ± 2.9A1 | 97.3 ± 41.1B1 | 2.4 ± 0.6A1 | 6.5 ± 2.0B1 | 2.2 ± 1.9A1 |
| M+U | 36.1 ± 20.8A1 | (12.4) | 74.9 ± 34.1B1 | 3.1 ± 1.7A1 | (5.6) | 1.8 ± 2.0A1 |
a
n = 6; n = 1 for data in parentheses. EC30, young leaf development; EC60, flowering; EC90, senescence. Significant differences of one treatment over three different plant development stages are indicated by different superscript letters. Significant differences among treatments at one plant development stage are indicated by different superscript numbers.