Table 2.
Effect of nitrogen deposition application and cropping system of invasive and native weeds on soil TOC content and soil pH
| Treatment | TOC | Soil pH | |||||
|---|---|---|---|---|---|---|---|
| Nitrogen level (N) | Aug | Oct | Dec | Aug | Oct | Dec | |
| Nº | 4.54 C | 12.5 C | 12.3 C | 6.63 C | 6.63B | 6.63 A | |
| N5 | 8.37 A | 16.8 A | 18.3 A | 7.32 A | 6.90 A | 6.65 A | |
| N10 | 5.26B | 13.5B | 13.2B | 7.21B | 6.83 A | 6.55B | |
| Cropping system (CS) | |||||||
| CK | 5.57B | 14.1 | 14.5 | 7.10AB | 6.79AB | 6.57 C | |
| SC | 6.77 A | 14.8 | 15.3 | 7.03B | 6.81 A | 6.66 A | |
| WC | 5.86B | 14.0 | 14.2 | 6.94D | 6.77B | 6.61B | |
| SC × WC | 6.03AB | 14.1 | 14.4 | 7.14 A | 6.78B | 6.60BC | |
| Interaction (N × CS) | |||||||
| Nº | CK | 4.73 | 13.0 | 13.8d | 6.96d | 7.01ab | 6.73bc |
| Nº | SC | 5.49 | 13.5 | 12.9d | 6.28 g | 6.47f | 6.55e |
| Nº | WC | 3.80 | 11.8 | 11.3e | 6.49f | 6.26 g | 6.72c |
| Nº | SC × WC | 4.13 | 11.7 | 11.1e | 6.80e | 6.77 cd | 6.53e |
| N5 | CK | 7.01 | 15.9 | 16.0c | 7.08 cd | 6.70de | 6.28 g |
| N5 | SC | 9.55 | 17.4 | 19.9a | 7.56a | 7.04a | 7.03a |
| N5 | WC | 8.21 | 16.8 | 18.4b | 7.19bc | 7.05a | 6.48e |
| N5 | SC × WC | 8.71 | 17.2 | 18.8b | 7.44a | 6.83c | 6.80b |
| N10 | CK | 4.98 | 13.4 | 13.7d | 7.25b | 6.67e | 6.71c |
| N10 | SC | 5.26 | 13.4 | 13.1d | 7.26b | 6.99ab | 6.40f |
| N10 | WC | 5.55 | 13.5 | 12.9d | 7.15bc | 6.93b | 6.63d |
| N10 | SC × WC | 5.24 | 13.6 | 13.2d | 7.18bc | 6.73d | 6.48e |
| ANOVA | DF | P | P | P | P | P | P |
| N | 2 | 131*** | 136*** | 678*** | 150*** | 32.4*** | 5.96*** |
| CS | 3 | 3.63* | 1.69NS | 0.85NS | 11.5*** | 3.10*** | 11.8*** |
| N × CS | 6 | 2.23NS | 2.22NS | 16.4*** | 31.8*** | 247*** | 219*** |
Note: 1 Lowercase letters indicate significant for the interaction of N rates and cropping system variability (p < 0.05)0.2 Uppercase letters indicate variability between nutrient levels and cropping system (p < 0.05). Nº= no N application; N5 = normal N application; N10 = higher N application; control (CK); pot having no plant, invasive S. canadensis mono-cropping (SC), native Wedelia chinesis mono-cropping (WC) and invasive + native intercropping system (WC × SC)