Table 1:
Characteristics of soil related factors from three rice agroecosystem fields.
| Soil-related factors | Rain-fed upland rice agroecosystem | Dry aerobic rice agroecosystem | Lowland double-rice cropping sequence agroecosystem | |
|---|---|---|---|---|
| Soil texture class | clay loam | clay loam | sandy loam | |
| Texture % | Sand | 20.3 | 23.3 | 62.8 |
| Silt | 37.8 | 42.6 | 26.1 | |
| Clay | 41.9 | 34.1 | 11.1 | |
| pH | 5.00 | 5.15 | 5.20 | |
| Total nitrogen (g/kg) | 0.55 | 0.71 | 1.74 | |
| Hydrolytic nitrogen (mg/kg) | 59.13 | 77.37 | 198.42 | |
| Total phosphorus (g/kg) | 0.36 | 0.34 | 0.73 | |
| Available phosphorus (mg/kg) | 4.54 | 2.30 | 10.70 | |
| Total potassium (g/kg) | 9.67 | 12.46 | 14.64 | |
| Available potassium (mg/kg) | 97.23 | 125.48 | 160.28 | |
| Organic matter (g/kg) | 10.11 | 14.53 | 32.71 | |
Figure 1:
Population dynamics of M. graminicola eggs and second-stage juveniles (J2) in the soil in the rain-fed upland agroecosystem (A), the dry aerobic rice agroecosystem (B) and the lowland double-rice cropping sequence agroecosystem (C) from May 2021 to February 2022. The initial M. graminicola populations in the soil in the rain-fed upland agroecosystem, the dry aerobic rice agroecosystem and the lowland double-rice cropping sequence agroecosystem were 102 ± 32 J2s and 36 ± 8 eggs/100 cm3 soil, 467 ± 102 J2 and 113 ± 38 eggs/100 cm3 soil, and 246 ± 64 J2s and 52 ± 17 eggs/100 cm3 soil, respectively.
Figure 2:
Fluctuations in root galling (A) and root galling index (B) caused by M. graminicola recorded on rice roots in the rain-fed upland agroecosystem (variety Huanghuazhan), the dry aerobic rice agroecosystem (variety Hanyou73) and the lowland double-rice cropping sequence agroecosystem (variety Xiangzaoxian45 and Zhuliangyou819) from May 2021 to February 2022.
Figure 3:
Zhuliangyou35 infected with M. graminicola. Population dynamics of M. graminicola eggs and second-stage juveniles (J2) in the soil and rice roots in the pot experiments under upland (A), semi-submerged (B) and flooded (C) conditions. (D) Microscopic observations of egg masses in the PF-127 gel.