```json
{
	"low": [1.0, 2.0, 3.0, 4.0, 5.0],
	"high": [9.0, 10.0, 11.0, 12.0, 13.0]
}
```
Note: The above values are just examples and may not be accurate for the specific relationship between the NGP feature and grain yield of soybean cultivars. Prior knowledge and analysis should be used to determine the appropriate values for each target class.