Based on prior knowledge, the number of grains per pod (NS) can have an impact on grain yield. Generally, a higher number of grains per pod can result in higher grain yield.

However, it's important to note that the appropriate ranges of values for NS may vary depending on the specific soybean cultivar and growing conditions. Without specific information about the cultivar and other factors, it is not possible to determine the exact ranges.

Based on this analysis, the dictionary with possible values of feature NS for each target class is as follows:

```json
{
	"low": [3.0, 3.5, 4.0, 4.5, 5.0],
	"high": [6.0, 6.5, 7.0, 7.5, 8.0]
}
```

Please note that the values provided are just examples and may vary depending on the actual data and context.