As for highly degraded plots of land, planting semi-artificial grassland is the umbrella-term that is used to address this type of restoration.[1] It includes weed control, fertilizing, reseeding, rodent control, and scarification.[2] Since weeds are so numerous in highly degraded grasslands and since they suck so many nutrients from the soil, it is important to eradicate them as much as possible; and this is done so quite successfully by herbicide solutions.[2] Semi-artificial grassland works best when the highly degraded land has 30% or more plant coverage.[2] For degraded plots that are worse off, and hence typically fall under the category of black soil or severely degraded Heitutan grassland, artificial grassland is required and entails weed and rodent control, plowing, seeding, and fertilizing.[3] These two methods are successful at restoring plant life to a certain extent but are also somewhat expensive.[2] For this reason research must be done to foretell if this method would be successful by, for instance, determining whether such seeds would thrive in that environment.[5] Once an area of land is reduced from, for instance, heavily degraded to moderately degraded, the methods of restoring it must also change.[2]