If so, how does the rotation actually enrich the soil in nitrogen?

Either by plowing or forking, deepen as well as enrich the soil.

Birds next come and rest on the island, and further enrich the soil.

They put nitrogen back in the soil, so they enrich the soil...

The rotation of crops does not enrich the soil, does not even maintain the fertility of the soil.

So sense and imagination, passion and reason, may enrich the soil that breeds them and cover it with a maze of flowers.

Hence much domestic waste, which would elsewhere be employed to enrich the soil, is thrown out into vacant places near the town.

All such materials are saved and used in the most advantageous ways to enrich the soil or to nourish the plants being grown.

Farmers did not know how to enrich the soil by the use of fertilizers or how to provide for a proper rotation of crops.

Next to enriching the soil, the most important step is to deepen it.

The vegetable material thus ploughed in lies over a season and enriches the soil.

There was a time when it was thought that the growth of turnips enriched the soil.

Thus it enriches the soil, or cools the air, or reflects back to the earth its radiated heat.

In preparing and enriching the soil, and especially in subsequent cultivation, concentrated fertilizers are very useful and often essential.

The guano that enriched the soil made every kind of vegetation thrive with an almost marvellous rapidity and luxuriance.

To meet this emergency and loss the farmer has another method of enriching the soil, again depending upon bacteria.