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Crop rotation, Soil


Every farmer has realized the dangers which follow from growing the same crop too frequently on the same land. Out of his experience and observations there has grown up the idea that one crop poisons another of the same kind, and that if he desires success he must do something to restore and maintain the fertility of the soil — and that crop rotation is one of the best means of accomplishing this result.

To ascertain what really lies at the basis of this idea — whether a plant excretes poison? and if so what is their nature and what relation do these bear to soil fertility -- has attracted the attention of both practical farmers and scientific investigators from the very earliest times. But it is only during the last few years that any advance has been made in the study of these plant poisons, which promises to throw some light upon problems of soil conditions and ecological relations.