PART III.
PART III.
ARE SOILS ENRICHED, IMPOVERISHED, OR POISONED BY VEGETABLE GROWTH? THESE QUESTIONS IN- CLUDE EXCRETION FROM ROOTS; SOCIABILITY OF PLANTS; ACCUMULATION OF SOIL IN WOODS ; GENE- RAL DENUDATION OF SOIL FROM WASH OF RAIN.
The food of plants is extracted from the soil. But if the plants are
returned to the soil, no impoverishment takes place. ; . 186 Roots do not excrete , , ; . . . . , . 189 Sociability of plants a fancy . . . 142 Sociability of holly and beech owing to belly bearing shade better
than other plants , , . , . 151 The soil of woods does not become poorer, but ‘richer , . . 155 Is there any other cause for this besides protection by the roots
from aqueous denudation? . . . . 155 Aqueous denudation is universal, and is not confined only to the
- lines of torrents and rivers. . . , . . . 157 No necessity for rotation in Nature’s cropping . . . , . 183