Question

what is substitutional agriculture how is it different from shifting agriculture

Answer 1

Shifting agriculture, system of cultivation that preserves soil fertility by plot (field) rotation, as distinct from crop rotation. In shifting agriculture a plot of land is cleared and cultivated for a short period of time; then it is abandoned and allowed to revert to its natural vegetation while the cultivator moves on to another plot. The period of cultivation is usually terminated when the soil shows signs of exhaustion or, more commonly, when the field is overrun by weeds. The length of time that a field is cultivated is usually shorter than the period over which the land is allowed to regenerate by lying fallow.