Read "Capital, Volume Three: The Process of Capitalist Production as a Whole" by Karl Marx online for free on Textopian. Full text with search, annotations, highlights, and AI-powered reading aids.
Let us assume the demand for grain is rising, and the supply can only result from successive investments of capital under conditions of under-productiveness in the rent-bearing soils, or by additional investment of capital, also with decreasing productivity, in soil A, or by the investment of capital in new lands of inferior quality than A.
Let us take soil B as representative of the rent-bearing soils.