They were mostly situated along the fertile floodplains of rivers, since the heavy demands of corn on soil nutrients required the deep, rich alluvial soils that were renewed by yearly floods (Hudson 1990:53).
(They; were mostly situated; along the fertile floodplains of rivers; since the heavy demands of corn on soil nutrients required the deep, rich alluvial soils) (the heavy demands of corn on soil nutrients; required; the deep, rich alluvial soils that were renewed by yearly floods (Hudson 1990:53)) (the deep, rich alluvial soils; were renewed; by yearly floods)
They the heavy demands of corn on soil nutrients the deep, rich alluvial soils
were mostly situated required were renewed
along the fertile floodplains of rivers since the heavy demands of corn on soil nutrients required the deep, rich alluvial soils
the deep, rich alluvial soils that were renewed by yearly floods (Hudson 1990:53)
by yearly floods