The sentence says that consumption will be lower than income earned by factors of production (labor, capital, land), and the difference will be the amount of savings.
(Keynesian theory in a nutshell: the economy produces X but people save Y so they only have (X-Y) to purchase the produced goods, some of which remain unsold; producers produce less in the subsequent period and a downward spiral sets in)
http://en.wikipedia.org/wiki/Factors_of_production