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True, it is still possible to modify the land/sea interface in producing 
marshes or sea-grass beds, but this, too is not a permanent solution. 
This usurpation of productive agricultural land is more serious than is 
generally understood. Let no one think that the areas needed for land dis- 
posal are or would be small. Mallory and Meccia (1975) estimate for the 
USA alone that no less than 7000 acres of new land would be required each 
year for the containment of material generated from maintenance dredging of 
marine channels by the Corps of Engineers alone. The situation becomes 
even more startling when we learn that 
(a) in the period from 1880 to 1952 tilled land the world over 
classified as "good" declined from 85% to 41% of the total, 
and 
(b) Borgstrom (1969) found that in the USA alone over 2 million 
acres of rural land are turned over every year to urban de- 
velopment, airports, highways, flood control measures, parks 
and wildlife refuges. 
What these figures portend for the curve of world food production with the 
passage of time is not hard to visualize - an asymptote and then a down- 
turn. If we add to this situation the inevitable increase of the world's 
population, estimated to soar to at least six billion by the year 2000 with 
about 85 percent of the population living in Asia and Africa, the downturn 
is not far off. Obviously it can be pushed farther into the future if 
usurpation of tilled land for unnecessary purposes is curtailed. In many 
instances the placing of marine-derived sediments on land is one such un- 
necessary act of usurpation. 
FOOD PRODUCING POTENTIAL - LAND VS. SEA 
To document the reality of the need to preserve the land for the production 
of food, let us compare some vital statistics of the land and sea. Those 
who look to the seas as a solution to the world's food problem will be dis- 
appointed. 
