John Keshishian 
about two hundred years after the erup- 
tion of Ilopango, people began to recol- 
onize the Zapotitan Valley and to farm 
its partly recovered soils. The land had 
a neutral pH and was fairly rich in ni- 
trogen, but it was very weak in phos- 
phorus, magnesium, manganese, calci- 
um, and potassium. And, if that were 
not enough, the earliest settlers dam- 
aged the soil by forest clearance, which 
allowed the rains to carry away sub- 
stantial amounts of the topsoil. The 
slightly sloping cornfield we have exca- 
vated shows that the Maya farmers at- 
tempted to counteract the erosion with 
low, crisscrossing ridges of soil. These 
ridges helped to force rainwater to pud- 
dle instead of run off, maximizing infil- 
tration of moisture into the porous soil. 
Then, about the year 600, only fifty 
or seventy-five years after the Zapoti- 
tan Valley was resettled, nearby Lagu- 
na Caldera erupted. The Ceren 
cornfield was buried in twelve to eigh- 
teen feet of ash with much deeper accu- 
mulations toward the source. The corn, 
planted at the tops of the ridges, was 
only four to six inches tall. Because the 
cornfield was not irrigated, we know 
that the eruption struck early in the 
rainy season — in late May or early 
June. 
Laguna Caldera not only buried and 
preserved agricultural fields and natu- 
ral vegetation, it also preserved the 
houses of a village. Based on the infor- 
mation available at present, houses 
were spaced about 165 feet apart, with 
their agricultural fields in between. On 
the average, that allowed each house- 
hold only about five-eighths of an acre. 
This would not have been sufficient to 
feed a family, especially since low soil 
fertility did not permit a high density of 
maize plants — only about 12,000 per 
acre, compared to 20,000 to 24,000 per 
acre in present-day fields in the high- 
lands to the northwest. The Ceren 
farmers were probably farming addi- 
The acropolis ofTikal represented 
Maya civilization at its height. 
Located in the lowlands of Guatemala, 
the city prospered after the eruption 
of Ilopango, when the main Maya 
trade route was diverted to the north. 
37 
