New Zealand Journal of Archaeology Index  >  Vol 28 Davisdon

 

NEW ZEALAND JOURNAL OF ARCHAEOLOGY ISSN 0110~540X ABSTRACT

 

 

Subterranean Storage Pits for Ku¯mara

(Sweet Potato, Ipomoea batatas L. Lam.):

Ethnographic, Archaeological and Experimental

Research in New Zealand

 

Janet Davidson1, Foss Leach1, Mike Burtenshaw2, Graham Harris2

 

ABSTRACT

Storage of tubers of ku¯mara (sweet potato) in pits was an essential part of the pre-

European Ma¯ori horticultural cycle, but the details are not well understood.

Ethnographic accounts of Ma¯ori storage pits (mainly dating to the late nineteenth and

early twentieth centuries) and archaeological evidence of storage pits are reviewed.

Contemporary recommendations for commercial storage of sweet potatoes are

summarised and modern peasant systems in countries such as China are touched upon.

An experiment in pit storage of the Ma¯ori cultivar ‘Taputini’ during the winter of

2004 is described. The experiment took place in Marlborough, close to the southern

limit of Ma¯ori ku¯mara horticulture. Environmental conditions in the pit were closely

monitored. It is shown that in this area, regular human intervention would be required

to ensure survival of seed tubers until the next planting season. People would have

to inspect each tuber, remove rotting ones, light fires in cold weather, and regularly

exchange air in the pit. In the absence of artificial warming the tubers began to rot

when the mean temperature fell below 8˚C and all tubers were rotten by day 154.

Such intervention would greatly reduce the space available for storage for several

reasons. We found that no more than 6% of the available pit volume could be used

for tubers compared with earlier published estimates of 50%. Contrary to expectations,

subterranean storage has only a trifling effect on lowering the average temperature

from above-ground storage (ÄT=0.87˚C over 154 days), but diurnal temperature

fluctuations are dramatically buffered by storage below ground. Even with human

intervention, pre-European Ma¯ori at the southern limits of ku¯mara cultivation were

only able to eat ku¯mara for about four, or at most six, months of the year.

Keywords: SWEET POTATO, KU¯MARA, IPOMOEA BATATAS, STORAGE PITS,

ETHNOGRAPHY, EXPERIMENTAL ARCHAEOLOGY.

1Honorary Research Associate,

Ó Copyright New Zealand Archaeological Association.

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