Nature of Indus Economy
Production of Large Quantities of Agrarian Surplus To maintain a
widespread civilisation like the Harappan, with almost a dozen cities and
several dozens of towns, an agrarian system, sufficiently well organised to
produce the necessary surplus must have existed. The granaries at Harappa
and Mohenjodaro clearly suggest that cereals were produced in such
quantities that not only were all the immediate needs of the people duly met
with, but there was also a surplus to face any future emergency. While the
cereals stored in public granaries were evidently controlled by the authorities,
even private individuals seem to have taken precautions, as indicated by the
occurrence of large storage jars. In one of the rooms at Kalibangan, many
such jars were found stacked one over another.
 For tilling fields, a wooden plough, with perhaps a sharp-ended copper bar
 attached to its end, seems to have been used. In addition to the evidence of
 a ploughed field at Kalibangan, Banawali has now yielded a complete
 terracotta model of a plough. These ploughs were drawn by bullocks that
 constituted a sizeable part of the cattle wealth of the Harappans. It has also
 been suggested that the Harappans practiced canal irrigation, but the
 evidence is rather meager. At the same time, the channelling of
 overflowing rain-water can be easily visualised. Thus, Harappan
 agriculture was largely dependent on lift irrigation rather than on canal
 irrigation and therefore, was highly labour-intensive. But we should not
 view Harappan subsistence exclusively in terms of agriculture.
Symbiotic Relations between Agriculturists and Pastoralists Keeping in
view the facts that there are large unoccupied spaces on the Harappan map
and that migratory pastoralists leave few archaeological traces, it is
conjectured that pastoralists must have lived in symbiosis with agriculturists
and might have provided the linkages (as carriers of goods or information)
between settlements, thus contributing to the uniformity of material culture.
The discovery of possible pastoral       campsites in the Hakra valley and in