During the period of the fourth century CE, also known as the Gupta period, there was a recorded decline in trade. This was mostly because of low surplus obtained from agriculture. Historians have speculated the reasons for the same.
The first reason being posited is that there were climactic changes that resulted in a paucity of rainfall. But there is no definite evidence to suggest this.
The second reason to which the fall in agricultural production is attributed is the depletion of fertile soil. This is because soil nutrients are not replaced when sapped through the process of cultivation. There may not have been a process of manuring or silting as we have today. But there is no direct evidence of this either.
The third reason posited is the decline in the available surplus due to a direct consequence of growth in human population. There may have been a lower land-man ratio, it is argued.
Hence there was a major “resource crunch” during the Gupta period. There were not a lot of facilities for irrigation, except in southern India with the delta of the Kaveri river.
Also, resources were not being properly utilised. This could be because of firstly, scanty and variable rainfall in north west parts and the Indus peninsula. This could further be because of excessive flooding on the banks of the Ganga river. In the foothills and the Himalayan forests, this could be because of swamps and marshy areas. Further, the Eastern and Western ghats were too steep for cultivation. Hence the above resources could not be properly harnessed for agricultural purposes.
However, these areas still provided valuable resources. These resources were harnessed variously: with hunting, fishing, sheep raising (which meant shifting cultivation), grazing cattle and dung for agriculture, manure of leaves, timber, etc.
The Gupta period thus had limited resources but even the ones at hand were socially and systematically divided to be best harnessed.
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