Which of the following was done by people in the sixth century BCE to increase agricultural production?

All of the above

The correct answer is Option 4 -All of the above

Option 1- Shift to plough agriculture.
Option 2- Transplanting Paddy crops.
Option 3- Use of irrigation, through wells and tanks, and less commonly, canals.
Option 4- All of the above

Strategies for increasing production:

One such strategy was the shift to plough agriculture, which spread in fertile alluvial river valleys such as those of the Ganga and the Kaveri from c. sixth century BCE. The iron-tipped ploughshare was used to turn the alluvial soil in areas which had high rainfall. Moreover, in some parts of the Ganga valley, production of paddy was dramatically increased by the introduction of transplantation, although this meant back-breaking work for the producer. While the iron ploughshare led to a growth in agricultural productivity, its use was restricted to certain parts of the subcontinent – cultivators in areas which were semi-arid, such as parts of Punjab and Rajasthan did not adopt it till the twentieth century, and those living in hilly tracts in the northeastern and central parts of the subcontinent practised hoe agriculture, which was much better suited to the terrain. Another strategy adopted to increase agricultural production was the use of irrigation, through wells and tanks, and less commonly, canals. Communities as well as individuals organised the construction of irrigation works. The latter, usually powerful men including kings, often recorded such activities in inscriptions.