The advance of agricultural production was greatly enhanced by the improvement of the plow, especially when the plow was harnessed to a strong pulling animal. Prior to the plow, farming was practical only in relatively soft ground that could be broken with digging sticks for the placement of seeds. The continually improving plow harnessed to an ox or horse could break open dryer and tougher ground much more quickly than hand tools. This allowed more land to be farmed and increased farm worker productivity.