According to the Mishnah on today’s daf (=page) there were places where reaping the new crop was permitted even before the korban ha-omer that permitted the new harvest was brought on Passover. In irrigated fields found in the valleys early harvest was permitted, either because the heat in those places led the grain to ripen early, and it would become ruined if it was not harvested, or because what grew in these places was low quality and the Sages’ injunction against harvest did not apply to them.
The Mishnah relates that in the city of Yeriho the farmers followed this policy and harvested early with Rabbinic approval; nevertheless when they stacked the harvested grain it was done without the approval of the Sages, who, nonetheless, did not stop them from doing so.
Yeriho is located in the Jordan Valley, one of the lowest places in Israel (and, indeed, in the entire world). Its fields were irrigated from ancient fresh water springs as well as from the Jordan River itself.
The Gemara relates a number of other activities done by the people of Yeriho, some of which were approved of – or at least accepted by – the Sages, others of which the Sages objected to. Among the activities that were done with Rabbinic approval was markivin dekalim kol ha-yom – that the farmers “grafted” palm-trees the entire day of the 14th of Nissan, even though traditionally people did not work on the day before the Passover holiday.
The date palm is dioecious, having separate male and female plants. Only the female trees can give fruit, assuming that they were pollinated by male trees. In nature or in areas with many palm trees, pollination takes place on its own. With cultivated trees, however, “grafting” was often necessary. Grafting palm trees involved placing a branch from a male branch among female trees, as closely as possible to the time that the female flowers opened. This often happened at mid-day, and there was a clear situation of monetary loss if the “grafting” did not take place at the appropriate time.