'Away-going' is a standard legal term referring to crops that are harvested after the lease on a plot of agricultural land has ended. In most jurisdictions descended from English common law, the right of the lessee to harvest away-going crops is taken as the default, and applies unless specifically addressed otherwise in the leasing agreement.
Away-going crops are an issue because crops are unpredictable, and a cool spring, a dry year, or rains during harvest time may push back the harvest beyond the expected time-frame. Winter wheat is also a common focus of away-going crops, although one that is generally pre-planned and may quite annoy the lessor if they were not expecting it.
The right to harvest away-going crops includes the right to freely access the land, the right from interference during harvesting, and potentially, the right to emblements that should have been the lessee's but were unfairly taken by the lessor.
Older texts may refer to offgoing crops, which is essentially the same idea. However, this often referred to leases for tenant farmers under long-term, highly-structured conditions that were often individualized to traditions in various English counties, and do not have any significant bearing on modern legal practices.