This may of course occur in different time periods, if the affected underground lines exceeds the borders of several fields, due to different local conditions and differences in the resistance of cultivated crops above it. See Opočno.
Hii bila shaka kutokea katika vipindi tofauti wakati, kama walioathirika mistari chini kwa chini unazidi mipaka ya mashamba kadhaa, kutokana na hali tofauti ya kienyeji na tofauti katika upinzani wa mazao ya kilimo juu yake.