SUMMARYGrowth and yield of cereals were measured at four sites in eastern England where crop patterns have been repeatedly observed on aerial photographs. The patterns were related to archaeological features, infilled river channels, interbedding of lithologically diverse pre‐Quaternary sediments, periglacial disturbance of shallow loamy soil over Chalk, and the occurrence of minor valleys incised into chalky till. They resulted from differential germination and growth rates, which were in turn related to differences in (a) available water in the soil, (b) the inhibition of root extension by hard chalk, (c) soil temperature and (d) the workability of soils during drilling of spring‐sown crops. Yield losses resulting from the patterns ranged from 15 to 51 %.