Variation across scales indicates that best progress in crop yields should come from farmer-centric research
Paper presented by Roger Sylvester-Bradley at ECPA 2019 on understanding the variaton in yield, highlighting the 'Farm Factor'
Four multi-site datasets with 188 to 14,155 wheat yields from the UK showed two- to five-fold variation. This was partitioned using REML into predictable and unpredictable effects, with the latter being ostensibly associated with season (year), and exceeding predictable variation. Of the predictable factors, ‘farm’ accounted for most variation in each case. Effects of variety choice and other husbandry factors were small. Some of the farm x season variation must have arisen from inter- and intra-field variation as well as from interactions with season; however, the extent of farm-scale variation suggests that progress in yield enhancement must come through research at farm-scale, to understand farmers’ attitudes and designs, as well as their soils, environments and husbandry.