Increasing plot length reduces experimental error of on-farm tests

Farmer conducted on-farm research is an effective tool for development of crop management practices. The randomized complete-block experimental design is being used in on-farm tests, with blocks consisting of two or more long, narrow, sideby-side plots. This study examined the relationship between plot length and experimental error, and assesses the probable statistical outcome of on-farm tests performed in the dryland region of the Pacific Northwest, USA. Fourteen trials were conducted in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) fields to measure yield variance of combine-width plots ranging in length from 250 to 1500 ft. The relationship between plot length and variance for each site followed a logarithmic decay model (average r 2 = 0.88) [...]