Soil respiration (R_s) is an important process where from living organisms (predominantly plants and microbes) emit carbon dioxide (CO₂) to the atmosphere. We show that a common explanation that R_s is controlled by temperature is oversimple and plant inputs are extremely important, causing the daily pattern of R_s to differ between crops. Measuring simultaneously at a single site will therefore not be a fair comparison; this must be considered in the design of future experimental comparisons.