Agricultural productivity is low in rural economies compared to that of developed economies, and there is disparity in measured productivity across farms. The dispersion of measured productivity might reflect (i) volatile conditions and (ii) sluggish adjustments in agricultural production to such conditions, e.g., due to market frictions or technological constraints. We combine exceptionally rich farm and crop panel data from Vietnam, featuring crop-specific inputs and outputs, with exogenous price shocks to each of those crops. This paper sheds light on the existence and nature of such imperfect adjustments by exploiting large shocks affecting the overall returns to production factors across crops, by measuring the adjustment of production (factors, inputs and cropping patterns) across and within farms, and by estimating a dynamic structural model of farm production. We use the model to assess the role of market frictions versus technological constraints. First results show that farmers engaged in just one crop variety are subject to a 19% income loss compared to multi-crop farmers due to factor misallocation. The findings suggest that factor misallocation may have important implications for the design and targeting of agricultural interventions and extension services.