“…These effects are slower but have substantial impacts on markets over time. The increase in productivity has 4 See, for example, Braschler (1983), Chavas (1983), Dahlgran (1987), Moschini and Meilke (1989), Verbeke and Ward (2001) and Boetel and Liu (2003). 5 Initial supply modeling work includes Reutlinger (1966) and Nelson and Spreen (1974), and the later work by Marsh (1983Marsh ( , 1984Marsh ( , and 1994.…”