Economies of Density versus Natural Advantage: Crop Choice on the Back Forty
利用北达科他州的卫星数据，研究农民在相邻地块的作物选择，区分自然优势（土壤特性）和密度经济（相邻地块同种作物的规模经济）的作用。
We estimate the factors determining specialization of crop choice at the level of individual fields, distinguishing between the role of natural advantage (soil characteristics) and economies of density (scale economies achieved when farmers plant neighboring fields the same). Using rich geographic data from North Dakota, including new data on crop choice collected by satellite, we estimate a model of how a farmer plants adjacent fields under the farmer's control. We find planting decisions on a field are heavily dependent on the soil characteristics of adjacent fields. Through this relationship, we back out the structural parameters of economies of density. © 2011 The President and Fellows of Harvard College and the Massachusetts Institute of Technology.