On Monoculture and the Structure of Crop Rotations

Abstract

An issue when seeking to identify rotation choice is persistence in yield-enhancement and input-saving carry-over effects. Focusing on carry-over length and the monoculture decision, we use quasi-convexity of choice functions to develop price-independent and price-dependent principles concerning rotation structure. Iowa corn-soybean rotation data suggest corn has one-year memory. For corn, soybeans in the prior year is yield increasing (16.5 bu./ac.) and nitrogen saving (51 lb./ac.). The hypothesis that soybean has two-year memory cannot be rejected. Corn in the prior year (two years) increases yield by 7 bu./ac. (11.6 bu./ac.). We simulate to find price and practice subsidy levels that support different rotations.