Effect of past soil erosion on crop productivity in Indiana

ABSTRACT:

Quantitative analysis of the effects of past soil erosion on crop productivity are limited. The effect of past soil erosion on crop productivity was evaluated in three Indiana counties on three soils (Miami, a fine-loamy, mixed, mesic, Typic Hapludalf; Morley, a fine, illitic, mesic, Typic Hapludalf; and Corwin, a fine-loamy, mixed, mesic, Typic Argiudoll) from 1981 through 1986. Slight, moderate, and severe erosion phases, using Soil Conservation Service criteria, were used to distinguish differing degrees of past erosion. Past erosion on the three soils evaluated reduced com yields 15% and soybean yields 24% on severely eroded sites compared to slightly eroded sites over the 6-year period. These reductions were significant at the 5% level, using Duncan's multiple range test, and greater than values previously reported for severely eroded soil. This reduction points out the need for a national data base, similar to this, of benchmark soils from which erosion-productivity models may be validated. A sampling procedure was developed in 1982 by sampling schemes within the row. Harvesting every fifth ear of corn resulted in an r² of .978 over all erosion phases and all soils and provided a good estimate of the actual yield for that row. This finding is important where a large number of samples must be collected over a short period of time with limited personnel.