Soil Erosion Effects on Corn Yields Assessed by Potential Yield Index Model
Soil erosion alters crop production via alteration of the soil chemical and physical environment. The objectives of this study were to: (i) develop a Potential Yield Index (PYI) model to index soil productivity based on simulated root growth, soil properties, and potential nutrient and water uptake of corn (Zea mays L.) through a growing season, (ii) utilize the PYI to estimate erosion effects on soil productivity by simulating the removal of 15 and 30 cm of soil, and (iii) simulate the impact of fertilizer additions to the eroded soil on the PYI. The PYI model independently estimates P, K, and water (W) uptake by corn. From these estimates, three separate yield indexes (PYIP, PYIK, and PYIW) are calculated. The lowest yield index is identified as the PYI for a given soil. The predicted PYIs for 45 soils in Iowa compared well to the 1984 10-yr average corn yield (R2 = 0.83) and corn suitability rating (R2 = 0.73) for each soil. Changes in the PYI were predicted for 15 and 30 cm of simulated erosion. After 15-cm soil loss, the PYI for all soils decreased, with all but three soils remaining within 15% of the uneroded PYI. The PYI decreased further after 30-cm soil loss, with only 12 soils remaining within 15% of the uneroded PYI. Fertilizer additions to the plow layer of the eroded soils were then simulated. The PYI returned to within 5% of the uneroded PYI for 38 soils with 15-cm soil loss and for 27 soils with 30-cm soil loss. The PYI indicated that the soil factor that most limited plant yield changed with the soil, amount of soil loss, and plow-layer soil fertility status.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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