1 Effects of Soil Erosion on Corn Yields of Seven IL Soils By K R Olson and E Nizeyimana Journal of Production Agriculture 1 13 19 The objectives of this study were to Quantify corn yield and plant population differences associated with moderately and severely eroded phases of seven Illinois soils Identify soil properties that affect corn yield Measure soil property changes produced by soil erosion Establish relationships between soils property changes and corn yields 2 Methods Methods Seven soils series at eight sites were selected to represent the diversity of soils in Illinois At each site separate map units of moderately and severely eroded phase of a soil series were located in the same field with similar high level of management These contrasting erosion phases of the same soil series occurred as a consequence of differential soil loss resulting from past farming practices at a site or because of slight differences in one or more of the following parameters percent slope slope shape slope length or landscape segment Methods Methods Two to four 0 0025 acre plots were then randomly selected within landscape units for sampling corn yield from each phase of all soil series Soil samples were taken with depth to measure the chemical mineralogical and physical properties of each phase of all soil series Soil samples were taken with depth to measure the chemical mineralogical and physical properties of each phase of all soil series Data were statistically analyzed by considering erosion phases as treatments and soil series sites as replication Soils were further grouped and analyzed by root restricting class with or without a root restricting subsoil 3 4 5 6 7 8 9 Summary The magnitude and direction of change in soils parameters including pH CEC K and base saturation varied with soil series Summary Summary Soils with low initial water storage capacities and root restricting subsoils showed the largest yield reductions when severely eroded Soils formed in loess without root restricting subsoils showed only slight yield reductions 5 to 9 with increasing severity of erosion Greater corn yield reductions 24 to 35 did occur for soils with root restricting subsoils Summary Summary The primary reason for corn yield reductions was the loss of topsoil organic carbon and water storage porosity of Ap The associated effects of increased clay content and reduced aggregation in Ap horizon cause reduced plant populations restricted rooting depth and reduced plant available water storage in the soil Most of the soil property differences between moderately and severely eroded phases of a soil series would reduce the ability of the soil to produce crops Successful management techniques for the restoration of the productivity of eroded soils will need to modify the chemical mineralogical and physical properties of the severely eroded soils 10
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