Author
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Williams, John |
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Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/31/2007 Publication Date: 3/1/2008 Citation: Williams, J.D. 2008. Soil erosion from dryland winter wheat–fallow ground in a long-term residue and nutrient management experiment in north-central oregon. J. Soil Water Cons. 63:2 53-59. Interpretive Summary: Soil eroded by runoff, rainwater that does not infiltrate into the soil profile, was measured in winter wheat/fallow fields on the Columbia Plateau. This experiment was originally begun in 1931 to examine the influence on soil fertility and crop production of nutrient amendments and crop residue management practices. We evaluated the influence of farming practices on the soil erodibility. Four of the farming practices were common in 1931, and two of them are still in use today. Our measurements are the first evaluation of these treatments, which represent a set of past and current cultural practices, on soil erodibility after such an extended (70 yr) period of implementation. Soil erosion was greater within treatments with low soil fertility and least in high fertility treatments. The responses in this research demonstrate the consequences of a soil resource in decline; more runoff and increased soil resource depletion. Technical Abstract: Soil property changes resulting from crop production practices are not often readily apparent after a few years or decades. The objective of the research reported here was to evaluate soil erodibility in treatments representing past and current cultural practices in a winter wheat–fallow field experiment established in 1931 near Pendleton, OR. Five treatments were evaluated: 1) fall burned residue / 0 kg N/ha/crop (no fertilizer), 2) spring burned residue / 0 kg N/ha/crop (no fertilizer), 3) spring burned residue / 90 kg N/ha/crop commercial fertilizer, 4) residue not burned / 90 kg N/ha/crop commercial fertilizer, and 5) residue not burned / 111 kg N N/ha/crop from manure. All treatments were moldboard plowed with multiple subsequent passes with secondary tillage equipment. Weirs, stage recorders, and sediment samplers were used to collect data from January through March of 1998, 1999, and 2000. Grab samples (1-liter) were collected to confirm digital stage data. Measured soil erosion progressively increased from plots with standing stubble (0.08 Mg ha/y), to plots in crop with manure and commercial fertilizer amendments with and without the crop residue burned (0.85 Mg ha/y), to plots in crop with crop residue burned and no fertilizer (3.30 Mg ha/y). These results provide direct evidence of the relationship between depleted soil quality and increasing erodibility, and demonstrates the importance of maintaining nutrient levels in semiarid dryland soils. |
