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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #244334
Title: Residue management impacts on field-scale snow distribution and soil water storage

Author
item QIU, HANXUE - Montana Department Of Environmental Quality
item Huggins, David
item WU, JOAN - Washington State University
item BARBER, MICHAEL - Washington State University
item McCool, Donald
item DUN, SHUHUI - Washington State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2011
Publication Date: 8/1/2011
Citation: Qiu, H., Huggins, D.R., Wu, J.Q., Barber, M.E., McCool, D.K., Dun, S. 2011. Residue management impacts on field-scale snow distribution and soil water storage. Transactions of the ASABE. Vol. 54(5): 1639-1647.

Interpretive Summary: Variation of soil water available to crops has an important impact on variation in crop yield and quality across a field. Studies in cold climates show that no-tillage (NT) practices as compared to conventional tillage (CT) can result in more soil water storage by retaining more snow in stubble, enhancing infiltration and reducing evaporation, and can also affect the spatial variation of soil water. We studied the effect of crop residue on snow movement and spatial variation of soil water in the Palouse area of southeastern Washington. Two side-by-side farms near Pullman, WA, one under NT, the other under CT, were surveyed for snow depth, snow water equivalent, and resultant soil water storage during the winter season of 2007–2008. Snow pack was distributed more evenly under NT, and compared to CT, NT retained 10–20 cm more snow on the ridge top because of its standing residue. Soil water followed a similar pattern. Although many factors may have contributed to the spatial variation of soil water, residues under NT retarded the generation of runoff, retained more snow on the ridge top and steep-sloped areas, and likely reduced the soil water spatial variation, improving the opportunity for uniformity of yield and better crop quality.

Technical Abstract: Spatial variation of available soil water has important environmental and economic effects and implications by affecting crop yield and quality and effective fertilization recommendation. Studies show that no-tillage (NT) practices, compared to conventional tillage (CT), can result in more soil water storage by retaining more snow in stubble, enhancing infiltration and reducing evaporation. We hypothesize that the residue also affects the spatial variation of soil water. Our objectives were to evaluate residue effects on snow redistribution and the spatial variation of soil water in the Palouse area of the PNW. Two side-by-side farms near Pullman, WA, one under NT, the other under CT, were surveyed for snow depth, snow water equivalent (SWE), and resultant soil water storage during the winter season of 2007–2008. Results indicated that snow pack on average was distributed more evenly and had less spatial variation under NT. Compared to CT, NT retained 10–20 cm more snow by its standing residue on the ridge top. Snow water equivalents followed the same pattern of larger spatial variation in CT. The resultant soil water in the spring was the lowest on the ridge top areas, and highest in valleys in both treatments. However, under CT, soil water on the ridge top area was 6% less than, and in valleys 17% more than, the average over the whole treatment. Such variation was much smaller in NT where soil water on the ridge top was only 4% less than, and in valleys 6% more than, the average. Although many factors may have contributed to the spatial variation of soil water, residues under NT retarded the generation of runoff, retained more snow on the ridge top and steep-sloped areas, and likely reduced the soil water spatial variation.