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United States Department of Agriculture

Agricultural Research Service

Research Project: Increasing Inland Pacific Northwest Wheat Production Profitability

Location: Soil and Water Conservation Research

Title: Contour Planting: A Strategy to Reduce Soil Erosion on Steep Slopes

Authors
item Long, Daniel
item Wuest, Stewart
item Williams, John
item Rauwendall, Randy -
item Bailey, Mike -

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 19, 2009
Publication Date: July 18, 2010
Citation: Long, D.S., Wuest, S.B., Williams, J.D., Rauwendall, R., Bailey, M.J. 2010. Contour Planting: A Strategy to Reduce Soil Erosion on Steep Slopes. In R. Khosla (ed.) 10th International Conference on Precision Agriculture Abstracts & Proceedings.

Interpretive Summary: GPS-based guidance systems are available for automatically steering tractors along curved paths. This technology might provide for contour plowing- the practice of farming across slopes following elevation lines. This study investigated contour planting as a means to reduce soil erosion on steep slopes. Contour planting was performed with a deep furrow drill. One pass with this drill on the contour would be enough to protect a steep slope from runoff provided the pass of the drill is at least 2% of the runoff collection area. Steering a tractor on a contour line will require a central processing unit with multiple sensors for automatically controlling steerable wheels and adjusting for downward slippage on sloping land. For this purpose, artificial neural networks are available that mimic the human brain and can accommodate multiple inputs.

Technical Abstract: Practices that combine GPS-based guidance for terrain contouring and tillage for runoff detention have potential to increase water infiltration and reduce runoff. The objective of this study was to investigate contour planting as a means to reduce soil erosion on steep slopes of the Columbia Plateau dryland wheat region. An exploratory field study was conducted on a Ritzville silt loam (coarse-silty, mixed, superactive, mesic Calcidic Haploxerolls) and 0-20 percent slopes. Planting was performed with a deep furrow drill on the contour to a depth of 20 cm. Our results demonstrate that a strip of deep-furrow seeding precisely contoured on the upper shoulder slope should provide sufficient detention storage to capture and hold the runoff from a 100-yr 24-h storm if the contour strip area was approximately 2% of the runoff collection area. This research also examined artificial neural networks for generating routing maps that optimize seeding on precise, GPS-guided contours. A contouring algorithm was evaluated in which the direction of a tractor is determined by contour-based neural activity whereby neurons corresponding to regions of the terrain of similar height to that of the tractor’s current position receive the greatest excitatory input. The contour region, therefore, has the global effect of influencing the whole state space to attract the tractor in the right direction.

Last Modified: 9/2/2014