Impact Of Wheel Tracks On Surface Drainage & Yield

Introduction

This case study examines the impact that tractor wheel tracks can have on surface drainage and then yield. The case study is from a farm in USA that grows vegetables. The field has some depression area that hold water after rainfall events but this problem is exacerbated by the small furrows create by the ‘controlled traffic’.  This is the clearest case we have seen showing the directions and depths of wheel tracks affecting drainage and then yield.  We have also seen this problem in grain crops around the world.

All tractor traffic is controlled by RTK GPS which forces the tractors to traffic over the same area each time also known as ‘controlled traffic’. Although ‘beds’ are not specifically created to grow the crop on, the continual traffic in each path compacts the traffic ‘lane’ so that  a small furrows is formed.  Soil is also pushed sideways away from the traffic lane to increase the effective depth for the furrow. The furrow created can be up to 4 inches deep (100mm).

Runoff from rainfall and irrigation concentrate in the wheel tracks and flow along the furrows towards a low point. If the wheel tracks were not there, then the water may have an opportunity to move sideways perpendicular to the furrows. But the water that stays in the wheel tracks waterlogs the crop and reduces yield.

See the video below to better understand the problem. Note how the water is standing in the furrows and the crop is decimated.

Existing Topography

Here is a map of the existing topography. Contour lines are 0.3ft apart. There is significant slope on this field.

There are only a few depression areas that would hold water if no wheel ‘furrows’ were present a show in the next map drainage.

ExistingTopography

Drainage Analysis

The next three maps are created by the Ponding Map generated by OptiSurface Designer’s Drainage Analysis Tool.  This tool uses the topography and simulates water buildup in the depressions of the field and can also look at the impact of furrows/beds, small furrows created by wheel traffic and even small furrows created by planters (eg 1 inch high in corn).

Drainage Analysis Without Traffic Furrows

The map below assumes no wheel track furrows   This map shows only 2% of field is ponded at +0.1ft or deeper.   This matches the deepest ponding areas in the video but misses most of the problem areas.
NoFurrows

Drainage Analysis With Traffic Furrows

Below is the Ponding Map if we assume 0.2ft deep wheel track furrows in east-west direction which matches the furrow direction in the video. This shows 13% of field ponded +0.1ft or deeper. This map is amazing similar to the areas where the crop has been lost or severely decimated  in the video.
EWFurrow

Drainage Analysis With Furrows Rotated 90 Degrees

Simply rotating the traffic direction by 90 degrees or north-south direction, (without earthworks) will reduce the ponding area. The map below shows ponding reduced to 10% of field with +0.1ft or deeper.  This is 30% lower than the current row direction, however earthworks are still recommended to totally solve the problem.
NSFurrow

Landforming

Normally an OptiSurface 4Way design would be recommended for a field like this if the wheel 'furrows' did not exist.  However, due to the significant depth of wheel tracks they need to be considered in the design. This means an OptiSurface 2Way design is recommended with cross drains at locations where it will require too much earthworks to drain water to the ends of the wheel tracks.

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