NDSU Extension - Griggs County

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June 8

The Extension Connection

By Megan Vig

                Wet weather results in shallow groundwater depths and saturated soils, whereas dry weather results in lower groundwater depths.  Increased evapotranspiration under dry weather results in increased wicking up of soil water (capillary rise) towards the surface, resulting in the “white barren areas” along headlands and road-sides or in-field ditches.  This week I share information from Naeem Kalwar, NDSU Extension Soil Health Specialist on saline-sodic headlands.

                Most headlands are adjacent to roadside ditches.  When ditches are full of water, the groundwater depths in the ditches and headlands are similar.  That leads to shallow groundwater depths in the headlands.  Subsoil salts and sodium found in the parent material dissolve in the soil solution and wick to the surface.  This results in saturated, saline and sodic soil conditions.  Over time, these areas grow and reduce productivity of once fertile soils.  The lack of plant growth increases erosion causing topsoil to blow away.  It is dollars directly out of a producer’s pocket when the precious fertile topsoil blows away.

                Planting cash crops like wheat, corn or soybean on these saline-sodic headlands will likely results in poor stands.  According to the NDSU projected 2018 crop budgets for northeast North Dakota, the average planting cost for spring wheat is $93.46 per acre, corn $169.33 per acre, and soybeans $82.27 per acre.  No production in the saline area results in a net loss.  By establishing perennial salt-tolerant covers, we can not only profit from these currently unproductive areas but can also minimize the blowing of topsoil.

                Establishing a vegetative cover is the key to utilize excessive soil moisture, intercepting salt-carrying water before it will affect productive areas, reducing evaporation from the soil surface, adding organic material and increasing microbial activity.  Annual crops like barley, oat, sugarbeet and sunflower can be good choices for a cover crop, however, often the electrical conductivity (EC) levels of the saline headlands are too high (saturated paste extract EC greater than 4.0 mmhos/cm).  This will prevent these crops to yield profitability.  In addition, annual crops will require planting every year. 

On areas having saturated paste extract EC levels of 8.0 or more mmhos/cm (or dS/m), planting strips of salt-tolerant perennial grasses may be a better option.  These grasses will grow at EC levels ranging from 14.0 to 26.0 mmhos/cm.  Strips could be 30 to 50 feet wide along the headlands, road-side or in-field ditches.  Seeding rate for the mix is 7 to 8 pounds per acre and costs about $30 per acre.  It takes about one year for these grasses to establish, and about two years to suppress weeds.  With active management, these strips will require mowing or haying. 

Plan on the remediation strategy to take three to five years.  Producers can either mow or bale hay from these strips.  If we experience a dry cycle shortly after establishing perennial strips, headlands may still be one of the worst areas of the field as there will not be enough rain or snow melt to push the salts out of the root zone despite lower groundwater depths.  However, with established perennial salt-tolerant covers, remediation of headlands will continue.  To get more information on recommended plantings from Naeem, contact the Extension Office at 797-3312. 

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