Camelina-based Soil Amendments

Researchers Involved:

Project Description:

In the presence of water, Camelina seed exudes a hydrophilic gum. (Fig. 1)The gum rapidly absorbs water and within a few minutes the seed is completely encapsulated, establishing its own water reservoir to support seed germination. When the camelina seed is crushed to extract the oil, the gum remains in the meal fraction.This meal can then absorb nearly ten times its weight in water.

After the oil has been extracted, the Camelina gum can be spread onto exposed soil. When the surface is wetted, it forms a gel across the surface of the soil. (Fig. 2) The thickness of the gel can be contolled by the rate of meal application. In greenhouse studies, this gel was shown to reduce soil eroision by nearly 90%.

In a later study, we discovered that the gel inhibits emergence of Canada thistle seedlings from infested soil (Fig. 3). The thickness of the meal layer dictates the suppressive effect implying that the meal physically prevents emergence of the weeds through the gel layer similar to mulching.

Here are a few other items of intrest that we discovered in our laboratory:

• Desirable reclamation seeds can be embedded in the meal prior to application of soil. In our preliminary study, we embedded Kentucky bluegrass seed into the meal, applied it to soil trays placed at an angle and monitored germination. The germination of the seed was not inhibited by the meal. The grass was evenly distributed across the tray as opposed to accumulating near the bottom of the slope.
• We have recently shown that inhibitory amino acids can be incorporated into the meal prior to application. These amino acids further inhibit emergence of sensitive weed plants.
• We propose that plant pathogenic bacteria and fungi could also be embedded in the meal matrix. The limiting factor of microbial biocontrol agents is often moisture. In this case, the meal holds moisture enabling the pathogen to germinate and attack the target weed. However, camelina meal contains compounds called glucosinolates which have some antimicrobial activity. The compatibility of camelina meal with a given pathogen will have to be evaluated.

Fig. 1 - Hydrated Camelina Seed

Fig. 2 - Soil treated with Camelina gum

Left: Camelina meal was mixed into green house soil at a ratio of 1:100.   Middle: Camelina meal was broadcast onto the top of soil at a ratio of 1:100. Right: Non-treated soil.   Each tray was flooded with water.  The amount of soil washed from the tray was measured.  The layer of camelina meal stabilized the soil in the middle tray.  The meal is being evaluated for erosion control in disturbed sites such as highway construction and burned areas.

Fig. 3 - Canada Thistle

Relatively thick laters of camelina meal inhibit emergence of Canada thistle.

The non treated control is on the left.