Pascual Hernandez
Pascual Hernandez

We may wonder if our rangeland grasses will cure with all the rain we’ve had.

We hear and use the term, but what exactly does that mean?

Curing refers to the annual or seasonal cycle of grasses dying and drying out.

It is a measure of grass ‘greenness’ and pertains to the percentage of grass material that is dead.

Grass curing is dependent on seasonal conditions such as moisture and temperature.

As grass dries off over the season, grass becomes more and more cured.

Certainly, curing is also dependent on plant species and land type.

Grasses growing on light sandy soils will dry out and cure much sooner than grasses growing in heavy clay.

Annual grass species will dry out and die off earlier in the dry season than most perennials.

To understand how curing changes plant quality, we must first look at the make up of plants.

Plant cells can be divided into 2 groups: cell solubles and cell wall material.

Cell solubles are contained within the cell wall and are easily digested. Cell solubles include crude protein, sugars, starch, and lipids (fats).

The cell wall, however, contains lowly digestible material called fiber which includes hemicellulose, cellulose, and the mostly indigestible substance lignin.

Cell solubles are highest in actively growing forage tissue and decrease as plants become mature and dormant.

Declines in cell solubles are due to increased fiber and to the movement of nutrients from leaves to roots in preparation for dormancy.
When cold weather comes and plant cells freeze, they rupture, releasing the readily digestible cell solubles.

Once cell solubles are exposed, rain can dissolve these substances which are then leached by the precipitation.

For that reason, grasses may contain 15 % protein content early in the growing season, but then decline to 5 percent protein once it is cured.

So at this point in the year, grasses will slowly go through their processes until the first killing frost or freeze.