Rangeland Health Assessment: Soil and Water Synergy

Rangeland Health Assessment: Soil and Water Synergy

 

The hydrologic function component of grasslands and rangelands is another step in our rangeland assessment and this encompasses factors such as the amount of bare soil, presence of erosion and litter cover. Helping us to understand the soil health which in turn relates to the pasture health and livestock health.

When we look at bare soil it will vary greatly depending on the ecosite you assessing because of the different production ability of soil types. You cannot compare a loam site to a badlands site because they will have entirely different levels of production and ability to support grazing livestock so we also expect them to have different levels of bare soil. Ideally on most sites, the ground is covered by at least a layer or club moss or ‘living skin’, for protection.

If we are finding areas of exposed soil, we ask is it is “management-caused”? This is when the amount of exposed soil exceeds what it normally expected and we begin to look at finding out why that is happening. If any area has experienced higher levels of disturbance from grazing, we will see more bare ground or if it is a high traffic from humans, livestock and wildlife. When we are picking where we are placing quadrats for assessment, we typically avoid higher traffic areas such as near dugouts, mineral tubs or salt blocks because we expect these to have high levels of disturbance. Limited rodent burrowing activity is also normal on sites but burrowing activity will increase with disturbance and the amount soil being exposed, at which it is then management-caused. It is important to note what is causing the increased bare soil for future reference or communications with the landowner.
If any erosion is seen, we take note of that as well. Erosion can look different depending on the landscape and causes and the earliest signs of erosion can easily go undetected unless you are down on the ground observing. Pedastalling of plants may be one of the earliest indicators and then in more severe cases we will notice more dramatic shifts such as gullying of hillsides. This photo shows the different types of erosion we can see. Once again, some erosion is expected on more unstable sites but if the erosion becomes more extensive due to management, then changes need to be made in order to keep the rangeland as stable as possible.

 

For long term soil stability and health, it needs protection. This protection or armour is a combination of living and decomposing vegetation and plays a vital role in the rangelands ability to cycle nutrients, retain moisture and remain productive. Litter is a one of the best ways to monitor this. Litter the dead plant material from the previous grazing seasons and it can be standing or lying and slightly decomposed. To learn more about litter, check out our blog post talking all about it!
 

The leftover plant residue will increase moisture retention and nutrient cycling that healthy rangelands need to remain functionable. When it is functioning properly, the rangelands can store and slowly release moisture. By having plant material on the soil surface, it can act as a filter and slow down water from simply running off and allow the ground to actually have time to absorb the moisture. It also protects the soil surface from wind, evaporative losses and brings down the soil temperature on hot summer days. The decomposition of the plants keeps nutrient cycling and provides a home for insects.

All of these components play an important role in the health of the rangeland in combination with the vegetation on the landscape. These are then scored out of 100 to give us an overall snapshot of the rangeland. In our final blog post on this series, we will cover how to interpret the results and adjust or maintain management plans.

 

Photo credit: Rangeland Health Assessment Native Grassland Booklet

Author: Mindy Hockley-Anderson