Healthy Rangelands: Part Ii: Time and Timing Of Grazing
|This historic photo of Mules Park shows gullies and erosion of the stream bank.|
|Mules Park as it looks today after time and timing of grazing practices have been implemented.|
In the first part of this series on healthy rangelands, grasses and how they grow was addressed. According to Harland E. Dietz, retired range conservationist from the soil conservation service, grass is the stockman's crop; a crop that rivals corn, wheat, and soybeans in importance. It's the backbone of our livestock industry, and also important to wildlife, watersheds and recreation.
Dave Bradford, range conservation officer for the forest service addressed the time and timing of grazing at the recent range management school held in Moab. Bradford said, "Grazing is a disturbance, which like all other disturbances may be good, bad or neutral in its impact on rangelands. The effects of grazing on plants depends on when the grazing occurs, how severe it is and how soon it recurs. Grazing during early growth will effect plants. Periodically change the time and length of grazing and the number of animals.
"The time of grazing refers to the length of time a grass plant is grazed. This affects the intensity of grazing and the frequency of grazing. How many times in a season is that plant grazed? Controlling the time of grazing provides for the health needs of the plants.
"The timing of grazing refers to the time of the season the grazing occurs. Grazing at different points in a plant's life affects that plant differently. Periodically changing the time of the year that a range is grazed provides benefits to grazed plants. If the timing of grazing cannot be changed then the time of grazing needs to be adjusted to provide sufficient recover to the grazed plants," said Bradford.
Bradford presented a slide show which displayed historic photos and a recent photo of different allotments and the improvements that have been realized on these allotments. Information is also included with each of these photos concerning the number of animals grazing, amount of time spent grazing and the amount of precipitation that year. Bradford talked about pasture rotation and how breaking large allotments down into pastures works well. These breakdowns can be accomplished with electric fence and natural barriers. "We must look for creative ways to divide and use the land," said Bradford.
Bradford also addressed the rapid increase in the number of elk on the grazing lands and their impacts. He said the improvements to the rangelands have resulted in increased numbers of wildlife.
Floyd Reed, retired forest service range conservation officer spoke about the grazing response index. He said, "It is a simple and effective method to evaluate annual grazing impacts. The GRI is used to assess the effects of grazing during the growing season using the following criteria: the frequency of grazing, the intensity of grazing and the opportunity for grwoth and regrowth. The frequency is the number of times a plant is defoliated during active growth. A normal defoliation is considered to be once in seven days, during active growth. The plants are given a rating, for example, if a plant has only one defoliation in a season it is considered positive and it rates a +1. If a plant is defoliated twice it has a neutral effect on the plant and is given a 0 rating. If a plant is defoliated three or more times in a season then its effect is negative and a -1 rating would be given.
"The next area where a rating is given is on intensity of grazing, the amount of leaf material removed during the grazing period. The key point being the amount of leaf material that is left for the plant to utilize. If light defoliation occurs with under 40 percent of the plant being utilized the rating +1 would be given. If moderate defoliation occurs 40-55 percent utilized then a neutral 0 rating would be given. If heavy defoliation occurs with more than 55 percent utilized a -1 rating would be given.
"Then next area is the opportunity for plant growth or regrowth. This category carries double the value of the frequency and intensity category because of its importance. For example, a pasture having a full season to grow and regrow is given a +2 rating, a pasture with most of the season for regrowth would receive a +1 rating, some chance to grow, 0 neutral rating, little chance for regrowth, -1, or no chance, -2 rating. This incorporates the time and timing of grazing," said Reed.
This GRI provides a positive, neutral or negative rating for assessing the grazing impacts for the year. This works to give the rancher an assessment of the grazing impacts for a year and whether or not grazing strategies are working. This also provides a basis for planning next year's grazing use. Reed stressed not to worry if a pasture receives a negative rating for one or two years, but a steady, continued negative rating is a cause for concern.
Reed said the GRI is easy to understand and communicate and incorporates stock density, time and timing of grazing, and plant growth and regrowth. It also eliminates or reduces confrontation and gives the rancher the opportunity to practice the art and science of rangeland management.
Reed presented slides of different allotments and discussed their GRI ratings based on frequency, intensity and opportunity. He stressed that the pasture rotation system really works and allows for recovery time for the plant. The rating for a pasture should come at the end of the growing season and not after grazing to see if recovery was realized. "This system does not replace other monitoring, but it does give the opportunity for permittees to be involved in monitoring. You can complete it in a couple of hours and it is a minor investment, but a useful tool," said Reed.
The next installment of this healthy rangeland series will address more monitoring strategies and animal health.