Reading the Range: Range Readiness, Grazing Timing and Drought Considerations

Apr 07, 2022

By Jessalyn Bachler

How do you know when your pastures are ready to be grazed? This question is especially important in years of drought when delays in forage production are commonly seen. If you graze too early, you can harm our valuable native range plants. If you graze too late, you risk invasive plant species getting a head start and miss out on the early spring nutrition bump. Grazing timing is key when managing rangelands during a drought.

How does grazing timing affect turnout dates?

It is critical to wait to turnout livestock until pastures are ready to be grazed. This decision should be based upon grazing readiness of the plant community that is found throughout the pasture. If the pasture is dominated by native grass species, such as western wheatgrass, needlegrasses, grama grasses, and big and little bluestem (Figure 1), the pasture will likely need longer to break dormancy and get started than if it were a tame grass pasture. Native pastures should not be grazed until later in spring or early summer. On the other hand, if the pasture is invaded with tame-season grasses, such as Kentucky bluegrass, smooth brome, or crested wheatgrass, the pasture will likely be ready to be grazed in early spring. Turnout should be timed with plant species composition found in the pasture.

Across South Dakota, turnout dates can vary by region. In northwestern South Dakota, proper turnout dates for native rangeland are generally around the end of May or beginning of June; tame grass pastures are usually ready for utilization in the beginning of May. As one progresses further south in South Dakota, these dates will change, and grasses should be ready to be grazed sooner. These are general rules of thumb for when pastures might be ready for grazing. These dates can be highly impacted in a drought situation; if adequate spring moisture is not received, turnout dates will be later (see Adaptive Management: One Strategy To Increase Your Operation’s Flexibility and Resiliency). If pastures are grazed too early before the grasses are ready, seasonal forage production can be decreased, in turn causing reduced livestock performance.

Another question to ask when looking at timing of grazing is if the pasture is dominated by cool-season or warm-season grasses because the growth curve for each group of plants is different. Pastures dominated with cool-season grasses are commonly seen throughout South Dakota. Cool-season grasses tend to be highest in crude protein and total digestible nutrients early in the growing season, when they temperatures are mild. They may also get a fall regrowth when temperatures cool down. Warm-season grasses are in active growth and have higher nutritional contents during the hot months of summer. Thus, timing of grazing is important to not only maximize forage production, but also to allow grazing to occur on the highest quality forage at the proper time to meet livestock nutrient requirements. Being able to identify the plant communities that are present in pastures will help ranchers utilize their available forage base to its fullest potential.

Native grasses that are commonly found throughout South Dakota rangelands

Figure 1. Native grasses that are commonly found throughout South Dakota rangelands.

When is the range ready to be grazed?

Crested wheatgrass ready to be grazed at the three-leaf stage

Figure 2. Crested wheatgrass ready to be grazed at the three-leaf stage.

After plant communities are identified in pastures, it is time to look at grazing readiness. One way to measure grazing readiness is to look at growing degree days (see Options for Spring Turnout). Another way to assess grazing readiness is to look at actual forage growth of the plant community in your pasture to see what stage the grasses are at.

Native cool-season grasses, such as western wheatgrass and green needlegrass, should not be grazed until they reach the 3.5-leaf stage to ensure no harm will be done to the plant. If native grasses are grazed too early, not only will it reduce forage production, but it will also cause negative changes in the plant community, such as allowing invasive grasses or weeds to become established. Pastures that are dominated with cool-season tame grasses, such as Kentucky bluegrass, crested wheatgrass and smooth brome are ready for grazing at the three-leaf stage (Figure 2). Tame grasses tend to reach maturity earlier and handle grazing pressure better; therefore, it is recommended to utilize these pastures first for spring grazing.

How does drought affect the timing of grazing?

Spring moisture and temperatures play the largest role in determining spring forage growth. This is particularly true of the months of April, May and June. Research has demonstrated that precipitation received during these months accurately predicts annual forage production in the central and northern Great Plains (Smart et al. 2020). Typically, if there is a drought and timely spring rains are received in April and May, we can possibly see normal amounts of forage production if soil moisture reserves were refilled the previous fall. If there is not sufficient spring moisture and turnout needs to be delayed, producers should expect to feed livestock longer until forage production is adequate for turnout.

As critical as spring moisture is, it is crucial to not downplay the importance of previous grazing management, as it will largely influence forage production as well. If pastures were harshly overgrazed in years prior, they need adequate time (up to a year) to recover. However, if pastures were managed with proper grazing management and enough residual plant material was left behind after grazing, a pasture may only need a few months to recover. It all comes down to how well you manage your grazing before a drought hits!

Summary

The type of plants that are found throughout your pastures will indicate when they are ready to be grazed. As a rule of thumb, tame grasses should always be grazed before native grasses in the spring. Pastures that are dominated by cool-season grasses should be utilized in spring and fall, while warm-season pastures should be grazed in the heat of summer. The timing of spring turnout dates for grazing can vary from year to year, depending upon spring moisture (drought status) and previous management. Thus, it is critical for ranchers to “read the range” to identify when their pastures are ready to be grazed, especially in years of drought.

Source : sdstate.edu

Video: Can Gene Editing Give Seeds a Stronger Start?

Reagan Reed has a way of describing his research that might make a plant breeder pause.

“I’m the sort of person who likes to break things to understand them,” he says.

What he breaks are genes involved in seed germination. Reed, a Ph.D. candidate at the University of California, Davis, is investigating whether changing those genes can help seeds establish healthy plants under a wider range of conditions.

Reed recently attended the National Association for Plant Breeding meeting in College Station, Texas, as an NAPB Borlaug Scholar. His work speaks to a question that matters well beyond a research lab: what does it take for a seed to get a crop off to a strong start?

A seed that germinates quickly, alongside the others planted with it, spends less time vulnerable to stresses before seedlings become established.

“If you’re able to bridge that gap between germination to stand establishment, then that’s going to give you the highest probability of having a solid yield that year,” Reed says. “There’s a bunch that can go wrong after that, but it maximises your yield from the start, at least.”

Reed works in Dr. Imtiyaz Khanday’s lab at UC Davis, where his research focuses on seed quality in tomatoes and potatoes. He brings an unusual academic background to the work: at Skidmore College, he studied both biology and Latin.

Reed believes that combination prepared him for research. Translating an ancient text means studying each word, weighing its possible meanings and using context to reach the best interpretation. There is rarely a way to know with complete certainty what an author intended. Science, he says, requires a similar willingness to work through uncertainty.

“Attention to detail and comfortability working with uncertainty,” is how he sums up what Latin taught him.

In the lab, uncertainty can produce a surprise. Reed describes changing one gene and seeing little effect. Changing a second gene also appears to do little. Put both changes in the same genetic background, though, and the result can be substantial.

“I break this gene, nothing really happens. I break this other gene, nothing really happens. I combine them into the same genetic background, and now there’s a massive effect,” he says.

Those interactions matter as researchers gain the ability to edit multiple genes at once. They also complicate any simple account of how a trait works: improving a seed may depend on understanding what several genes do together.

For Reed, the question is whether that knowledge could help seeds germinate reliably when conditions are difficult. Some of the genes he studies prevent germination under certain conditions. That response may serve a plant well in one setting while limiting its usefulness in agriculture. He wants to learn what happens when those genes are changed, and whether the result improves establishment.

Yet a discovery that works in a lab still has a long way to travel before it reaches a field. Reed argues that agricultural biotechnology faces an economic challenge as well as a scientific one. New tools can create value for farmers, he says, but developing them requires a way to support the work in an industry where margins can be thin.

His fellowship with Flagship Pioneering gave him a view across AI, agriculture-related work and human health research. It also reinforced the importance of bringing people with different expertise into the same conversation—a benefit of gatherings such as the NAPB meeting.

“You need to have a team of people with different backgrounds who are willing to work together and approach the same problem in different perspectives and different ways,” he says.

That thinking connects the different parts of Reed’s path. Latin taught him to examine details without expecting a perfect answer. Gene editing lets him test what individual genes do—and what happens when their effects combine. Working with people beyond his own field helps him ask what those findings could become.

He came to agriculture because of its reach: the possibility that work by a small group of researchers could eventually make a difference on a much larger scale. His immediate focus is smaller and more precise. He wants to understand what helps a seed get through its first days and become a healthy plant.