Pasture and Forage Minute: Grazing Management After Wildfire, Pasture Fertility and Cross Fencing
Soil Sampling Pastures
Are you considering skipping fertilizing your pastures or alfalfa fields this year due to the high fertilizer prices? Now might be a great time to invest in soil sampling your fields to see what you have for soil fertility in your field’s profile.
Soil fertility is key to maintaining yield and alfalfa fields should ideally be sampled each year to check soil pH, potassium and phosphorous levels across all soil textures. If your field is sandy, eroded or highly weathered, you may want to test for sulfur as well. It is important to remember that compared to row crop ground or grass hay, nitrate-nitrogen is not a concern since alfalfa can fix atmospheric nitrogen. However, digging a few plants up and checking nodulation will provide some insight to your plant’s ability to fix nitrogen.
To collect soil samples, you will need to collect soil cores to eight inches deep. If the field was previously sampled to only six inches stay with the historic depth for comparison. It is important to be consistent on your sampling depth because values change the deeper or shallower we go in the soil profile. You can use a file or a sharpie marker to measure eight inches on your soil probe to make constancy easier when pulling cores.
When soil sampling, there are a few ways you can go about pulling the cores, but for alfalfa fields, sampling by soil type or representative samples for every 40 acres would be the most cost-effective choices. You will need to pull 10 to 15 random soil cores across your soil type or 40-acre area to be represented. Then mix those soil cores together in a plastic bucket. From there, take about two cups of soil and place it in a labeled bag to be sent in for analysis. Repeat this process across the field for every 40 acres or by the soil types in your field. When shipping, be sure to follow the laboratories submission instruction for proper packaging. Once you have your results you can see where you might be able to reduce fertilizer inputs this year. You can always reach out to your extension educator, fertilizer dealer or agronomist for more help.
Grazing Management Following Wildfire
There have been several wildfires this spring that have affected range and pasturelands across Nebraska. Although the immediate aftermath of a fast-moving fire can look quite devastating, most of our perennial pasture grasses will recover with adequate moisture.
One of the key impacts of a wildfire is the loss of plant residue and litter that protects the soil surface. This residue is important for reducing wind and water erosion and the loss of soil moisture. Some of the wildfire areas had significant winds during and after the fire. This likely led to some scouring erosion around the plants. At the time of the fire, many cool-season grasses had started their initial spring growth or green up. They will be set back a little but will recover.
An important grazing management recommendation following a wildfire is to delay turnout, possibly as long as one month. This is both for fire recovery and drought potential. This will allow the grass plants to maximize growth given the current soil moisture conditions and result in greater season-long production.
Secondly, stocking rates should be reduced with the objective of leaving adequate residue, which will become litter on the ground. This is to replace what was lost in the fire. Rainfall in May and June will be most critical and should be the guiding factor affecting any of the above management decisions.
It is not uncommon to see a greater number of annual weeds show up in a pasture after a fire. While this may look concerning, these weeds can actually be useful and have some forage value or will turn into residue and cover at the end of the season. There numbers will decline the following year.
A byproduct of a wildfire are areas that were disked for a fire break. Ideally, these areas should be reseeded using the same grass species found in the rest of the pasture. If this cannot be done within the next few weeks, a summer annual forage crop could be planted as a cover, and then plan for reseeding the perennial grasses next spring.
Temporary Cross Fencing
As we move through spring, you may think it’s time to put away your electric fence from grazing crop residue this winter. Don’t do it just yet. It can be a useful tool to stretch your pasture this summer.
Electric fence is the easiest and cheapest way to increase utilization in summer pastures. Dividing pastures with an electric cross fence encourages cattle to graze pastures more completely. By increasing uniform consumption across a pasture, grazing time in the pasture can be extended, resulting in a longer recovery period following grazing. This time off allows plants to regrow and can improve their health and vigor. With high pasture rent and rumors of a hot, dry summer, stretching grass a bit early may pay off in the long run.
Temporary electric fence won’t replace the role permanent fencing options like traditional barbed wire and high-tensile electric fencing systems still hold. However, the low cost and easily moveable nature of temporary fence make it invaluable for a cross fencing tool. This is especially true if you already have electric fencing your animal’s respect. Being able to change paddock size on the go is a benefit permanent fence installations don’t provide. Additionally, using fencing equipment you already have provides an inexpensive opportunity to experiment with where you might eventually place a more permanent cross fence.
The electric fence that keeps your cows on stalks during winter can give you this inexpensive opportunity to try some cross fencing where you have been reluctant to try it before. More grass might be the result.