– Victor Shelton, Retired NRCS Agronomist/Grazing Specialist
Stand evaluations are usually worth the time. Do you have enough clover?
It is approaching the time of year in which you start seeing signs of spring. I start watching for any new green growth emerging slowly from the leftovers of last year. In my neck of the woods, it seems a bit earlier than normal but that can turn on a dime.
I like to walk over the pastures in the late winter or early spring for a number of reasons. First of all, to check plant density, diversity and soil cover. If there was extra soil disturbance in the past few months, it might mean that we have small gaps in the perennial plants that could give way for optimistic weeds to surface. Now is a good time to try and address that. Overseeding or frostseeding clover is probably one of the easiest and surest methods, especially if you lack sufficient legumes in the stand.
Gaps in the forage that are most optimistic for weeds are spaces where there is no cover and bare soil presents itself. If there are areas or spots that have been grazed tightly to the ground and only tolerable species are left, such as bluegrass and native white cover, it is generally a sign of a long-term issue and it stands out quite loudly when it’s adjacent to taller avoided forage species such as rank left-over summer growth of tall fescue.
I also like to observe how much residual plant material (residue) is left behind from the previous season that might provide added protection and added benefits for slightly earlier grazing, if needed. That leftover forage does a decent job of armoring the soil surface, especially if it comes from significant tall cool season forages which, in turn, will then have a more substantial root mass below ground to support livestock under slightly wet conditions and provide excellent dry matter to go with new high moisture early green forage. I’ve found that the more pasture you have with ample leftover forage, the quicker or earlier you may be able to graze without hurting later production.
Though it is not the most perfect time to evaluate legumes in the stand, it does give you the opportunity to get at least an idea on how much clover or other legumes you may have in the stand. Clover estimated at this time of year is generally about half of what is actually there. It’s best evaluated later in the spring but then it’s past the frost-seeding time frame.
A transect is a good way to get an accurate account of what is there by species or by group. You can do this by “stepping off” so many steps using the same number of steps each time and landing on the same foot each time and then recording the species present at the toe of your boot. If you do this at least 50 times and then add up the number of each species noted and multiply it times two, you will get a good estimate of each species present. This method is commonly called “Step Point.”
There are several factors that will affect the nitrogen content and somewhat the correspondingly crude protein content of the new spring growth which includes the quantity of existing legumes we’ve been talking about, the amount of stored organic nitrogen in the soil, and certainly any nitrogen that has been added from commercial fertilizer or additional animal manure.
Legumes fix nitrogen with the help of Rhizobia bacteria species. As soon as the legume roots start growing in the spring and the root hairs start to multiply, the Rhizobia start to colonize and the legume nodules start to form. Inside the nodules, the bacteria continue to multiply and convert the nitrogen from the soil’s air spaces to ammonium. Ladino type white clovers can add up to 200 pounds of nitrogen to a well-managed healthy pasture. Each Rhizobium is species specific, thus the reason it takes specific inoculants when planting legume seeds. Have I sold you on legumes yet?
Commercial fertilizer is always an option. Nutrients need to be kept in balance. Too high a level of potassium may result in grass tetany and milk fever problems. Too much nitrogen and you may get more growth than you can use at one time. Excessive nitrogen applied in the spring can create a lot of competition for the cool season legumes in mixes, especially recently frost-seeded ones.
Most people will fertilize with nitrogen or a combination with nitrogen in the early spring. This is not a problem if we want to cut it for hay, but for a pasture with cool season grasses such as orchard grass and fescue, we are just adding fuel to the fire. These cool season forages will normally produce two thirds of their total dry matter by mid June. Fertilizing early promotes early growth that may be difficult to manage in a grazing system – especially if we have a wet spring.
If you think the grass stand is thin, then you can enhance the stand temporarily by broadcast seeding some Italian or annual ryegrass on the stand at about 40 pounds or ideally drill it into the stand at about 20-25 pounds per acre. This will help provide quality forage in thin areas for the present season but will most likely be overtaken by taller cool-season forages within a year or so depending on the density of the existing stand and grazing management.
Frost seeding or broadcast seeding large grass like tall fescue and orchardgrass is generally a waste of time, money and seed. It is advisable to use a non-selective herbicide to either kill the entire existing stand or at least set it back quite a bit in order to allow the new seedlings a fighting chance to survive. Small seedlings have a hard time competing with established forages, thin or not. If you truly want to change or improve the forages of the pasture, then starting over and killing out the existing stand is probably the best thing to do.
On the conservative side, if the stand is really only a little thin and you are satisfied with the existing forages and your livestock likewise, then I would probably rely a little more on the existing seed bank and do any needed creative grazing required to return the stand to its prior level of performance and condition. Allowing longer recovery between grazing periods, allowing more desirable forages to fully express themselves and then grazing in a slightly more mature stage will help revive the stand.
Lastly, that early spring walk is a good time to start checking and fixing fences for deer damage, tree limbs or large fallen pieces of trees. Dead and dying ash trees are quickly becoming a menace and in some cases a huge workload.
Remember, it is not about maximizing a grazing event, but maximizing a grazing season! Keep on grazing!