Is It Time to Think about Renovating or Planting a New Pasture or Hay Field? Part 3: Planning to Planting

In Parts I and 2, I covered testing the soil in the field in which you plan to establish a new pasture or plan to do a total renovation and species selection.  Depending on how close you are to planting and whether you will be working the soil or planting using a no-till drill, it’s probably time to recheck soil pH and fertility levels in the field to be planted or renovated.  The final soil test should be taken approximately 6 to 9 months after the earlier limestone application.  This should be enough time for previously applied lime to react with both the active acidity (hydrogen ions in soil solution) and the reserve acidity (hydrogen and aluminum ions on the clay and organic matter cation exchange sites) and the soil pH to be reaching an equilibrium state.  In this way if another smaller application of limestone is needed to move the soil pH slightly higher, the lime can be applied and worked in the soil, assuming some type of tillage for incorporation of the limestone. In no-till situations, the process of adjusting the soil pH takes much longer and should be started as much as two or three years in advance of seeding or renovation  since lime moves downward through the soil at about one inch per year.

Now that the soil fertility requirements have been completed, it’s on to the planning and planting process.  One of the biggest challenges these days, especially if you have a small number of acres in the field, is finding someone with equipment the right size to fit the field and a willingness to do the job in a timely fashion.  Of course even if you’re lucky enough to find the equipment and operator, cost is going to be a critical factor when making the decisions of what parts of the plan are actually doable.  Another factor that has become more of a challenge in recent years is the availability of forage seed of the selected species and variety.  Many forage seed production fields have been converted to row crop production and in some locations restrictions on burning seed production fields have allowed disease issues such as ‘choke’ to reduce forage seed yield potential.

In planning the whole procedure, your time will be a valuable asset.  With high prices, limited seed supplied, and challenges in finding equipment and help to fertilize, lime, control weeds, and plant seeds, the time you take to shop around should pay big benefits.  July and August are the time to do these chores since the fall planting season is right around the corner.

For planting date, forage agronomists often list from mid-August through September as being the time to plant as long as soil moisture is adequate.  Soil moisture for many hay producers and grazers in the state and region really will be at critically low levels for much of August.  This can extend late into September due to the drought and hot weather conditions we usually experience during July and August.  With all our pre-planning and planning activities, the final decision on when to plant and even whether to plant on time will be determined by the weather conditions during August and September.  You may be tempted to plant as soon as the field receives the first rainfall in the planting window but you should keep in mind that if the deeper layers of soil are deficient in moisture the new planting will likely fail if fall turns dry.  Use a shovel or your soil probe to test the soil for moisture at the 6 to 12 inch depth.  If the field hasn’t received enough rainfall to supply this soil depth with at least some water, a new planting will be very much at risk if rain events do not continue from planting until winter dormancy takes hold.  Only you know the amount of risk you are willing to take to establish the new seeding this season and none of us know what the future weather will be.

What if enough rain to supply water to the deeper soil layers doesn’t fall until very late in September?  Certain species, such as low alkaloid reed canary grass, require a specific amount of time between planting and first frost (six weeks minimum for reed canary grass) but almost all species will not only yield less the following year but take a lot more time to reach full establishment if planted late.  Again, the hay producer or grazer must evaluate the amount of risk they are willing to take on when deciding to plant after September.

You should maintain frequent contact with your fertilizer/lime dealer, seed dealer, equipment supplier, and others who will be helping you with the process of planting the new pasture or hay field.  If you will be using equipment provided through the county conservation districts, be sure to get your name on the list as early as possible since many folks may want to seed about the same time when moisture conditions become favorable.

This article was submitted by Dr. Richard Taylor, Extension Agronomist, University of Delaware.  Dr. Taylor can be reached at rtaylor@udel.edu

Is It Time to Think about Renovating or Planting a New Pasture or Hay Field? Part 1

Part 1: The Pre-Planning Process…

Over the years since I first came to Delaware, I have received numerous requests concerning overseeding or renovating pasture and hay fields.  Unfortunately, these requests usually come about just before someone wants to actually plant.  In reality, producers should begin considering the process as much as a year ahead of the actual time that they want to plant a field.  Since our fall plantings of forage crops seem to perform better than spring plantings, it’s a good time to begin a discussion of the process.  Often, we find ourselves moving into mid- to late-fall without having taken the time to really consider all decisions that have to go into improving the odds that the planting will be successful.  Seed costs alone can equate to more than a hundred dollars per acre in investment expense; and, if we really take into account all the variable costs, a new pasture or hay field can easily represent an investment of hundreds of dollars per acre.

So in the pre-planning process, what’s first?  I know many get tired of hearing the phrase but testing the fertility of your soil far ahead of time is still the number one issue.  The proper sampling depth is 0 to 4 inches in fields where you will be using a no-till drill to seed the forage and on fields that you do not plan to use deep tillage and have not been applying significant quantities of commercial nitrogen (N) fertilizer.  In these instances, you will not be incorporating lime to neutralize acidity from the N fertilizer or incorporating large amounts of phosphorus [P or (P2O5)] or potassium [K or (K2O)] fertilizer.  Your expectation is that the soil test will indicate that the soil pH is in the 6.0 to 6.8 range and the P and K levels are in the medium to optimum range.  If your expectations do not prove true and the pH is low enough to require several tons per acre of limestone or the P and K levels are low to very low and the fertilizer and lime needs to be mixed into the soil thoroughly, you will need to change plans and consider some type of tillage to incorporate fertilizer and/or lime.

If you have used large quantities of commercial N fertilizer in the past, you really should take both a 0-2 inch depth sample for determining the soil acidity in the upper soil layer as well as a 0 to 4 inch depth sample for nutrient content (phosphorus, potassium, calcium, magnesium and other essential elements).  If you are unsure when limestone was last applied to the field, sampling both depths is a good approach since it will provide you with more information about the nutrient status of your field.

The reason for this distinction is that the ammonium or urea N forms that are applied as fertilizer are converted by soil bacteria into nitrate through a process called, nitrification,  In this process, the soil bacteria oxidize the reduced form of N and release hydrogen ions that cause the soil to acidify.  Since the N is all surface applied, the release of acidity near the soil surface can create a condition known as ‘acid roof’ where the top inch or two of soil is much more acidic than the deeper layers of soil.  A second reason involves the very slow movement of limestone down through the soil.  Studies on pastures in Connecticut many decades ago showed that lime moves downward at a rate of about 1 inch per year.   Therefore, it takes a very long time to have an impact on the entire rooting zone of the forage grasses and legumes.

In fields where tillage is planned prior to establishing a forage crop, the traditional plow layer sample (0 to 8 inches) for both soil pH (acidity) and essential nutrient status is the appropriate choice.  If the soil sample indicates that the soil must be limed, apply the recommended amount of limestone and work it into the soil as soon as possible to allow time for the limestone to neutralize soil acidity before planting time.  If the weather after lime application and incorporation remains dry, the limestone will not completely dissolve and neutralize the soil acidity.  I recommend that producers take a second soil test before planting in late summer or early fall to determine if any additional lime is needed.  Additional agricultural lime and the recommended P2O5 and K2O fertilizer as well as any other needed nutrients can be applied and worked into the soil shortly before planting the field.

Everyone asks the question of whether to apply N at the time you plant a new field or seed a field you are renovating.  My preference is that you should wait until the new grass is several inches tall and has enough biomass and roots to compete for applied N and store any extra N for future growth.  Very small forage seedlings use and need very little N, no more than a couple of pounds N per acre, until they reach 2 to 4 inches in height.  Often the residual N from organic matter mineralization during the summer, will supply the small amount of N the seedlings require.  Once the forage plants have enough leaf area to capture the sun’s energy and convert it into more plant tissue or into sugars for storage, the demand for N will increase significantly.  When forage seedlings are very small, weeds or current vegetation in renovated fields are likely to be better  able to compete with new forage seedlings for N, light, water, and other nutrients.  Although annual weeds and/or current vegetation will be present when N fertilizer is finally applied to the new seedlings, the perennial forage seedlings will be in a better competitive position to compete for the components needed for growth and establishment.  Summer annual weeds that germinated with the forage crop will be killed at the first fall/winter frost and provide the forage plants with more space, sun, water, and nutrients.

In the next installment, I’ll cover the question we most commonly receive, “What should I plant?”

This article was submitted by Dr. Richard W. Taylor, Extension Agronomist, University of Delaware.  Dr. Taylor can be reached at rtaylor@udel.edu