Posts Tagged ‘hay’

Fall Weed Control in Pastures and Hay

Friday, August 31st, 2012

Quintin Johnson, Extension Associate, Weed Science; quintin@udel.edu

Fall provides an excellent opportunity for perennial weed management in pasture and hay with herbicide applications. Most herbicides labeled for use in pasture are translocated, or moved, to various parts of the plant. As fall approaches, perennial weeds like curly dock, Canada thistle, horsenettle, pokeweed, and others are beginning to replenish stored carbohydrates in root structures to prepare for over-wintering and new spring growth. Translocated herbicides are able to reach the rooting structures more efficiently during this period, thus providing more effective perennial weed control. However, if weeds are drought-stressed, herbicide translocation may be slower or incomplete, resulting in less effective control. Delay herbicide applications until after you receive adequate rainfall. Fall applications should be made at least 7 to 10 days before a mowing for greatest effectiveness. In well established perennial weed populations, multiple years of good weed control will be needed to significantly reduce the rootstock of perennial weeds.

There are several things that must be considered when choosing an herbicide for pastures or hay fields including: forage species grown; weed species present; risk of herbicide contact with desirable plants through root uptake, drift, or volatility; residues in composted straw or manure; herbicide rotational, over-seeding, grazing, or harvest restrictions; and cost. Be sure to follow all precautions and restrictions on herbicide labels.

The “Pasture and Hay Weed Management Guide” for Delaware is available from the University of Delaware Cooperative Extension. Access a pdf version on-line at http://www.rec.udel.edu/weedscience/WS_ManagementGuides.html.

Fertilizer Management on Hay Fields

Friday, June 1st, 2012

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

For those producers very worried about the impact of the shortage of rainfall so far this year, I suggest a two-pronged approach. First, soil test your fields to determine if any phosphorus (P), potassium (K), or limestone (to adjust soil pH) will be needed this year. If P is required, all of it can be applied at this time as well as limestone to both correct soil pH and to make nutrients such as P more available to the forage plants. If K is also required, it should be applied either all at this time, if less than 100 lb/acre is recommended, or should be applied in two equal applications when the recommendation is for more than 100 lbs/acre. For K, the second application should occur in late August or early September and is designed to help the forage grasses and legumes better tolerate winter weather.

Unless you are using manure or compost on your hay fields, you will not be using a soil test to check on nitrogen (N) recommendation rates. In general, the suggested rates for nitrogen range from 40 to 60 lbs of N per acre for each expected ton per acre of hay produced. Especially in drier years when drought may be a serious concern, the lower suggested rate should be used to avoid the possibility that high levels of nitrates will accumulate in the grass. My suggestion for N fertilization is to apply it very sparingly between each hay harvest or to evaluate the soil moisture levels and if they are adequate for a good period of growth the N can be applied at that time. A number of folks have recently completed their first hay harvest and in the fields I’ve check the soil moisture level is severely limited. The rain earlier this week was insufficient to refill the soil moisture holding capacity and I would suggest waiting a bit longer to see if more rain will come out way before applying N to stimulate grass growth. In the past few years, we’ve seen damage to grass hay fields when N was applied during hot, dry weather. Finally, don’t forget to consider fertilizing with N in a fashion similar to the turf industry and by that I mean applying N in early and mid-fall to encourage fall root growth to help the grass be in better shape for growth during the following spring and summer.

Pasture and Hay Crop Nitrogen Fertilization

Thursday, April 26th, 2012

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

The very dry spring that we’ve experienced in 2012 has made it questionable as to whether a second or late spring application of nitrogen (N) might be advisable or economical. Thanks to the rainfall last weekend and the possibility of additional rainfall this week and over the coming weekend, another application of N to pastures and hay fields following the first cutting of hay should have a much reduced chance of injuring your grass crop and should also produce additional grazing or second cutting of hay. However to be on the safe side before you apply that additional N fertilizer, take a soil probe, hand trowel or shovel and check the soil moisture level in your soil. What you would like to find is that the subsoil moisture level has recovered and that the crop will be able to not only draw on soil water from the normal 0-8 inches of soil where most of the roots can be found but also can pull water from the deeper soil layers to support growth when temperatures begin to warm up in May and early June.

Hay producers are at the biggest risk for the current moisture to dissipate before the first hay harvest is taken. If you produce hay, you should be certain to check the soil moisture levels before applying N after the first harvest. Even if inadequate soil moisture is present, N fertilizer will promote more top growth and this growth response under unfavorable conditions can lead to plant death or injury reducing stand longevity. Timothy producers should be especially careful since the first harvest often occurs very late in the spring and unless they are using one of the more heat tolerant varieties such as ‘Derby’ stands can be significantly impacted.

Finally, consider using at least some potash (K) fertilizer when fertilizing in the mid-May to mid-June period. I understand that K has become very expensive but it is the best nutrient to add to help forage grasses and legumes to tolerate the heat and drought stresses of summer. In addition if you are growing orchardgrass, there is a growing concern that we are not adequately fertilizing this crop with enough K to balance the N used to promote yields. There is some evidence that the orchardgrass decline problem that we’ve been experiencing in the Mid-Atlantic may, in part, be caused or at least aggravated by too little K fertilizer in relation to the N rate used.

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 3: Pasture and Hay Planting Time Has Arrived

Friday, August 19th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

In previous articles, I’ve discussed some of the decisions and planning that needs to be taken ahead of planting hay and pasture fields but we now have entered the ideal planting time for forage grasses and legumes. This holds true at least for those parts of the state that have received the recent rainfall — some areas in southern Delaware still have inadequate soil moisture levels to even think about attempting to seed new forage fields. For those areas that have remained dry and do not receive the rain currently in the forecast over the next five days, the decision to plant will have to be delayed until adequate surface and subsoil moisture is present.

Some species have specific requirements that limit how late in the fall you can plant. For example, reed cararygrass requires at least six weeks between planting and the average date of the first frost, otherwise the crop can be winterkilled or be severely weakened over the winter so that it’s unable to compete with the usual weed competition crops experience in the spring. Other species, such as Kentucky bluegrass, just take a very long time (21 to 28 days) to germinate and begin fall growth and so should not be planted very late in the fall. Before deciding to plant a species or mixture, be sure to study the species in question to avoid problems with late plantings.

In other areas of the state that received some of the recent downpours and that now have adequate soil moisture reserves, planting can begin. Early planting can lead to well established forage seedings that will be able to survive the winter and get off to an early vigorous start the following spring. Early planted stands are much better at competing against weeds the next spring and will often yields much better as well. Work by Dr. Marvin Hall at the Pennsylvania State University showed significant yield decreases for all forage species tested as the date of fall planting was delayed with higher losses occurring the further north the site was located.

If planting into a prepared/tilled seedbed, be sure that all weeds have been killed during soil preparation and that a good smooth (clod-free), firm (your shoe should not sink deeper than the sole level) seedbed is prepared for planting. Seed can then be broadcast over the seedbed and then firmed into the soil with any number of devices but seed should only be pressed into the soil and not buried more than 1/8 to ¼ inch deep. Covering the seed is ideal since the seed will be able to take in water from the soil but not be quickly dried out again by the sun’s rays. Seed can also be planted using a brillion seeder followed by a cultipacker or roller or seed can be placed in the soil using a drill. Since drills place the seed in rows from 4 to 8 inches apart, depending on the drill, I generally recommend that you drill at half the recommended seeding rate and run the drill at about a 45 degree angle across the field. This will help bring the rows closer together and allow the seedlings to more rapidly fill in the space so competing weeds can’t find space to grow.

Another method of seeding is to use a no-till drill following an herbicide burndown program. This is especially useful when perennial weeds with underground rhizome systems are present. Examples of these weeds are hemp dogbane, Canada thistle, and horsenettle. Although several herbicide treatments are often needed to get these weeds under control, one of the best times to apply herbicide is in the fall when the weeds are sending carbohydrates (sugars) down into the underground storage organs (rhizomes). If a systemic herbicide that can move in the plant is used, it will be taken with the sugars down to the rhizomes and help kill the meristem buds or next year’s growing sites in the weed. Read the herbicide label for exact requirements between treatment and seeding but generally for Roundup® or glyphosate you should wait several weeks after herbicide application before planting.

The no-till drills are similar to other grain drills in that the seed is placed in rows and then the open slot in the soil is closed with some type of packer wheels. I again recommend that you calibrate the drill for half the seeding rate and go over the area twice at a 45 degree angle to minimize the distance between rows.

In all cases I’ve talked about above, be certain to calibrate your seeding equipment and make sure the drills or other equipment is clean and functional before entering the field. These days forage seed is quite expensive so make the most of the money you spend by accurately calibrating your equipment. This involves the following procedure: weigh out some seed to add to the planting equipment, determine the width of area covered with seed by the equipment (in feet), run it for a certain number of feet (the length—say 50 or 100 feet); multiplying the two numbers together to get the number of square feet covered by the seed; divide that number by 43,560 (number of square feet in one acre); and finally weigh the amount of seed remaining in the equipment. Subtract the final weight from initial weight and divide that number by the number of acres you covered (usually this will be a number such as 0.15 or even 0.015 or other very small number). If your seed weights were in pounds of seed then the number you calculate at the end will be in pounds per acre or if you had access to an egg scale or something that measures in grams then divide the number of grams of seed used by 454 (grams per pound) to obtain pounds of seed and then divide that number by the number of acres planted in the calibration test. If all else fails, email me or give me a call and I’ll help you do the calculations.

The other articles in this series are:

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 2: Planning to Planting

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 1: The Pre-Planning Process

Fall Pasture and Hay Fertilization

Friday, August 19th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

I had a question this week from a hay producer about whether it was best to apply the soil test recommended fertilizer the first thing in the spring or not. Since his crop was an alfalfa orchardgrass mix, he was not thinking about nitrogen (N) which is the first thing most people think of in the spring. He was asking about potash (K) and phosphorus (P). The answer really lies in the function of these nutrients.

Phosphorus really helps plants establish or grow a better root system and we’ve discovered that root development really goes on for quite some time in the fall for two reasons. First, we generally get more rain in the fall; and, when that is combined with the lower air temperatures and shorter days, it means that soil moisture levels are usually higher in the fall than in the summer months. Secondly in the fall, we’ve found that the soil temperatures stay warm until fairly late in the year unlike spring time when soils start off very cold from winter and tend to warm up slowly throughout the spring. The combination of available moisture and warm soil temperatures and the accumulation of fixed carbohydrates (sugars) and translocation of the sugars down to the roots means that fall applied P will further help plants establish a vigorous root system for better growth during the next spring growing season.

Potash has a number of functions in the plant ranging from enzyme activation to stress reduction to the control of transpiration and water use in the plant. For us, fall K fertilization helps plants lower the freezing point of the cell sap so there will be less winterkill or winter freeze damage to the plant crowns. In addition, fall K helps plants fight off disease problems and other pest injury. For K, I prefer that growers split their application with half going on the pasture or hay field in late May or early June and the other half going on in late August or September.

Finally thanks to research in the turfgrass industry, the forage industry is beginning to discover the benefits of adding at least some N in late summer or early fall to help grasses regrow after summer grazing or summer drought. Some recommendations even suggest a second application in mid-October that the previously N stimulated grass can pick up and store for early green-up growth the next spring. This second application negates the need for an early spring N application and seems to help prevent excessive forage growth the next spring. Too many people apply much of the nitrogen forages need in the spring causing such excessive growth that their grazing plan can’t keep up with it or causing so much yield in the first hay cutting that there is a significant delay in being able to dry and cure the hay. This can lead to poor quality first cut hay or to hay that retains too much moisture so that it either spoils or is at risk for spontaneous combustion.

In conclusion, think about changing your fertilization timing from the early spring to early fall. There are many potential benefits from this change as outlined above.

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 1: The Pre-Planning Process

Friday, July 8th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

I have received several requests over the past several weeks concerning overseeding or renovating pasture and hay fields and feel it’s a good time to begin a discussion on the process. All too 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. You need to keep in mind that seed costs alone can equate to a hundred dollar an acre investment; and, if we really take into account all the variable costs, that 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. If the field will not be tilled and you have not been applying significant quantities of commercial nitrogen (N) fertilizer to the field, sample at 0 to 4 inches deep in each field or management zone (an area of the field treated in a similar fashion and not much different from other areas of the field in soil type).

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).

The reason for this distinction is that the ammonium or urea N forms that we apply as fertilizer are converted by soil bacteria into nitrate and in the process acidity is released into the soil. 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 at a rate of about 1 inch per year so it takes a very long time to have an impact on the entire rooting zone of forage grass and legume plants.

For fields that will be tilled and a new planting established, the traditional plow layer sample (0 to 8 inches) for both soil pH (acidity) and essential nutrient status will be the correct 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. Although, if it remains dry, lime may not completely react, and a second soil test still would be useful to determine if any additional lime will be needed. Additional agricultural lime and the recommended phosphorus (P) and potassium (K) and 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 the applied N and to store any extra N for future growth. Until forage plants have enough leaf area to rapidly capture the sun’s energy and convert it into more plant tissue or into sugars for storage, weeds in new plantings or the current vegetation in renovations are likely to outcompete the new seedlings for N and then for light, water, and other nutrients. When waiting to apply N although weeds and current vegetation will still be present, the new seedlings will at least be in a better competitive position when the N is finally available to stimulate growth.

Now that you’ve taken care of any soil fertility issues that can reduce the chance for a successful stand, the next decision involves choosing the right seed to plant. I’ve had the opportunity over the years to read many seed labels on various pasture mixes offered for sale. I understand the convenience of buying a prepared pasture mix and the allure of these mixes. The buyer often assumes that the seller has spent the time and energy studying the issue and has come up with a mixture that in their opinion and experience has the best chance of success. I certainly can’t speak to motivation of the seller but keep in mind that from a business point of view, seed that is mixed and offered for sale need to be sold over as large an area as possible to justify the expense of wholesaling large quantities of seed, blending, packaging, and labeling the seed. In my opinion, this nullifies the expectation that the seller has designed the mix for your particular field or location.

After looking at the species of forages used in the prepared pasture mixes, I find that these mixes are more like a shotgun approach to seeding where you plant a little of everything in hopes that something will establish in all areas of the field. Usually they contain a quick establishing grass such as ryegrass that can germinate in as little as 5 to 7 days so the buyer can feel comfortable with the new seeding. The mixes also usually contain the feel-good or highly recognized grasses such as timothy and Kentucky bluegrass in horse pasture mixes and at least some orchardgrass and probably an endophyte-free tall fescue to provide more permanent cover. Finally, a legume such as white or ladino clover, red clover, or alsike clover will be in a pasture mix to provide the N-fixing legume everyone would like in a pasture.

The convenience of these mixtures comes from not having to mix them yourself before you fill the seed drill and the allure comes from not having to make a decision other than how much seed per acre to plant and not having to choose individual species to plant. For most buyers, the convenience and allure end up costing them many, many dollars per acre in seed costs for seed of grasses that won’t survive in grazing situations or won’t survive more than a season or two at best or will be unproductive for much of the grazing season.

So what should you do? I prefer going with a simpler mixture using forage species that are adapted to our region. In most cases, the only species that will survive for many years in our transitional zone climate is tall fescue. Because of endophyte (an fungus growing in some tall fescue plants) issues, many growers have tried the endophyte-free tall fescue varieties and some have had success with keeping a stand for many years while others have seed stands decline or disappear quickly. The newest chapter in this issue has been the development of novel or friendly endophyte tall fescue varieties. The novel endophyte tall fescue varieties do not produce the chemical compound (alkaloids) that interfere with animal performance but still provide benefits to the tall fescue plants helping them survive in many stressful environments. A limitation still in evidence with these new tall fescue varieties is that horse owners who breed horses do not all accept tall fescue as a feed source for their animals. This limits tall fescue’s acceptance.

What other species can you include in your simple mixture? Orchardgrass is another grass that many producers like to include in a pasture mixture but you should be aware that many orchardgrass fields are failing due to a disease/insect/environment/management complex interaction we’ve been calling orchardgrass decline. If you choose to include orchardgrass, keep it as a small proportion of your mixture. The other grass to include at least on the heavier soils is Kentucky bluegrass. Be sure to include several varieties of the Kentucky bluegrass to help with disease resistance. It will be most productive early in the year (early spring to early summer) and mid- to late-fall. Finally, add in a legume to help with providing N for the grass to use as well as to improve the protein and forage digestibility of the pasture. For grazing, most people prefer a ladino-type of white clover. Although slobbers (the animal produces excessive amounts of saliva) is a potential concern with all clovers, it seems to be mostly associated with red clover. Often included in commercially sold horse pasture mixtures, alsike clover is known to cause photosensitivity (sunburn) especially in horses and should not be included in your pasture mix.

You will find it useful to talk to your seed dealer about the various varieties of each species that are available. Once you decide on the varieties to use and you purchase seed, you can mix your own pasture mix by either purchasing or renting a cement mixer and combining the seed in the proportions you decide are best for your purpose and field. Since many legumes now come pre-inoculated with the N-fixing bacteria and often are coated with a fine limestone, do not over mix the seed and when you re-bag it store it where it is protected from high temperatures and humidity. Stored properly, the seed can be held over the winter if something prevents you from seeding this fall but you should plan to plant as soon as possible after purchasing seed. Not only are the N-fixing bacteria alive; but, if you use a novel endophyte tall fescue variety, the endophyte has a limited storage time (around a year under good conditions) before it should be planted. Although the tall fescue seed will germinate after longer storage times, the endophyte fungus may no longer be alive. The fungus only lives in the plant and is not soil-borne.

Next time, I’ll cover some of the other management issues to consider, such as planting date.

The other articles in this series are:

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 3: Pasture and Hay Planting Time Has Arrived

Thinking of Renovating or Planting a New Pasture or Hay Field? Part 2: Planning to Planting

 

Getting the Most from Your Hay Operation (For Those Who Primarily Feed Their Own Hay)

Friday, May 20th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

On my way to work each day, I drive by a dairy farm and often enjoy watching all the activities occurring on the farm. The thing that has struck me in particular over the years is not just how much hay has been stored along field borders and roadways and around the barnyard in the fall; but how much of that hay remained the next year and beyond (Photos 1, 2 and 3). I watched as the oldest round bales stored on the wood line gradually decayed and disappeared. This was caused in part due to on-ground storage that allowed moisture to wick into the bale (Photo 3). Being somewhat dense (on occasion), it took me a long time before I realized that he was actually cutting hay for quantity rather than for quality; I guess the grower had in mind that some of the low quality hay could be used in the TMR feed as a fiber source while the remainder could be fed to dry cows or heifers if feed ran short.

Photo 1. Hay (6 months post harvest) stored in round bales along wood’s edge on a dairy farm. This hay although in contact with the soil was stored at the top of a hill but the quality was declining and the amount of spoiled hay was rapidly increasing.

Photo 2. Hay from previous years’ harvest stored along field edge on a dairy farm. Wrapped in this fashion, soil moisture was not causing spoilage although wildlife damaging the plastic was contributing to hay losses. Late in the spring this hay was actually fed to the herd.

Photo 3. Hay stored in contact with the ground along a wood’s edge deteriorates with time. At another location with twine wrapped bales, I was too late to even find recognizable bales.

The next question that came to mind was whether cutting hay for quantity rather than quality is the correct way to manage this valuable resource when year after year more old hay is added to the fence line compost line. With diesel prices at or near four dollars per gallon at the pump, nitrogen and other fertilizer inputs near all time highs, and hay equipment and supplies also very expensive, producers need to place a higher value on the hay they do harvest. For dairy producers, the cost of importing feed onto the farm is another consideration when deciding whether to harvest hay for quality or quantity. That extra effort to harvest hay for quality rather than quantity can really pay premium dollars in reduced input costs and, if you sell hay, in the price you can charge customers.

Still there will be times when there’s a mismatch between the weather and the forecast that results in poor quality hay lying in the field and to preserve the health of the grass or legume stand the hay must be removed. Other times, a long period of poor hay-making weather will result in an overly mature hay crop. In these cases, you may end up with “fence-row” hay. One thing you can do in these situations is to minimize your hay making inputs by using the simplest, least expensive method of removing the hay from the field. If it’s still good enough, use this hay for animals with minimal nutritional requirements or advertize and sell it as mulch or compost hay. Creative marketing may just help you cover at least a portion of the input costs incurred.

 

 

Spring Hay Harvest Timing

Friday, May 6th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

When deciding on the time for the first hay harvest of the new growing season, a number of factors come into play. First and probably foremost among these is the question of whether to delay harvest until the grass or legume hay crop is in full flower to obtain the maximum amount of yield possible or to harvest early reducing yields but gaining in quality. That is a question each hay grower will need to answer for him or herself. If the hay is for your own operation, which do you need? – high quality or more quantity? If the hay is to sell, have your buyers demanded real quality in the past? or just pseudo-quality (a green color to the hay, fresh smell, and hay free of dust and mold)?

If quality rather than strictly quantity is your goal, then you need to be aware that at least historically the first half of May offers the best chance of good hay making weather we’ll have before mid- to late-June. I’ve come to the conclusion that rather than relying on the weather forecasters you have an equally good chance and maybe even a better chance of predicting the possibility of rainfall or poor hay making weather in your location if you examine the national weather maps and look for patterns indicating a chance for good weather. We’ve become so dependent on what the weather forecaster has to say that we tend to ignore our own brain’s ability to interpret the weather maps and create our own forecast.

So what happens if you have hay making weather and you decide to harvest your hay early? Remember that as the grass or legume crop goes from vegetative growth into the reproductive stages, yield, fiber components, and lignin increase and crude protein, digestibility, and palatability (intake) go down. The closer the crop gets to flowering the more rapid the decline in quality and the more difficult it can be to make quality hay. In part, this is because as tonnage per acre increases, the time it takes to dry the hay increases. Hay left in the field for longer periods also increases the risk that it will be rained on and cause even further declines in hay quality.

Perhaps the easiest crop to make the timing decision on is alfalfa since it is often near the ideal stage for harvest in early to mid-May in most years. We already make use of early harvesting on alfalfa if we find that alfalfa weevil is becoming a problem since the early harvest often solves the problem. In addition, alfalfa tonnage can rapidly increase with a delay in harvest and cause all kinds of drying problems.

A more difficult decision surrounds many of the grass hays that we use. Orchardgrass although it may have some seed heads visible is not approaching its maximum yield potential yet. Early harvest with this crop will result in excellent quality hay (if not rained on) but yields will be low. The second harvest will be heavier than normal and many of the side, younger tillers of the plants will produce seed heads, boosting yield and making the second harvest appearance more like the first harvest. Depending on the time of harvest for the second cutting, the quality may be a little below that of the traditional second cutting orchardgrass but should still be very good. The total tonnage of the two harvests when the first one is taken very early will not be as high as that for the typical almost mature late first cutting and leafy second cutting system.

Kentucky bluegrass in many areas is approaching full head emergence so the first half of May harvest for this crop will work fine. Similarly, the ryegrasses should respond well to this early cutting system when weather permits growers to harvest in May. Timothy harvest in Delaware seems to vary greatly so scout the crop carefully to assess its stage of maturity. When the heads are mostly emerged but still relatively small and not yet flowering, you’ll be at the point that is the best compromise between quality and quantity.

 

Hay and Pasture Fertilization This Spring

Thursday, April 14th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

In many areas of the state, pastures and hay fields are either just beginning to green-up (northern sections) or while having started the process of greening-up several weeks ago are making slow growth with the cool, often cloudy and rainy weather. Now that calendar-wise, we are into mid-April, it’s time to apply nitrogen (N) fertilizer to hay and pasture grasses to boost production.

With fertilizer prices still high and the threat of frequent showers in the forecast, growers will want to limit their application rates of N to ensure maximum plant uptake and minimum loss to leaching or denitrification (wasted fertilizer dollars). The slow start to forage growth this year suggests that at least some N will be useful in encouraging forage (grass) production for grazing animals and reducing the need for supplemental hay or grain.

For pastures or hayfields that contain a significant proportion of legumes (clover, alfalfa, Birdsfoot trefoil, or lespedeza), N application rate should not exceed 30 lb N/acre/application. Otherwise, the N-fixing value of the legume will be lost to the grower.

On pure grass pastures not fertilized with N last fall, an application of 30 to 50 lb N/acre will be sufficient to boost grass productivity. On pastures fertilized with N last fall, the N stored in the plants should be adequate for much of the early grazing season but watch the pastures carefully for the first sign of slowing growth and then apply additional N at that time, probably in mid- to late-May.

For hay fields, research from The Pennsylvania State University and Dr. Marvin Hall suggests that an application of 40 to 60 lb N/ton of expected yield will maximize production of most forage grasses while minimizing the risk of nitrate toxicity. I would suggest going with the lower rate this year because of the growing conditions we’ve experienced so far this season.

 

Evaluating Alfalfa Stands in the Spring

Friday, March 11th, 2011

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

This season I’ve already had a couple of questions asked as to when and how to evaluate alfalfa stands. Below are descriptions of two methods that can be used to determine the viability of an alfalfa stand. An alfalfa producer should use not only one of these methods but their feel for the vigor of the particular stand they wish to evaluate, as well as the production history of that field.

The first method consists of counting the number of plants per square foot. Current research information suggests that when stand counts fall below 3 to 5 plants per square foot, it’s time to either rotate out of pure alfalfa or interseed a grass crop such as orchardgrass, festulolium, tetraploid ryegrass, or annual ryegrass or interseed another legume not hurt by the autotoxicity seen in year old or older alfalfa stands. Red clover is the legume of choice and should be planted at 6 to 8 lbs pure live seed per A either by broadcasting it on in very early spring or seeding it with a no-till drill (plant either in very early spring or in early to mid-Sept after the last harvest of the season).

The second evaluation method derives from research out of Wisconsin by Dr. Dennis Cosgrove that indicates that stem number, rather than plant number, is a more accurate determination of when to plow down or interseed an alfalfa stand. Cosgrove suggests using a value of 55 or more stems per square foot to indicate that the stand will produce maximum yield. A reduction in stem number per square foot to 40 stems or less will result in a 25 percent yield reduction. At this critical level, alfalfa fields begin to lose profitability and should be rotated to another crop for one or two years.

Although you can get some idea on the potential of your alfalfa stand by counting either the number of plants or the number of tillers per square foot, you will need also to consider checking on the health of those plants to have an accurate basis for a decision on keeping or destroying an alfalfa stand. To do this, in the spring when new growth is about 4 to 6 inches tall, check a random one square foot site for each 5 to 10 As of alfalfa or at least 4 to 5 sites on small fields. Dig up several plants at each site and slice open the crown and root (longitudinally) with a sharp knife to determine the health of the crown and tap root. Healthy roots and crowns will be firm and white to slightly yellow in color. Diseased roots will have dark brown areas extending down the center, especially if crown rot is a problem. Reduce your counts of plants per square foot or tillers per square foot so only the healthy plants present are counted. Plants with roots that are mushy or soft are likely to die; and although those with a few brown spots may survive, the overall vigor of the stand will be compromised by the presence of disease.

If you must decide on whether to reseed before growth begins in the spring (and you do not plan to take a first harvest of alfalfa before planting another crop) or after a very hard winter with significant heaving or winter injury, base your decision to reseed on the number of plants per square foot (Table 1). If a decision to reseed can be made during the growing season or after about 4 to 6 inches of growth has occurred in the spring, either evaluation method can be used (Table 1). In Table 1 below, I’ve modified various estimates for good, marginal, and poor stands to give the grower possible guidelines to consider in making a decision on keeping the stand or interseeding a grass or other legume.

Table 1. Suggested plants per square foot or tillers per square foot (#) criteria for evaluating alfalfa stands on Delmarva.

Age of stand

Good stand Marginal stand Consider replacement1 or renovation2 with interseeded grass or red clover
Plants per square foot with spring tillers per square foot in parentheses
New 25-40 plts (> 75) 15-25 plts (< 55) < 15 plts (< 50)
1 year old > 12 plts (> 60) 8-12 plts (< 55) < 8 plts (< 45)
2 years old > 8 plts (> 55) 5-7 plts (< 50) < 5 plts (< 40)
3 years old > 6 plts (> 50) 4-6 plts (< 45) < 4 plts (< 40)
4 years old or older > 4 plts (> 50) 3-4 plts (< 40) < 3 plts (< 40)

1 If the stand is to be plowed for replacement, growers often find it economically favorable to take a first cutting and then plow and plant a rotational crop that can use the nitrogen mineralized from the decomposing alfalfa plants. Rotate out of alfalfa at least until the next fall (14 to 18 months) but preferably for 2 to 4 years. This will allow time for a reduction in the potential for alfalfa diseases and provide the grower the opportunity to correct soil nutrient and pH (acidity) problems as well as make use of the residual N mineralization potential that exists in a field following an alfalfa crop.

2 If you consider renovation or extending the stand life, try no-tilling a grass crop such as orchardgrass, tetraplpoid annual or perennial ryegrass, or one of the new varieties of festulolium (a cross between meadow fescue and one of the ryegrasses). The grass will increase your tonnage especially if you fertilize for the grass with nitrogen fertilizer. This also has the effect of driving out alfalfa at the same time as production levels are maintained for an additional year or two. Another option for extending an alfalfa stand’s life for 1 to 2 years is to seed in 6 to 8 lbs of red clover per A. This option will maintain the higher protein production from the field.