Hay, Pasture, & Silage Fertility for Grasses and Legumes

With the arrival of spring many farmers are applying or are getting ready to apply fertilizer to their hay fields, silage acres, and pastures. Nitrogen application will be on most peoples lists, but adding some phosphorous  potassium, sulfur, lime, and perhaps a little boron will probably be worth the investment on many acres. While this blog post will focus on general recommendations to responses to different fertilizers in forage fields, it's very important to regularly soil test (and maybe tissue test) in order to have the best recommendations based on the nutrients already in the soil on individual fields.

Nitrogen (N)

A lot of nitrogen fertilizer is generally put down on hay fields and pastures. For every ton of grass harvested about 40 pounds of nitrogen is removed and every ton of legume removes 80 pounds of nitrogen. Fields that contain only grasses can use 150-200 lb/acre of nitrogen throughout the growing season. Generally nitrogen applications are split 75-100 lb/acre at spring green up, and 50 lb/acre after each cutting. Fields with legumes that are less than 50% of the stand usually respond to between 30 and 75 lb.acre of nitrogen throughout the growing season. Nitrogen application applications are generally not needed for pastures or fields that have more than 75% legumes, unless irrigation is used and there is high yield potential (greater than 4 tons per acre per year), Table 1.

Table 1. Nitrogen Application Rates to Forage Fields Based on Legume Content and Yield Potential

Adapted from Utah State University Extension

Many farmers have questions about treating their nitrogen fertilizers to reduce the losses to the environment after application. Three types of these nitrogen "efficiency enhancers" or stabilizers" are on the market: ›nitrification inhibitors, urease inhibitors, or slow release fertilizers. 

Nitrification inhibitors slow the growth of Nitrosomonas bacteria which change ammonium (NH4+) to nitrate (NO3-). N-Serve (DowAgroSciences) and Guardian (Conklin) are widely used for this and generally provide 4-10 weeks of protection for fall or spring applied nitrogen for grain crops. They are not labeled for pasture, hay, silage use. 

Urease inhibitors prevent ammonium from volatizing into the atmosphere. Agrotain (Koch Agronomic Services) is the most widely used, and generally provides 10-14 days of protection. This is ideal for nitrogen applications to pastures, hay, and silage in the spring because of the unpredictability of rainfall that would incorporate surface applied urea or other nitrogen fertilizers.

Slow release nitrogen fertilizers have a protective outer coating that requires microbial activity and moisture to break them down over time to release the nitrogen. Sulfur coated urea or ESN (Agrium), Osmocote (Scotts), and IBDU (Nu-Gro) all have been shown to be effective slow release fertilizers for many crops including pastures and forage fields. These products should only be used as a partial supply for forage nitrogen needs as they often are not immediately available to the plant. Combining a slow release nitrogen fertilizer with regular nitrogen fertilizer (urea, UAN, etc.) treated with a urease inhibitor would maximize nitrogen protection while still having some nitrogen available to the plant. Ammonium sulfate is not as vulnerable to nitrogen losses as urea and other fertilizers and would be a good choice for fertilizer pastures, hay and silage fields.

Phosphorous (P2O5 or P)
Responses to phosphorous fertilizers application are highly dependent on soil test levels. If soil tests are in the  "very low", "low", "medium", or "high" ranges for phosphorous, fertilizer should be applied. Soil tests and phosphorous fertilizers are almost always reported as P2O5 and not actual phosphorous. One pound of P2O5 is equal to 0.44 pounds of actual phosphorous. Original methods of analysis were only capable of measuring the oxide forms of phosphorous (P2O5) and potassium (K2O). This form of reporting analyses has continued to this day and most recommendations are made using P2O5 and K2O (not actual phosphorous and potassium content). Most phosphorous is applied as MAP (monoammonium phosphate), DAP (diammonium phosphate), super-phosphate, or a blended fertilizer.  The amount of phosphorous fertilizer that is needed increases as soil test levels of phosphorous decreases and are described in Table 2 for established forage stands. 

Table 2: Phosphorous Application Rates to Forage Fields Based on Soil Test Levels

Adapted from Cornell Cooperative Extension's Guide for Integrated Field Crop Management

Newly established pastures, hay fields, and silage stands should have an additional 20-30 lb/acre P2O5 for all soil test levels including "very high". Additionally if growing alfalfa in a high yield potential environment (>5 ton DM/acre) the phosphorus application rates in the above table should be doubled.

Potassium (K2O or K)
Forage stands, especially those with legumes, require high levels of potassium to remain productive and potassium recommendations are often based on the percentage of legumes in the stand. Additionally alfalfa stands require more potassium than clover or trefoil fields. Furthermore, different soil types have a large range in their capacity to supply potassium to crops. As a result, potassium applications can range from 0 to over 250 pounds per acre of K2O. A pound of K2O is 0.83 pounds of actual potassium. Table 3 describes the application rate of potassium based on soil tests and yield goals for alfalfa.

Table 3: Potassium Application to Alfalfa Fields Based on Soil Tests and Yield Goals

Adapted from Alfalfa Fertilization

If an alfalfa stand is more than three years old, potassium application should be increased by 20% to help prevent winter-kill  Potassium applications to alfalfa are often split after first and third cuttings in order to reduce tissue K test levels to help prevent milk fever, reduce fertilizer loss (potassium leaches), and prevent salt injury. Potassium applications to grass and clover fields should be reduced by at least half of the recommendation amounts for alfalfa in Table 3 because alfalfa has much higher potassium requirements compared to other forage plants. Different soil types also vary greatly in their ability to supply potassium to forage plants. Sandy soils often need twice as much potassium as clay soils because they have lower cation exchange capacity. Loamy soils fall between sands and clays in their ability to supply potassium to soils. 

Sulfur (S)
The air is simply cleaner now than it was 20 years ago, Figure 1. This means that most pastures, hay fields, and silage stands in the Northeast and Midwest will respond to 15-25 pounds per acre of actual sulfur. Each ton of grass or legume removes about 5 pounds of sulfur. Ammonium sulfate, potassium sulfate, and gypsum are excellent sources of sulfur during the growing season because the sulfur is immediately available to the plants. Elemental sulfur (S2) cannot be absorbed by plants and must be converted to sulfate (SO4-2) before plants can use it. However, when establishing an alfalfa stand either elemental sulfur or the other fertilizers will provide the sulfur needed in the 2nd and 3rd years after establishment (University of Wisconsin). 

Figure 1: Change in Sulfur Deposition in the United States 1994 to 2011

From National Atmospheric Deposition Program

Boron (B)
While only needed in small amounts, boron can greatly increase the establishment and persistence of legumes. On sandy soils 1 lb/acre per year of actual boron  should be applied, while on clays and loams only 2 lb/acre over the course of 3 years. Response to boron application will also be more likely in dry years and where no manure is applied to field.

Other Micro-Nutrients
The likelihood of a response in yield or quality to other micro-nutrients in pastures, hay fields, or silage stands  will be very low in most situations. Fields with high soil pH (>7.0), low pH (<6.0), low organic matter (<1%), muck soils, sandy soils, and fields without a history of manure application may respond to micro-nutrient applications when grain crops are grown, but legumes usually only respond to sulfur, boron, and occasionally small amounts of molybdenum and grasses respond to sulfur. Manganese can be applied as dolomitic lime if the soil levels are low, but is generally not a concern. 

Lime
Managing the soil pH is critical to managing nutrients in forage systems. Generally soil pH should be maintained between 6.0 and 7.0. Keeping soils in this range will maximize the availability of nutrients to grasses and legumes, Figure 2.

Figure 2. Availability of Soil Nutrients Based on pH

From Pennsylvania State University

The Rhizobia bacteria that fix nitrogen from the air for legumes generally require a pH close to 7.0 to function well. Some soils are naturally alkaline (>7.0, i.e. the Great Plains) or acidic (<6.0 Southeastern US) and consequently some plants are easier or more difficult to grow in these regions. Applying nitrogen fertilizer and growing plants make soils more acidic over time because acids are formed in the soil as ammonium (NH4+) is converted to (NO3-) and as plant roots exude acids to take up nutrients. Liming recommendations should be made based on soil test pH, the soil's buffering capacity (higher in clays-lower in sands), and the calcium carbonate equivalent values of the lime. A future blog will discuss this topic in-depth.

Bottom Line.
1. Adding nutrients to soils are critical for harvesting high yields of pasture, hay, and silage.

2. Applications of nitrogen, phosphorous, potassium, sulfur, lime, and for legumes boron are often necessary for forages to maximize yields.

References
Alfalfa Fertilization
Ketih Kelling, University of Wisconsin

Cornell Cooperative Extension's Guide for Integrated Field Crop Management
Forage Production Section-Jerry Cherney, Cornell University

Fertilizer Management for Grass and Grass-Legume Mixtures
Rich Koenig, Mark Nelson, James Barnhill, & Dean Miner, Utah State University Cooperative Extension

National Atmospheric Deposition Program
University of Illinois

Will Alfalfa Respond to Sulfur in Wisconsin?
John Peters and Keith Kelling, University of Wisconsin

Winter Small Grain Silage Fertility

Many farmers planted winter triticale, winter rye, or winter wheat last fall in order to take a spring harvest to make up for the low haylage yields in 2012. Applying enough nitrogen at green-up will be crucial to raising the yield potential from 2 to 4+ tons of DM per acre. Supplying enough spring nitrogen will also increase crude protein from about 14% to nearly 20% DM if the silage is harvested by the flag leaf stage (Feeks 9, Figure 1) The application rate of spring nitrogen needed for high yielding, high quality winter small grain silage may range from 0 to nearly 100 lb. per acre depending on the previous crop in the rotation, and the field manure history.

Figure 1: Growth Stages of Winter Small Grain Silages

Photo from Cornell Agronomy Fact Sheet 56

Fertility Management at Planting

Typically rates of 10-20 lb. of nitrogen per acre are applied at planting for wheat that is grown for grain. Fall nitrogen rates for small grains grown for silage are currently being re-evaluated across NY with support from the New York Farm Viability Institute (grant summary). Too much fall nitrogen leads to excess fall growth, leaving the small grains more vulnerable to damage over the winter. If the small grain is greater than 6 inches tall going into the winter, the crop will likely be partially or completely damaged by snow mold. Placing enough phosphorus with the small grain seed at planting is also critical for winter survival and spring growth if the fields do not a have a history of manure. Work by Peter Johnson in Ontario has shown that mixing 100 lb/acre of MAP with the wheat seed had higher yields (92.5 bu/acre vs. 82.9 bu/acre) and better winter survival (85% vs. 35%) than wheat without phosphorous. 

Spring Fertility Management Depends on Field History

One of the most common planting situations for winter grain silage last fall was after corn silage. The amount of spring nitrogen needed will depend on the amount manure applied before planting the small grain. Winter grain silage fields with high manure rates (>5,000 ga/acre) may still respond to a small nitrogen application at green-up (20-30 lb/per acre). Fields where 3,000 to 5,000 ga/acre of manure was applied may respond to up to 50 lb/acre of nitrogen. If little or no manure was applied at planting than small grain silage yields and quality may respond up to 75-100 lb. of nitrogen per acre. Manure nitrogen content can vary greatly from farm to farm and should be taken into account before deciding how much nitrogen fertilizer should be applied to small grain silages in the spring. 

Small grain silage following a haylage field that contained over 50% alfalfa or clover and had at least 6 inches of growth will probably not require much spring nitrogen fertilizer. Lodging can occur from over fertilization of nitrogen without responses to yield or quality. In these situations farmers may still want to apply 20-30 lb. nitrogen per acre at green-up as the nitrogen from the previous legume will not start to mineralize and become available to the small grain until temperatures increase later in the spring. The nitrogen from manure and soil organic matter will also not start to become available until the temperatures rise. If fields were mostly grass and did not receive manure, then at least 75 lb. per acre of nitrogen should be applied.

Small grain silage planted after soybeans, field peas, or snap beans will likely to respond to a middle range of nitrogen rates (40-60 lb. per acre) as there will be some legume nitrogen that should be available to the small grain silage.

Small grain silage planted after a small grain will likely require between 75 & 100 lb. of nitrogen per acre. Yields of small grain silage following a small grain will likely be lower due to higher disease, insect, and weed pressure compared to the other scenarios described above.

Currently a state-wide effort in New York is underway to fine-tune these general recommendations for nitrogen application to small grain silages. This blog entry will be updated as appropriate. The Google Map for the Winter Small Grain Silage Nitrogen Study 2013 is now online at https://maps.google.com/maps/ms?hl=en&gl=us&ie=UTF8&oe=UTF8&msa=0&msid=200860025394836250060.0004d93b822cfdf9fcd98&t=h&z=9&vpsrc=1. Photos will be uploaded from now until these trials are harvested in May 2013. Click on the individual markers for more information and photos from each on-farm location.

Spring Applications of Phosphorous, Potassium, and Sulfur
Small grain silages may also benefit from applications of other nutrients besides nitrogen in the spring. While fertilizer response rate trials studying phosphorous, potassium, and sulfur have not yet been conducted on small grain silages, results from previous research on winter triticale, rye, barley, and oats grown for grain will likely meet all the nutrient requirements of silage

Bottom Line

1. Managing nitrogen fertility can increase winter small grain silage yields from 2 to over 4 tons of DM/acre.

2. The amount of nitrogen fertilizer needed is very dependent on field history.

References:

Phosphorus Response in Wheat Production
Peter Johnson, Ontario Ministry Agriculture and Food

Winter Forage Triticale

Tom Kilcer, Jerry Cherney, Karl Czymmek, Quirine Ketterings Cornell University
Cornell Agronomy Fact Sheet 56

Managing Forage Inventories

This blog entry is a follow up to "Taking Forage Inventories", an article written for the AgFocus monthly newsletter from January 2013 and "How to take forage inventories" from the February 2013 issue of Progressive Dairymen. Many farmers will be short on hay and silage in the coming months and tough management decisions will need to be made in 2013. Most management options available boil down to one of four areas: 1) reducing on-farm losses of forage, 2) buying replacement hay or silage, 3) feeding alternative forage sources, and 4) selling animals to match forage inventories. Prior to making these decisions, a forage inventory should be taken in order to determine how long current stocks of forage will last.

Reducing On-Farm Losses of Forage
Silage and hay can be lost at many points from the field to the cow. See the December 2012 blog entry for a more in-depth discussion of Reducing Hay and Silage Harvesting Losses. Many steps can also be taken to minimize forage losses during storage and feed-out. Unfortunately for farmers many of the decisions that contribute to storage and feeding losses have already been made. However, maintaining at least 6 inches of feed-out a day from bunkers and bags, keeping hay stored out of the elements, and patching holes in the plastic covering silage can help reduce storage losses. A future blog post will discuss Reducing Hay and Silage Storage Losses in more detail. Large amounts of forage can also be lost at feeding. One example is that a lot of hay is often wasted because animals are fed with inefficient feeders. Well designed feeders greatly reduce the feed that is wasted. Reducing Hay and Silage Feeding Losses will also be discussed in more detail in a future blog post.

Buying Replacement Hay or Silage
This option for filling short forage inventories has already occurred on many farms, and farmers have paid record high prices across the nation for that hay and silage. In some areas there simply is not any feed left to buy. Many hay and silage pricing tools and auction prices are reported on-line to assist farmers in arriving a a fair local price for buyer and seller. The Weekly Hay Market Demand and Price Report for the Upper Midwest is one of most widely viewed sources. It quotes multiple hay auction prices for a wide variety of hay qualities and bale types. Archived prices are also listed on this website. Buying forage online is very risky proposition, especially if there is no off-line connection between buyer and seller. Only pay after hay has been delivered and verified by lab test or inspection that is the quality claimed by the seller.

Feeding Alternative Forage Sources
Most farms will seriously examine alternative forage sources in order to bridge the gap before the 2013 crop can be harvested.

Small Grain Silage
Many farms planted oats for silage last summer and harvested them last fall. Winter triticale, winter wheat, and winter rye have been planted across the country either as cover crops or for grain.  Research from Cornell University (Winter Triticale--A Cropping Opportunity and Winter-Forage Small Grains to Boost Feed Supply: Not Just a Cover Crop Anymore!) has demonstrated that 2-5 tons of DM  of 15%+ crude protein (CP) and less than 60% neutral detergent fiber (NDF) are attainable from winter small grain silage. Timely fall planting, sufficient nitrogen fertility in the spring (75-100 lbs per acre of total nitrogen from legumes, manure, or fertilizers), and harvest at the flag leaf stage (no seed heads emerged) are necessary to achieve high yields and quality. Work from the University of Wisconsin has shown that when harvest of winter wheat, winter rye, and winter triticale is delayed until the boot stage, yields are consistently 3 tons of DM per acre, but CP content declines to 12-14% (Winter Cereals for Spring Forage). A feeding trial from the University of Minnesota demonstrated that winter triticale silage with nearly 18% CP was equal to alfalfa silage in dry matter intake (DMI), fat corrected milk production, and milk composition when fed as the sole forage in the ration to dairy cows compared to alfalfa silage (Alternative Field Crops Manual: Triticale).

Work from Iowa State has shown that 1.0+ ton of DM of spring planted oat silage that has 20-22% CP, 52-54% NDF, and 75% total digestible nutrients (TDN) can be grown if harvested at the boot stage. Delaying harvest can increase yields up to 3 tons of DM per acre, but forage quality declines rapidly (Oats for Forage). The introduction of oats bred for forage production has increased the yield potential of spring planted oats to 2-3 ton DM per acre, and oat silage yields are generally higher for late maturity grain varieties than earlier maturity varieties (Pea and Small Grain Mixtures). 

Fibrous Byproducts
Adding fibrous byproducts to rations can greatly extend forage inventories. By-Product Feedstuffs in Dairy Cattle Diets in the Upper Midwest by Randy Shaver, University of Wisconsin provides a great description of the feeding values of beet pulp, brewers dried and wet grains, corn gluten feed, cottonseeds, distillers dried and wet grains, hominy, malt sprouts, soy hulls, and wheat by-products. Generally these byproducts can replace between 10-30% of the forage without decreasing DMI or milk production. Dr. Shaver's paper also discusses high-protein and unusual by-products that can be fed to cattle. Farmers should consult with their local nutritionist to evaluate if these products or others can be incorporated into their rations.

Alkali Treated Straw or Corn Stalks
Beef producers have long used various methods of treating straw, corn stalks, or corn cobs with a alkali product in order to increase the digestibility these materials for their cattle. Recent work from the Nebraska University (Digestibility of Crop Residues After Chemical Treatment and Anaerobic Storage) has shown a 10 to 15% increase of in vitro DM digestibility after treating with sodium hydroxide or calcium oxide and storing in sealed plastic for 30 days. The University of Nebraska-Lincoln Extension Midyear Husker Beef Nutrition Conference June 20, 2012 also discussed this topic in great detail (Use of Corn and Residues in the Future for Beef Cattle). See the video "Demonstration of treatment of corn stalks and wheat straw" for some practical ways to implement this practice on farm. Residue digestibility can be increased 15-60% according to Shane Gadberry's, University of Arkansas outline of treating residues with calcium oxide, sodium hydroxide, ammonia and urea (Treating Corn Stalks and Other Crop Residues to Improve Feed Value) depending on the material and treatment method. Generally, these treatment processes involves grinding the material, rehyrdating the residue to 50% moisture, applying calcium oxide or sodium hydroxide at 5% DM of residue weight, and then storing in a silage bag for at least 7 days. Urea is applied at 3% DM of residue weight after the residue has been brought to 50% moisture and stored for at least 21 days in a sealed bag. Ammonia is pumped through a pipe into a sealed stack of hay or straw at 3% of DM weight and left for at least three weeks prior to feeding. Safety is big concern with these practices, and precautions need to be taken when handling these materials. Rehyrdrating the residues also requires large quantities of available water. Results from a feeding trial at the University of Wisconsin where corn stover was treated with CaO and partially replaced corn grain in dairy diets are available (Lime-treated corn stover: How to do it and it's feed value).

Poor Quality Hay
Already many cattle have been consuming feed that normally would make their farmers cringe. Poor quality hay (i.e. an old pasture that has the feeding value of straw) fed in small amounts may buy farmers some time before finding better hay or buying an higher quality feed/byproduct. Feeding bad hay should be avoided at all costs. It is one of the most risky management decisions to make when short on forage. Foreign material, the presence of harmful alkaloids, and unknown residual compounds are just a few of the risks of feeding bad hay to cows.

Selling Animals To Match Forage Inventories
While no farmer wants to consider this option, it will need to be on the table on many farms in 2013. Beef farmers in the South and Great Plains have already liquidated much of their herds in recent years prior to the drought of 2013. Cull prices for dairy cows have been strong in recent months and farmers should consider removing the least productive and efficient animals before cull prices fall. This can be a very difficult decision, but seriously considering it, along with the other options will help farmers make it through until forage inventories are replenished.

Bottom Line
1. Taking forage inventories and discussing management options now is necessary across the US.

2. Farmers will be able to manage short forage inventories by a combination of reducing on farm forage losses, buying replacement hay or silage, feeding alternative forage sources, and/or selling animals to match forage inventories.

References:
Alternative Field Crops Manual: Triticale.
E.A. Oelke, Department of Agronomy and Plant Genetics, University of Minnesota
E.S. Oplinger and M.A. Brinkman, Department of Agronomy and Cooperative Extension, University of Wisconsin.

By-Product Feedstuffs in Dairy Cattle Diets in the Upper Midwest 
Randy Shaver, Dairy Science Department, University of Wisconsin

Digestibility of Crop Residues After Chemical Treatment and Anaerobic Storage
Adam L. Shreck, Crystal D. Buckner, Galen Erickson, Terry Klopfenstein, Michael J. Cecava, University of Nebraska-Lincoln

Lime-treated corn stover: How to do it and it's feed value
Dave Combs, University of Wisconsin

Oats for Forage
Steve Barnhart, Department of Agronomy, Iowa State University

Pea and Small Grain Mixtures
Dan Undersander, University of Wisconsin

Treating Corn Stalks and Other Crop Residues to Improve Feed Value
Shane Gadberry Associate Professor, Animal Science, University of Arkansas

Use of Corn and Residues in the Future for Beef Cattle
The University of Nebraska-Lincoln Extension Midyear Husker Beef Nutrition Conference on the use of corn residues.June 20, 2012.Agricultural Research and Development Center, Mead, NE.

Weekly Hay Market Demand and Price Report for the Upper Midwest
Ken Barnett, University of Wisconsin-Extension

Winter Cereals for Spring Forage
Edward S. Oplinger Extension Agronomist, University of Wisconsin

Winter-Forage Small Grains to Boost Feed Supply: Not Just a

Cover Crop Anymore!
Tom Kilcer, Advanced Ag Systems
Shona Ort, Quirine Ketterings, and Karl Czymmek, Nutrient Management Spear Program, Dept. of Animal Science, Cornell University, PRODAIRY, Dept. of Animal Science, Cornell University

Winter Triticale--A Cropping Opportunity

Tom Kilcer, Advanced Ag Systems

Reducing Hay and Silage Harvesting Losses

Hay and silage account for half the cost of most livestock farms. Too often, valuable feed is lost: 1) in the field, 2) during storage, and 3) at feeding. In years when feed supplies are tight, it is especially critical to minimize these losses. This blog entry is the first of a three-part series, and will focus on strategies to reduce the losses during the field operations of hay and silage making. Mowing, conditioning, drying, and harvesting operations all contribute to field losses of forage.  

Mowers and Conditioners

Work at Michigan State University and the University of Wisconsin have shown that rotary disc mowers tend to have 3-4% higher field losses than sickle cutterbar mowers. This is due to greater respiration (plant breakdown) losses for the rotary cutterbars (4.2-4.8%) compared to sickle bars (0.3%), Rotz and Sprott (1984). Additionally higher losses occur in the baler when rotary disc mowers (2.1-2.2%) are used compared to sickle cutterbars (1.5%), Koegel et al. (1985). Rotary disc mowers allow for faster harvest than sickle cutterbars which typically operate at 6-8 mph. Rotary disc mowers can more easily harvest lodged fields than sickle cutterbars, but more forage will be left in the field with rotary disc mowers. For more detailed discussion of adjustments to the both types of harvesters to minimize losses see Machinery Designs and Adjustments for Minimized Field Losses.

Figure 1: Rotary Disc and Sickle Cutterbar Mowers

Source: Case IH Mower Conditioner Brochure

Properly adjusting conditioners have a greater impact on field losses than the type of conditioner. Shattered leaves and over-conditioned (bruised) alfalfa stems are the primary sources of field losses from conditioners. When using a roll conditioner, the clearance between rolls and the pressure should be reduced for low-yielding harvests and the clearance and pressure should be increased for larger harvests. The timing of the inter-meshing rolls also needs to be adjusted to prevent over-conditioning (dark green discoloration on stems) and reduce leaf shatter. Impeller conditioners should only be used for making grass hay. Even if the impeller speed is reduced, alfalfa and clover crops will have high leaf losses. When trying to make silage there is no need for any conditioner in the mower provided the haylage is laid in a wide swath (>70% of cutterbar width) and properly tedded. Conditioning only helps to dry out the stems once the stomata on the leaves are closed. Spend the money instead on a wider mower and tedder/merger to increase the amount of haylage that can be cut and dried quickly. When making wide swaths for silage drying remove the deflector shields or place them all the way up with metal bars attached to spread the swath back out wide. For more discussion on drying hay and haylage see Reducing the Drying the Time of Hay and Silage in the Field. 
The hood height can be lowered to provide more aggressive conditioning or raised to reduce the conditioning action on impeller units for pure grass crops. Few, if any, differences in field DM losses have been shown between molded rubber (5.2%), tire cord (5.4%), rubber and steel (5.8%), and two steel conditioning rollers (5.9%), Shinners et al. (1990).

Figure 2: Flail Impeller Conditioner and Roll Conditioner

Source: John Deere Windrower Brochure

Rakes, Tedders, Mergers, and Inverters

Pickup height, tractor speed, and forage moisture are the most important factors influencing field losses during field operations of rakes, tedders, and mergers. Rake height needs to be adjusted to pick up the forage while minimizing the rocks and dirt that end up in the forage. Side rakes, tedders, and mergers do not have to touch the ground in order to turn the windrow/swath, but wheel rakes need to touch the ground in order to work properly. Faster tractor speeds increase the amount of leaves lost in alfalfa, but a compromise between working fast enough to get the job done and not losing valuable feed needs to be struck when doing these operations. Losses from tedding operations can be minimized by tedding when the forage crop is 60% moisture or greater, while raking, merging, and inverting should be done when the forage crop is at least 40% moisture.

Figure 3: Side Rake, Wheel Rake, Tedder, and Merger

Source: New Holland Hay and Forage Equipment Webpage

Balers and Silage Harvesters

Similar to tedding, raking, merging, and inverting, the most important factors influencing field losses when making bales or silage are the crop moisture, pick-up height, and ground speed. Leaf losses increase as crop moisture goes down, Figure 4. 

Figure 4: Hay Leaf Losses Increase as Hay Moisture Decreases

From the Prairie Agricultural Machinery Institute

Round bales should be made at a uniform density, about 10 pounds/ft³. Adjustments may be needed throughout the baling process and will vary depending the type of baler used. Making uniform bales will make for easier handling, storage, marketing, and cost calculation. When round baling narrow windrows (less than half the pick-up width), picking up on one side of the windrow for 10-12 seconds and then quickly crossing over to the other side of the windrow (pattern a) makes more uniform round bales than constantly swerving across the windrow (pattern b) or driving straight down the windrow (pattern c), Figure 5. 

Figure 5: Round Baler Pick-Up Strategies Effect Bale Shape in Narrow Windrows

Source: Grisso et al., Biological Systems Engineering Virginia Tech

Making wide windrows or swaths that are equal to the baler pick-up width will also result in more uniform bales, and enables driving directly down the windrow. Matching the ground speed to PTO speed will result in quickly formed bales which minimizes leaf loss. If harvesting full windrows that are equal to the pick-up width, ground speeds of 4-6 mph usually result in uniform bales. Using a round baler with a variable or expanding chamber instead of a fixed chamber will also result in more uniform bales and lower leaf loss (3.75-4.25% vs. 3.5-8.0%), Prairie Agricultural Machinery Institute.

Silage losses in the field are most often due to leaf loss of alfalfa, exposure to rain, improperly adjusted equipment, and delayed harvest operations. Similar to baling hay, silage harvester ground speed should be adjusted to match pick-up with PTO speed, but minimize leaf losses. Silage bleaching occurs when rain falls on the silage, which reduces many of the digestible nutrients and results in white windrows. Field DM losses of 22%-44% of silage can occur with only 1 to 1.6 inches of rainfall a day or two after cutting, Rankin and Undersander (2000).

Bottom Line
1. Properly adjusted and maintained equipment go a long way to reducing field losses of hay and silage.

2. Optimizing the speed of field operations and conducting these operations at the appropriate crop moisture levels reduce field losses of forage. 

References:

Drying Rates, Losses and Fuel Requirements for Mowing and Conditioning Alfalfa
Rotz, C. A. and D. J. Sprott, Michigan State University, 1984. Transactions of the ASAE, 27(3)715-720.

Forage Growers Guide to Round Baling
Prairie Agricultural Machinery Institute.

Machinery Designs and Adjustments for Minimized Field Losses
Ronald T. Schuler, Extension Agricultural Engineer, Biological Systems Engineering Department, University of Wisconsin-Madison.

Management Tips for Round Bale Hay Harvesting, Moving, and Storage 

Robert Grisso, Extension Engineer, Biological Systems Engineering, Virginia Tech

Ray Smith, Forage Specialist, Crop and Soil Environmental Sciences, Virginia Tech

John Cundiff, Professor, Biological Systems Engineering, Virginia Tech

Quantification of Mechanical Losses
Koegel, R. G., R. J. Straub and R. P. Walgenbach, University of Wisconsin, 1985. Transactions of the ASAE, 28(4)1047-1051.

Rain Damage to Forage During Hay and Silage Making
Mike Rankin and Dan Undersander, University of Wisconsin, 2000. Focus on Forage.Vol. 2: No. 4.

Leaf Loss and Drying Rate of Alfalfa as Affected by Conditioning Roll Type
Shinners, K. J., R. G. Koegel and R. J. Straub, University of Wisconsin,  1990. ASAE aper 901048. St. Joseph, MI, 14 pp.

Reducing the Drying Time of Hay and Silage in the Field

Harvesting high quality hay and hay silage has been a challenge in a number of hay growing regions because of the unpredictability of rainfall. Rain falling on hay that is laying down in the field causes a number of problems. Soluble nutrients are lost, reducing feeding value and fermentation potential. Wet hay may also undergo spontaneously combustion. Forages can be ensiled or baled at a wide range of moisture contents (Figure 1). Whether making silage, hay, or baleage, some field drying will be necessary.  A number of practices can reduce the amount of time that cut forages are exposed in the field.

Figure 1: Forage Harvesting Methods and Associated Field and Storage Losses

Adapted from Grass Silage Jerry Cherney & Debbie J.R. Cherney, Cornell University

Wide Swaths

Cutting implements that lay hay down in windrows that are 70% or more of the cutting width dramatically reduce drying time. The wide rows maximize the amount of area hay exposed to the sun and allow air to move underneath the swath. This maximizes the drying rate in Phase I (Figure 2) of the dry-down process. This is very important because the plants will continue to respire and use nutrients while the stomata (holes in the leaves) stay open. The outer 0.75 inch of the swath/windrow dries quickly, and having wide, shallow swaths essentially allows all of the forage to dry rapidly compared to a small percentage on the outside of a traditional deeper windrow.

Figure 2: Sequence of Drying Forages

From Drying Forage for Hay and Haylage, Dan Undersander, 
University of Wisconsin Forage Extension

Field experiments in the Midwest and Northeast have shown that alfalfa cut in the morning and laid down in wide rows dries down to about 65% moisture about 5-7 hours later and is ready to be chopped for silage that same day during good drying conditions (warm, windy, sunny day). Adjustments can usually be made to the mower to increase the swath width. If swath width cannot be increased to at least 70% of the cut width farmers can use a tedder immediately after cutting, weld metal bars or bolt metal deflectors (Figure 3) to the back of the mower to spread out the feed, or find a neighbor or custom operator who has the equipment to spread the forage out. Cutting with a simple sicklebar mower (without conditioning attachments) also lays the silage or hay out wide to allow for quick drying. 

Figure 3: Farmer Mower Modifications to Increase Swath Width

From Tom Kilcer's Advanced Ag Systems May 2010 Newsletter

From Tom Kilcer, Advanced Ag Systems

In the past there was a large concern about driving on windrows because of the risk of leaf loss. While this would be a concern on very dry hay, few leaves are lost when a wide swath is driven on during the initial drying stages (Phase I and Phase II, Figure 2) unless extremely wet and muddy field conditions exist at the time of harvest. No detectable difference in forage quality has been found in the areas driven over compared to the other parts of the swath.

Conditioning  

There are two types of conditioners available to farmers:  roller crimpers and flail impellers.

Roller crimpers are made out of rubber or steel. They are used to crush the stems of alfalfa to increase the dry down rate in Phases II and III (Figure 2). If alfalfa is being made into hay then it should be conditioned with a roller crimper. If the alfalfa is made into silage it does not need to be conditioned if laid down in a wide row. Narrow windrows (less than 70% cut width) should be conditioned whether the alfalfa is made into silage or hay if the windrows are not spread out soon after cutting. Before harvesting, the rollers must be properly adjusted in order to crush the stems. Check your machine's owner's manual or refer to Mower-conditioner Adjustments for Rapid Forage Drying in the Field for more information. Various crimper designs are available, but no consistent differences have been shown between the various designs in the dry down time.

Flail impellers are used primarily for grass hay or entangled forages. The deflector must be properly adjusted to ensure that the grass surfaces are cut by the flails. Impellers are not very effective tools to condition alfalfa.

Tedding, Raking, Inverting, & Merging

Raking and tedding are two of the most well known practices to increase the dry down rate of hay in the field. They can, however greatly increase the ash content and leaf loss of the hay if done improperly. Lower leaf loss occurs if the hay is tedded or raked between 40-65% moisture (i.e. with the morning dew on). If a farmer lays down a wide swath when making hay they could ted/rake the next morning, while a farmer with narrow windrows would typically have to wait an additional day or two to reach this moisture content. Tedders and rakes should also be adjusted to minimize the amount of ash (dirt) they pick up off the ground. Inverters and mergers are used to flip and merge swaths and windrows. Inverters tend to pick up less ash than rakes or tedders. Mergers are used before chopping or bailing to merge multiple windrows (swaths) into one bigger windrow. Some drying occurs when the windrows are flipped, but not as much as wide swathing or conditioning operations.

Desiccants

Dessiccants are drying agents that can be sprayed on forages which can reduce the time needed for hay to dry. They are most often applied at cutting. The most effective products have potassium or sodium-carbonate based solutions. These treatments are most effective on alfalfa cut in the summer months. The major drawback to using desiccants is the large volume of water required to apply the products to the hay.

Preservatives

Preservatives are applied at baling to ensure the quality of hay, often at a slightly higher moisture content (20-25%). When rain is coming, applying a preservative can allow baling at these higher moisture contents.  The most effective preservatives on the market are made from proprionic acid. Other organic acids (acetic acid, etc.) can work as well, but proprionic acid-based products are the most reliable. They are generally applied at 1-2% of hay weight.

Inoculants
Many products are available to inoculate silage and baleage. These products do not increase the drying rate of forages or make up for poor field handling, but can preserve or increase forage quality if applied correctly. Many products on the market have not been independently tested so farmers should take some time before the season to evaluate which of the available products have truly shown consistent results outside of company trials.  Most of the products contain at least one of three types of bacteria: homolactic, heterolactic, or propionibacteria. 

Homolactic bacteria ferment sugars to lactic acid which improves initial fermentation by quickly dropping pH. Enterococcus faecium and several Pediococci species have been shown to be effective in modifying initial fermentation. 

Heterolactic bacteria convert moderate amounts of lactic acid to acetic acid after initial fermentation and improve aerobic stability during feedout. Lactobacillus plantarum (once thought to be a homolactic bacterium) and Lactobacillus buchneri are the only heterolactic bacteria consistently shown to increase the aerobic stability of silage during feed out. 

Propionibacteria theoretically convert lactic acid to acetic and proprionic acids in the bunk, but currently no species or strains have been shown to actually increase aerobic stability in the field.  For a more in depth discussion of silage inoculants and situations in which to use them refer to, Help in Choosing an Effective Silage Inoculant.

Bottom Line

1. Drying forages occurs much more quickly in wide, thin swaths than thick, narrow windrows. Silage can be made the same day as cutting if the forage is spread wide. Inoculants can enhance, but not save silage

2. Hay and silage making often require using multiple management practices (wide swaths, conditioning, raking, tedding, desiccants, preservatives, inoculants, etc.) and a little bit of luck in the humid regions of the U.S. in order to make high quality hay and silage.

Disc Mowers vs Sicklebar Mowers

No difference in drying rate is noticeable between disc and sicklebar/cutterbar mowers. 

  

References:
Advanced Ag Systems May 2010 Newsletter

Tom Kilcer, Advanced Ag Systems, Kinderhook, New York

Drying Forage for Hay and Haylage

Dan Undersander, University of Wisconsin-Madison Forage Research and Extension

Effectiveness of Equipment to Speed Hay Drying

C. Alan Rotz, Agricultural Engineer USDA-ARS, Penn State University

Grass Silage 

Jerry Cherney & Debbie J.R. Cherney, Cornell University

Help in Choosing an Effective Silage Inoculant
Limin Kung, Jr, University of Delaware

Mower-conditioner Adjustments for Rapid Forage Drying in the Field
Ronald T. Schuler, Agricultural Engineer, Wisconsin Extension

Making and Storing Quality Hay

Jimmy C. Henning and Howell N. Wheaton, University of Missouri Extension

Wide Swathing for High Quality Forages

Jerry Cherney, Tom Kilcer, Debbie J.R. Cherney, Cornell University

The Value of Increasing Pasture Numbers

Historically pastures have been seen as low yielding land and little, if anything, was done to increase their productivity. In recent years management intensive rotational grazing has done much to change this perspective and high yielding, high quality pastures now form the backbone of many profitable livestock farms. This blog entry will describe one of the management practices that has greatly increased pasture yields--managing a larger number of pastures.

Increasing Harvest Efficiency

Farmers that practice rotational grazing manage many paddocks (small pastures 2-5 acres in size) instead of a smaller number of large pastures. This practice results in very large increases in harvest efficiency.  The traditional pasture typically had cows continuously grazing throughout the whole growing season. Under this system only 30% of the potentially available feed is harvested by the cows. However, as graziers add pastures, cow harvest efficiency greatly increases up to 75% of available feed when at least 24 pastures/paddocks are grazed in rotation. Figure 1 demonstrates this by using 5 tons DM of available feed per acre for a single growing season multiplied by the appropriate harvest efficiency as pasture numbers increase. Harvest efficiency data was taken from the USDA grazing stick. For more information about the USDA grazing stick see the instructional video and availability.

Figure 1: Increasing Pasture Number Increases Feed Grazed

Generally once a pasture is grazed, farmers wait 25-40 days before returning their cows to that pasture. This rest period allows enough regrowth in order for the grass and legume root carbohydrate reserves to be resupplied. Additionally rotational graziers don't graze their pastures until the soil is bare, but rather they tend to "take half and leave half" . Leaving at least 4 inches of grass is necessary in most cases to maintain desired  species in the pasture. Clipping the pastures once a year helps maintain an even stand without unpalatable clumps of dead plants. In many areas graziers will harvest a number of their pastures for hay or silage in the spring because often there is more feed than can be grazed. They then feed the spring harvests during the summer or winter in order to supplement or replace the pastures.

Increasing Feed Quality

Increasing pasture numbers not only increases the quantity of pasture that cows eat, but it also increases the quality of the pasture. In management intensive rotational grazing, grasses and legumes are grazed when they are in the vegetative growth stage. Pastures grazed at this time are more palatable, higher in protein, higher in fiber digestibility, higher in starch and sugar content, and lower in fiber content. Figure 2 outlines generally how forage quality declines with increasing plant maturity.  As pasture plants age they lose leaves and gain more stems resulting in lower forage quality.

Figure 2: Declining Forage Quality with Increasing Plant Maturity

From page 4 in Understanding Forage Quality

Grazing generally begins when the pastures are at least 8 to 12 inches tall. If pastures are grazed too soon in the spring cattle will often get diarrhea and will need supplemental fiber from low quality hay.  Having many pastures allows for staggered plant maturity across the farm. This allows cows to continuously graze high quality feed. Grass heading date determines how long grass will be in the high quality vegetative growth stage in the spring. Different grass species and different grass varieties have heading dates from a week to a month apart. By planting different grass species and/or varieties with different heading dates in separate pastures graziers can more effectively maintain pastures constantly in the vegetative growth stage. When using rotational grazing beef producers will generally move their animals every one or two days, while dairy farmers will move their animals to new pasture after every milking during the growing season. Maintaining high levels of pasture fertility, selecting proper plant species and varieties, building appropriate fences, supplying adequate water, sheltering animals from extreme weather conditions, and other factors are also necessary in order have a well managed, profitable rotational grazing farm.

Bottom Line

1. Dividing one large pasture into two dozen or more paddocks can double the amount of feed that cows will be able to graze over the course of growing season.

2. Having many pastures enables grazers to have the highest feeding quality through the growing season, because plants are constantly in the vegetative growth stage.

References
Understanding Forage Quality
Don Ball, Mike Collins, Garry Lacefield, Neal Martin, David Mertens, Ken Olson, Dan Putnam, Dan Undersander, and Mike Wolf

USDA Grazing Stick Availability
Debra Heleba, University of Vermont Extension

USDA Grazing Stick Instructional Video 

Sarah Flack, Sarah Flack Consulting & Amanda Gervais, University of Vermont Extension