• Introduction
• Soil Fertility
• Moisture
• Legume-Grass Mix
• Organic Fertilizer
• Economics
• Conclusions
• Highlights

Introduction

Note: this webpage has a greater focus on hay production for winter feed. Grazing management can also improve forage productivity over time and is another significant area of research.

Canada’s cow-calf sector is at a competitive disadvantage internationally because of a relatively higher per unit cost of forage ($/tonne) compared to other countries (source: agri benchmark study 2013).  Hay yields in Canada have been steady over the past 60 years, while annual crops have had significant yield improvements.

By increasing forage production on grazing land, higher stocking rates can be used and animal performance may improve. Increasing production on hay land reduces the cost of unit of production, which means reduced winter feed costs per cow.

Over the long term, improving forage productivity is crucial for future competitiveness of the cattle industry. While it may be more profitable for a producer to obtain additional hay or pasture from another source in the short term (i.e. buying or renting more land, or purchasing hay), reducing the per unit cost of production is necessary over the long term.  Current competition for land from other crops and urban development is putting further pressure on the forage industry to increase margins or risk being converted into a more profitable commodity.

Moisture and soil fertility are essential factors that affect forage productivity and management strategies. 

Soil Fertility

Nutrient deficiency in soil is an important factor limiting forage productivity in Canada. Forages are generally grown on marginal land and their production can be increased significantly with fertilization (Malhi et al. 2004). Forages remove more nutrients from the soil than other crops because more biomass is harvested. However, current application of fertilizer on forages in Canada is minimal; it is estimated that only 25% of the improved pasture and hay is fertilized and only 15% of alfalfa hay fields is fertilized. Given the level of nutrient removal by forages and these low levels of fertilization, it is little wonder that forage stands are only maintained for 3-5 years in high moisture regions of western Canada and 6-9 years in semi-arid regions.

Low forage yield is the most commonly cited reason for terminating a stand. Rather than terminating the stand through tillage and reseeding, rejuvenation by fertilization may be the most economic and practical method to improve production and quality in some situations (Lardner et al. 2002).¹ Optimum levels of forage production require adequate levels of soil nitrogen (N), phosphorus (P), potassium (K), and sulphur (S) as well as micronutrients. Soil testing to determine what nutrients are limiting is recommended.

Moisture

Uncertainty about moisture conditions discourages fertilizer use as dry conditions can result in volatilization (i.e. evaporation of N) and a limited production response, while wet conditions can result in runoff causing environmental concerns. Studies show that forage response to fertilizer application is directly related to the amount and distribution of growing season precipitation and the ability of the soil to store water. This has resulted in wide variability in yield responses to recommended fertilizer rates.

A 10-year study in Manitoba shows adding fertilizer increased productivity of grass pastures.² Fertilizer was applied to full soil test recommendation, however the target forage yield was often not achieved due to moisture limitations. Soil can have a significant impact, as very low water holding capacity (such as that found on sandy loam soil) limits moisture availability severely reducing plant growth, forage quality, stocking rate, and animal gain as well as reducing the benefit of fertilizer.

Malhi (2004) showed that the timeliness of rainfall during the growing season can significantly affect productivity. A 19 year study on thin Black Chernozemic soil at Crossfield, Alberta had lower dry matter yield and limited response to applied N in many years. This appeared to be at least partially associated with a lack of timely rainfall.³

Legume-Grass Mix

Grasses are often seeded in mixture with legume. Properly inoculated alfalfa can fix large amounts of N from the atmosphere and consequently, additional N is not normally required to obtain increases in dry matter yield and protein content. While grass:alfalfa mixes may not require nitrogen, other nutrients such as P and K can influence stand productivity and longevity of the stand. Responses are affected by soil and climatic conditions.

Research has recommended that due to the high variability in response to fertilizer on tame grass, the most cost-effective way to increase forage yields is to add alfalfa to the mix as it increases productivity without annual application costs.⁴ This has been widely adopted across the prairies over the past decade as management experience and products have reduced death losses from alfalfa related bloat. Over the past 30 years, the area of alfalfa and alfalfa mixtures as a percentage of total tame hay production steadily increased from 44% in 1971 to 66% in 2011.

Research by Kopp et al. (2003)⁵ found that on sandy soils in Manitoba, incorporation of alfalfa into grass pastures improved carrying capacity by 28% compared to meadow bromegrass alone, while incorporating alfalfa with fertilization (N,P,K,S) improved carrying capacity by 57%. The alfalfa with fertilization treatment had significant financial risk as it was only a cost-effective strategy when precipitation was sufficient; the alfalfa without fertilization treatment was always a cost-effective approach as it did not entail financial risk.

Managing Legumes

Maintaining a legume stand is one of the challenges in a grass-legume production system. A study in Swift Current, Saskatchewan⁶ showed that alfalfa and sainfoin plant counts both dropped by 50% over the four year grazing trial. Kopp et al. (2003) also found that the alfalfa percentage in the mix declined from 75.4 - 84.1% to 32.5 - 40.3% over a four year period.

These management techniques can help to maintain legumes in a stand:

• In the spring, wait until alfalfa is three to four inches tall before grazing. After the spring grazing period ends, allow the alfalfa to regrow for about 25 to 40 days before cutting for hay.
• Allow plants rest during September and October, or control grazing to maintain at least 6 to 8 inches of standing alfalfa at all times.
• Avoid reducing stubble height to less than 2 or 3 inches in late fall to help protect alfalfa from winter damage.
• Allow plants to grow without cutting or grazing for at least four to six weeks prior to the first killing frost.

The risk of bloat is another challenge of grazing alfalfa. To reduce the risk:

• Do not move cattle onto new pasture when it’s wet with heavy dew, rainfall or irrigation water. Grazing alfalfa when it is wet increases the possibility of bloat, so it’s better to move animals to a new pasture in the afternoon rather than in the morning.
• Never allow animals to stand hungry before turning them to an alfalfa pasture, as it can lead to overconsumption of fresh alfalfa.
• Wait until alfalfa is in full bloom to graze. Bloat risk is highest when alfalfa is in vegetative to early bloom stages of growth. As alfalfa enters into the full bloom or post bloom stages, soluble protein levels decrease, plant cell walls thicken, lignin content increases, and the rate of digestion of alfalfa in the rumen decreases.
• Do not graze alfalfa for three days to two weeks following a killing frost. Frost may increase the incidence of bloat by rupturing plant cell walls, leading to a high initial rate of digestion. Delay grazing alfalfa until the stands dries. The time required to dehydrate varies by location and weather.

More information about alfalfa management and grazing strategies:

Legume Grazing
ForageBeef.ca
http://www1.foragebeef.ca/$foragebeef/frgebeef.nsf/all/frg38

Grazing Alfalfa
Volesky, Jerry D., and Bruce Anderson - Historical Materials from University of Nebraska-Lincoln Extension (1999)
http://www.ianrpubs.unl.edu/live/g2030/build/g2030.pdf

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Organic Fertilizer

In addition to chemical fertilizer or composted manure, in-field winter feeding systems are another fertilization strategy to consider. Bale grazing can be a cost-effective winter feeding option that improves forage productivity. Bale grazing not only deposits nutrients through raw manure, bale waste will also make nutrients available to plants (once soil microbes are done feeding). Bale grazing sites must be rotated to prevent excessive nutrient deposits which can lead to problems.

An experiment⁷ conducted near Biggar, Saskatchewan on a smooth bromegrass-alfalfa field during 2009-2011 showed that bale grazing has positive impacts on soil and plant nutrients (higher protein in forage). Forage yield for the two year period following bale grazing was higher than an ungrazed site, then dropped back to historic levels. Other experiments conducted in the Peace Region of Alberta⁸ and in Clearwater, Manitoba⁹ also showed improvement in soil fertility, forage yield and quality following bale grazing.

Bale Grazing

When bale grazing, producers should consider animal density and bale placement to ensure the optimum deposit rate of nutrients from manure, urine and leftover material and avoid excessive nutrient buildup. Bale grazing should also be avoided on environmentally sensitive sites such as on high water tables, on sandy soil, or in riparian zones where runoff will flow directly into surface water.

For more information about bale grazing management and cost/benefit analysis:

Extended Grazing
BeefResearch.ca
http://www.beefresearch.ca/research-topic.cfm/extended-grazing-45

Bale Grazing Calculator
Saskatchewan Ministry of Agriculture
http://www.agriculture.gov.sk.ca/Default.aspx?DN=56c8e6df-754e-4897-9000-638fea280172

Research has indicated that fertilization can bring the productivity of a stand back to its original level without the expense of re-seeding. However, even when fertilizer is applied at recommended rates, the target yields are often not achieved, making it a risky proposition. The goal of fertilizing is to decrease the per unit cost of production. Higher yields do not necessarily translate into lower costs or increased profits. Only when the value of the additional production surpasses the cost of application does it reduce the per unit cost of production and increase margins. The profitability of fertilizing forage crops is highly variable and depends on the cost of the fertilizer and hay prices. As these factors change, so will the feasibility of fertilizing. Given the high fertilizer prices and poor margins in the cattle industry in recent years, many producers are hesitant to increase input costs.

Forage fertilization must compete economically with alternative sources such as rented or purchased pasture, purchasing hay or incorporating alfalfa in the seeding mix. However, buying more land leaves the per unit cost of production the same and therefore does not add to one’s margin or long term sustainability.  As more marginal land is converted to annual crops and land prices increase, the productivity on land becomes more critical. As land prices increase, greater investments into that land to intensify production and increase revenues from the same land base by becoming more efficient with existing resources are more easily justified. Knowing the per unit cost of production on hay ($/tonne) is key to determining the price at which buying hay is the economical choice.

Numerous researchers in the past forty years have studied the effectiveness of fertilization on forage production, however the variability in response means a well-developed yield response model is not available.  Without standard yield responses, economic analyses in this area are lagging behind annual crops. Within the limited amount of economic analyses, there is no strong evidence for economic benefit of fertilizing forage crops, especially on grass-legume mixtures.

Learn more about the economics and see simulations of the economic impacts of fertilization and the optimum fertilization rates under different price scenarios in this fact sheet: Historical review of forage fertilization research (http://www.beefresearch.ca/factsheet.cfm/historical-review-of-fertilizing-forages-research-169)

Forage response to fertilizer as a management strategy vary widely based on the stand composition, soil fertility, and moisture conditions throughout the growing season with timing of moisture being more important than quantity. Due to this wide variety, longer term studies have provided different results than short term studies. 

The goal of fertilizing is to decrease the per unit cost of producing forage. Higher yields do not necessarily translate into lower costs or increased profits due to fertilizer and application costs. Optimal fertilizer costs are affected by hay prices, fertilizer prices and the base land cost. As hay prices increase, the willingness to pay for fertilizer should increase. As base land costs increase, the willingness to pay for fertilizer should increase. Therefore, it is important for producers to know their cost of production and adjust their strategy based on the current price situation.

In addition to chemical fertilizer, forage productivity could also be improved by inoculating legumes or using in-field winter feeding systems. While these strategies bare less financial risk as they are less affected by weather and input prices, good management techniques are required to ensure high yields and environmental sustainability.

Highlights

• Hay yields in Canada have been steady over the past 60 years; annual crops have had significant yield improvements.
• Nutrient deficiency in soil is one of the important factors limiting forage productivity in Canada.
• Yield response to fertilizer is unpredictable.
• The profitability of fertilizing forage crops is highly variable. Its feasibility depends on the cost of fertilizer, hay prices and land value.
• A cost effective way to increase forage yield is to add legume (alfalfa) to the mix. Management experience and use of available products prevent death losses from alfalfa related bloat.
• Bale grazing systems have the potential to improve soil nutrient levels, hay quality and forage yield.
• Research on forage varieties with higher yields and longer stand life is needed.

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