May 3, 1999

Forage Selected Articles No-till good fit for alfalfa Bunker walls worth the bucks Shedding light on your shadow yield Drought-proofing pasture

No-till good fit for alfalfa

Contrary to what some may think, corn residues should not be detrimental for no-till planted alfalfa

BY DAVE LOCKMAN

As we modify our farming practices and change the equipment we own, it's important to expand our knowledge on various farming techniques. Erosion is a growing concern, leading more farmers to make the transition to no-till equipment wherever the combination of soil structure and climate make it possible.

No-till is more energy efficient than conventional till and helps reduce erosion on light soils or hilly sites.

No-till alfalfa is well suited to most fields normally used for growing alfalfa. It excludes fields with drainage limitations or low fertility that may be difficult to correct. However, these fields are not usually used for alfalfa - at least not used successfully. There are several factors to consider when adopting no-till: the sequence in your crop rotation, weed control, seeding requirements and pest concerns.

Contrary to what some may think, the quantity of residues should not be detrimental for alfalfas planted no-till in the spring. Actually, heavier residues, such as corn residues, will provide protection to the growing seedlings and offer adequate ground cover to limit erosion. The type of residues will have no effect as long as the material is dead. No-till alfalfa is well adapted to be planted into corn, soys and annual grains.

The most problematic crop to introduce alfalfa to without tilling is sod (alfalfa stand or pasture). Perennial species such as grasses will offer serious competition; alfalfa's natural pests and diseases might be present; and allelopaths and/or decaying vegetation can inhibit seedling growth and development.

Due to these factors, killing the sod becomes a very important part of the no-till operation. The ideal scenario for a spring planting would be to kill the sod or old hay field with glyphosate plus 2,4-D or dicamba in the fall. This can also be repeated in the spring pre-plant to increase weed control. Doing so will also allow for an earlier spring planting. As well, the killed vegetation will have time to decay, limiting allelopathic effects on the growing alfalfa seedlings while also providing a less favourable habitat for pests.

If the sod cannot be controlled with glyphosate until the spring, delay planting for at least three weeks until the sod has turned brown and begun decaying. A good rain will allow the allelopathic effects to dissipate. The three weeks rule also applies if 2,4-D is used. This will allow the 2,4-D to decompose since alfalfa is not tolerant to it without the safener (the safener is the "B" in 2,4-DB).

Maintaining weed control in the no-till field can be a challenge. Mowing can be very effective in controlling annual and perennial grasses. However, mowing does not apply to quackgrass as it grows mostly in the fall. Quackgrass must be controlled prior to seeding because it becomes nearly impossible to control once it is established into the stand. Adding perennial forage grasses such as smooth brome, timothy, orchard grass or tall fescue can be effective in keeping weeds out by providing cover in between alfalfa plants.

If all else fails, spot spraying the field with glyphosate or flaming the obnoxious perennials might be a last resort alternative. Mechanical weed control such as harrowing or rotary hoes are not recommended. The crown may be damaged by such activities therefore risking infection by disease organisms.

Although nematodes are not a major pest for alfalfa in most parts of Ontario, their presence may be a limiting factor in certain fields. Using non-host crops such as beans or grains can reduce the risk of this occurring. Another possible pest is the potato leafhopper. Using a potato leafhopper resistant variety would be the wisest choice in this situation. Otherwise an insecticide program might be necessary.

An adequate soil pH (6 or above) is vital for alfalfa establishment. Enough lime must be applied on the surface to correct the pH in the first 2.5 to five centimetres of soil.

Proper seeding equipment is essential for success. A good no-till drill will cut through the residues easily and will offer accurate seed placement. Precision in seed placement is key. The alfalfa seed must be no deeper than two centimetres on lighter soils or one centimetre on clay loam soils. Following seed placement, the soil above the seed must be compacted. This will allow for a more even emergence.

The most important feature on a no-till seeder is a press wheel to ensure proper soil-seed contact and a precise seed depth control mechanism. Without these features uneven emergence and poor germination become increasing risks.
Dave Lockman is an agronomist with Pickseed Canada Inc.

© copyright 1999 Agricultural Publishing Company Limited.

Bunker walls worth the bucks

Cutting bunker silo construction costs by building a wall-less pit is a false economy, says Pioneer Hi-Bred dairy specialist Kurt Ruppel. He says construction savings are eaten up because feed has greater exposure to air and suffers increased dry matter losses.

Poured concrete walls are five times as expensive to build as poured floors. Some cost-minded dairy producers are trying to cut their capital investment in storage facilities by leaving the walls off. They are constructing floors tilted at a 15- to 20- degree angle to contain the stored feed and eliminate the need for forms during construction.

A walled pit that stores 7,500 tonnes of feed at 33 per cent dry matter costs US$64,500. A pit of the same capacity with tilted floors costs US$36,500. Amortized over the silo's expected life of 10 years, the wall-less pit saved the farmer US$2,800 a year.

But Ruppel warns that the wall-less silo has more silage within three feet of the surface, about 23 per cent of the pit capacity, compared to 15 per cent with a walled silo. There is solid research to show that between 15 and 43 per cent of silage in the surface three feet is lost, depending on whether it is covered or uncovered.

Using a mid-range of 33 per cent to calculate the possible losses, 107 tonnes of silage will disappear from the walled structure and 162 tonnes from the slanted wall pit. At US$30 a tonne, silage worth US$4,860 would be lost to save US$2,800 in construction costs. - Don Stoneman

© copyright 1999 Agricultural Publishing Company Limited.


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Shedding light on your shadow yield

Farmers planning expansion should not overlook increased forage needs

BY DON STONEMAN

Farmers who got caught short of forage last year may want to think about the "shadow yield" of their farm.

Shadow yield is a new term to farmers in this province, but it is catching on in New York. The shadow yield is the amount of the expected crop yield that can be lost to bad weather before a farm is put in financial jeopardy, says Tom Kilcer, Cornell University extension specialist.

Estimating shadow yield becomes part of a risk management plan. It is especially important to expanding farms. Too often, dairy farmers fail to plan adequately for expansion, says Kilcer.

Absorbed in the details of building the structures, farmers barely nod at their increased needs for forage. After the builder leaves the income falls short of projections.

When forage planning is inadequate, all feed must be fed to the cows, regardless of its quality. With poorer feed, potential milk yield is compromised. More grain is fed to compensate, and sub clinical acidosis results, eroding production even further. In some cases undersized harvest systems that fit the old operation wear out under the increased use and must be replaced, at a cost that wasn't taken into consideration during the initial expansion.

Typically, farmers facing bad weather must pay twice for their forage - once by planting, growing and harvesting a crop that fails to meet expectations, and again by buying forage to fill their needs.

Kilcer says farmers should take their current potential to produce feed into account before they plan to grow. Most small farms, in New York at least, don't really know how many acres they have available to crop, and operators may be surprised at the amount of land that is out of operation. He says a key to consider before any expansion is how much feed a farm should grow.

An imbalance in the feed storage system can ruin feed. Some farmers switching to bunkers from tower silos and employing custom operators produce unstable, low-nutrient silage because they weren't able to pack the bunker fast enough.

Smart farmers deliberately over-store feeds, squirreling away as much as a year's surplus to make up for a bad harvest season.

A full season's feed supply as a back-up is unnecessary, but 25 per cent seems like a good number, Kilcer says. Another 25 per cent of needs can be covered by switching to a minimum forage diet.

Any carryover must be stored carefully, Kilcer cautions, so that it isn't mixed with feed being stored from a new season's harvest. Properly sited baleage or agbag storage is one solution.

Farmers should use caution if they are going to put haylage this spring into a silo that will be used to store corn silage in the fall. It must all be fed out before the corn silage season starts.

Mixing forages in a bottom-unloading silo is a nutritionist's nightmare, Kilcer says. It's difficult, if not impossible, for milking cows to reach their potential if the ration changes constantly.

Another nightmare is "launching pad" bunker silos, where the silage is piled higher at one end than at the other. Adequate packing is difficult, so dry matter losses are excessive. Indirect losses include feeding poor nutrient silage, increased grain costs and potential herd health problems because of mycotoxins. The higher end has nearly double the face to feed than the lower end. Because most farms start feeding at the lower end the high face gets fed during warm weather the following spring and summer, increasing feed wastage.
Dave Lockman is an agronomist with Pickseed Canada Inc.

© copyright 1999 Agricultural Publishing Company Limited.


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Drought-proofing pasture

By DON STONEMAN

Farmers need to build some flexibility into their pasturing systems to be better able to cope with drought, says University of Guelph professor Ann Clarke.

They need to avoid the predicament of graziers who last year ran out of grass early and had to buy hay as prices skyrocketed.

Clarke expects that the variable weather patterns of the last couple of seasons will be repeated. She says farmers should be prepared and either buy hay early, under-stock their swards on purpose, or stockpile pasture.

One solution is to stock pastures to get 400 to 500 pounds of gain per acre. "Aim for a realistic goal," she says. You don't need to stock for the worst year; stock for a middle year, she advises.

If farmers deliberately under-stock, then the amount of hay that they harvest every year will vary season to season.

In a good year the excess can be harvested as hay, or stockers can be brought in to graze the extra forage.

Another technique is summer stockpiling. Clarke advises graziers to run their cattle through all their paddocks for two cycles, then leave some paddocks to grow. The sward will have finished its reproductive stage and will grow leafy rather than stemmy, she says, maintaining a relatively high feed value.

This growth should be allowed to accumulate. Rested fields should be brought back into the paddock rotation in August when the rest of the pasture dries off. The fields that were held back will be good through October.

Clarke says this technique was tested last year at the North Fork pasture farm at Guelph's Elora Research station. Different levels of fertilizer were added to the fields. Unfertilized fields yielded about 500 kg of dry matter per acre. She found that 60 kg of actual N added per acre boosted the yield by 60 per cent over no fertilizer, but 90 kg boosted yields by more than 100 per cent. The fertilizer was applied June 11 and the forage was harvested July 20.

Choose your fields carefully for best results, she says. This practice seems to work best on lower-lying fields and heavier soils that retain moisture.

Clarke isn't sure that the yield boost was economical. The only way to determine the economics of this practice is to compare it to the current price of hay purchased to feed the cattle.

In droughty weather, farmers have to be more conscious of risk management, Clarke says. They have to make sure that they aren't damaging their sward's ability to survive the winter. They should rate their paddocks weekly on a scale of 1 to 10, with "1 being just grazed," to see how they are progressing in the adverse weather.

© copyright 1999 Agricultural Publishing Company Limited.


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