In zero tillage systems, it is important to have good fertilizer placement without sacrificing seed placement. Seeds need to be placed where they will germinate and emerge quickly, and undamaged from fertilizers or herbicides. Fertilizer management and seed placement may change under zero tillage. This component outlines important options in achieving both good seed and fertilizer placement.

Zero till offers a better seedbed for quicker emergence in a moister soil. This advantage needs to be nurtured by good fertilizer management. Extra N fertilizer may be needed to fully optimize the no-till moisture benefit. However, N must be applied away from the seed using one of many techniques discussed.

Uniform chaff and straw spreading is essential in all no-till farming operations. If crop residue is not spread uniformly, the next crop to be planted will have problems. Seeding through thick residue will be hard. Most disc openers will not cut through residues very well and hoe openers or air seeder shanks will cause bunching of the residue as it moves through the soil. Both of these situations will cause problems for the emerging seedling due to the thickness of the matt.

SEED PLACEMENT

Good no-till crops begin with proper seed placement. In fact, in terms of return on your zero till investment, good seed placement is extremely important. All the crop inputs in the world cannot resurrect a crop that is seeded too deep.

The goal of seeding is quick establishment of a vigorous crop that competes well with weeds. Ensuring good seed-soil contact will help achieve this. Zero tilled seedbeds are more firm and moist than tilled seedbeds. This seedbed advantage of the zero till system should be maximized.

Good seed placement gives the seed what it needs; moisture, oxygen and adequate heat. Crop establishment in zero tillage is effected by crop residue, seeding date and depth and fertilizer placement.

CROP RESIDUE

Several no-till manuals explain the absolute need for uniform spreading of straw and chaff. Whether using traditional harvesting equipment or the recently introduced stripper-header, management of residue at harvest-time is a key to no-till farming. Proper residue management allows seeding equipment to operate more efficiently and helps to provide seed-soil contact.

Chaff collection will reduce residue problems and improve zero till crop establishment. In cereals, chaff typically constitutes 13-35% of the residue.1

Equally important for good seed placement is rotating high and low residue crops. In our cool northern climate, crop residues decompose slowly. Successive high residue cereal crops may accumulate excess surface residue no matter how well it is chopped and spread.

For optimum seed placement, stubble height should match the residue clearance and soil penetrating ability of the seed opener. Stubble higher than 25 cm (10") is best for low disturbance disc seed openers. Shorter stubbles are better for seeding with hoes or sweeps.

Compounds released by residue-feeding microbes can stop germination and seedling development. This process, called allelopathy, is not well understood.

SEEDING DATE

In most cases on the northern plains, zero tilled crops can be sown on the same day as conventionally sown crops. Usually, the zero tilled fields are slightly cooler. However, zero till places the seeds nearer the soil surface where it is as warm (Figure 1) as the deeper, conventionally-sown seed is placed. With zero till, the soil is also more firm and moist than conventional tilled seedbeds. On similar seeding dates, zero till gives better crop establishment. In fact, many zero till fields can be sown earlier than conventional till fields. This is because zero till soils have better structure and more residue cover which provides improved traffic-ability.

Early zero tillers found that hoe-type seed openers gave better crop emergence in cool soils compared to disc openers. The hoe openers reduced hairpinning, giving better seed-soil contact and faster warming in the seed zone. This knowledge still pays off today. With suitable residue management, zero tilled fields can be seeded early for maximum yield potential.

SEEDING DEPTH

Zero tillers can and should seed shallow. Seeding depths common in tilled seedbeds are not appropriate for no-till seeding. Sowing at 7.5 cm (3") depth in no-till instead of 3.7 cm (1.5") can be a disaster (Figure 2).3 Increasing seeding depth from 2.5 to 7.5 cm (1 to 3") can delay emergence by three days and reduce yields.Seeding depth with no-till should be 2.5-5.0 cm (1-2") as this promotes quick emergence and allows the crop to get a head start on weeds.

Cereal crops sown too deep have uneven emergence, poor root growth and fewer tillers. Winter wheat sown deeper than 2.5 cm (1") will have poor winter survival because of delayed emergence.4 Semi-dwarf wheats have short coleoptiles which makes it hard for them to emerge from deeper than 5 cm (2").

Small seed crops like canola, flax and sorghum are very slow to emerge if sown deeper than 2.5 cm (1"). Deep seeding also reduces plant vigour, making the plant more susceptible to diseases such as root rot (Figure 3).5

SEEDERS AND PLACEMENT

Many no-till seed openers are now available (Figure 4).6 Most recent developments focus on simultaneous seeding and fertilizing.

Opener performance varies with soil and environment. No one opener is superior in all conditions. But, most no-till openers are capable of good seed placement if residue is managed properly.

The strength of hoe openers is that they can clear residue from the seed row, allowing heat from sunlight to be absorbed into the seed row. At night, this heat is released, protecting seedlings from frost. In warmer, more arid climates, seed row warming is not so critical. In fact, less soil disturbance conserves soil moisture. In cooler, more humid climates, seed zone warming is more important. But there are trade-offs.

Increasing soil disturbance increases fuel use and weed germination. For these reasons, seed row disturbance is best kept to a narrow band, immediately around the seed.

Disc openers pull more easily and give more precise depth control than hoe openers. They also disturb less soil and therefore stimulate fewer weeds. However, they may hairpin residue into the seed row and require more maintenance than hoe openers.

A newer approach to seeding is to install residue manager wheels or row cleaners in front of the seed opener (Figure 5). These wheels work like a hay rake to clear residue from the path of the opener. This reduces hairpinning with discs, and contributes to seedrow warming with little or no soil disturbance.

Figure 5: Resdidue manager wheels clear residue from the path of the opener and reduce 'hairpinning', particularly in cereal stubble.

Both disc and hoe openers are available on air seeders. Because of their efficiency, air seeders are now common. Most air seeders have shank-mounted openers. Depth control is by a rigid frame linking load carrying wheels in front with press wheels in the rear. Depth control is adequate but can be a bit uneven in rolling terrain due to the distance between the front and rear wheels (Figure 6).6 On some air seeders, depth can be controlled on individual openers by adjusting a press wheel mounted on the shank of each opener. Having press wheels attached in this way will reduce trash clearance.

Depth control on single disc seeders is by a gauge wheel mounted on the side of the disc, or by a press wheel fastened to the framework of the disc (Figure 7).6 Generally, disc openers with gauge wheels offer more precise depth control.

Press wheels

Press wheels and on-row packing ensure the seed is in contact with moist soil for quick germination. On-row packing also compresses the soil above the seed, reducing seeding depth. For these reasons, on-row packing greatly increases crop emergence and establishment7 (Figure 8) and is almost a necessity in the northern plains.

Both shank-mounted openers and disc openers use press wheels, but in different ways. There is debate over which system is best. On most seeders, the press wheels set seeding depth and perform on-row packing.

The most appropriate packing pressure for press wheels under a range of conditions is probably 22-45 kg (50-100 lbs) of down pressure on each packer wheel.8 Somewhat less pressure is needed in wet soil; more pressure is needed in dry soil conditions. Because the press wheels carry part of the weight of the machine, packing pressure may be too high in very wet soils. Crusting of the seed row may occur and delay crop emergence.

Most airdrills sold today have packing pressures of about 68 kg (150 lbs) /wheel with one or two approaching 90 kg (200 lbs)/wheel. Packing systems mounted to the back of conventional airseeders have different settings but exert a maximum of about 26 kg (60 lbs)/wheel (20 cm (8") spacing). Shank mounted packers are also adjustable, but can be set at higher pressure than the mounted gang packers.

Row spacings and press wheel width will change the packing pressure of each wheel. Even though machines with wider row spacing are generally lighter, there is still proportionally more weight to bear by each wheel. This may not make a big difference to airdrills, but it improves the rear mounted packers. Here's one manufacturer's example:

• 8" spacing - max 60 lbs/wheel (20 cm spacing - 26 kg/wheel)
• 10" spacing - max 75 lbs/wheel (25 cm spacing - 32 kg/wheel)
• 12" spacing - max 90 lbs/wheel (30 cm spacing - 39 kg/wheel)

Wet soil can cling to press wheels and upset seed placement. A lightly loaded, flat-surfaced, steel, press wheel will pick up more soil and residue than a narrow rubber wheel.

On single disc drills with side-wheel depth control, adjustable pressure press wheels follow immediately behind the disc, setting the seed in moist soil. They do not support the seeder. Instead of a dense, highly packed ribbon of soil over the seed, the seed row is covered by loose soil by a second low pressure closing wheel. Loose soil over the seed allows easier plant emergence.

Most commercially available zero till drills do not always adequately space large seeds such as corn and sunflowers planted at low rates. If these crops are included in the rotation, a zero till row crop planter will do a much better job of seed placement.

Seeding tools which allow optimal seed and fertilizer placement in a range of crops are still needed. Hopefully, farmers and manufacturers will continue to experiment with new concepts in seeding. If made affordable, precision planting systems used in row crop production would improve seeding for zero tillers in the northern plains.

"I'd say for fertilizer placement be flexible; for seed placement be absolutely rigid - get the seed where it needs to be."

Ron Bell, Birtle, Manitoba

Straw Management and Harvesting Equipment

The stripper header for harvesting small grains will allow you to harvest 50-60% more acres per hour than straight cut headers. This is due to much faster travel speeds of 8-10 km/hr (5-5.5 mph). Faster speeds are possible as very little straw is put through the combine. Less straw inflow increases harvester efficiency, as very little additional threshing of heads is needed and separation is easy as little straw is inside the combine.

Stripper headers are also excellent for picking up lodged grain, and the straw does not require spreading over the field as it stays in its original position. Seeding the next crop into tall standing stubble has been done successfully with disc drills. If an air seeder is being used, a set of coulters mounted on the front of the seeder has proven successful for direct or no-till seeding.

Vern Hofman

Extension Agric. Engineer, Fargo, North Dakota

FERTILIZER

Crop nutrition is foremost on the minds of no-till farmers. Successful zero tillers are constantly experimenting with new equipment and fertilizer products to achieve better returns. What has developed is a sense that seeding and feeding the crop go hand-in-hand. Each must be optimized to make the system work.

Achieving the high yield possible with zero till requires an aggressive fertility program. Current fertilizer recommendations are usually based on conventionally tilled systems. However, zero tillage has more yield potential and, therefore, may require more fertilizer than conventionally tilled crops.

N FORMS AND LOSSES

Nitrogen is our most common yield limiting nutrient. Its sources are the natural breakdown of soil organic matter, N fixation by legumes, and manure and synthetic fertilizer. All forms are used in zero tilled systems.

ORGANIC MATTER

In general, the rate of turnover of N from crop residues is slower in zero till than in conventional till, particularly in the first 3-5 years. It is usually recommended that 10-20% more N be applied in this period. After about five years, a new equilibrium of N release is reached when additional inputs are no longer needed.

Growing legumes in the rotation, with proper inoculation and good management of the residue, will improve the N supplying power of the system. Legume residues release N more quickly than non-legumes. The amount and type of legume also affects the rate of N breakdown and subsequent fertilizer needs. Annual legumes release N more quickly than perennial or biennial legumes.

Legume breakdown benefits are equal in zero and conventionally tilled soils. But when it comes to atmospheric N fixation, recent studies with peas and lentils show that more N is fixed in zero till versus tilled soils (Table 1).9

In a Saskatchewan study, the average yield of spring wheat in a pea-wheat rotation was 986 kg/ha (15 bu/acre) greater than in a wheat-wheat rotation.10 In addition, the protein content of the wheat seed in the pea-wheat rotation, was 15.4% compared to 13.9% in the wheat-wheat rotation. Decomposing crop residues contributed more N to building grain protein in the pea-wheat rotation than in the wheat-wheat rotation. Most of the yield benefit probably came from disease control as only 6% of the N in the pea-wheat rotation came from the pea residue.

Legumes provide more benefits to following crops than just N. These benefits are not well understood, but include less root disease and better soil structure. Legumes also allow subsequent crops to use more nutrients, perhaps due to increased root growth. Yield increases from having legumes in the rotations require that other nutrients be monitored so they do not limit yield.

"A good fertilizer program is important for many reasons. It is as important to minimizing disease problems as any other management strategy. If you have a crop under stress from nutrient deficiency, it will be susceptible to diseases. You need a good program of fertility."

Ardell Halvorson, USDA-ARS, Mandan, North Dakota

MANURE IN NO-TILL SYSTEMS

Information on the use of manure in zero till systems is limited. However, manure should be considered as a soil-building nutrient rather than a waste product.

Applying 25 t/ha/year (10 t/acre) of cattle manure probably is not a problem to zero till seeding, and tillage is not needed to give a yield response from the manure. Fresh or composted manure gives similar yield responses.

Manure spreading will put some viable weed seeds back on the field. Weeds with hard seed coats, like red root pigweed and lambs-quarters, are not affected by animal rumens. In fact, the rumen may break dormancy. Grassy weeds without seed coats, do not usually survive the rumen. Composting manure will also reduce weed seed viability.

Manure from swine and dairy operations can be separated into liquid and solid portions. The liquid could be dribble-banded onto standing forage, or even annual zero tilled crops.

SYNTHETIC FERTILIZER

Fertilizer N can be applied as urea or ammonium nitrate in granular form, or as a blend of these in liquid form. Anhydrous ammonia is also used extensively. In the soil, moisture allows the enzyme urease to convert urea to ammonium. Microorganisms then convert the ammonium to plant-available nitrate.

All forms of N, from organic matter and from applied fertilizer, can be lost if crop rotation intensity is not adequate. Nitrogen can be lost as a gas, leached below the root zone or tied up by soil microbes. In some cases, N leached below the root zone pollutes ground-water. Fortunately, since soil erosion rarely occurs in no-till, contamination of surface water is avoided.

Losses of applied N fertilizers are costly for farmers. Different application methods, formulations and soil conditions affect these losses. For example, urea left on the soil surface is partly lost when urease in the crop residue converts the urea to ammonia gas. Consequently, surface application of urea is not recommended for zero till in the northern plains.

Nitrate is subject to leaching because it is easily carried in the soil water. Any applications of nitrate should occur close to when the crop will use it. Similarly, applications of urea or ammonia fertilizers, which are converted into nitrate in the soil, should occur under conditions that do not favour subsequent N losses.

FERTILIZER PLACEMENT

Good fertilizer placement is critical for economic yields. It can also prevent losses of nutrients to the ground water and atmosphere. But what constitutes the best fertilizer placement depends on crop rotation, equipment, labour and financial resources. However, seed placement should never be sacrificed for better fertilizer placement.

Crops can take up more N, P and K when the nutrients are banded, although the reasons for this vary. Losses of fertilizer are reduced because banding decreases fertilizer exposure to the soil environment and reduces its rate of conversion to a plant available form. This plant available form can be lost by leaching, or by turning into gas and escaping into the atmosphere.

PRE-PLANT BANDING

Banding fertilizer in a separate operation does not run against the philosophy of zero till. Banding can be done in the spring or the fall and the seeding operation can then concentrate on one thing - good seed placement. Some producers can use the same equipment for seeding and banding fertilizers.

Fall banding increases the choices of seeding equipment. Since there are many good seeding equipment options which do not have fertilizer application capability, fall banding removes the need for more costly one-pass seeding equipment. While fertilizer may be less expensive in the fall, fall banding does increase fuel and labour costs at that time of year, and it will disturb the soil. In wetter, colder soils, banding provides soil drying and warming before seeding.

Some fall applied N can be lost before the crop can use it. However, these losses can be reduced by banding in late fall, when the soil is 5-10 C (41-50 deg F). If ammonia or urea rather than leachable nitrate are used at these temperatures, then the N will stay as non-leachable urea, ammonia or ammonium for a longer time.

Nitrogen can also be pre-plant banded in the spring, or it can be injected (nested) into the soil in the fall, near planting or after planting. Spoke wheel injecting of liquid N is useful as it gives even less soil disturbance than banding. As a result, fewer weeds germinate.

Spring banding offers an advantage over fall banding in that fertilizer rates can be adjusted in direct response to spring moisture conditions. On soils where denitrification causes fertilizer loss over winter, spring banding can improve fertilizer use over fall banding. However, spring banding can be disruptive to the zero till seedbed. The first pass fertilizer application tends to loosen residue giving clearance problems for seeding and making uniform seed placement more difficult.

Overall, spring banding is perhaps the least preferred of the fertilizer application systems.

BANDING AT SEEDING

Banding fertilizer at seeding time offers considerable planting flexibility, in that last minute plan changes are not limited by any pre-plant operations. Because the one-pass seeding is the first pass over the field, there are fewer problems with crop residue plugging equipment. On the other hand, some types of one pass openers may disturb the seedbed too much, preventing uniform seed placement. Large amounts of fertilizer may have to be handled at seeding time.

Nitrogen can be side or mid-row banded during the one-pass seeding operation. One-pass seeding saves time and allows earlier seeding with higher yield potentials. This will also allow the full N rate to be applied without seed damage.

Depending on the system, one-pass seeding costs more because of the horsepower needed to pull the equipment, and the number of openers needed to apply the seed and fertilizer. Mid-row banding requires a set of openers dedicated to fertilizer placement. Side banding requires specially designed openers (Figure 4).

To offset the cost of one-pass side-banding openers, row spacings up to 30 cm (12") have been used with no effect on yield.11 It is possible to avoid the purchase of one-pass seeding openers by dribbling liquid N through hoses on the shank onto the soil surface near the opening. With this system, fertilizer placement is less precise, but seed placement can be optimized.

Seed openers are available for safely side banding anhydrous ammonia. Using this less expensive N helps pay for the one-pass seeding equipment. If anhydrous ammonia is used, it must not be allowed to escape its band and enter the seed row at the time of seeding. Particular caution should be exercised on light textured soils.

Anhydrous ammonia should be at least 4-5 cm (2") away from the seed. Some producers have successfully placed NH3 at the tip of sweeps and spread seed over the remainder of the sweep width.

Choosing the right one-pass opener can be difficult as there are many on the market. It is difficult to tell at the time of purchase whether seed placement will be sacrificed to get 'one-pass' capability.

In fact, as long as toxicity is avoided, the exact location of the banded N is not critical as there is enough early N movement in the soil for good early crop growth. Any banding technique will reduce soil reactions with the applied fertilizer and, therefore, will limit losses of N from the soil.

SEED PLACED N

Seed placed N is also a form of banding and an effective form of application. However, N fertilizers can be toxic to seedlings if too much is placed with the seed. Because of this, low rates of seed placed fertilizer may have to be supplemented with an additional fertilizer operation to ensure enough N for adequate crop growth.

Toxicity is most common in soils that are light textured, high in salts, low in organic matter, have poor fertility, high pH with free lime, and are cool and dry. Toxicity is also more likely with narrow seed openers, wider row spacings and small seeded oilseed crops. The amount of damage will vary from year to year and with fertilizer type.

The amount of N that can be placed with small grain seed at planting (Table 2) is based on seeder row spacing, seeder and opener type and how much 'seedbed is used' (SU). Seedbed use is determined by the following formula:

% SU = (Seed spread x 100) / Seed Row Spacing

There is a lot of variation in the amount of N that can be safely spread with the seed across the width of points, even a sweep point. This is due to differences in soil texture (Table 3). Table 4 shows spring wheat yields as influenced by spread width of seed and dry fertilizer behind a sweep. Nitrogen rates can be more safely increased as the sweeps provide space between the N and seed. This works best with dry fertilizer.

UREASE INHIBITOR

Like other forms of N, urea can cause crop damage when high levels are placed close to the seed. Damage from urea conversion during germination increases as the soil dries after seeding. Rain, on the other hand, decreases damage.

A urease inhibitor called n-(n-butyl) thiophosphoric triamide (NBPT or Agro-tainÆ) will reduce urea losses and toxicity. NBPT slows the conversion of urea to ammonium and ammonia to over a 14 day period. This decreases seedling damage and reduces ammonia losses, making more N available for crop growth with less leaching. NBPT will also improve N uptake from topdressed urea.

Field studies in Manitoba showed that NBPT put with seed-placed urea increased both seedling emergence and grain yield in barley on two soil types from 35-90 lb N/acre (Figure 9).13

SPRING BROADCASTING

Broadcasting urea is not recommended. However, ammonium nitrate containing fertilizers may be a practical choice for some zero tillers. Broadcasting allows higher rates of N to be applied with minimum equipment, time and labour costs.

Spring broadcasting allows flexibility in application rates at time of seeding. It is also a useful way to apply extra N where one-pass seeding is not used or when growing conditions warrant a higher total N application. It is a technique which can be used from before seeding until after the crop has emerged.

Broadcasting N works better in more humid areas where there is a better chance of a spring rain to wash the N into the soil. Nitrogen should not be broadcast onto thick residues, as surface microbes may tie it up.

Fertilizer N can be applied in-crop, but delaying application will reduce yield potential from applied N. However, applications up to heading or after flowering of wheat may still increase grain protein.

"I don't think there's any question that the best way of putting our phosphorous is either seed-placed or side-banded... dual deep banding is another option, but I don't think it's as good. We may have oversold a specific placement of nitrogen - you can manage your overall system by manipulating source and timing to get around placement problems."

Cynthia Grant, Agric. & Agri-Food Canada, Brandon, Manitoba

POSITIONAL P & K AVAILABILITY

While N and S are mobile within the soil, and will move readily with soil water, Phosphorus (P) and potassium (K) are relatively immobile and remain close to where they are placed. Therefore, fertilizer P and K are most efficiently used when placed near the seed.

Lack of mobility of P and K make it difficult to take representative soil tests and accurately interpret a field's fertility status. Phosphorus deficiency can occur in cool soils when root growth is slow and phosphorus release is restricted.

WEED INTERACTIONS

Fertilizers used to improve crop growth will increase weed growth unless they are placed near the crop and away from the weeds. Consequently, broadcast N may give weeds an advantage while banding N near the seed will give the crop an advantage.

Other practices can also reduce weed competition. Combining N placement with a taller winter wheat variety with higher seeding rates can further reduce weed growth (Figure 10). Each cultural practice, when used alone, will reduce weed growth but the interaction of these practices magnifies their benefit.14

PRECISION FARMING

Achieving the higher yields that are possible with zero till means that more fertilizer is needed. On eroded areas, continuous zero tillage will increase the yield potential and improve the uptake of fertilizers. Also, different parts of fields will respond differently to fertilizers and may ideally require varying rates.

Computers and satellite guidance systems allow crops to be produced more efficiently by enabling farmers to better manage small areas of land. It has great potential for zero tillers and others to improve efficiency.

Research is being done to determine if there is an economic benefit to precision farming for small grains. Yield monitors are becoming popular and are a good first step into precision farming. It is interesting to see the variability in crop yield as the combine moves across the field.

For yield data to be useful, a global positioning system (GPS) receiver, along with a memory system and yield data processing software is needed. Remote sensing of the crop canopy can also be used to measure potential crop yields.

For variable rate fertilizer application, a controller is needed for each fertilizer applied. This allows the fertilizer rate to be changed on the go as the applicator moves across the field.

Variable application is desired so that appropriate rates of fertilizer can be applied. The rates are based on topography, soil type, soil tests, soil moisture and the yield goal. Prior to precision farming, all parts of the field received the same fertilizer rate. This was regardless of the productive potential of the various areas within the field. Consequently, some areas would receive too much fertilizer and other areas too little.

FALL BANDING

(+) allows use of the least expensive source of nitrogen (ammonia) and it spreads the work load. This means the spring operation concentrates on seeding. Fall banding saves equipment expenses and increases the choices of seeding equipment available since there are many good seeding equipment options which do not have fertilizer application capability. Fall banding allows the correct amount of fertilizer to be applied for each crop without risk of crop damage. In cooler, wetter areas, fall banding permits the soil to warm quicker and allows earlier seeding the next spring.

(-) requires separate equipment and an additional trip across the field which is expensive in both fuel and labour. The extra fall operation dries the field and it tends to promote volunteer growth and stimulates weed germination the next spring.

SPRING BANDING

(+) offers the same advantages as a fall banding operation with the added benefit that fertilizer rates can be adjusted in direct response to spring moisture conditions. All types of fertilizer, including NH3 and liquid UAN, can be used in a spring banding application. On soils where denitrification causes losses of fertilizer over winter, spring banding gives more efficient use of fertilizer compared with fall application.

(-) includes the extra expense of the added operation. It disrupts the zero till seed bed and makes uniform seed placement difficult.

SEED PLACED

(+) is generally considered the simplest fertilizer placement system. A one pass seeding/fertilization operation is efficient in time and fuel costs. Many available machines are capable of placing seed and fertilizer together. That fertilizer which is with the seed is used very efficiently by the plant.

(-) fertilizer amounts are limited by the danger of seedling injury. Reduced plant populations which result from excess fertilizer placed with the seed can mean later maturity and/or lower yields. Seed placed fertilizer may have to be supplemented with an additional fertilizer operation to ensure that sufficient nutrient amounts have been provided for the crop. Handling more fertilizer at seeding time slows down seeding.

BANDING AT TIME OF SEEDING

(+) allows the total fertilizer requirement to be placed with one pass at seeding time. Placement is near enough to the seed to offer efficient use of the fertilizer but sufficiently separated from the seed to minimize toxicity concerns. Because of the proximity to the seed row, side banded fertilizer is most accessible to the seed and least accessible to weed seeds between rows. The single operation is cost efficient in fuel and labour and gives planting flexibility. Because the one pass operation is the first pass over the field, there tend to be fewer problems with the crop residue plugging the equipment. All forms of N can be used.

(-) requires specialized equipment. Some types of side banding equipment may disturb the seedbed and cause problems with uniform seed placement. There may be high horsepower requirements at seeding because of high draft requirements of some side banding drills. Large amounts of fertilizer need to be handled at seeding. Generally, anhydrous ammonia is not used for side banding so overall fertilizer cost may be higher.

SPRING BROADCASTING

(+) allows flexibility in application rates at time of seeding. It is a useful means of applying extra nitrogen when one-pass banding equipment is not available or when growing conditions warrant a higher total nitrogen application. Broadcasting is a fast method of application with a low power requirement which can be used when it is convenient from before seeding until after the crop has emerged. When fertilizer is broadcast before seeding, even zero till seeding will provide some minimal incorporation. Generally, ammonium nitrate (34-0-0) is the most efficient form of broadcast nitrogen. Liquid UAN can be dribble banded on the surface close to seeding.

(-) there is inconsistent fertilizer efficiency in high residue situations and in dry years. Broadcasting also means an additional operation in the spring when time is limited.

Prepared from information provided by:

Donald Tanaka, USDA-ARS

P.O. Box 459, Mandan, ND 58554

Telephone (701) 667-3063 Fax (701) 6673054

Email "tanakad@ars.usda.gov"

Cynthia Grant, Agriculture and Agri-Food Canada

Brandon Research Centre

Box 1000A, RR3, Brandon, MB R7A5X3

Telephone (204)726-7650 Fax (204) 728-3858

Email "cgrant@em.agr.ca"

Vern Hofman, Agricultural and Biosystems Engineering

P.O. Box 5626, Fargo, North Dakota 58105-5626

Telephone (701) 231-7240 Fax (701) 231-1008

Email "vhofman@ndsuext.nodak.edu"

Blaine Schatz, NDSU Carrington Research Extension Center

P.O. Box 219, Carrington, ND 58421

Craig Stevenson, Department of Soil Science

University of Saskatchewan, Saskatoon, S7N 5A8

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1. Bullman P (1995). U of Manitoba (unpublished)
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6. Hofman V et al (1994). AE-826 North Dakota State U
7. Radford BJ and Wildermuth (1987). Aust. J. Exp. Agric. 27:579
8. PAMI & SSCA (1994). Direct Seeding Manual
9. Derksen DA et al (1996). PARI Factbook
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11. Lafond GP (1994). Can. J. Plant Sci. 74:703
12. Diebert (1994). Ext. Publication North Dakota State U
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Anderson R (1996). (pers comm) Akron, Colorado