Terry Gregoire, Frank Sobolik

Area Agronomy Agent, Area Agronomy Agent

No till, or zero tillage, has attracted interest since research began in North Dakota in 1977. In 1981 an estimated 31,000 acres were in no till production. This figure grew to 650,000 acres in 1986.

No till has advantages:

• Soil erosion from both wind and water is substantially reduced by crop residue left on the soil surface.
• Fuel savings have been demonstrated. Fuel savings of 3 to 4 gallons per acre are common.
• Time savings are realized by elimination of primary tillage such as plowing, rock picking, and seedbed preparation.
• Tractor horsepower and other tillage equipment needs are reduced.
• Reduced soil crusting.

Generally, surface soil moisture content at seeding time is higher with no till. An additional 2 inches of soil moisture may be available when compared to conventional tillage systems. This moisture may increase yields, especially during seasons of below normal precipitation.

Disadvantages of no till are:

• Possible increase in perennial and winter annual weeds.
• Shifts in weed populations.
• Increased reliance on herbicides that may cost more for weed control than tillage.
• Increased knowledge required of herbicide use and weed species identification.
• Possible Increased insect and disease problems.
• Cooler soil temperatures at planting time.
• Conventional tillage cannot be used to incorporate fertilizer and herbicide.
• Spring seeding may be delayed because of higher surface soil moisture content.
• Heavy residue may result in poor seed soil contact.

The following time line suggests major no till practices and the months these practices may be implemented.

Figure 1. No till time line for spring crops.August/September
August/September	October/November	April/May
Harvest, Residue Management	Fertilization	Fertilization
Soil Test	Wineter annual weed control	Spring burndown weed control
Perennial weed control
Volunteer Crop weed control

Various production problems are solved differently when comparing no till to conventional tillage systems (Figure 2). Tillage is used to manage straw, control perennial and winter annual weeds, incorporate fertilizers and herbicides, and prepare the seed bed for conventional drills. No till systems accommodate straw management without tillage. Weeds are controlled by herbicides, but preplant incorporated herbicide options are not available. Fertilizer application must rely on rainfall or drill placement for proper incorporation.

Yields from North Dakota experiment stations and from farmers using the no till crop production system indicate that once a no till system is familiar to the operator, crop yields are similar to conventional systems. Row crops such as sunflower, which today rely heavily on preplant incorporated herbicides and cultivation for broad spectrum weed cotnrol, will often yield less under no till than under conventional tillage. However, more post emergence herbicides are becoming available for row crops

Figure 2. Crop Production Comparison, No Till Vs Conventional

Problem	Production Practice to Correct Problem
	No till system	Conventional tillage system
Residue accumulation	Straw & chaff spreaders, harrow	Tillage
Perennial & winter annual weeds	Herbicides	Herbicides & tillage
Fall fertilization	Surface granules & liquids Anhydrous Ammonia (where rocks are not a problem & soil disturbance can be minimized)	Anydrous Ammonia, granules & liquid
Spring fertilization	Liquid, granules, drill or surface applied, drill or surface applied, Ammonia. Drill applied	Anyhdrous ammonia granules, liquid, incorporated, drill
Rocks	Not picked	Rock picker
Seedbed prep.	Burndown herbicide`	Tillage

Seeding No till drill or modified equipment No till production systems require a different management system to produce yields equal to conventional tillage systems. The following sections briefly discuss management differences of no till compared to conventional tillage.

RESIDUE MANAGEMENT

Several methods are used to manage straw and chaff that remain after harvest. A combination of at least two of the following methods is often required.

• Straw chopping and chaff spreading with a combine.
• Baling straw.
• Collecting straw and chaff for feed.
• Harrowing the straw and chaff immediately after harvest. However, harrowing by itself will not adequately distribute straw and chaff.

Proper residue management is essential for satisfactory planting. Evenly distributed residue will assist In proper seed placement and crop emergence. Residue management should be completed during or immediately following harvest to be most effective.

WEED CHANGES IN NO TILL SYSTEMS

Effective weed control is crucial for successful no till crop production. Both chemical and nonchemical control measures are required In the system.

Figure 3. Residue management is best handled during the harvest operation. Many chaff and straw spreaders are available.

Good field sanitation procedures, particularly along field borders, and weed free seed are required to prevent new weed infestations. Soil disturbance should be minimized to reduce weed seed germination. Crops must be rotated and managed to allow proper herbicide selection and provide maximum competition.

In general, more herbicides are available in small grain no till systems for weed control than are available In broadleaf crops such as sunflower, soybeans or dry beans.

Producers who are beginning a no till production system emphasize small grains in the initial rotation. Winter wheat, barley, spring wheat and oats are more competitive with weeds than broadleaf crops. Planting small grains may make weed management easier for the beginning no till producer. Winter wheat has proven to be a good no till crop. When established well, winter wheat is very competitive with spring annual weeds.

WEED POPULATION CHANGES

Weed populations change when the tillage system is altered. Annual weed populations generally decrease when soil is not disturbed. Research trials and field experience have shown wild oats, green foxtail, smartweed and wild buckwheat populations are generally reduced under no till. Perennial weeds such as Canada thistle, quackgrass and foxtail barley have potential to increase.

Volunteer crops can be a problem in any continuous cropping system. With no till, fall and early spring cultivation is not used to stimulate volunteer crop germination. Volunteer crop control may be necessary in the planted crop. Select a crop rotation which allows for chemical control of volunteer crops.

New weeds may invade from adjacent undisturbed land areas. Control measures for many of these weeds have not been developed for field crops. They have not been common field problems. The list of potential invaders Includes tansy mustard, wildrose, dandelion, and similar weeds frequently found in undisturbed areas. Additional hard to control Invaders include bromegrass, absinth wormwood, crested wheatgrass, foxtail barley, false chamomile and common milkweed.

A sanitary border around field and rock piles will help control invader plant species.

HERBICIDES

Herbicides are commonly used at three points in the crop management system.

• In the fail before a killing frost to control winter annuals, volunteer crop and perennial weeds.
• In the spring just prior to planting to kill volunteer grains and spring weeds.
• Postemergence as is common in conventional systems.

WEED CONTROL SUMMARY

• Know your weed problem. Learn to identify weeds as seedlings. Proper herbicide selection, application rate, and application time depends on proper weed identification and growth stage.

DO:

• Prevent weed spread from adjoining areas such as fencelines, roadsides, farmyards, pastures and waste areas.
• Use clean seed to reduce weed problems.
• Monitor fields closely to detect changes in the weed population.
• Minimize soil disturbance to reduce annual weed populations.
• Manage crops to achieve maximum competition with weeds. Vigorous, uniform crop stands are required.
• Apply recommended herbicides as required in the fall, in the spring before crop emergence, and selectively after emergence.
• Rotate crops to allow use of required herbicides and to prevent a buildup of crop associated weeds.
• Consider spraying weed patches In the crop with nonselective herbicide to control perennial weeds before they spread.

DO NOT:

• Initiate no till on fields heavily infested with perennial weeds.

FERTILIZER MANAGEMENT

Fertilizer application In no till is different from conventional production systems. Fertilizers are surface applied without incorporation or drill applied since tillage Is now available for incorporation. Recent innovations in drill design offer many different fertilizer placement capabilities. Meeting total crop fertility requirements is not possible at seeding time.

Surface applied nitrogen fertilizers (urea or ammonium nitrate) should be applied late In the fall or early In the spring when soil temperatures are low and there Is a significant chance of rainfall to aid incorporation. Application on frozen ground should be restricted to sites where run off will not occur.

Using no till equipment increases the time, placement and application options available for fertilizers, especially nitrogen. Many nitrogen products are available, varying in cost and. application requirements. Seedling injury occurs when high nitrogen rates are applied with the seed. This requires high nitrogen rates to be applied before or after seeding or to the side or below the seed row when applied at planting time.

The newest small grain designs have the capability of placing anhydrous ammonia to the side of the seed rows at seeding time. Caution should be used when placing anhydrous ammonia below the seed row as the risk of seedling injury increases compared to side row placement.

A portion of surface applied nitrogen will be utilized for decomposition of crop residues before the nitrogen becomes available for plant growth. Placing all nitrogen products below surface residues eliminates the need for the 30 extra pounds of nitrogen initially recommended for the first two to three years of no till production.

Proper placement of phosphorus fertilizer is more crucial In no till than in conventional tillage systems. Broadcast phosphorus applications and surface residue accumulation will result in high phosphorus levels in the upper Inch of soil under no till management. Phosphorus that accumulates in this zone may not be available for mid and late season plant growth except in wet years. Broadcast phosphorus applications should only be considered as a means of building soil fertility prior to implementing no till. New drill designs allow phosphorus placement below planting depths. This design helps reduce phosphorus availability problems in dry surface soils.

Phosphorus needs in most crops can be met through drill application. Side band application may be necessary In some crops.

The timing of fertilizer application depends on producer convenience. Spring or fall application gives essentially equal yields.

EQUIPMENT

No till management Systems usually Involve less equipment than conventional tillage systems. Primary tillage Implements are not needed. Most farmers have equipment available for no till

operations with the exception of a no till drill or seeder. Equipment needed for no till planting includes a pesticide sprayer, a no till drill or seeder, an adequate straw and chaff spreader on the combine, and possibly a harrow if straw spreading is inadequate after combining.

Until recent years the most limiting factor in no till production was an adequate drill. Drills should minimize soil disturbance, resist rock damage, and have the capability to penetrate surface residue. Good seed soil contact Is essential. Fertilizer attachments are necessary for fertilizer application, either with seed or as a side band application.

Increased use of herbicides for weed control requires a convenient to use sprayer with the capability to accurately apply different herbicides with minimum adjustments. Accurate calibration Is essential. Various spray systems are available each with advantages that should be investigated for a particular farming situation and need it is essential a marking system be used while spraying. Tracks are often hard to follow in stubble and herbicide overlap or skip problems can occur. improper application can be expensive because of Increased chemical usage and possible crop injury. Skips may require hand spray control.

Good straw and chaff spreading equipment is necessary (Figure 5). Excessive trash, especially chaff, can prevent adequate drill penetration, resulting in poor germination and crop growth. Several chaff and straw spreader devices are available. They do an adequate job with proper adjustment. A follow-up harrowing is often done to increase residue uniformity.

Figure 4. Soil marker systems are essential for accurate pesticide application and avoidance of field skips. Markers include mechanical, foam, electronic and tramlines.

ROTATIONS AND DISEASE

Maximum yields and reduced disease incidence result from crop rotation. Rotations vary in North Dakota depending on the production area, cropping customs, and crop adaptation. Wheat following a broadleaf crop will yield better than wheat following wheat. The same relationship is true for broadleaf crops. The use of small grain and broadleaf crops in a rotation will provide maximum opportunity to combine cultural and chemical methods for weed, insect, and disease control.

Rotation to broadleaf crops in no till systems is limited by weed control methods. However, experimental herbicides show promise for future use in broadleaf crops in no till rotation systems.

Diseases may increase In no till production systems unless good management practices are implemented. Surface crop residues harbor leaf, stem and head disease pathogens. Without tillage to bury residues and disease organisms, the amount of disease inoculum can be higher early in the season, especially when crop rotation is not used. For example, when wheat follows wheat, early disease infection may occur and result in more severe disease problems as the crop matures. Oats, barley, or rye following wheat reduces plant disease potential. Rotation to broadleaf crops would be ideal.

Volunteer plants and weeds also can harbor disease organisms. If weed and volunteer plants are not controlled adequately in no till, they may be an important source of disease for the crop.

Disease control management is done through proper crop selection, rotation control of volunteers and weeds, use of resistant varieties, and fungicides. Disease control management, regardless of tillage system used, also requires periodic scouting of the crop during the growing season to determine if fungicide use is warranted (Figure 5).

INSECTS

Economically important insects that may increase in a no till system are grasshoppers, cutworms, wireworms, and wheat stem sawfly. Conventional tillage practices have helped keep insect populations to a minimum. Examples include a breakup of wheat stubble infested with wheat stem sawfly larvae, exposure of cutworms and other soil insects to predation, and burying crop stubble that attracts cutworm moths for egg laying. Wireworm populations are frequently high in pasture and sod areas where soil has not been disturbed. No till areas may require monitoring for wireworm buildup.

Crop monitoring for insect activity is a necessary part of minimum and no till production. Monitoring lets the grower know if insecticides designed for individual insects should be used. Seed treatment for wireworms or granular planting time treatment with systemic insecticides may be necessary for grasshoppers when these insects are known to present an economic threat. Crop rotations and resistant varieties can help reduce crop specific insect species such as wheat stem sawfly.

The need for insect control may occur during any part of the growing season. Producers will need to acquaint themselves with insect pest common to the crop grown and the economic thresholds for each insect.

Figure 5. Management Items Needing Attention for Profitable No Till Production
Equipment Spray equipment calibration and marker use is necessary Careful seeding-fertilizer equipment selection Chaff and straw spreaders are necessary	Crop Diseases  Know and identify diseases on seeding crops, monitor crop regularly Plan for crop rotations Control volunteer crops and weeds
Fertilizers  Proper placement is necesssary to limit nutrient tie up and increase use efficiency	Insects  Know and identify crop insect threats Understand insecticides and their control limitations Plan rotation alternative for insect threats
Weeds Know and identify weeds as seedlings Understand herbicides and their weed control limits

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ECONOMICS

Total production costs of no till are similar to conventional tillage However, individual Item costs shift dramatically Table 1). Herbicide costs increase while costs for machinery ownership, labor, repairs, fuel and lubrication decrease. Fertilizer costs may or may not increase. Availability of sideband fertilizer placement in newer drill designs has allowed more efficient placement of least cost fertilizer products, resulting in reduced costs compared to 1981.

Herbicide costs vary with each producer, depending on weed species present. No till systems require herbicides for fall and spring weed control, perennial weeds and chemical fallow as well for use in the growing crop. The presence of perennial weeds dramatically increases herbicide costs. Competitive crops such as winter wheat or winter rye help reduce herbicide costs.

RODENTS AND ROUGH GROUND PROBLEMS

Begin no till with smooth ground. Some no till fields have had increased activity of pocket gopher, ground squirrel, and other rodent species. Mounds, holes and disturbed areas cause field roughness. Controlling gopher populations early helps reduce the future population.

Table 1. Input cost differences in no till compared to conventional tillage for spring wheat production in different crop rotations in North Dakota In 1981.
	Location, Crop Rotation
Costs	Eastern N.D., continuous	Central N.D., crop-crop-fallow	Western N.D., crop-fallow
	$ per acre
Fertilizer	+4.20(a)	+.73	0.0
HerbicIdes	+12.47	+13.98(c)	+ 14.60(c)
Machinery repair	-1.54(b)	-.78	- .62
Fuel and lubrication	-5.17	-3.75	-2.85
Machinery ownership costs	-8.79	-8.43	-6.48
Labor	-2.23	-1.81	-1.35
Other costs	+1.90	+1.88	+ .77

a (+) indicates the amount by which no till costs are greater than costs under conventional tillage

b (-) indicates the amount by which no till costs are less than Costs under conventional tillage

c(+) includes chemical fallow costs of $20/A, replacing original assumptions costing $40 for central North Dakota and $30 for western North Dakota.

Swenson, Andrew L - An Economic Comparison of Zero Till and Conventional Tillage for Small Grain Production in North Dakota, M.S. Thesis, 1981. (Page 141).