Principles and Practices of No-Till

Dr. Dwayne Beck

Dakota Lakes Research Farm

Pierre, South Dakota

I. Different Farming Systems Use, Varying Levels of Tillage, Technology, and Cultural Practices.

A. Ancient systems used almost no tillage, little technology, and numerous cultural practices.

B. Systems used on the plains from the time of the pioneers until perhaps the late 1920's used moderate tillage, some technology, and many cultural practices.

C. Modern farming practices which have evolved in the last forty years rely on intensive tillage and substantial amounts of technology in order to reduce use of cultural practices.

D. High residue farming systems will require renewed utilization of cultural practices to limit excessive reliance on technology.

II. The Impact of No-Till on Weeds, Diseases, and Insects.

A. Weeds

1. Some weed types are favored by tillage and inhibited by lack of disturbance. This is especially true for broad leaf weeds with large seeds and only slightly less applicable for grassy weeds with large seeds.

2. Small seeded weeds are favored by minimum tillage and high disturbance direct seeding.

3. Low disturbance seeding techniques result in less weed pressure and more uniform weed flushes.

B. Insects

1. Most insects which are harmful to crops are not affected either directly or indirectly by tillage method.

2. A few harmful insects are indirectly affected by tillage in terms of how it impacts the habitat they need for winter survival, etc.

3. Almost all insect problems blamed on use of high residue systems can be traced to failures in sanitation or rotation practices.

C. Diseases

1. Plant diseases require three factors to be present in order for plant health to be affected. Those factors are a susceptible host, a pathogenic organism, and a suitable environment for infection to occur. Tillage method is only important in how it affects these factors.

2. Some diseases are tillage neutral in that tillage plays no role in the cycle of the disease. An example would be leaf and stem rusts of wheat.

3. Some diseases are reduced due to the environment created by use of high residue techniques. Diseases caused by dry soils or by soil splash to leaves are examples.

4. Several diseases can be favored by systems which leave residues on the soil surface.

a. Many of these diseases can be dealt with by using adequate rotational intervals and proper sanitation techniques.

b. In some cases it may be cost effective to use fungicides if effective, labeled, products are available to obtain shorter rotation intervals.

III. Sanitation

A. Preventing weeds from going to seed.

1. Mowing field borders.

2. Spot spraying patches.

B. Avoid introducing weeds or diseases.

1. Cleaning equipment.

2. Using clean seed.

3. Remove and feed chaff.

4. Compost manure.

5. Limit Disturbance

6. Exercise great care if grazing is to be used.

7. Treat borders and field margins.

C. Break insect and disease cycles through proper inter-crop and in crop management.

1. Control weeds and volunteer plants prior to periods when flights of cutworm and armyworm moth are expected.

2. Maintain a "no green" period especially before seeding winter wheat to break insect cycles associated with wheat streak and barley yellow dwarf mosaics and to minimize vulnerability to certain root diseases.

3. Volunteer crop and other weeds serve as hosts to carry disease and insect problems through rotational years.

D. Probiotic Vs Antibiotic or Antiseptic; Utilize biological methods rather than physical methods to lower population of harmful organisms.

1. Present systems sanitize with tillage, burning, etc. designed to kill all organisms. Hope only good ones return. Physical methods.

2. Biological methods focus on creating an environment which lowers populations through competition, predation, and planned impotence.

a. Similar to use of probiotics in livestock where introduction of beneficial or non harmful organisms lowers populations of harmful ones.

b. Establishment of crop canopy conditions which cause resting phases to become active while a non susceptible crop is being grown. (impotence)

1. green fallow Vs chem. fallow

2. continuous cropping with good rotations.

3. less inter-crop period but longer interval between the same crop type.

c. Earthworms and other soil fauna are predators.

d. Biological activity is much more rapid under full canopy conditions

IV. Competition.

A. Encourage fast uniform canopy formation.

1. Accurate seeding depth.

2. Starter fertilizers.

3. Good seed quality and seedling vigor.

4. Narrow rows.

5. Spread straw and chaff completely.

6. Move residue from the row area in some conditions.

7. Wheat with Black straw (allows faster warm-up)

B. Provide less than optimum conditions for weeds.

1. Limit disturbance.

2. Place fertilizer.

3. Spread straw or chaff.

V. Rotations (Diversity, Intensity, and Profitability)

A. Diversity

1. In crop type, seeding, and harvesting date.

a. Cool-season grasses

1. Winter wheat

2. Spring small grains

b. Cool-season broadleaf crops.

1. Flax

2. Canola

3. Lentils

4. Field peas

5. Lupine

c. Warm-season grasses.

1. Corn

2. Sorghum

3. Millet

4. Rice

5. Forage sorghum

d. Warm-season broadleaf crops.

1. Soybean

2. Sunflower

3. Safflower

4. Cow peas

5. Chick peas

6. Cotton

7. Edible Beans

e. Perennial and biennial crops

1. Alfalfa

2. Clovers

3. Vetch

4. Perennial and biennial grasses.

f. Fallow

2. Diversity in herbicide program used.

a. Know herbicide families

b. Rotate herbicides to prevent resistance.

3. Diversity to spread risk and work load.

a. Bad weather at the wrong time for one crop can be good weather for another crop type

b. Handle more acres with the same fixed costs.

4. Diversity to create proper conditions for the subsequent crop.

a. Seedbed conditions.

1. Dark colored residue produces warmer seedbed in spring.

2. Heavy residue with light color provides more surface moisture.

b. Soil moisture

1. Most moisture with light-colored, upright, heavy, residue in areas where it snows.

2. Areas without snow save more moisture with flattened residue.

3. Interval between harvest and peak water use determines potential water storage.

5. Diversity to aid in weed control.

a. Variations in seeding dates.

b. Differing spectrum of herbicides available.

c. Each crop type favors and discourages a different spectrum of weeds.

d. Variation in harvesting dates.

e. Perennial and forage crops can be excellent tools to control certain weeds.

f. Winter wheat or rye compete very well with summer weeds.

6. Diversity to aid in disease control.

a. Not all diseases are residue (rotation) related.

b. At least three crop types preferred in a rotation. Two grasses; one broadleaf.

B. Intensity: Dryland Rotations Must be More Intense.

1. Put water saved by no-till to work.

a. If water saved by no-till is not put to good use it will cause problems. (Saline seeps)

b. Full benefit of no-till will not be evident unless intensity is increased.

c. Growing crops provide competition for weeds and can help break certain disease cycles.

2. Less fallow and more high water-use crops.

a. Minimizes loss of nitrogen and water below the root zone.

b. Lower land costs provide competitive advantage in producing crops normally grown in higher rainfall areas.

c. No-till fallow is expensive.

3. Proper intensity reduces risk.

a. Rotations with insufficient intensity will be too wet.

1. Poor plant growth in normal to wet years.

2. Loss of nutrients.

3. Trafficability problems.

4. Potential for more disease.

b. Rotations with excessive intensity will be too dry.

1. Poor plant growth in normal to dry years.

2. Difficulty in establishing adequate stands.

4. Proper intensity will depend on:

a. Weather.

1. Use two or more rotations with varying intensity if weather tends to be variable.

2. Use rotations which allow adjusting intensity based on weather conditions. (i.e. forage-grain flex crops)

b. Soils: Some soils hold more water than others.

1. Soils with high water holding capacity.

a. more intensity.

b. more high water use crops.

c. longer "fallow" periods.

2. Shallow soils or coarse soils.

a. Slightly less intensity.

b. More short season crops.

c. Shorter inter-crop periods.

c. Location: Precipitation and heat interact.

1. Warm environments require more water per unit of production.

d. Irrigation: Similar intensity as when tillage is used. (lower water costs.)

1. Irrigated systems normally have intensity limited by the heat available rather than moisture unless water supply or cost are constraints.

2. Savings occur in amount of irrigation water used.

a. runoff reduction.

b. less evaporation loss.

3. Opportunity to utilize more efficient sprinklers with lower operating pressure.

5. Native vegetation is best indicator of proper intensity.

a. Integrates precipitation, temperature, and soil factors.

1. Environments with trees will support the most intensity.

a. more water than heat.

b. easily become too wet.

c. 100 percent high water use crops and/or over crops and multiple cropping.

2. Tall grass prairie mixed with trees.

a. typical of the corn belt and black soil zones in Canada.

b. supports substantial intensity.

c. Nearly 100 percent high water-use crops and/or cover crops and multiple cropping.

3. Tall grass prairie with few trees.

a. Too dry some years with very intense rotations (all high water use crops)

b. 75 to 100 percent high water use crops with limited use of cover crops and multiple cropping.

c. Dark brown soil zone in Canada.

4. Mixed grass prairie.

a. Too dry most years for very intense rotations.

b. 50 to 75 percent high-water use crops. No multiple cropping and few cover crops.

c. brown soil zone in Canada.

5. Short grass prairie.

a. Almost always too dry for very intense rotations.

b. 50% or less high water-use crops.

c. Longer inter crop periods required.

d. Some producers may use a small amount of fallow.

e. Rotations which allow varying intensity fit for some producers.

f. brown soil zone in Canada.

6. Short grass prairie mixed with more drought tolerant plants.

a. Almost always too dry for a high water-use crop.

b. Few if any high water-use crops in the rotation.

c.. Rotations with fallow and/or flexible intensity.

6. Getting started and varying intensity.

a. Look at conventional tillage rotations in areas with similar temperatures but 2 to 4 more inches (50 to 100 mm) of rain.

1. Should be about right in terms of intensity but may not have other desirable characteristics.

b. Start with rotations more intense than those used with tillage.

1. Wheat-Fallow may become Wheat-Corn-Fallow or Wheat-Sorghum-Fallow

c. Experiment with increasing intensity even more by changing one component of this new base rotation.

1. Substitute a green manure crop, forage crop, or flex crop on part of the fallow acres.

a. Wheat-corn-black lentil

b. Wheat-corn-oat/pea (for forage)

c. Wheat-corn-pea (flex)

1. Forage if dry year.

2. Grain if wet year.

2. Substitute a cool-season broadleaf crop for fallow on part of acreage.

a. Wheat-corn-peas

b. Wheat-corn-lentils

c. Wheat-corn-flax

d. Wheat-corn-canola

3. If even more intensity appears possible, try some more intense rotations.

a. Wheat-corn-soybean

b. Wheat-corn-sunflower

c. Wheat-corn-safflower

d. Wheat-w. wheat-corn-soybean

e. Wheat-w. wheat-corn-edible bean

f. W. wheat-sunflower-corn-canola

g. many more variations depending on climate and grower preference.

C. Profitability: Risk Versus Return

1. Each situation requires balancing diversity and intensity to achieve the desired risk and return characteristics.

a. High intensity with high diversity is difficult to obtain in many environments due to lack of adapted crops or length of growing season.

b. High intensity with low diversity can offer high risk but also potentially high return per acre until major problems develop.

1. Low diversity limits acreage or requires more fixed cost/crop acre.

2. Continuous corn and corn-soybean rotations would be examples in the US wheat-canola or wheat-edible beans would be examples in Canada.

c. Moderate intensity with high diversity (at least 3 crop types and 40% to 80% high water-use crops). Less risk, less gross return/acre but can increase total net profit.

1. Spreads workload and fixed costs.

2. Reduces price and weather risks.

3. Reduces potential for weed, disease, or insect problems.

4. Examples

a. S. wheat-corn-soybean

b. S. wheat-corn-canola-w.wheat-soybean

c. S. wheat-corn-soybean-corn-soybean

d. S. wheat-w.wheat-corn-soybean

5. Seems to fit in areas between the corn-soybean and wheat-fallow belts in US

d. Low intensity with high diversity (less than 40% high water-use crops at least 3 crop types) used on soils with lower water-holding capacity and in short grass prairie areas.

1. Similar characteristics as previous type.

2. Trades reduced risk in dry conditions for less gross return in good years.

3. Examples

a. W. wheat-corn-cool season broadleaf

b. W. wheat-corn-forage or flex crop

c. W. wheat-corn-broadleaf-fallow

d. W. wheat-millet-broadleaf

e. Low intensity with low diversity (only one or two crop types with few if any high water use crops) Combines high fixed costs/acre, higher risk, and lower gross return.

1. Little or no potential for these rotations in most no-till situations.

2. Some have worked well with tillage.

a. tillage adds intensity (uses water)

b. tillage partially replaces diversity by burying residue.

3. Examples:

a. Wheat-fallow

b. Continuous small grains.

c. Wheat-canola

4. Look good only in very dry years.

VI. Each Producer Must Determine System Which Works Best for Him.

A. Ability to accept risk/need or desire to maximize return.

1. Personality

2. Landlord, banker, partner, or spouses personality.

3. Debt

a. Low debt load allows the producer to accept more risk if he desires.

b. Moderate debt load may preclude taking large risks until debt is reduced.

c. High debt load may require taking more risk in order to increase returns.

B. Other enterprises in the operation.

1. Cattle and Sheep

a. Makes forage/grain flex cropping more feasible.

b. Can utilize crops which do not initially have established local markets.

1. feed peas, corn, sorghum, forages, millet, etc.

c. Can use chaff and other aftermath to add value to the crop.

d. Planned grazing or forage sequences add diversity with little risk.

1. Grazing no-till can increase weed pressure because of disturbance.

e. May limit acreage of some crops because peak times overlap.

2. Swine and poultry

a. Can utilize grains such as peas, corn, sorghum.

C. Off-farm interests.

1. Job

2. Spouse's job.

3. Hobby and leisure activities

4. Children's activities

5. Travel

a. Leisure

b. Farm or professional activities.

D. Resources

1. Labor

2. Land

3. Machinery

VI. Mistakes Will Occur

A. Tilled systems sometimes failed

B. Problem not that no-till does not work rather some component in the system was wrong.

C. Look to Rotation, Sanitation, and Competition for solutions.

Conclusions

Crops other than small grains can be successfully and profitably produced all areas of the Great Plains. Adding diversity to present rotations by growing alternative crops can have positive ecological benefit while at the same time improving the potential profitability of most operations. High residue systems benefit most from inclusion of alternative crops and in many cases use of these systems is necessary to assure adequate moisture is available to grow them. Combining high residue systems with alternative crops increases management requirements but also provides the greatest potential for increasing returns by spreading workload, optimizing efficient utilization of water; and reducing weed, disease, and insect concerns. Defining Diversity and Intensity

It is not the intent of this paper to be a comprehensive guide to rotational planning. There are, however, a couple of tools that have been helpful in our work at Dakota Lakes that make the process of evaluating rotations more straightforward in the initial phases. The first is an intensity rating. Rotational Intensity can be evaluated by assigning a value of 1 to cool-season and short-season crops and to crops used for green fallow. Examples would be all small grains, canola, pulses, millet, etc. A value of 2 is assigned to full-season crops grown during the warm part of the summer. Examples would be corn, forage sorghum, safflower, sunflower, edible beans, etc. Fallow receives a value of 0. Average the intensity value for each crop in the rotation. For instance a wheat-fallow rotation produces a value of 1 plus 0 divided by 2 equals 0.5. Continuous wheat, wheat-canola, etc. give values of 1.0. Wheat-Corn-Pea produces intensity of 1.33. Intensity values of no-till systems should be 0.5 to 1.5 points higher than those used with tillage depending on the tillage that was used and soil moisture holding capacity parameters.

The other tool being developed to aid rotational planning is a Diversity Index. This index attempts to quantify diversity in rotations in as simple manner as possible. Like the intensity rating it designed to be used in preliminary planning only. More careful scrutiny of promising rotations is suggested. There are two steps used in determining the Diversity Index. The first involves determining the average interval between crop types in the rotation. Crops used in the rotation are classified into one of four types (cool-season grass, cool-season broadleaf, warm-season grass, and warm-season broadleaf). Determine the number of years between each cool-season grass and the one that preceded it in the rotation. If it was the same crop (i.e. wheat both times) use the number of years as its interval. If the preceding crop was of a different crop (i.e. oats or barley) add 0.5 to the number of years. Do the same thing for the warm-season grass crops (corn, millet, forage sorghum, sorghum, etc.). Perform the same operation for the broadleaf crops disregarding the difference between warm and cool-season types. In other words use the interval between the crop of interest and the last broadleaf crop of either type. This is done since many of the broadleaf crops share diseases in common. Just as with the grass crops, remember to add the 0.5 if the preceding broadleaf was not the same crop. Average these numbers across the rotation. Fallow is treated as another crop type. Some examples are: Wheat-Fallow (1 + 1 = 2 divided by 2 years in the rotation produces and interval average of 1.0); Wheat-Corn-Pea (2+2+2=6 divided by 3 equals 2); Wheat-Barley-Canola (1.5 + 0.5 + 2 = 4 divided by 3 equals 1.33); Wheat-Wheat-Canola ( 1+0+2=3 divided by 3 equals 1.0); Wheat-Canola-Millet (2+2+2=6 divided by 3 equals 2.0).

Once the interval average has been determined, the Diversity Index for a rotation is obtained by adjusting the interval average to account for some work-load spreading, weed, and disease concerns. If both a grass and a broadleaf crop are used in the rotation add 0.5. If both a fall and spring seeded crop are used in the rotation add 0.5. If both cool and warm-season crops are used add 0.5.

Adjust for broadleaf intervals by averaging the following scores for each broadleaf interval in the rotation: if the broadleaf to broadleaf interval is 2 years assign a 0; use 0.5 is for each broadleaf-broadleaf interval of 3 years or more; use a -0.5 for an interval of 1 year; for back to back broadleaf sequences use -1.0. Examples include rotations like wheat-canola or corn-soybean with interval averages of 1 receiving a deduction of 0.5. Wheat-corn-pea and similar rotations receive no deduction or bonus. Wheat-wheat-corn-sunflower receives a bonus of 0.5. More complex rotations like wheat-sunflower-wheat-corn-pea require that the scores from the sunflower-pea (interval = 2 years, score =0) and the pea-sunflower (interval = 1 year, score = - 0.5) segments be averaged to produce the -0.25 deduction for this rotation.

Adjust for workload spreading benefits by determining the largest proportion of the seeded acreage which shares ideal seeding time and deducting this number. Determining ideal seeding times requires local knowledge since some crops (spring wheat and canola for instance) will share seeding times in some environments and not in others. Examples would include deducting 1.0 when evaluating rotations such as spring wheat-barley, spring wheat-pea, continuous corn, and spring wheat-barley-canola since all crops need to be seeded in the same time frame in many environments. Wheat-fallow would also receive a deduction of 1.0 since all of the acres to be seeded must be drilled at one time. Rotations such as spring wheat-millet-canola in the same environment would face a deduction of 0.67. Corn-soybean, wheat-corn-fallow, wheat-soybean, wheat millet, etc. would receive a deduction of 0.5. Deductions of 0.4 would be made for a rotation like corn-soybean-corn-soybean-wheat. Wheat-millet-flax receives a deduction of 0.33 as would similar rotations. In a rotation like spring wheat-winter wheat-corn-soybean the deduction falls to 0.25.

A further deduction is made for harvest interference or where harvest of one segment interferes with seeding of another. Use of deductions for harvest and seeding-harvest conflicts (just as for seeding time conflicts)need to be made based on local knowledge. The deduction used is one-half the proportion of the acreage seeded for harvest in which conflict occurs. In most cases this value will be one-half of the value obtained for seeding conflicts. For instance, in a wheat-soybean rotation where the seeding interference deduction would be -0.5 the deduction for harvest conflict would be -0.25. In some instances, seeding will conflict but harvest will not (early maturing barley and late maturing peas share seeding times but not harvest times). If this was the case a barley-pea rotation would have a seeding deduction of 1.0 and a harvest deduction of 0.25 (one-half of 0.5). In some instances conflicts will occur between seeding one crop and harvesting another. An example would be winter wheat and millet. Millet harvest conflicts with winter wheat seeding in some environments. Consequently, in a winter wheat-millet rotation the total deduction for harvest and seeding harvest interference is 0.5. This is derived by adding the harvest interference of 0.25 (one-half of 0.5) and the potential seeding-harvest interference of 0.25. In a winter wheat-corn-millet-fallow rotation the total deduction would be 0.33 since both the seeding and harvest-seeding interference affect only 1/3 of the seeded acreage.

Rotations with high Diversity Index Values (greater than 2.5) will provide the most workload spreading and present the least disease and weed risk. They will produce the most return only if they also have proper intensity, and adapted crop types are used. In some environments it may be difficult to obtain ideal levels of both diversity and intensity due to a lack of adapted crop types. In the early stages of no-till producers often have success with rotations which have proper intensity but lack diversity. Part of this is due to the fact that the land being used has not had a history of many of the crops being used (especially the broadleaf crops) so disease and weed problems have not yet developed. Another factor is that the producer's machinery is sized for a tilled system so he does not realize the potential value in adding diversity (smaller machinery or more acres). Use of both grass types and a broadleaf provides the most diversity possible especially if winter cereal is incorporated into the system.

The following table demonstrates how diversity and intensity affected profitability for 15 rotations in 1994. This is a one year snap-shot. Some of the profitability values are not expected to retain the same ranking over the long term. It is clear that both diversity and intensity are important to overall profitability in no-till. In general the best profits involved rotations with intensity ratings of 1.33 to 1.5 and diversity indexes of 3.0 or greater.

*Used 1997 Production Costs for calculating 1993-1997 Cost/Unit of Production.

*Used 1997 Production Costs for calculating 1993-1997 Cost/Unit of Production.

*Used 1997 Production Costs for calculating 1993-1997 Cost/Unit of Production.