Adrian M. Johnston, P.Ag2

Presented to 17th annual Manitoba-North Dakota Zero Tillage Workshop, Brandon, Manitoba.

Jan. 23-25, 1995.

2 Farming Systems Agronomist, Melfort Research Station, Agriculture and Agri-Food Canada, Box 1240, Melfort, SK. SOE TAO; Phone: 306-752-2776 (ext. 223).

SUMMARY

In this paper the concept is proposed that environmental conditions are the principle factor controlling the adoption of conservation farming practices.

In the dry Brown and Dark Brown soil zones soil conservation, achieved by preventing wind erosion on the inescapable summer fallow lands, is the principle role of conservation farming practices. Efficiency in the farming operation is achieved by controlling the cost of summer fallow practices which optimize crop residue cover to prevent erosion.

In the moist Dark Brown and Thin Black soil regions conservation farming practices have been demonstrated to provide improved moisture conservation, resulting in either significant reductions, or elimination, of summerfallow. By increasing the plant-available water to crops with direct seeding we can change the entire farming system, through extending the crop rotation, increasing the diversity of crops grown and minimizing the variability in production and farm incomes in this region.

In the moist Black and Gray soil zones economic and energy conservation are the principle benefits fostering the rapid expansion of conservation farming practices. Conventional tillage practices in this region are energy inefficient and capital asset intensive. Anything which can control cost of production, while providing equal or improved grain yields, will increase enterprise profitability.

INTRODUCTION

Conservation farming means different things to different people. While we are all fond of citing the advantage of conservation tillage practices in preventing soil erosion by wind and water, only recently have we begun to think of how conservation tillage has influenced soil moisture management, weed populations, machinery operations, and ultimately crop management decisions. As a scientist who is just beginning his career, I do not have volumes of my own data to present to you. Instead, and at the request of the conference organizing committee, I am going to present a series of observations on what I believe to be the factors influencing the adoption, or rather I should say the adaptation, of conservation farming practices into farming systems on the Canadian prairies.

DRY BROWN AND DARK BROWN REGIONS

Water is the limiting factor controlling crop production across all of the prairies. However, it is of particular importance for farmers in the dry Brown and Dark Brown soil zones where evaporation rates result in high moisture deficits (Table 1). If you do not have adequate water to seed a stubble crop, whether it be due to low growing season precipitation, or soils with poor water holding capacity, your cropping options are immediately restricted. Summer fallow becomes a key component of the cropping system, a practice which has the claim to fame of reducing soil organic matter, fostering soil erosion by wind and water, leaching nitrates into the subsoil, increasing soil salinization and most recently has been implicated in increasing the atmospheric addition of C02. With such a long list of complications, its no wonder that summer fallow has received so much attention.

An economic evaluation of crop rotation and tillage studies at Swift Current concluded that zero and minimum tillage production methods were generally less profitable than conventional tillage for either fallow-wheat or continuous wheat (Zentner et al. 1993). Zero tillage seeding systems showed total costs averaging $15 .47/ac higher for fallow-wheat, and $10.1 3/ac higher for continuous wheat, when compared with conventional tillage practices (Table 2). The cost of replacing tillage with herbicides was the principle factor effecting profitability. Wheat yields, either fallow or continuous cropping, showed little or no response to a reduction in tillage. The price of glyphosate, the principle herbicide used for tillage replacement, would have to decline by more than 50% of its 1993 retail cost for conservation tillage systems to be as profitable as conventional tillage in this region.Table 1. Mean annual wind speed, air temperature, and precipitation (1951-80) and calculated potential evapotranspiration (ETp) and moisture deficit from select locations on the Canadian prairies (from Campbell et al., 1990).

Crop diversification options such as lentil, mustard or sunola have been shown to use the same amount of water as wheat. However, none of these crops leave enough residue to protect the soil surface. Responsible land management in dry regions requires that crops be selected to provide maximum residue production, and every attempt made to maintain it on the soil surface during the 21 month summer fallow period. While there is abundant evidence to indicate that summer fallow method has little impact on moisture conservation, using low disturbance tillage implements such as a wide blade cultivator, or replacement of tillage with herbicides, is effective in minimizing erosion losses.

In summary, conservation farming in the dry Brown and Dark Brown soil zones focuses on soil conservation. Cost effective measures which minimize soil loss by wind and water erosion during the summer fallow period are the cornerstone of sustainable farming in the region. Identification of suitable alternate crops, which would compliment the dominant wheat and summer fallow rotation, is a key component to the development of more economically stable cropping system.

MOIST DARK BROWN AND THIN BLACK REGIONS

Typically referred to as the transition region from the dry prairies to the wet parkland, this production area represents the largest acreage of arable farm land on the prairies. However, it is also a region which has received considerable attention over the years in the development of water conserving farming practices.

There is abundant evidence to indicate that if there is at least 3 inches (80 mm) of plant-available soil moisture on stubble land in the spring, then the prospects for successful recropping are high (Dejong and Steppuhun, 1978). Annual surveys of soil moisture in the spring indicate that there is as much as 20 million acres on the Canadian prairies that are fallowed which have at least 3 inches (80 mm) of available moisture in the rooting zone.

A thorough review on the subject of fall tillage failed to reveal any study where the practice resulted in significant yield increases to subsequent crops (Lal and Steppuhun, 1980).

Trail results indicate that those tillage treatments which omitted fall cultivation had the highest yields, with the one-pass zero till treatment providing the highest yields (Rourke and Hargrave,

1994).

Direct seeding, combined with low/no cost snow management practices, have the potential to increase plant-available soil water and improve the efficiency with which it is used to produce grain in a continuous cropping system (Brandt et al., 1993).

Improved soil moisture conservation with zero and minimum tillage (no fall cultivation) were reported to increase grain yields relative to conventional tillage, while at the same time did not increase cost of production. The result is increased net returns for cropping systems which combine the practice of no fall tillage and minimizing soil disturbance at seeding (Lafond et al., 1993).

The full economic advantage from reduced tillage cropping systems is achieved only with the elimination of summerfallow (Brandt, 1994).

Indian Head (thin Black, clay texture) and Scott (moist Dark Brown, loam texture) Experimental Farms have both provided a very comprehensive, and recent, set of research results on the impact of conservation tillage practices on crop production in the moist Dark Brown and Thin Black regions. As the above summary points indicate, the impact of reduced tillage cropping practices on enterprise economic viability in this region is a function of your ability to manage water. Any practice which prevents the loss (or enhances) soil moisture content, increases the success of annual (continuous) cropping, and eliminates the lost production and cash costs associated with summer fallow.

Stewart Brandt, Agronomist at Scott Experimental Farm, calculated a variability index on both the yield and net returns associated with a number of crop rotation evaluated between 1986 and 1991 (Table 3). Rotations with a high proportion of cereals provided returns that tended to be lower and more variable than rotations that had a balance of cereals and oilseeds or pulses. Continuous cropping to wheat had the lowest net returns and the highest risk. A balanced rotation of barley -canola - lentil - wheat showed the highest net returns and only a slightly higher risk (16%) than fallow - wheat. The second highest net return, and lowest risk, was recorded for the fallow canola - wheat rotation, a common rotation in this region. Until recently, low wheat prices relative to the broadleaf crops such as: canola and lentil, revealed that producers were prepared to accept the increased risk associated with a mixed crop rotation.Table 3. Yield, estimated net return and year-to-year variability for several rotations in two crop rotation studies at Scott during 1986-1991 (From Brandt et al., 1993).

Similar results to increasing the crop mixture were obtained from a tillage trial conducted at Indian Head (Table 4). Shifting from a conventional to a minimum or zero tillage production system did not have a major impact on increasing cost of production in this study. Increasing cropping diversity in rotation resulted in a progressive increase in net returns, regardless of tillage system. The rotation which included both an oilseed and pulse crop, in mixture with cereals, showed the highest net return. As long as a minimum or zero tillage production system was adopted (no fall tillage), the elimination of summer fallow from the rotation was found to significantly increase profitability per acre.

At the 1994 Manitoba - North Dakota Zero-Tillage Workshop in Minot, David Rourke reported on a rotation by tillage study conducted at Minto, Manitoba (Rourke and Hargrave, 1994). The principle variation between the Minto and Indian Head studies is that at Minto both conventional and minimum tillage included fall tillage, whereas fall tillage was only used with conventional system at Indian Head. As with the Indian Head study, very little difference was recorded in cost of production between the three tillage treatments (Table 4). With the exception of rotation #2, no difference was observed for net returns between two and one fall tillage operations (conventional vs. minimum). The high net return for MT with rotation #2 was a result of a very low net return with conventional tillage (used as the base value of 100). Diversifying the rotation through the inclusion of either one or two oilseed crops resulted in significant increases in net returns over the 100% cereal rotation.Table 4. Average annual cost of production and net returns for three tillage systems and three crop rotations at Indian Head, 1987-1990 (adapted from Lafond et al., 1993) and Minto, 1991-1993 (Rourke and Hargrave, 1994). Values are presented for tillage treatment, within rotation, using conventional tillage as a base of 100.

In summary, conservation farming in the moist Dark Brown and Thin Black soil zones is a function of moisture conservation. By discontinuing fall tillage, and implementing methods to increase snow trapping, summer fallow for the purpose of moisture storage is no longer required. Annual, or continuous, cropping allows for increased diversity in the rotation, increasing profitability and minimizing risk relative to continuous cereal rotations. There is general consensus amongst most research and extension agronomists that the moist Dark Brown and thin Black soil zones have the greatest potential for increased grain productivity and enterprise economic viability from the implementation of direct seeding technology.

MOIST BLACK AND GRAY REGIONS

The moist Black and Gray soil zones are found in regions which are characterized by:

Sufficient plant-available moisture at seeding for annual cropping due to good overwinter snow accumulation and low evaporation rates,

One of the principle reasons for the moist characterization is the dominance of clay and clay loam soil textures, which provide superior water holding capacity,

Adequate growing season precipitation to prevent mid-season drought stress,

Late springs and early falls, leading to a short growing season,

Wide spread use of diverse and intensive crop rotations, and

Intensive tillage practices which are the envy of all fuel dealers!

Rather than conservation farming practices, research priorities in these high moisture regions have focused on short season variety development, efficient use of fertilizers, and weed and plant disease control strategies. While these regions are not immune to soil erosion by wind, water erosion from snow melt runoff and thunder storms can be devastating as a source of Soil degradation. Low summer fallow acreage, averaging from 8-12%, is practiced primarily for weed control, forage breaking or to minimize risk and investment associated with canola based rotations.

Results from research projects in this region show considerable variability in yield response to tillage. Ken Bowren, reporting in 1984 on research conducted at Melfort, concluded that the intensive tillage practices in the region were principally used to incorporate crop residues as part of preparing a seedbed, and challenged the use of tillage for effective weed control (Bowren, 1984). In general, fall tillage was not found to reduce grain yields, except in years of below average spring and summer moisture, such as 1981 (Table 5). In the Peace River region, wheat, barley and canola yields were not found to be significantly different under zero, minimum or conventional tillage (Arshad and Coy, 1993). An evaluation of barley grain yields in this region showed a positive response to zero tillage in dry growing seasons, a negative response in excessively wet years and no difference from conventional tillage in the remaining years (Arshad and Dobb, l 991).Table 5. Effect of seed bed preparation on grain yield at Melfort (1979-1983).

The absence of any consistent grain yield advantage to zero tillage requires that any economic benefit come from a reduction in cost of production. Unlike the drier regions of the prairies, where a shift from conventional to minimum or zero tillage may mean the elimination of 1 or two tillage operations, adoption of direct seeding in the moist Black and Gray soil zones can result in large reductions in machine operations. In northern Alberta Dave McAndrew evaluated the effect tillage intensity on the production and returns for barley (McAndrew et al., 1994). While the grain yield response to conservation tillage was minima] the impact on cost of production was very supportive of direct seeding (Table 6). As was reported for the Indian Head tillage study, the removal of fall tillage from the minimum tillage treatment resulted in yields similar to zero tillage.

The role of the implement used for direct seeding in the moist Black and Gray soil zones has a greater influence on production system success than in drier regions. It is my opinion that this is almost entirely due to soil texture and residue condition, rather than residue amount. The challenges associated with seeding a small seeded crop, shallow into a wet clay soil, covered with heavy wet cereal residue, requires a special piece of equipment - with a heavy emphasis on good management skills. Past research was done almost exclusively with disc type drills, the only commercially available zero till drills. A study conducted in the Peace River region of northern Alberta indicated that removal of the crop residue, in a band 3 inches wide over the seed row, increased seed zone soil temperature and seedling growth rate, without affecting soil moisture (Arshad and Azooz, 1994). Replacing the disc drill used in this study with a hoe type opener, which through normal operation would blacken a 2 to 3 inch strip of soil over the seedrow, would likely provide similar results. The dominance of hoe type drills and air seeders on direct seeding farms is an indication of machinery adaptation to specific problems.Table 6. Grain yield, cost of production and net returns from barley production systems at 3 locations in Alberta (from McAndrew et al., 1994).

Tom Thorson presented an economic overview of the impact of shifting from conventional to minimum or zero tillage seeding on hypothetical farms in the dry (50% cropped), transition (75% cropped) and wet (100% cropped) regions of Saskatchewan (Thorson, 1994). The economic benefit from shifting to direct seeding increased as cropped acreage increased, reflecting a) the number of acres that any debt servicing is spread over, and b) the greatest potential for reduction in machine operations. Considering machinery hours alone, he reported savings of 90, 250 and 400 hours per year in moving from 50 to 75 to 100% cropping. The switch to direct seeding resulted in tractor hours being reduced in half, in turn doubling the productive life span of this asset. Thorson concludes that if you are going to replace your machinery then equipment should be selected which will allow the farm to move towards some form of direct seeding system.

The current cost of energy to agriculture does not appear to be influencing production and management decisions by farmers. The rise in fertilizer nitrogen prices in the fall of 1994 had little to do with the cost of natural gas, rather the international demand for the product. University of Manitoba student Scott Henry conducted an evaluation of the energy requirements of two crop rotations, using conventional and zero tillage (Henry, 1994). On a simulated 1250 acre farm, using a wheat-flax-barley-canola rotation, the shift from conventional to zero tillage production systems resulted in a total energy saving of 6%, equivalent to of 1779 gallons (8087 1) of diesel fuel. In a rotation of wheat-pea-wheat-canola, which removed some of the fertilizer N required in the production of peas, zero tillage used only 92% of the total energy input required for conventional tillage. Using a diesel fuel equivalent this amounted to a saving of 1907 gallons (8667 1) per year on a 1250 acre farm. It is apparent from these calculations that future increases in energy costs to the farmer could influence both tillage and crop rotation practices.

In summary, conservation farming in the moist Black and Gray soil zones is a function of economics and energy conservation. While the yield benefit from conservation tillage practices may not be as consistent and positive as recorded in the drier regions of' the prairies, a reduction in the cost of production can positively influence net returns. The more intensive the tillage practices used, the greater the benefit which can be expected. The impact on machinery hours and life' span, labour; and energy consumption must all be considered in the cost of conversion to a conservation tillage production system.

GENERAL COMMENTS

I frequently hear from concerned farmers and agrologists that we seem to have hit a plateau in the adoption of conservation farming practices. This concern is likely a function of survey results which show a 5-7% adoption of direct seeding. However, it is my opinion that we should not be asking ourselves what is holding up the total acreage of zero tillage, but rather how many producers have actually changed their farming practices as a result of current and ongoing promotion programs? There is general consensus that total tillage, and in turn potential soil erodibility, is on the decline. The easiest indicator, however simplistic, might be to 100k at total air seeder sales in western Canada in the last five years. This high clearance implement allows all crops to be seeded with reduced total operations, in addition to providing future modification for low disturbance direct seeding production systems. As suggested by Tom Thorson, farmers who are replacing machinery are making choices which will provide them the option to switch seeding system with limited additional cost.

Over the past 10 to 15 years we have established a comprehensive data base on the feasibility of direct seeding practices on crop production. Whether your advantage comes from reducing soil erosion, replacing summer fallow with annual cropping, or reducing cost of production, our current technology is providing farmers with equal or superior grain yields with the elimination of tillage. We must now shift all of our attention, and resources, to addressing the specific and quantifiable benefits achieved from the management of low disturbance direct seeding systems. Fertilizer efficiency, crop water-use, crop sequence in rotation, weed management systems, crop residue management and machine evaluation are all issues which require our attention. In Manitoba you have the Manitoba Zero Tillage Research Farm, a producer controlled initiative, to provide leadership in addressing these issues. Continued pressure is inevitable on the funding of public research institutions such as universities and research stations. Only through cooperative initiatives, where the research planning and priorities are established jointly by producers, extension and research, are we going to make efficient use of our limited resources in moving forward with conservation farming practices on the Canadian prairies.

REFERENCES CITED

Arshad, M.A. and R.H. Azooz. 1994. Residue management for no-till planting for early crop growth in cold regions. pp.358. Agron. Abstracts, 1994. American Society of Agronomy, Madison, WI.

Arshad, M.A. and G.R. Coy. 1993. Tillage and cropping systems for soil conservation and sustained crop production in the Peace River region. CARTT (Component B') - Final Report, Pmject No.600791. Alberta Agriculture, Edmonton.

Arshad, M.A. and J.L. Dobb. 1991. Tillage effects on soil physical properties in the Peace River region: Implications for sustainable agriculture. in Proc. 28th annual Alberta Soil Sci. Workshop. Lethbridge, AB.

Bowren, K.E. 1984. Tillage alternatives for the Black and Gray soils in Saskatchewan. pp.143-158. In The optimum tillage challenge. Div. of Extension, Univ. of Saskatchewan, Saskatoon, 5K.

Brandt, S.A. 1994. Crop rotation research - What's going on? pp.5-12. In Proceedings of the crop rotations conference. Jan. 24-25, 1994 Saskatoon. Div. of Extension, University of Saskatchewan, Saskatoon, SK.

Brandt, S.A., F.B. Dyck and R.P. Zentner. 1993. Crop response to tillage on Brown and Dark Brown soils. In Proceedings Western Canada Agronomy Workshop, July 7-9, 1993, Red Deer, Alberta. Potash and Phosphate Institute of Canada, Saskatoon, Sask.

Brandt, S.A., R.P. Zentner, C.A. Campbell and V.0. Biederbeck. 1993. Crop rotations for direct seeding systems. pp.8-18. In Direct Seeding: Making it work in drier zones. Saskatchewan Soil Conservation Ass~ciation, Indian Head, Saskatchewan.

Campbell, C.A., R.P. Zentner, H.H. Janzen, and K.E. Bowren. 1990. Crop rotation studies on the Canadian prairies. PubI. 1841/E, Research Branch, Agriculture and Agri-Food Canada, Ottawa, ON.

Henry, 5. 1994. The energetics of cropping systems: A study of two crop rotations utilizing conventional and zero tillage production methods. Dept. of Plant Science, University of Manitoba, Winnipeg, MB.

Lafond, G.P., R.P. Zentner, R. Geremia and DA. Derksen. 1993. The eH'ects of tillage systems on the economic performance of spring wheat, winter wheat, flax and field pea production in east-central Saskatchewan. Can. J. Plant Sci. 73: 47-54.

McAndrew, D.W., K. Handford, R.P. Zentner, M. Gorda and J. Doner. 1994. Agr()n()n~ic and economic considerations in various barley production systems in East central Alherta. pp.97-110. h~ Proceedings of the 1994 Manitoba - North Dakota Zero-Tillage Workshop, Minot, N.D.

Rourke, D. and A. Hargrave. 1994. Zero till - is it the answer. pp.73-83. In Proceedings of tl~c 1994 Manitoba - North Dakota Zero-Tillage Workshop, Minot, N.D.

Thorson, T. 1994. Economics of direct seeding. pp.161-175. In Designing a sustainable agneultural system, 1994 SSCA Direct Seeding Workshop. SSCA, lndian Head, 5K.

Zentner, R.P., F.B. Dyck, S.A. Brandt, G.P. Lafond, C.A. Campbell and A. Moulin. 1993.Economics of conservation tillage systems in western Canada. hi Proceedings Western Canada Agronomy Workshop, July 7-9, 1993, Red Dcer, Alberta. Potash and Phosphate Institute of Canada, Saskatoon, Sask.