Advancing Sustainable Agriculture in the Pacific Northwest

Conservation Tillage Systems

Information Resource

PNW Conservation Tillage Handbook Series
Chapter 2 - Conservation Tillage Systems and Equipment, No. 19, May 1997

Direct Seeding Movement Aimed at Global Competitiveness, Soil Productivity and Erosion

Author: Roger Veseth, WSU/UI Conservation Tillage Specialist

We are entering a new and exciting era of crop production across America and around the world. It is a time of phenomenal increases in the use of direct seeding systems, driven to a large degree by farm profitability and competing with direct seeding growers across this continent and in other major grain producing countries. On the other side of the direct seeding coin, is an increasing recognition of the tremendous potential benefits for improving soil quality and productivity. Add to that almost zero soil erosion with everyone benefiting in improved water and air quality, and it all sounds like a dream come true. But it is not a dream. It is happening all around us and Northwest growers can not afford to wait and be left in the dust. Albeit the learning curve can be steep and rocky at times, but direct seeding is a win-win opportunity, both short and long term, one that growers can’t afford to pass up.


Competing with the Competition

Direct seeding and other minimum tillage systems offer the potential to reduce production costs, and increase profitability, helping growers become more competitive in an increasingly global marketplace. Northwest growers need to be aware of what production systems their national and international competitors are using. The Conservation Technology Information Center (CTIC) documents that the acreage of no-till in the U.S. has grown from 13 million acres in 1989 to over 42 million acres in 1996. They estimated that there were about 74 million acres of the world’s cropland under no-till in 1993. This included 39 million in the U.S., 22 million in Brazil, Argentina, Australia and Western Europe, and more than 12 million in Canada....some major U.S. wheat producing competitors.

Examples of 1996 data show that the trend towards no-till is growing rapidly. Data from Canada show that direct seeding of annual cropping acreage in large grain producing Provinces of Alberta, Saskatchewan and Manitoba were 37%, 55% and 43%, respectively. Estimates from Argentina show increases in the percentage of total cropland under no-till from less than 2% in 1990 to 9% in 1993 and 19% in 1996, with about 10 million acres currently under no-till. In Idaho, Oregon and Washington, less than 6% of the "small grain" production was under no-till in 1996, according to CTIC surveys. One exception was winter wheat in Idaho at almost 10%. Based on total cropland, there was only about 4% of the Northwest cropland under no-till in 1996

If we are going to compete economically and protect our cropland resources, we need to consider the production efficiency and soil productivity potentials of no-till direct seeding and other minimum tillage systems.


Shaking Off the Farm Bill Shackles

For decades, U.S. Farm Bills have been major obstacles to successful no-till and minimum tillage systems in the Northwest and across the country. Commodity program restrictions largely locking Northwest dryland growers into short crop rotations in order to maintain their wheat base acreage, and high proven yields for winter wheat. To help manage weeds and diseases, they were forced to rely on intensive tillage. When growers began in the 1970's to explore direct seeding their traditional 2-year rotations with winter wheat, many experienced reduced yields or crop failures due to soilborne diseases and winter annual weeds. At that time there was also little research base or grower experience to guide growers in managing these new conservation tillage systems. Since then, great strides have been made in management technologies for direct seeding. With the 1996 "Freedom to Farm" Bill, growers also now have more cropping flexibility to develop crop rotations critical to the success of direct seeding and other minimum tillage systems. Now is the time to seriously begin exploring new options for crop rotations, equipment, and management technologies for direct seeding or other minimum tillage systems.


New Insights into Tillage Impacts and Direct Seeding Benefits

Intensive tillage largely serves as a pest management substitute for crop rotation and other pest management practices. For many growers, there was little choice when they were locked into short rotations with winter wheat under decades of Farm Programs. But intensive tillage has had some high costs, many of which have been overlooked because of gradual soil impacts. In addition to high production costs, cropland resource costs of intensive tillage systems have included 1) soil loss by water and wind erosion and the associated reduction in productivity, 2) loss of soil organic matter, which leads to deterioration of soil structure, tilth, fertility, water holding capacity and increased erodibility, and 3) low water storage efficiency because of high rates of evaporation and runoff -- resulting in a reduced yield potential. When growers change from intensive tillage to direct seeding and other minimum tillage systems they can change these costs into benefits.

Recent research lead by USDA-ARS scientists in Minnesota has begun to document carbon dioxide emission from the soil after tillage, and the effect that has on soil organic matter and productivity. The results are revolutionizing our understanding about the impacts of tillage on soils. Soil organic matter or organic carbon is a critically important soil component directly related to soil fertility, water holding capacity and infiltration, aggregation and structure, erodibility, biological activity and a long list of other soil properties affecting soil productivity and soil quality.

The researchers point out that the reduction in soil organic carbon following tillage results from the addition of oxygen to the soil, similar to stoking a slow-burning fire. The increased oxygen level and higher soil temperature with bare soil after residue incorporation stimulate intense microbial activity under moist soil conditions. The result is accelerated loss of soil organic carbon as crop residue and soil organic matter is decomposed -- tillage is biologically burning off soil organic matter. In one study, they found that carbon loss in 19 days after fall plowing under moist conditions was greater than the total carbon contained in the stubble of the previous wheat crop. Contrary to the common belief that returning crop residue to the soil with tillage builds soil organic matter, the real impact of tillage is a continual decline in soil organic carbon. In their studies, no-till systems resulted in very low carbon loss and consequently have the potential for increasing soil organic carbon. Intermediate carbon losses occurred from minimum tillage systems. The greater and more frequent the soil disturbance, the greater the carbon loss.

Direct seeding systems offer the greatest potential in erosion control, soil quality improvements, water conservation and lower production costs, although 2- or 3-pass minimum tillage systems can also achieve significant improvements in these areas. Because of improved water conservation and soil productivity, no-till and minimum tillage systems also have a higher dryland yield potential than under intensive tillage. The challenge for growers and Ag support personnel is to develop the crop management systems for control of pests previously controlled by intensive tillage in order to take advantage of the higher yield potential.


A New Ball Game with New Direct Seeding Technology

Much has changed since Northwest growers began trying no-till drills in the 1970's. Many of the pest problems that occurred during the past 25 years can now be largely avoided because of new research developments in management technologies, and NOW, Farm Program flexibility in crop rotations. Northwest research has shown that there are a number of important management components needed for successful conservation tillage systems. Crop rotation is the MOST EFFECTIVE pest management tool under conservation tillage. For example, Northwest research has shown that a 3-year rotation with 2 years out of winter wheat effectively minimizes crop losses from several winter annual grass weeds and soilborne diseases that commonly reduce winter wheat yields in shorter rotations under conservation tillage.

Until now, a 3-year crop rotation, such as winter wheat - spring barley - fallow or legumes was often difficult for growers to change to if the farm had a high wheat base or limited barley base, or both. Recropping with spring crops, either for a couple years or longer term can also effectively control many pest problems associated with winter wheat production. Formidable challenges like jointed goatgrass are driving grower into spring cropping systems. Utilizing direct seeding or minimum tillage systems for establishing spring crops offers the greatest potential for efficient use of water for spring crop production, as well as soil conservation.

Direct seed spring cropping is becoming an attractive production option to winter wheat-fallow in the lower precipitation areas, particularly when there is adequate soil water for spring recropping. Flex-cropping of winter and spring crops based on water is now a management option, and has the greatest potential under direct seeding. In the past, direct seeded winter wheat on chemical fallow had only limited success after conventional tillage practices in the Northwest due to lack of seedzone water for timely crop establishment and weed competition. We now need to re-evaluate direct seeded winter wheat on chemical fallow after rotations with years of direct seeded spring crops. That would be is a very different winter wheat planting environment because of increases in organic matter content, surface residue levels, improvements in soil structure, and very low levels of many winter annual weeds and soilborne diseases associated with winter wheat in 2-year rotations.

In addition to crop rotation, the success of no-till and minimum tillage systems are influenced by a number of other management practices identified by Northwest research. An important starting point is uniform combine residue distribution at harvest, particularly the chaff, which contains the weed and volunteer grain seeds. Control of weeds and volunteer grain that provide a "green bridge" root disease host for spring crops should begin in the fall, when possible, and early in the spring at least 2-3 weeks before seeding. Fertilizer placement below seed depth and near seed rows has been shown to make the crop more competitive under pressure from root diseases and grass weeds. New seed treatments and plant resistance also offer growers improved control of some disease and insect problems in conservation tillage systems.


The Team Effort Challenge Ahead

The agricultural industry and researchers are being challenged to expand and refocus research efforts to better address grower needs as they make the transition to direct seeding and minimum tillage systems with new crop rotations now possible under the new Farm Bill. Several new research projects are now underway through support from STEEP III, Washington Wheat Commission, the Columbia Plateau Wind Erosion Project, Monsanto, Conservation Districts and other sources. Most of the projects are collaborative on-farm testing efforts to evaluate new crops and management strategies. More than ever before, there is a need to develop strong partnerships between growers, researchers, Ag service industry and Ag support personnel to help growers make a successful transition into direct seed intensive cropping systems....the farming systems of the future, here today.


The Pacific Northwest Conservation Tillage Handbook is a large three-ring binder handbook that is updated with new and revised Handbook Series publications. It was initiated in 1989 as a PNW Extension publication in Idaho, Oregon and Washington. Updates to the Handbook are provided when the updating card is returned. By 1997, 34 new PNW Conservation Tillage Handbook Series have been added to the original 98 publications Copies are available for $20 through county extension offices in the Northwest or ordered directly by calling state extension publication offices: Idaho -- (208) 885-7982; Oregon -- (541)-737-2513; Washington -- (509) 335-2999 (some shipping and handling charges and sales tax may apply).

It’s now accessible on the Internet! All of the PNW Conservation Tillage Handbook and Handbook Series are being put on the World Wide Web Home Page ( titled Pacific Northwest STEEP III Conservation Farming Systems Information Source. The Web site also contains recent issues of the PNW STEEP III Extension Conservation Tillage Update, listings of other conservation tillage information resources, coming events and much more. For more information on the Handbook or updates to the Handbook, contact Roger Veseth, WSU/UI Conservation Tillage Specialist, Plant Soil and Entomological Sciences Department, University of Idaho, Moscow, ID 83844-2339, phone 208-885-6386, FAX 208-885-7760, e-mail (

Pacific Northwest Conservation Tillage Handbook Series publications are jointly produced by University of Idaho Cooperative Extension System, Oregon State University Extension Service and Washington State University Cooperative Extension. Similar crops, climate, and topography create a natural geographic unit that crosses state lines in this region. Joint writing, editing, and production prevent duplication of effort, broaden the availability of faculty, and substantially reduce costs for the participating states.

For herbicide application recommendations, refer to product labels and the Pacific Northwest Weed Control Handbook, an annually revised extension publication available from the extension offices of the University of Idaho, Oregon State University and Washington State University. To simplify information, chemical and equipment trade names have been used. Neither endorsement of named products is intended, nor criticism implied of similar products not mentioned.

Cooperative Extension programs and policies comply with federal and state laws and regulations on nondiscrimination regarding race, color, gender, national origin, religion, age, disability, and sexual orientation. The University of Idaho Cooperative Extension System, Oregon State University Extension Service and Washington State University Cooperative Extension are Equal Opportunity Employers.

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Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA (208)885-5971
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