Oregon State University
Washington State University
University of Idaho
Direct Seed Newsletters
  PNW Update Newsletter


Cropping Systems Approach to Crop Health Management in Conservation Tillage

Roger Veseth, WSU/UI Conservation Tillage Specialist

Introduction and Background

Taking a cropping systems approach to crop health management simply means striving to look at your entire crop rotation and production practices as a whole interconnected system. You need to be aware of the potential effects that your management choices have on plant growth and nutrition, weeds, diseases, insects and other environmental stresses that can affect the health and yield of all crops in your rotation under conservation tillage. Changing one piece of the production system, such as tillage practices, will undoubtedly have effects on other physical, biological, or chemical factors affecting one or more of the crops in your rotation. The more you are aware of research findings and grower experiences on the effects of different management options, the better you will be able to develop and maintain successful conservation tillage systems.

The development of successful conservation tillage systems is an evolutionary process for most farmers. It is a process of searching for new technologies and management strategies and then evaluating and adapting appropriate options to your own farm. It is not easy and it requires commitment to designing a conservation tillage systems that works for you in order to achieve the increased potential profitability and resource protection and enhancement it can provide.

In the Pacific Northwest region of the United States, an increasing number of innovative growers began experimenting with different conservation tillage implements in the 1970's and early 1980's. The primary focus was on drills that could plant through residue from the previous crop with little or no prior tillage. Most growers had no experience with how to adjust other aspects of crop production when changing from tillage-intensive systems to conservation tillage systems. At the same time, there was little research base to provide guidance to growers in this transition. Numerous early attempts ended in failure, usually because of severe weed and/or disease problems. Looking back, it now seems obvious that this was the result of trying to change one part of the cropping system -- the tillage practices -- without having all of the "pieces of the new cropping system puzzle" in place. At that time, however, they were doing the best they could with the information they had.

In the 1990's, the prospects for developing profitable, effective conservation tillage systems have greatly improved. Significant advances in production and equipment technologies now provide growers with more of the pieces of the management puzzles for their conservation tillage systems. Beginning in 1975, the large, interdisciplinary STEEP (Solutions to Environmental and Economic Problems) research program on conservation farming systems in Idaho, Oregon and Washington began to help solve a number of the production problems encountered earlier. The 5-year STEEP II program continued and expanded the research and educational efforts starting in 1991. A STEEP III program is scheduled to begin in 1996. The STEEP conservation farming programs would not have been possible without the continued involvement and support of grain grower and conservation district organizations in the region. The dramatic diversity of soils, climatic conditions, crop rotations and production practices across the Northwest demands continued research and grower innovation to develop and adapt conservation tillage technologies for local production conditions.

There have been many new management technologies and strategies developed for a cropping systems approach to crop health management under conservation tillage in the Pacific Northwest. A few examples to be discussed here include combine residue distribution, fertilizer placement, crop rotation, "green bridge" management, equipment considerations, and on-farm testing of new technologies. Some key references for more information will also be suggested.

Combine Residue Distribution

Most no-till and minimum tillage growers will tell you that uniform distribution of residues and crop and weed seeds from the combine is an important starting point for successful conservation tillage systems. Uniform distribution is critical to achieve good seed-soil contact, reduce tie-up of soil and fertilizer nutrients, improve effectiveness of weed control practices, minimize soilborne diseases and reducing cover and food for rodents.

Combine header widths and crop residue production have both increased over the past several decades. Most standard factory-run combines have not been equipped to uniformly spread the large volumes of straw and chaff produced. Shop modifications of existing spreading equipment or additions of commercial spreading attachments can eliminate production problems associated with combine straw and chaff rows in conservation tillage systems.

Fertilizer Placement

Pacific Northwest research has shown that deep fertilizer banding below or near the seed rows and below seeding depth for early root access often increases crop yield potential in conservation tillage. Some advantages include: increased early plant vigor, less competition from grass weeds and improved ability of the crop to compete with weeds; less nutrient tie-up during microbial decomposition of residue; increased winterhardiness of fall-seeded crops; and higher fertilizer use efficiency.

Research on patterns of cereal root and tiller development has played an important role in fertilizer placement strategies in conservation tillage. Cereals have two types of roots: seminal roots, which at the seed; and crown or nodal roots which form at the base of the crown. As tillers emerge, corresponding crown roots develop. Until the cereal plant has 4 leaves and one tiller, it is entirely supported by the seminal root system. Plant stress from low nutrient availability, root disease or other environmental factors as early as the 2-leaf stage can result in the skipping or abortion of the first tiller, which is the highest producing tiller. Because of the seminal root geometry and potential plant need for early fertilizer access, fertilizer band placement below seeding deep near the seed row for early seminal root access can often be important in conservation tillage, which is can be a more stressful seedling environment than under conventional tillage. This research on patterns of cereal root and tiller development, and fertilizer placement has greatly influenced the design of no-till and minimum tillage drills, and direct-shank fertilizer applicators used in the region.

Fertilizer placement can be an important pest management tool in conservation tillage systems. This will be discussed in the following section on pest management strategies.

Pest Management Strategies

Effective pest management strategies are crucial to optimizing crop health and yield potential under conservation tillage. Northwest research has helped to identify what disease, weed and insect problems were most yield-limiting in the major dryland crop production regions, and how the pest problems were affected by management options. The following are some important components of pest management strategies developed for conservation tillage systems.

Crop Rotation

Crop rotation has proven to be one of the single most effective pest management tool. This is not "new science," but recent research has documented its importance in conservation tillage systems. Soil fumigation has been used as a research tool in the Northwest to determine crop yield loss from root diseases and estimate attainable yield limited only by available water and other environmental constraints. Based on 15 years of field research by the USDA-Agricultural Research Service in eastern Washington, yields of continuous winter wheat were increased by an average of 70 percent by soil fumigation. With a 2-year winter wheat-spring dry pea/lentil/or fallow rotation, there was a 22 percent average yield increase with fumigation. In 3-year crop rotations, such as winter wheat-spring barley-spring pea, there was only a 7 percent average yield response to fumigation. These research results demonstrate that crop rotation is nearly as effective as soil fumigation for controlling many root diseases which can cause severe yield losses under conservation tillage -- only it takes longer.

The importance of crop rotation and benefits of conservation tillage were recently illustrated in a 6-year USDA-ARS integrated pest management (IPM)-conservation cropping system project near Pullman, Washington in a 21-inch annual precipitation zone. It was conducted with field-scale equipment on an 80-acre research site from 1985-91. The project compared 12 cropping systems comprised of combinations of two crop rotations, conservation and conventional tillage, and three weed management levels. A 3-year rotation of winter wheat-spring barley-spring dry pea (WBP) was compared with continuous wheat -- winter wheat-winter wheat-spring wheat (WWW). The conservation tillage system included no-till seeding winter wheat after peas (WBP) and spring wheat (WWW). Minimum tillage, beginning with a straight-shank chisel, was used after winter wheat and spring barley. Primary tillage under the conventional tillage system was moldboard plowing after wheat and barley, and the disc after peas. Weed management levels were minimum, moderate and maximum, all with labeled herbicide rates.

Under conservation tillage, there was nearly a 25% increase in winter wheat yield after peas (WBP) compared to after spring wheat (WWW), when yields were averaged over weed management levels. The yield response was largely attributed to improved control of soilborne diseases and winter annual grass weeds, and more available soil water after peas. Approximately 10% higher winter wheat yields (averaged over weed management levels) were achieved with direct seeding after peas and spring wheat compared to conventional tillage because of increased soil water storage overwinter in dryer years and improved winter survival. In addition, the direct -seeded wheat fields always retained adequate surface residue to meet farm conservation plan requirements while winter wheat under conventional tillage did not.

Fertilizer Placement

Fertilizer placement for early root access is a good general production practice, although the crop response to different fertilizer placement options is often strongly influenced by crop rotation, which in turn, influences root disease potential and other pest problems. Northwest research has shown that fertilizer placement below or near the seed row and below seeding depth can significantly reduce the effects of roots diseases when cereals are planted after cereals under conservation tillage. Conversely, fertilizer placement is less important when cereals are planted after non-cereal crops.

Several Northwest studies have demonstrated that, compared to surface broadcasting, deep banding of most of the crop's nitrogen fertilizer requirement can significantly reduce populations of grassy weeds, such as wild oats and downy brome, and increase crop competitiveness and yield potential of cereals in conservation tillage systems.

Green Bridge Control

Early control of volunteer grain and weeds between harvest and spring planting has recently been identified as another important component in crop health management strategies under no-till and minimum tillage in the Pacific Northwest.

Research has shown that the roots of volunteer grain and weeds growing between harvest and planting of the spring crop can serve as a "Green Bridge" host for root diseases to attack spring crops under conservation tillage, particularly with direct seeding. In the past, a common practice with no-till and minimum tillage seeding of spring cereals in the Northwest had been to spray volunteer grain and weeds with a non-selective herbicide, such as glyphosate, shortly before seeding. This short time interval between spraying and seeding greatly increases the potential for some root diseases, particularly Rhizoctonia root rot, Pythium root rot and take-all. The population of root pathogens already on or in the roots of these plants rapidly increases as the plants slowly die and are often at a peak population a few days after spraying -- when no-till seeding often occurred.

Earlier control of the green bridge, ideally beginning in the fall after harvest and at least 2-3 weeks before spring seeding, sharply reduces root disease potential and commonly increase yields of direct-seeded spring cereals after cereals by 20 to 50 percent compared to letting the green bridge grow up until shortly before planting.

Early green bridge control can increase the success of spring crops and the feasibility of using conservation tillage in spring crop production. More profitable spring cropping, in turn, permits longer crop rotations in winter wheat production areas, which reduce root diseases and other pest problems for all crops in the rotation under conservation tillage. Early green bridge control is also very important in rotations with continuous spring cropping. The best part about the green bridge-disease management tool is that there are little or no additional costs -- it is only a matter of timing.

The use of tillage for spring seedbed preparation can also reduce the "green bridge effect" on root diseases for the following spring crop by accelerating the decomposition of roots of volunteer grain and weeds before root pathogen populations can increase. However, Northwest researchers have found that early green bridge control with a non-selective herbicide before direct-seeding of spring cereals without prior tillage has resulted in yields that were as good as and often better than with tillage. Tillage increases soil water loss by evaporation and surface runoff, thus reducing yield potential for spring crops. Spring tillage on wet soils also increases soil compaction problems. If a non-selective herbicide is used ahead of tillage in a minimum tillage system, preliminary research results indicates that it still may be advantageous to spray 2-3 weeks ahead of seeding. More research is needed on the importance of spray timing ahead of seeding spring crops under minimum tillage systems. The important thing to remember is that crop residue is not the primary food source for root pathogens affecting spring crops under conservation tillage -- it is the roots of volunteer grain and weeds growing between crops.

Early elimination of volunteer and weeds with a non-selective herbicide in the fall and/or early in the spring can also improve control of winter annual grass weeds while increasing water conservation, and minimizes the need for tillage. With tillage alone, control of volunteer cereals and winter annual grass weeds, such as downy brome, is often difficult in the spring because wet spring conditions often result in "transplanting" of the weeds. This is particularly a problem if they become "sodded-in" in a dense matt in the spring.

Equipment Considerations

Equipment options for conservation tillage systems in the Pacific Northwest have changed dramatically over the last 25 years -- a major "revolution" in equipment design for and use in conservation tillage. A wide variety of tillage implement are now available to reduce tillage intensity and manage more surface residue. Improvements and modifications in fertilizer application and planting equipment have particularly increased grower options for conservation tillage systems. An important advantage growers now have with new equipment options is that research and grower experience has provided many of the management pieces for the "cropping system puzzle" to maintain and improve crop health and yield potential with the transition to conservation tillage.

One-pass Drills

In the early 1970's, there were only about 5 models of direct seeding drills available in the Northwest, none of which were capable of deep banding fertilizer -- most of the nitrogen was being broadcast under no-till systems. Today, over 60 different models of commercial and grower-built direct seeding drills are being used across the region, nearly all with deep fertilizer placement options, and they vary considerably in the degree of soil disturbance and residue retention. Important drill capabilities include: penetrating hard dry soil; deep banding fertilizer below seeding depth and near seed rows; penetrating crop residue to prevent hair-pinning of residue in the seed row, or plugging of the drill; and seeding at an accurate depth with good seed-soil contact.

One minimum tillage approach to one-pass planting with "chisel-drills" has become increasingly popular in the annual cropping region. The chisel-drill typically consists of a standard chisel, modified for deep banding of fertilizer, followed by a 3-point hitch double disk drill. The idea originated through a University of Idaho STEEP research project and has been adapted by innovative growers and some agricultural equipment and chemical dealers. More than 50 chisel-drills have been built for one-pass planting in the annual cropping area of eastern Washington and northern Idaho. Benefits growers often cite for planting winter wheat with the chisel-drill system include: loosening soils compacted during planting of spring crops under wet soil conditions; reducing root disease potential with tillage; reducing runoff and erosion with surface roughness, retention of much of the surface residue and improved water infiltration; deep banding fertilizer reasonably close to the seed rows (commonly results in a paired-row effect in the field); maintaining or increasing yield potential; and a relatively low equipment cost.

"Shank-&-Seed" Minimum Tillage Systems

The introduction of heavy duty, direct-shank fertilizer applicators has eliminated the need for a primary tillage operation (commonly the disk) in order to use conventional shank-type fertilizer applicators in pea and lentil ground and after other lower residue crops. They are also used to a lesser degree for fertilizing chemical fallow. In the last 10 years, most fertilizer dealers in the Inland Northwest have built their own versions of direct-shank fertilizer applicators available to growers they serve. Depending on the type of fertilizer applicator shanks, depth, speed and soil conditions, direct shanking of fertilizer can often maintain about 90 percent or more of the residue on the surface and create a relatively rough surface. A significant number of growers have also added fertilizer injection equipment on chisels and cultivators to accomplish the same purpose.

With direct-shank fertilizer injection, and the minimum tillage associated with the operation, growers can then use their conventional drills (without options for deep banding of fertilizer) for seeding in minimum tillage systems. They do not have to invest in a no-till drill to have an effective conservation tillage systems.

These new fertilizer equipment options have enabled the development of what has become know as "shank (fertilizer)-and-seed" systems which are now used extensively for planting winter wheat after low-residue crops in the Inland Northwest. In the strictest sense, it means direct shanking of fertilizer, followed by a non-selective herbicide application before seeding. However, a cultivator or cultivator-rod weeder combination is frequently used in place of the herbicide, and, when used properly, can result in only a minor reduction in surface residue and surface roughness.

Soil Compaction

In any tillage system, it is important to minimize field operations under wet soil conditions to reduce the potential for soil compaction. A variety of crop health and production problems can be associated with soil compaction, such as restricted root growth, increased root disease potential, and greater surface runoff and erosion potential.

One caution with direct seeding of winter wheat after "conventionally-planted" spring pea, lentil or other low-residue spring crops is the potential for soil compaction problems created during spring seedbed preparation and planting when soils are wet. Depending on the degree of soil roughness and fracturing of the compacted soil, direct seeding with no-till disc drills may not improve water infiltration and internal drainage as much as shank-and-seed systems with more and deeper soil disturbance. If the fertilizer shank depth on the fertilizer applicator or no-till drill is adequate, the shanks can help fracture compacted surface soil. No-till drills that do little soil disturbance and rely primarily on the limited amount of surface residue after low residue crops for runoff and erosion protection may be at a disadvantage under these conditions.

As an alternative solution to this problem, there is increasing interest in expanding no-till and minimum tillage seeding of low-residue spring crops in the Pacific Northwest to minimize this "carryover compaction" effect and, equally important, to increase surface retention of the previous spring crop's residue through the low-residue crop and winter wheat establishment. A new research effort on this conservation approach is underway with growers through on-farm testing. A breeding program is also underway to develop legume varieties and alternative crops that produce more residue and/or residue that decomposes at a slower rate.

There is also increasing interest in using a subsoiler as a conservation and production tool in the Northwest. However, more research is needed to determine the value and effective use of subsoiling in the different cropping regions of the Northwest. Several new research efforts are currently underway. Soil compaction can potentially be a significant contributor to runoff and erosion problems in much of the region, as well as a yield limitation through restricted root growth and soil water storage, and increased root disease potential.

Tillage Rotation

In the annual cropping areas, instead of trying to make one tillage and planting system work in all crops in the rotation, most growers are typically rotating tillage systems along with the crop rotation. They are direct seeding where they have the greatest chance of success, typically after low residue crops, such as peas, lentils, canola, winter rape, and other spring crops. After high residue crops, particularly winter wheat, growers are gradually beginning to switch from the traditional fall moldboard plowing to fall chiseling and using other combination tillage implements in minimum or reduced tillage systems. Used properly, however, the moldboard plow can still be part of conservation cropping systems in some areas. Growers who uphill plow -- turn the furrow uphill in sloping cropland -- retain more surface residue and feel that it is an effective conservation tool to help counter the serious tillage erosion problem that has occurred from downhill plowing and other tillage operations.

Interest in continuous no-till systems is growing, although only a limited number of growers are doing this now. So far, continuous no-till spring cereals in the low and intermediate precipitation zone has been the most successful. Most growers using no-till drills in the higher precipitation areas are using some fall tillage after winter wheat and most spring cereals to prepare a warmer, dryer seedbed for direct seeding or minimum tillage seeding in the spring. It is also difficult to direct seed after these high residue crops with most drills available. Research efforts are underway to develop new technologies and strategies for continuous no-till systems across a wide range of precipitation zones and cropping systems. Preliminary results from long-term no-till research efforts and grower experiences across North America indicate that there may be a potential for substantial improvements in soil quality (organic matter content, microbial activity, aggregation, "tilth", and so on) and crop productivity compared to other tillage systems.

On-Farm Testing

Growers have always evaluated new farming technologies in their own fields in order to improve the effectiveness and profitability of their farming system. This process is as old as the farming profession itself.

Today, however, growers need to make more accurate, informed choices from the seemingly endless list of options in production practices, products and equipment for conservation tillage. One of the best ways for growers to select some management options is to evaluate them in their own fields, under their production conditions -- in essence, to evaluate them as a component of their "cropping system." Substantial costs or returns frequently hinge on decisions based upon the results of these field evaluations, so they need to be accurate. In order to make more accurate field evaluations, growers need a basic understanding of scientific experimental methods and designs -- from a practical standpoint.

"Traditional" approaches to making field comparisons of a new practice with current production practices have often included: 1) splitting fields; 2) making a few passes around the field using the new practice; 3) comparing a whole field under the new practice with a nearby field without; 4) comparing the yield of a field using the new practice with yields from the same field in previous years; or 5) comparing one strip of the new practice with the rest of the field. Although growers can see how a new practice "looks" with these approaches, they can not be sure if it results in higher or lower yields. Natural field variability can overshadow or exaggerate the effects of the practice itself. When evaluating most new production practices, growers need to determine the bottom line -- is it more or less profitable than their current practices.

On-farm testing is emerging as an important tool in the Northwest to accelerate the development and adoption of conservation tillage practices at a local level. Methodologies for farmer-conducted, replicated field experiments have been developed as part of a STEEP II on-farm testing project in Idaho, Oregon and Washington.

Soil properties and production limitations can vary dramatically within and between fields in Northwest cropland. The effects of this variability on crop yield and other production considerations can be very obvious at times, but are often quite difficult to notice visually. Northwest research conducted in "uniform" areas of 13 wheat and barley field across the region has shown that it is not uncommon to have yield differences of 5 to 10 bushels per acre in adjacent combine strips due to natural field variability -- variability you would not see in the field. Statistical analysis of replicated comparisons with the proper design and randomization can help remove the effects of natural variability and provide growers with accurate comparisons of practices.

Research on on-farm testing methods indicated that at least three and preferably four replications of the side-by-side comparisons gives good statistical power of separating differences between treatments. Randomizing the location of the treatment within each replication (e.g. left or right plots) also avoids misleading conclusions due to directional yield gradients which are common in most fields. Plot lengths of 700 to more than 1,500 feet generally tended to remove more of the natural field variability than shorter lengths -- allowing more accurate identification of differences due to effects of practices being compared. But, plot length depends largely on local field sizes, variability and landscapes. It is important to take full combine header cuts to prevent yield errors in harvest area calculations. Portable truck scales and weigh wagons have made yield determinations faster and more accurate. Combine yield monitors are also becoming more available, accurate and affordable.

In addition to comparing yields in on-farm tests, replicated test designs are critical for accurately evaluating practices for soil water storage, soil erosion control, pest control and other management considerations. Special trial designs have been developed to compare practice effects on runoff and erosion in sloping cropland.

Summary and Information Resources

In summary, the development and maintenance of successful conservation tillage systems depends on a cropping systems approach to crop health and resource protection. It should involve a combination of available physical, biological and chemical options integrated for maximum overall effect, but with due consideration to ecological and economic limits of the crop and the cropping systems.

The following are brief descriptions of some major Northwest references which provide more details on all of the topics addressed in this presentation, and many more management considerations in a cropping systems approach to crop health in conservation tillage. Addresses and phone numbers are provided for accessing copies of most of the references.

Wheat Health Management - The first and most comprehensive reference is a book titled "Wheat Health Management" which is North American in scope. It was printed in 1991 as the first book in a new "Plant Health Management Series" by the American Phytopathological Society (APS) Press. An underlying theme throughout this book is optimizing wheat health and yield potential under conservation tillage systems.

Wheat Health Management was written to help guide wheat health managers -- farmers, fieldmen, farm advisors, Extension and other agricultural service and support personnel -- to an understanding of the basic concepts and approaches to wheat health management. It is a unique crop production guide in that it integrates all important facets of wheat health management into a decision framework to help growers develop more efficient, environmentally-sound production systems which optimize yields within the constraints of the environment. This book focuses on the whole "cropping system" -- not just on the wheat crop or on individual management choices apart from interactions within the overall production system. Although the book is about wheat production, many of basic principles of crop health management apply to other crops.

The authors are R. James Cook, Plant Pathologist with the USDA-Agricultural Research Service at Washington State University in Pullman, and myself. We want to stress that, as authors, we receive no royalties on book sales, just the satisfaction of contributing to a healthier, more sustainable wheat industry. To request more information on the book or to order a copy, call APS Press toll-free at 1-800-328-7560 between 8 a.m. and 4 p.m. CST. The book price is $45, including shipping and handling.

PNW Conservation Tillage Handbook Series - The second major reference is the 1989 Pacific Northwest Conservation Tillage Handbook Series, which is a compilation of much of the applied research results developed through STEEP and related research projects since 1975. As of December 1995, the Handbook consists of 130 PNW Conservation Tillage Handbook Series publications, 32 of which have been added to the Handbook since it was printed. The publications are written from the perspective of how the new research developments can fit into a grower's management systems and where they apply in the diverse crop production regions of the Northwest.

The large 3-ring binder Handbook can be purchased through local Northwest county extension offices or ordered for $20 payable to Ag Publications, from: Ag publications, Building J40, Idaho St., University of Idaho, Moscow, ID 83844-2240 (208-885-7982). The price includes postage and handling, and new Handbook Series publications that keep the Handbook up to date (distributed when the Handbook "updating card" is returned).

USDA-ARS IPM-Conservation Cropping System Project - The results of this 6-year IPM/conservation cropping systems project are summarized in a 30-minute video "Profitable Conservation Cropping Systems -- Insights from the USDA-ARS IPM Project." It shows how conservation cropping systems, with longer crop rotation and effective pest management strategies, can be more economical and less risky than conventional systems that use intensive tillage. The video, VT0029, is available for $15 payable to WSU Cooperative Extension Publications, from: Bulletin Office, Cooperative Extension, Cooper Publications Bldg., Washington State University, Pullman, WA 99164-5912 (509-335-2999).

The first of a series of publications have recently been completed summarizing various aspects of the 6-year project. A detailed description of all the management components and inputs for the project are included in IPM Research Project for Inland Pacific Northwest Wheat Production, 1993, WSU Research Bulletin XB1029. It is available free of charge from WSU Cooperative Extension (address/phone above). Professional journal papers summarizing portions of the study so far include: Profit and Risk for Integrated Conservation Farming Systems in the Palouse, 1994, Jour. Soil and Water Conservation. Vol. 49 (6):601-606; Tillage and Weed Management Affects Winter Wheat Yield in an Integrated Pest Management System, 1994, Agronomy Jour. Vol. 86:147-154; Integration of Weed Management and Tillage Practices in Spring Dry Pea Production, 1994, Agronomy Jour. Vol. 86:868-874; and Case Studies of Integrated/Whole Farm Systems Designs: Field-Scale Replicated IPM Trials, 1994, American Jour. Alternative Agric. vol. 9, Numbers 1 & 2:52-56. Most libraries would have or could access copies of these journals. A series of PNW Extension publications are being developed to increase availability of the project results.

Combine Residue Management - Uniform Combine Residue Distribution for Successful No-till and Minimum Tillage Systems, PNW Extension Bulletin 297, reviews the research and grower experience behind the importance of combine residue management in conservation systems (copies available for $.50 through UI or WSU addresses above). Additional references on the topic can be found in Wheat Health Management and several PNW Conservation Tillage Handbook Series.

Fertilizer Placement - Fertilizer Band Location for Cereal Root Access in No-till and Minimum Tillage Systems, PNW Extension Bulletin 283, provides an in-depth review of research on patterns of cereal root development and research on crop response to fertilizer placement in conservation systems (copies available for $.50 through UI or WSU addresses above). Additional information on the importance of fertilizer placement as a management tool for root diseases and grass weed control is covered in Wheat Health Management and several PNW Conservation Tillage Handbook Series.

Managing the Green Bridge - A Washington State University Cooperative Extension video titled Managing the Green Bridge: Root Disease Control in Conservation Tillage, WSU Cooperative Extension video VT0040, was completed in 1993. The 17-minute video begins with a series of animated graphics to explain the interactions between volunteer growth, timing of the non-selective herbicide and root disease potential. It then features field interviews with two USDA-Agricultural Research Service scientists and field footage of the effects of early versus late green bridge control for spring barley after spring wheat under no-till and conventional tillage. Two Washington growers also explain their experiences with early green bridge control in their farming systems and how it increases the opportunity for profitable spring cropping under conservation tillage. It is available for $15 payable to WSU Cooperative Extension Publications (address/phone above). More information on the green bridge can also be found in the PNW Conservation Tillage Handbook Series and Wheat Health Management.

New Residue Management Guide - The 1995 publication Crop Residue Management to Reduce Erosion and Improve Soil Quality -- Northwest, USDA-ARS Conservation Research Rpt. No. 40, is one of six regional publications designed to bring research results and experiences of experts in the field of crop residue management to the attention of growers and their advisors. Teams of Northwest scientists developed a series of chapters on crop production and pest management for conservation tillage systems in the low, intermediate and high precipitation zones and under irrigation. Each of the six regional books also include a number of chapters on broader conservation issues related to residue management. Copies are available without charge through Northwest conservation districts or can be ordered for $10 payable to Conservation Technology Information Center at 1220 Potter Drive, Room 170, West Lafayette, IN 47906 (317-494-9555).

On-Farm Testing - There are an increasing number of references available today on Northwest considerations for on-farm testing. A 1992 publication from the Northwest is Washington State University Cooperative Extension Bulletin 1706 "On-Farm Testing: A Grower's Guide." It is available for $1.00 payable to WSU Cooperative Extension Publications (address/phone above). A new series of PNW Extension publications is being developed on on-farm testing. Two have been completed so far in 1995: Using an On-Farm Test for Variety Selection, PNW Extension Bulletin 486 ($1.50), and On-Farm Test Record Form, PNW Extension Bulletin 487 ($.50). These can also be ordered through the WSU Bulletin Office. The 1994 Pacific Northwest On-Farm Test Results, WSU Crop and Soil Sciences Dept. Technical Rpt. 95-1, summarizes 52 on-farm tests conducted in the region during the 1994 crop year. Copies are available free from the Extension Office, Crop and Soil Sciences Dept., Washington State University, Pullman, WA 99164-6420 (509-335-2915). A limited number of copies of the 1992 and 1993 PNW On-Farm Test Results are also available.

World Wide Web Home Pages - For those with access to the Internet and World Wide Web computer network, a new PNW STEEP World Wide Web home page is being initiated to increase access to STEEP and related technologies for conservation farming systems. The address is: http://coopext.cahe.wsu.edu/~pnwsteep/. Recent PNW Conservation Tillage Handbook Series on pest management strategies are online now. An extensive compilation of Northwest conservation tillage information resources will be put on the home page, including links to other Web information resources. "Dryland Cropping Systems" at Washington State University's Crop and Soil Sciences Department and Cooperative Extension is a closely related and linked home page with a considerable amount of information currently on line. The address is http://coopext.cahe.wsu.edu/~drycrops/.


Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA
Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU