PNW Direct Seeding Status — and What’s Driving it

Chapter 2 – Conservation Tillage Systems and Equipment, May 1999

Pacific Northwest Conservation Tillage Handbook Series No. 25

Author: Roger Veseth, WSU/UI Extension Conservation Tillage Specialist, Moscow, ID

There is tremendous interest in direct seeding systems and more intensive crop rotations across the Northwest, America and around the world. As one example of the Northwest interest, about 900 growers and Ag support personnel attending each of the last two Northwest Direct Seed Cropping Systems Conferences in Pasco, WA in 1998 and Spokane, WA in 1999. That is a dramatic increase from the 200-350 attending similar PNW no-till and conservation tillage conferences over the past 20 years. The dryland Inland Northwest cropping areas are also showing significant increases in acreage under direct seeding in the past few years. The purpose of this publication is to provide some insight into why growers are moving to direct seed systems and how the Northwest compares with some of our national and global competitors in adoptions these new farming technologies.

First, what IS direct seeding? As the name would indicate, all direct seed systems have at least in important factor in common – no traditional “full-width tillage” for seedbed preparation with field cultivators, or other secondary tillage implements prior to planting. Direct seeding basically means the same as no-till, which has the current definition: “soil is left undisturbed from harvest through planting except for strips up to 1/3 of the row width.” Low-disturbance direct seed systems best fit this classic no-till or zero-till description. Two-pass direct fertilize and direct seed systems that do not have full-width tillage can also fit in the traditional no-till category. High-disturbance direct seed implement with wider hoe or sweep openers may stretch that definition a bit, but are generally included. There are also some variations of direct seeding that fit into the “mulch-till” category of tillage systems instead of no-till. One example is “fall mulch-till – direct spring seed system,” which has full-width mulch tillage the proceeding fall, but not spring tillage before direct seeding. The important things to keep in mind with tillage system definitions are the end results – erosion control, soil quality and productivity, production efficiency and profitability.

What’s Behind the Direct Seed Movement?

What is behind this huge interest in direct seeding and more intensive cropping systems? Some important factors driving these changes include:

1. Increasing national and international competition in the global market and the need to reduce costs and improve profitability;
2. New crop rotation flexibility under the 1996 Farm Program;
3. Increasing grower and public concern about cropland soil loss by water and wind erosion;
4. Greater awareness of the soil quality and productivity benefits of direct seeding and detriments of intensive tillage; and
5. Advances in management, equipment and product technologies for direct seeding.

The following discussion should help provide a better understanding of how these factors are affecting the movement toward direct seeding and more intensive cropping.

National and International Competition

Some examples over the past 10 years provide insights into how we compare with our national and international competition in the adoption of direct seeding system to be more competitive in our increasingly global market. Improving production efficiency is an important part of competitiveness and direct seeding can offer that potential.

Table 1 shows a 1989-98 comparison of the PNW with the Northern Great Plains states of Montana, and North and South Dakota. Use of direct seeding on the total cropland basis in the PNW is slightly behind those three states and the growth rate is also lower. South Dakota is considerably ahead of all those in the comparison in most categories. Direct seeding of spring grains generally showed the largest and most consistent growth across all the states.

Table 1. Comparison of the percentages of cropland under direct seeding in 1989 and 1998 in the Pacific Northwest and three Northern Great Plains States.

Examples of some PNW county-level changes in the use of direct seeding typically show stronger trends than at the state level (Table 2). Growth in direct seeding of spring grains seems to be the strongest and most consistent. Counties in the higher precipitation / annual cropping areas tend to have a greater use of direct seeding in winter wheat production.

Table 2. Comparison of the percentages of cropland under direct seeding in 1989 and 1998 in selected counties of Idaho, Oregon and Washington.

On a broader scale, 5% direct seeding in the PNW is considerably behind the U.S average and some important international marketing competitors in the adoption of direct seeding (Table 3). Direct seeding rates of 20-50% are not uncommon in some of those countries. Some examples of the rapid trend towards direct seeding in some of these other countries also helps illustrate the tremendous growth that is taking place. In 1990, less than 2% of Argentina’s cropland was direct seeded. That grew to 6% in 1994, 19% in 1997, and 28% in 1998, nearly 15 million acres. The 5% of Northwest cropland under direct seeding in 1998 is similar to Argentina’s 6% in 1994. One could say that we are about four years behind Argentina in adopting more efficient farming technologies. Western Australia is another striking example of rapid growth in direct seeding, increasing from 0.1% in 1990 to about 50% in 1998, around 10 million acres.

Table 3. Comparison of the percent of cropland under direct seeding in the PNW, the U.S. and several countries that are important in PNW international markets.

New Crop Rotation Flexibility

The “Freedom to Farm” in the 1996 USDA farm program finally gave growers the cropping flexibility needed to develop crop rotations critical to the success of direct seeding systems. For about 50 years, U.S. Farm Bills have been major obstacles to successful no-till / direct seed and minimum tillage systems in the Northwest and across the country. Commodity program restrictions largely locked Northwest dryland growers into short crop rotations in order to maintain their wheat base acreage, and high proven yields for winter wheat. To manage weeds and diseases, they were forced to rely on intensive tillage. Early NW attempts at no-till beginning in the 1970’s, in their traditional 2-year rotations with winter wheat (wheat-fallow or wheat-grain legume), often resulted in reduced yields or crop failures due to soilborne diseases and winter annual grass 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, the use of longer, more diverse crop rotations have been shown to greatly enhance the success of direct seed systems.

Over the past 10-15 year or more, PNW growers have been working to lengthen their crop rotations (within the constraints of the USDA farm programs) to reduce pest problems, particularly as they began to use less intensive tillage systems. With limited crop options in the region, spring grains have been the main crop available, primarily spring wheat and spring barley. More recently, there is increasing production of oilseeds, grain legumes and other “alternative crops” (at least new alternatives for some areas).

We are beginning to see changes in the proportions of PNW dryland crops and rotation sequences, due partially to cropping flexibility in the 1996 farm program. On a statewide basis in the PNW, fallow acreage has generally declined and spring grain acreage has increases, since both 1989 and the new USDA farm program in 1996 (Table 5). One exception has been a decrease in spring grain in Idaho, where much of the production is under irrigation and acreage is more influenced by prices of the major cash crops in rotation.

From 1996 to 1998 there were about 186,000 fewer acres of fallow and 190,000 more acres of spring grain. Obviously, other factors can contribute to these cropping changes in addition to increased farm program flexibility in crop rotations. These could include new land enrollment in the Conservation Reserve Program (CRP), return of some CRP land to cropping, problems with winter annual grass weeds or diseases winter wheat, changes in crop prices, etc.

Table 4. Changes in summer fallow and spring grain acreage from 1989 to 1998, and 1996 to 1998 (since the 1996 farm program) in Idaho, Oregon and Washington.

Table 5. Changes in summer fallow and spring grain acreage from 1989 to 1998, and from 1996 to 1998 (since the 1996 farm program) in selected counties in Idaho, Oregon and Washington.

Effective Soil Erosion Control

Water and air quality are becoming more important issues, so the need for cropland erosion control will continue to increase. It is well documented by research and grower experience worldwide that direct seeding systems can effectively reduce or totally eliminate water and wind erosion. It is important, however, that all crops in the rotation be managed under direct seeding or other minimum tillage systems to optimize erosion control and soil productivity benefits.

New Insights into Tillage Impacts and Direct Seeding / Intensive Cropping Benefits

The results of recent research and long-term grower experiences in North America and around the world are revolutionizing our understanding of the impacts of tillage on soils. Contrary to the long-held belief that returning crop residue to the soil with tillage builds soil organic matter, the real impact of intensive tillage systems is a continual decline in soil organic matter content. Organic matter 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 quality and productivity.

The increased oxygen level and higher soil temperature present after tillage stimulate intense microbial activity under moist soil conditions. Carbon is released as carbon dioxide during tillage and this accelerated microbial decomposition of soil organic matter. The end result is that tillage is biologically burning off soil organic matter faster than it can be built with the addition of new crop residues under our current dryland cropping systems under intensive tillage. Research shows that direct seeding systems offers the greatest potential for increasing soil organic matter content over time. The greater and more frequent the soil disturbance, the greater the carbon loss potential.

In addition to increased soil organic matter content, another important related soil quality benefit of direct seeding is the improved soil macroporosity. That refers to the proportion of larger soil pore spaces for water and air movement created by undisturbed root chanels, earthworm holes and other soil fauna. Part of this improved soil structure is also attributed to increased microbiological activity with rising organic matter content, which increases soils aggregation and “tilth,” as well soils fertility.

With improved water conservation under direct seeding there is a corresponding higher yield potential. For wheat, it is around 5 to 7 bushels/acre per inch of additional water. The challenge for growers and Ag support personnel is to develop the crop rotations and management systems to control of pests previously controlled by intensive tillage in order to take advantage of the higher yield potential.

New Direct Seeding Technologies

There have been some significant technology advances since Northwest growers began trying no-till drills in the 1970’s. Many of the pest problems that occurred during the past 30 years can now be largely avoided because of new research technologies. Here are a few important examples.

Longer, more diverse crop rotations have been shown to be very effective in controlling weeds, diseases and insect pests that often occur in direct seed systems under short crop rotations. Northwest growers, researcher, and industry representatives are actively searching for more profitable alternate crops and crop rotations adapted to the different production areas of the region.

Another big technology advance was identifying the impact and management of the “Green Bridge,” which has been a major cause of crop failures or sharply reduced yields in direct seeded spring crops in the Northwest for over 25 years. Northwest research showed that the short time interval between spraying volunteer and weeds with a non-selective herbicide shortly before direct seeding created a “green bridge” for root diseases and some insects to attack the new crop. The problem can be effectively eliminated by spraying as early as possible before seeding. The best spraying time for spring crops would be in late fall, weather conditions permitting, in order to provide the longest break in the green bridge. If a fall spray is not possible, or there is considerable early growth in late winter or early spring, spraying at least three weeks before seeding also effectively reduces the root disease problem. In addition, early control also reduces water and nutrient use by the weeds and volunteer grain. After this early control options, spraying of very low populations of small, late-emerging weeds and volunteer just before seeding will then have little green bridge potential for root disease and provides effective weed control. Uniform distribution of chaff from the combine is also an important starting point in managing the green bridge and other concerns in direct seeding.

Research developments on seeding equipment designs for fertilizer and seed placement have revolutionized equipment for direct seeding. In the early 1970’s, there were only about 5 models of “no-till” drills available in the Northwest, none of which had deep fertilizer banding capability. Research has shown that deep fertilizer placement below seed depth and near the seed row can significantly improve yield potential under direct seeding, particularly with cereals after cereals. Today there are over 40 models of direct seed drill / air seeders, nearly all with deep fertilizer placement options. Improvements are still needed in hillside performance and residue handling capabilities under some Northwest conditions, but grower now have a large variety of equipment options. There are also numerous examples of excellent grower and industry equipment modifications to improve performance of direct seeding equipment in the region.

Summary and Future Direction

Although growth in direct seeding in the Northwest has been slower than in some competing states and countries, we are now making substantial progress, particularly when you look at the county level in major dryland cropping areas. Growth in spring direct seeding has been the most dramatic. Northwest crop rotations are changing with reduction of about 190,000 acres in fallow acreage and similar increase in spring grain acreage since 1996, when the last USDA farm program was initiated with new crop rotation flexibility. Total changes since 1989 show the same strong trend.

There are a number of factors driving the increased interest in direct seed systems in the Northwest and worldwide. The need for increased production efficiency and profitability in our increasingly global markets is a major incentive, with improved erosion control and soil productivity becoming important side benefits. Advances in management and equipment technologies with today’s increased cropping flexibility (in the U.S.) greatly improve the chances of successful direct seed systems compared to much of the past three decades.

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.