Bob
McNabb, Minnedosa, Manitoba | Advancing The Art ~ SUSTAINABILITY |
The earth's thin covering of soil is very fragile. There is overwhelming evidence that over-cultivation is leading to its destruction. For centuries, tillage has been used to grow crops. Today, farmers are expected to produce food in ever increasing quantities. To meet this expectation, soil erosion will have to be conquered. Zero tillage farming can produce abundant food while protecting the soil. Additional benefits to air, water and wildlife make no-till farming the most sustainable choice for us all. Society and farmers need to work together to ensure that agriculture and the environment have a good future.
THE SOIL ISSUE
Soil erosion is the longest running environmental concern of farmers. But, for the greater urban population, environmental priorities are often diverted elsewhere. Media focus on more graphic environmental catastrophes has left our soil in the background. Against rainforest destruction and giant oil spills, the slow decline of our soil seems mundane. But, how different is soil erosion from wildlife extinction or pollution?
THE SOIL AND US
In communities dependant on agriculture, conserving biodiversity or preventing pollution means saving the soil. People in these regions know the essential links between the soil and environment.
The ecosystems which flourished in the northern plains prior to European settlement produced some of the most fertile soils in the world. This soil gave growth and prosperity to two young nations. But, as agriculture developed to provide food and fibre for a growing population, major changes occurred.
Crops and tillage replaced grasslands, the bison, forests, and fire and much land was drained. Life changed on the northern plains, from the largest animals down to microorganisms. Some species adapted and others disappeared. Some even found the new surroundings hospitable and flourished.
The soil changed as well. Tillage became an integral part of early farming's contribution to the new landscape. Tillage helped provide food and income in an era of small farms, cheap energy and low world food demand. Eventually with widely adopted mechanization, tillage gave rise to soil erosion.
EROSION AND US
The soil is alive. It lives, breathes, dies and lives again in a grand and complex web. Erosion of the soil breaks this web. Fungi, bacteria and insects, which provide food to plants, are among the first to go. Life in the soil world becomes difficult and, at this very basic level, biodiversity declines.
Eroded soil is deposited into streams and rivers. This slows their flow and diverts their course through silt deposits, which also fill dams. Nutrients which were meant for crops are washed into lakes with the soil. These nutrients feed algae which choke out plants and fish, destroy lakes and upset nature's balance.
When soil erodes, plants lose their anchor. Soil alone can not trap and hold most of the snow or rain that falls on it. Soils that have been degraded by excessive tillage lose their structure and instead of the water percolating down to the root zone where plants can use it, it rushes off the land creating even more erosion.
Unless you live on or near 'the land', these events are hardly noticed. However, when soil erosion causes water pollution; or when electricity-generating dams silt up, causing energy costs to rise, or when recreation, transportation or other forms of commerce are interrupted, the effects of soil erosion become more well known.
In extreme examples throughout history, unchecked soil erosion has reduced the capacity of people to feed themselves and civilizations have collapsed as a result.1
THE ZERO TILLAGE SOLUTION
A few decades ago many northern plains farmers recognized the soil erosion problem. When it threatened their way of life and that of their children, they took action. Considering the importance of soil, these farmers adopted the practice of zero tillage which quickly improved the quality of the soils and viability of their farms. These farmers have now mostly conquered soil erosion.
Zero tillage benefits farmers in ways described in this manual. Mostly, zero till offers a better chance to make a decent living by farming in a more soil-caring way. Zero tillage also benefits the whole of society as it allows farmers to produce a secure and stable food supply.2
Zero till helps maintain and improve the environment, too. Zero till farms use less fossil fuel since tractor use is dramatically reduced. This reduces emissions of green house gases and other pollutants. As well, zero till soils build up their organic matter which is made of decomposing plant material, insects and earthworms. Carbon from the air is a big ingredient of organic matter. Gains in soil carbon reduce the amount of CO2 in the atmosphere where greenhouse gases may already be excessive.
The study of how no-till effects wildlife is still young. Well-managed zero till soils can develop to more closely resemble the original soils of the native grasslands.3 Healthy soils support a greater diversity of insects and microorganisms which are important to the broader ecosystem. Studies in Manitoba4 and North Dakota5 showed improved habitat for ground-nesting birds especially where fall-seeded crops are planted, in zero till systems. Cultivation in the spring would otherwise destroy their nests. In addition, these same birds survive better in zero till fields because their predators feed on insects and small mammals which are abundant in no-till fields.
NO TILL - THE PERFECT SYSTEM
Of course, no system is perfect. Organic farmers, often viewed by the public as a panacea for sustainable agriculture, must deal with problems of soil erosion and reduced yields. Likewise, no-tillers must ensure their crops efficiently use the extra water they trap to avoid it carrying nutrients and herbicides into ground-water. Zero till rotations (component 4) can alleviate this problem while being profitable today and sustainable tomorrow.
Long-term sustainability will only be achieved if farmers are allowed to make economically viable choices in the short term. Without these short-term options farmers can be forced into mining, rather than nurturing the land. Lingering frontier-day myths about the boundless resources of the plains must be rejected and the development of superior farming systems must be encouraged. For their part, zero till farmers want to keep "advancing their art" to ensure their precious capital, the soil, will continue to improve.
Pesticides are an important tool of conservation-minded farmers. Without doubt less expensive glyphosate, the non-selective herbicide used in place of tillage to control weeds, gave farmers the means to adopt zero tillage. Today's zero till farmers use pesticides as part of a planned and integrated pest management (IPM) strategy. The economic advantages of IPM help farmers earn a living in both an environmentally and socially responsible way. At present, neither would be possible without pesticides.
ADOPTING ZERO TILL
With society's support, it is up to farmers to ensure that zero tillage stays with us. So - how can farmers adopt and maintain zero till?
Each farm is a system. No single part of the system, like soil, location, climate, crops, weeds or tillage, can be viewed independently from the others. The farmers who manage the operation, and their families, must also be thought of as a part of the system. One of the fundamental mistakes made by many beginning zero tillers is to view the change in tillage method as independent from most other parts of their system.
Simply substituting a spray where tillage was previously used is a recipe for long term disaster. It can work agronomically for about 6 years or so, but invariably, problems occur. Financially this approach never takes full advantage of the benefits of zero till and may eventually lead the producer to return to tillage. Failure might occur if zero tillage is used in crop rotations that are designed for tillage. In order to optimize the benefits of zero till, it is imperative that every part of the system be designed and directed specifically for zero tillage.
We offer these comments to help orient the reader to the thought processes needed to most successfully use this manual. By necessity, this manual is broken down into chapters which are subsequently referred to as components. The reader must gather the information from these components and other sources and design a system that works in an individual situation. For instance, using a diverse rotation to exhaust weed supplies does little good if high disturbance seeding or fertilizing operations are also used.
Among successful, veteran zero till farmers, the process of learning to use a systems approach is often referred to as 'the brain transplant'. There will be similarities and differences among systems designed by neighbouring farmers, just as with their conventional systems. There are no set recipes for success. Success comes from understanding the system and managing it to take advantage of the substantial benefits of zero tillage.
"Archaeologists can show where, in the past, tillage has destroyed 'milk and honey' soils and caused civilizations to collapse. We don't want to repeat their error! We now have the technology that will help us save the soil - if we use it wisely."
Bob
McNabb, Minnedosa, Manitoba
Prepared by:
Bill Poole, Ducks Unlimited Canada
Box 1160, 1 Mallard Bay, Hwy 20, Stonewall, MB, R0C 2Z0
Telephone (204) 467-3000 Fax (204) 467-9028
Email "webfoot@ducks.ca"
John Gardner, Carrington Research Extension Center
Box 219, Carrington, North Dakota, 58421
Telephone (701) 652-2951 Fax (701) 652-2055
Daryl Domitruk, Manitoba Agriculture, Soils and Crops Branch
Box 1149, Carman, Manitoba, R0G 0J0
Telephone (204) 745-2040 Fax (204) 745-2299
Email "soilcrop@mb.gov.ca"
Bill Crabtree, Esperance Agricultural Centre
PMB 50, Melijinup Rd, Esperance 6450, Western Australia
Telephone 011 61 90 83 1111 Fax 011 61 90 83 1100
Email "bcrabtree@agesp.agric.wa.gov.au"
Dwayne Beck, Dakota Lakes Research Centre
P.O. Box 2, Pierre, South Dakota 57501
Telephone (605) 224-6357 Fax (605) 224-0845
References:
Duebbert HF and Kantrud (1987). J. Soil Water Conserv. 42:50
