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Where water leaves the farm

Improve your productivity by starting where water leaves your farm, and then work backwards

In the chase for higher yields and improved production, farmers have tapped into everything from precision ag systems to a return to cover crops. Now comes a concept that might not only boost yields and enhance soil health, it might also alleviate some of the pressure on farmers that starts with surface run-off heading into the Great Lakes.

Don Lobb, a retired Huron County farmer and long time advocate of soil conservation and tile drainage mentioned this concept at the 2015 annual meeting of the Innovative Farmers Association of Ontario (IFAO).

In Lobb’s view, the quality of the water as it leaves our cropland is an obvious measure of our soil management. This means that if we take steps to improve that water’s quality, we will also be improving soil management and thus the long-term productivity of our soil.

It may not be a new concept, judging by some farmers who are urging that more must be done to control the amount of sediment and nutrients leaving farms, particularly in southwestern Ontario.

A midsummer editorial in the Windsor Star worried that the algal bloom in western Lake Erie in 2015 could get as bad as in 2011, which in turn sparked a 2012 study by the International Joint Commission (IJC).

What’s interesting is that 2015 has seen more severe rain events and less spreading of phosphorus-based fertilizer. And, as one senior agronomist in southwestern Ontario observed in 2014, sales of fertilizers in general are less than half of what used to get sold 20 years ago.

There’s also a political angle to consider. According to census figures, 10 million Canadians live in southern and western Ontario. For them, water pollution ranks with bee health and use of transgenic traits in corn and soybean production as key concerns about agriculture.

From the farm community’s point of view, those concerns can get labelled as overreactions based on misinformation spread by special interest groups that are often opposed to crop production methods. Yet Lobb believes there’s as much to be gained focusing on water quality from an urban viewpoint as there is from a farming perspective.

“The public judges our competence as land managers by what they see in their water, so land management becomes a societal issue,” says Lobb.

Most cropland water enters waterways as surface run-off or through subsurface drains. Surface water run-off almost always carries sediment and nutrients. By improving soil aggregation, Lobb says, we can decrease sediment loss and increase water and nutrient infiltration.

The result is clearer water leaving cropland through drains, and healthier, more productive soil.

Farmers are well aware of the benefits of subsurface drainge, but encouraging farmers to look at the link between the quality of the water coming off the farm and how it relates to reduced soil and nutrient loss is taking that concept one step further.

To Lobb, the word “drainage” in an agricultural context can be part of the problem. To an urbanite, the word conjures up images of storm sewers, pollution and algal blooms.

From a farm perspective too, it can encourage producers to think of drainage simply as a means to remove excess water so they can get their crops planted faster.

The real reason for drainage

“The modern role of subsurface cropland drainage (tile drainage) is much different,” says Lobb. “It’s root-zone soil moisture management.

“We want a favourable balance of air and water in the root zone, while also maintaining water at the base of the root zone to supply water during dry periods.”

A well-designed subsurface drainage system allows for this, Lobb says.

At the same time, well-managed fine- and medium-textured soils with good aggregation and little compaction allow precipitation to move down through the soil to subsurface drains and to the subdrain water reserve.

This movement filters and purifies water that would otherwise leave the field as surface run-off, something that’s been visible and prevalent in fields across much of southern Ontario in 2015.

“On well-managed soils, the end result of subsurface drainage is cleaner water and reduced peak flows in our waterways,” says Lobb.

During storms, a subsurface drainage system combined with no-till practices and the use of check dams can further protect cropland and water quality.

What’s at stake, ultimately

Lobb’s view is unequivocal. In his experience, tillage is an unnecessary contributor to water degradation.

He knows many farmers still believe that tillage increases profits and that plowing is a valuable contributor to soil productivity. But he maintains this is incorrect.

In fact, argues Lobb, there has never been any conclusive research that indicates plowing increases productivity.

“Tilled soils have little or no soil aggregation, and clay soils are almost always compacted,” says Lobb.

“With these conditions, subsurface drains can then contribute little to reduce run-off of water sediment and contaminants,” he continues. “When tillage-degraded soil cracks, water easily reaches subsurface drains.

“This does lead to water degradation in drains and outlet channels, and is really the outcome of bad soil management, not the use of subsurface drains.”

Lobb makes five key recommendations for reducing run-off contamination, and he believes these recommendations will also work backwards to help boost productivity through healthier soils:

  1. Stop compacting, the sooner, the better. Tillage is the primary contributor.
  2. Add organic matter, be it from manure or cover crops. Tillage destroys organic matter.
  3. Protect soil biota, which is linked to recommendations #1 and #2. Tillage destroys biota.
  4. Improve soil aggregation, which is linked to all three above. Tillage destroys aggregates.
  5. Use nutrients wisely. Test for the need for supplemental nutrients, and do not surface apply.

With these five practices, however, another dimension has to be factored in. That is time. It takes time to see the benefits from these measures, but the sooner they’re implemented, the sooner the benefits will become visible.

To continue to ignore the issue of water pollution and surface run-off is to invite urbanites and other non-farming special interests to become involved, usually to the detriment of primary producers. Even if Lake Erie pollution is found to originate primarily from livestock farming along the Maumee River watershed in Ohio, or from sewage discharges by the cities of London, Windsor and Detroit, farmers in Eastern Canada are under increasing scrutiny. Degraded water will bring regulation because the public sees algae in our waterways.

“Reduced compaction and improved soil aggregation will reduce run-off contamination,” says Lobb. “We can see dirty water or soil erosion, and through regulation we can attach monetary penalties to degraded water, or treat water degradation as disgraceful and irresponsible. This is no longer an ‘ag issue.’ This is a public issue as it affects sustainable soil production, air quality and water quality.”

The public and policy-makers are growing impatient, Lobb says. “They can impose rules for soil management. Farmers need to figure out now how they’re going to reduce negative soil management outcomes, or the public can simply look at their water and say, ‘Fix it!’”

Additional resources

YouTube: Slake and infiltration test by Ray Archuleta

The slake test and demonstration give a very visual representation of well- and poorly aggregated soils and their reactions in water. Hosted by Ray Archuleta.

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CG Production Editor

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