Lessons learned from #plant17: Dealing with saturated soil
"Across most of south-central and southeastern Ontario, there’s been 50 to 100 per cent more rain than normal,” says Scott Banks, a cropping systems specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). “It’s certainly been a challenging year. There isn’t really a silver lining to all this rain: no crops like being so wet. But growers have experienced tough years before. Outside of controlling the weather, there isn’t a whole lot they can do other than trying to minimize the issues and crossing their fingers for a warm, open fall.”
September 19, 2017 By Madeleine Baerg
Once farmers gained access to fields this spring, many struggled with what to plant into the still over-wet ground. Few crops fare well in a muddy, smeared seedbed. However, some crops can tolerate moderately wet feet better than others – corn can manage slightly more moisture stress than soybeans and oats tend to suffer less than barley.
Because moisture is conducive to disease development, in wet years producers should choose varieties that offer strong resistance genetics to the diseases most common in their fields or area.
“Variety selection continues to be the most important tool available to producers from a disease management perspective,” says Albert Tenuta, OMAFRA field crop pathologist at the University of Guelph’s Ridgetown campus. “Often producers choose the highest yielding variety or hybrid but they also need to be looking at disease resistance. Disease resistance genetics are critical to maximizing yield and returns.”
To complement strong genetics, producers should also make agronomic choices that minimize disease, including applying fungicidal seed treatments, planting at proper timing to support quick emergence, being ready with subsequent fungicide applications where necessary and utilizing cultural practices such as good rotation and drainage.
Genetic resistance is not yet available for some of the most problematic soil-borne diseases, including Pythium, Fusarium and Rhizoctonia in corn. Producers who have battled these diseases in the past might opt to plant an alternate crop in a cool, wet year.
After producers decided what to plant in their fields, they faced a whole different problem: research shows 80 per cent of soil compaction occurs on the first pass when growers move equipment through fields that are just dry enough to begin working. Soil compaction causes a whole host of issues, from impeded root growth to decreased water, nutrient and air flow through soil. While patience is the very best option, dual wheels, low pressure tires and large flotation tires can reduce compaction somewhat.
To remediate compacted soils and improve drainage for future years, growers should consider incorporating cover and forage crops. A deep rooting forage like alfalfa creates channels that help water percolate down deep into the soil, while grass forages and certain other cover crops have fibrous root structures that mellow the topsoil. In addition, cover crops reduce erosion, limit nutrient runoff and can disrupt pest outbreaks – all major benefits in wet years. They can also help minimize the soil crusting that’s common when waterlogged soils dry, which will otherwise decrease water and air penetration and obstruct seedling emergence.
Those farmers tempted to plant the most immediately lucrative rotation – a straight soybean or corn-soybean rotation – should first analyze the long-term benefits of incorporating forages. Forages’ positive effect on the soil’s physical, biological and chemical attributes, particularly in wet years, can result in higher yielding subsequent crops, evening out the financial equation. While improvement is slow – good soil structure can take years to develop – the benefits are equally long term.
Sometimes even the most well structured soil simply can’t manage the volume of water that flows onto it in a wet spring. In saturated soils, adequate drainage can make or break a crop. Though installing drainage is a daunting upfront cost, Banks says the investment virtually always pays dividends in heavy soils prone to excess moisture.
“Like the old saying goes: you’ll pay for drainage one way or the other. You’ll either pay to put it in or you’ll pay in lost yield. In terms of getting a crop established and thriving, those with better drained fields were many steps ahead this year.”
Luckily, not all moisture management priorities require costly financial investments: scouting requires only the investment of time. In cool, wet years, disease pressure tends to be high, both because the conditions suit disease proliferation and because weather-stressed plants are less able to fight off disease. This year stripe rust and corn rust both blew in and took hold early, and at press time, Fusarium was expected to be an issue due to moisture.
Unfortunately, increased disease pressure this year will translate to higher disease risk in subsequent years.
“As you build up disease levels in fields, your risk increases. Pathogen populations can build to the point that they become chronic,” Tenuta says.
Growers thinking they can breathe a sigh of relief on the insect front are mistaken. While wet years tend to support disease and dry years usually support insects, pests don’t always follow the rules.
Despite the excessive moisture, pockets of southern Ontario are facing significant potato leaf hopper pressure. Although they are typically found in new seedling alfalfa, leaf hoppers are actually chomping their way through established alfalfa stands this year, suppressing growth in mature plants.
“You’ve absolutely got to keep scouting your fields, even if you wouldn’t expect to see specific pests,” Banks says. “Pests can come up from the U.S. on currents of warm air even when conditions might not seem ideal here. And the beneficial insects that would normally control them might be delayed due to our weather conditions, so they might not be able to suppress them as they typically could.”
Farming is risky; farming in a cool, wet year that does not support strong crop growth is especially risky. As such, Tenuta has one other piece of early season advice for growers to keep in mind as they start planning for 2018: “One of the very most important management tools is to have a backup plan. You need to be prepared for the worst: what is your plan if you lose part of a field? What is your trigger for replanting? At what point should you decide to start all over again?”
But, he continues, even the worst-case scenario is not all bad.
“Everything you learn from this year – every piece of information you gain every year – is valuable. The more information you have and keep, the better you will be prepared for next year.”
Looking back at #Plant17
on March 20, 2017
Today marks the #firstdayofspring and the start of a fresh new year on many Ontario farms #plant17 #ontag
on April 24, 2017
Preparing a cozy seed bed for grain and hay seeds today in Southern Ontario. Anyone else on the land? #plant17 #OntAg #cdnag #farm365
on May 1, 2017
Not sure when the clay regions in Ontario will be able to go in. Down in Niagara region it is pretty wet… No #plant17 anytime soon.
on May 3, 2017
Significant snow in the U. S. mid-west, flooding rains in Ontario. Will it be a June #plant17?
on May 12, 2017
#plant17 getting rolling in southwestern Ontario.
on May 20, 2017
75% in the ground here in northern Ontario, it’s a pretty average #plant17 year
on June 11, 2017
It’s finally over, I don’t think I’m ever going to forget this one. #plant17 is in the books #ontag