Knowing Your Roots

Archive for the ‘Potatoes’ Category

Vegetable Growers Pushing Advanced Irrigation and Conservation Practices in Wisconsin

We need to conserve our natural resources to guarantee that they will be there for future generations!  We all work to conserve — in our own homes, work places, towns and communities — and we expect our industries to do the same.  Irrigated vegetable growers in Central Wisconsin agree and their highest priority is to conserve the water that they rely on to irrigate the crops that supply food to our tables!  Below are some comments taken directly from growers in Central Wisconsin that reflect that commitment.  Since water conservation is essential for the long term sustainability of the vegetable industry, growers are working to use advanced technologies and best management approaches directly on their farms to maintain these resources.

“Water conservation is important to our farm because we believe in promoting a sustainable environment; both for our farm as a whole and for the community around us.”

“The more water we conserve now the higher availability in the future.”

“Water conservation is important so we don’t …waste ground water which everyone depends upon.”

“We need to be stewards of the resources so we can continue for generations to come.”

“Sustainability is always an important goal on a family farm!”   (more…)

Using Less Water to Grow More Food

Blog 20

Wisconsin’s Central Sands is a unique and bountiful place. Its rain-fed groundwater aquifer feeds one of the nation’s most productive potato and vegetable growing areas. The sandy glacial soils and easily accessible aquifer for irrigation allow Wisconsin to rank in the top three in green beans, peas, sweetcorn and potatoes, which contribute to our diverse and healthy agricultural economy. With an average annual rainfall of 32”, our aquifer is replenished yearly and the groundwater level remains constant, with minor fluctuations.

Ever mindful of the importance of a sustainable groundwater supply and how this resource has been depleted in other parts of the country, potato growers recently measured the depth to groundwater in over 50 irrigation wells in Portage county and found that all but 3 have groundwater at the same or higher levels compared to those recorded when they were first drilled over the last half century. This careful scrutiny is being expanded across the 6-county sands area to ensure that our groundwater is not at risk.

This same aquifer is also connected to and essential for the well-being of the many streams, lakes and wetlands that make the sands an ideal place to live. Wisconsin potato growers are at the forefront in managing these fragile ecosystems, and making sure they remain healthy during dry climate years, when the need for agricultural water use increases. The potato industry is sensitive to these concerns and is actively seeking new ways to irrigate their crops using less water. One logical approach is to increase productivity so that more food can be grown on fewer acres. Potatoes are a good example where this has been achieved. Over the past decade, innovations in production gained through improvements in varieties, fertility, soil health and pest management have allowed growers to produce 95% of the potatoes they did a decade ago but on 20% fewer acres, saving a whopping 25% of the water needed to grow potatoes!

Growers are now actively working with UW researchers to reduce water use still further. In the Department of Horticulture, a research group led by Mike Drilias, is looking at ways to induce crops to root deeper and use the water in the soil more efficiently. One method currently being studied is to simply apply less water to the crop (deficit irrigation) throughout the growing season and force the roots go deeper to find it. Mike has found that crops respond differently to such treatment. Potatoes differ by variety with some less affected while other varieties lose yield and, surprisingly, sweetcorn attained the same yields with 25% less water. Withholding water at specific growth stages (deferred irrigation) is another approach that is rapidly gaining acceptance by growers. Naturally deep-rooted crops such as soybeans, field corn and sweet corn, tend to ‘cheat’ when water is plentiful near the surface and develop shallow root systems but when water is withheld early in the season roots will go deeper and use water that would otherwise be lost. Such tactics can save growers over 2 inches of water on an acre of cropland—that’s 7 million gallons on a single field—without sacrificing yield.

An exciting new concept is also now being investigated that could prove critical in conserving water in irrigated agricultural systems. This takes advantage of the differential use of water by crops, which has been studied by UW departments of Horticulture, Soils, Agronomy and Biological Systems Engineering faculty and students. This differing need for water among crops opens the potential for designing future agricultural landscapes that can be profitable and yet use less water. Such landscapes have been evolving naturally, driven by economic and production considerations over the past 20 years. As potato acreage, (which requires 18 to 22 inches of total water throughout the growing season, including rainfall), has declined in response to greater productivity, the acreages of green beans (which need only 6.5 inches) and sweet corn (needing 12 inches) have increased to fill the gap, resulting in landscapes that actually use 25% less water. The potato and vegetable industry is actively supporting research in this area with the goal of designing landscape strategies to develop crop rotations in space and time to promote water conserving farmscapes.

For more information contact: wyman@ wisc.edu

Drip Irrigation: Doing More with Less

Blog 19

Most people are already familiar with drip irrigation—they’ve used soaker hoses in the garden or seen those thin tubes in greenhouses or even in orchards. However, on large-scale agricultural lands within Wisconsin, drip irrigation is rarely seen.  Since water is usually plentiful in the state, irrigation is delivered to crops with overhead sprinklers, traveling water guns or with rotating center pivot systems. This doesn’t happen in areas where water supplies are scarce.  In other grower regions – either in the U.S. or worldwide – growers use watering systems that can be controlled to only deliver the exact amount of water the plants need, via the system known as drip irrigation.

Drip irrigation was first used commercially in Israel in the mid-1900s when the advent of plastics made it possible. It continues to be a dominant form of irrigation in many arid (dry) regions where water is the most limiting factor in crop production. In the U.S., drip irrigation is found predominantly in dry agricultural regions, such as California and Florida, where hundreds of thousands of acres of high-value crops are produced using drip irrigation.  Historically, drip irrigation had been primarily used with permanent tree and vine plantings, but new research and applications have made it increasingly desirable for specialty crops, vegetables and even row crops like cotton and corn.

In Wisconsin, less than 1% of the 500,000 irrigated acres use drip irrigation (under surface drip, subsurface, trickle or other forms of micro irrigation) and much of this acreage is in small-scale vegetable production. Wisconsin growers may not face the level of water scarcity seen in the western part of the country, but as concerns over groundwater quality and quantity increase, it may be necessary to explore alternative production strategies.

Drip irrigation has been shown to allow for significant reductions in water and nutrients by better localizing applications in the crop root zone where they can be delivered only when needed by the plant. Also by creating a drier micro-climate in the plant canopy, the risks posed by plant diseases, which thrive in moist conditions, are also greatly reduced. Drip irrigation can provide additional advantages such as a precise delivery system for plant protectants without harming beneficial insects or the environment.  With these benefits, why don’t we see more drip irrigation used in Wisconsin?   Simple, the high costs of implementing this technology have limited its use, and it remains unclear if these benefits could justify its use in more humid climates with a drought-sensitive crop like potatoes.

Looking to the future where sustainable use of water resources in potato production has emerged as one of the industry’s highest priorities, Sarah Page, a UW-Madison Masters student in Agroecology and Horticulture under the direction of AJ Bussan, has conducted research trials at the Hancock Agricultural Research Station to address just those questions. She compared tuber yield, size and processing quality under standard center pivot irrigation practices and three rates of drip irrigation for commonly grown potato varieties. She found little effect of irrigation treatment and in most years and with most varieties, there were no differences in total yield or tuber size distribution. Surprisingly, the lowest water application rate for drip irrigation yielded slightly higher than the other two rates. This was likely due to increased nutrient leaching under the more heavily irrigated plots, which was supported by nitrate levels detected in plant tissues. A potential negative consequence of lowering irrigation amounts could be drought and heat stress on the tubers, which could have negative consequences for processing quality. However, when Sarah looked into this, she found little effect of irrigation treatment on reducing- sugar content – a contributing factor to undesirable dark colors when potatoes are fried.

Sarah’s research shows that it was possible to reduce water application rates by 25% without negatively affecting potato yield and quality attributes. That’s a lot! There are many steps that need to happen before drip irrigation could be economically feasible and sustainable on a large scale in the sands of Wisconsin, but it’s one more potential tool to add to the box.

For more information, contact Sarah Page at sapage@wisc.edu.

Water – The Critically Important Resource for our Nation’s Food Security

Blog 16

In this current blog series we have been featuring graduate student research on potatoes in Wisconsin, and so far we have covered research in plant breeding, seed production and pest management. We are concluding this student series with 4 blogs on a topic that has emerged as one of the most critical issues facing agriculture today—water.  Will there be a sufficient supply in the coming decades to maintain the productivity and security of our nation’s food supply while guaranteeing the long-term sustainability of the resource in future generations for all to enjoy?

In Wisconsin, the issue of water and its availability is particularly acute in the Central Sands region, which is one of the top five vegetable growing regions in the nation where potatoes, sweet corn, green beans, peas, carrots and cucumbers all rank near the top of U.S. production.  The foundation of the region’s productivity lies in its geological history, which began during the glacial ice age that encompassed Wisconsin over 15,000 years ago.  The Central Sands is a large and relatively flat glacial outwash plain that deposited abundant sandy soils—ideal for vegetable production—and is underlain by a deep groundwater aquifer that provides the water, vital for crop growth and productivity.

The region covers nearly 1,400 square miles and now supports 200,000 irrigated acres, but prior to the 1950s it was not farmed because there was no efficient way to utilize the abundant water supply and as such, much of the area remained undeveloped.  In the mid-1950s, however, this largely unused, resource-poor area was transformed rapidly when modern irrigation technology became available and affordable due to aluminum supplies increasing after World War II.  This raw material provided farmers the ability to build and deploy the center pivot irrigation systems that could, for the first time, deliver water to 160 acre crop fields in less than 24 hours.  This quickly transformed the regional economic landscape into a thriving specialty crop production area which now supports a $6.4 billion food production industry and generates close to 40,000 jobs within the state of Wisconsin.   (more…)

The Battle against Late Blight, From the Irish Potato Famine to the New Millennium

Blog 15

While hard to believe, the Late Blight pathogen that caused the Irish potato famine in the 1840s and 1850s and caused the starvation deaths and forced migration of hundreds of thousands across Europe, is still a major concern in food production worldwide. The fungus-like organism, Phytophthora  infestans, is aggressive and can cause disease that can rapidly destroy whole fields of potatoes  and tomatoes. This centuries old threat is still with us and causes major concerns for potato growers in Wisconsin each year!

The pathogen can be spread quickly over whole areas by wind movement of its spores from infected source plants. These are either brought into the state as already infected tomato transplants or seed potatoes or can develop locally from un-harvested tubers or crop waste that survive freezing.  Because it can spread so rapidly under cool moist conditions, Late blight is considered a ‘community disease’ that can affect both commercial growers and home gardeners alike. Crop fields must therefore be monitored   early to detect symptoms and potential disease sources.  Growers ensure that seed is disease-free to prevent the introduction of the pathogen into the fields. They control potato volunteers and nightshade weeds that may be infected in and around production fields. And, by WI state law, growers, homeowners and garden centers are required to destroy all disease sources by May 20th before the start of the growing season.     (more…)

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