Knowing Your Roots

Posts tagged ‘UW-Madison’

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.

Band Aids® won’t help these potatoes?

Blog 6

Like humans, potatoes develop scabs. Although they look similar – raised, rough, brown growth on the surface of the skin – they are fundamentally different. The scabs you got when you scraped your knee as a child are part of the human body’s natural healing process. When the scab finally falls away, new, unblemished skin is left underneath. In contrast, potato scabs are a disease that infect the tuber skin; these scabs don’t heal and can even get worse as the disease progresses.  A better name would be “potato ulcers.”  Ulcers are open wounds that are slow to heal, originally thought to be caused by factors such as stress or skin irritation but later, were shown to actually be caused by bacteria.

Potato common scab is caused mainly by the bacterium Streptomyces scabies. The scabs produced by these bacteria are largely cosmetic and limited to the surface of tubers, but they drastically reduce marketability and are rated as one of the top 5 potato diseases in the U.S. Common methods of controlling infection – using pesticides and increasing irrigation – are expensive and often ineffective. In organic production, scab can be the major cause of tuber rejection. This is a classic example where breeding a potato with natural immunity to common scab is the most effective and perhaps the only realistic approach to managing this serious disease threat. There are currently no varieties of cultivated potato that are immune to common scab, but wild potato species offer a wealth of genetic diversity and have long been viewed as a potential source of desired traits such as disease resistance. Researchers at the UW-Madison have identified a line of the wild potato species Solanum chacoense from South America that is highly resistant to common scab and a closely related line that is susceptible.    (more…)

What makes a great potato? – The science of breeding for the future

Blog 2

Go to your supermarket these days and you will see an emerging trend in the fruit and vegetable section – an increasing array of varieties on display that are specifically designed to meet consumer demands. Apples lead the way with dozens of different varieties on display with specific tastes, textures and uses. Other food favorites are jumping on the apple bandwagon with potatoes now joining the chase.  Five years ago your potato choices were likely to be limited to russets, round whites and reds, served up in small or large bags with cost often being the a prime driver.  Now, potato choices have rapidly changed as new varieties with multiple colors, shapes and sizes are part of the consumer’s palate.  Today’s consumers are looking for specific varieties based on how they taste and whether they are using them for fries, chips, baked, mashed or salads.

The evolution of choice in potatoes is moving fast now but it has taken generations of painstaking and exacting science to get to where we are today.  Over the coming weeks, the New Family Farm site will explore the art and science of breeding potatoes through the work of graduate students.  Since the beginning of agriculture, humans have been identifying, creating and refining new varieties of food plants for their productivity, appearance and culinary characteristics.  This process, known as plant breeding, continues to help improve potatoes to meet the evolving needs of society by bringing together the skills of several disciplines such as genetics, molecular biology, plant pathology, engineering and others.

The first step in plant breeding is to create individuals with novel genetics that may express the traits we are seeking.  Just as humans create children by combining their genetic makeups, potatoes can be enhanced through genetics. Most new potato varieties are created by “mating” or cross pollinating existing varieties with other varieties, or ancestors, with the goal of combining the best characteristics of the parents to create a new potato that has the features we desire.  Those green, tomato-like fruits, formed on pollinated potato plants contain hundreds of seeds, each one genetically distinct. It takes the artistry of the breeders to grow these thousands upon thousands of seeds in the greenhouse, identify the traits they express, select the most promising, re-cross to obtain the best balance and ultimately propagate them in the field. It can take years to develop a promising new potential variety.   (more…)

Behind the Scenes: Potato Late Blight, There’s Blight on the Wisconsin Landscape!

Blog 26

Late blight caused the Irish potato famine in the 1840s and 1850s.

This disease and its related problems caused massive hunger, starvation and poverty, resulting in mass emigration from the region.  This disease is still a concern today.

The fungus which caused the Irish potato famine is still active today.  It was identified in Portage County just last week.  It can cause serious problems for potato, tomato, eggplants and other solanaceous crops today.  Phytophthora infestans (“infests”) is the cause of potato late blight.  It is a fast moving, community disease that growers, home gardeners and garden center managers must take seriously and properly manage to ensure a healthy, adequate food supply.

There are many concerns for Wisconsin vegetable growers every year whether farmer or home gardener.  Weather, growth problems, pests, water, market demand—but one pest problem, foliar or leaf blight, is especially challenging.  This can commonly attack tomatoes, potatoes, carrots and cucumbers.  These diseases cause perfectly healthy appearing green plants to break out in brown spots, turn yellow and die prematurely.  Many home gardeners run to their local garden center for a remedy.  But by the time leaves begin to yellow and the brown spots appear the disease may have progressed to a point where there is no stopping it.

On the farm, vegetable growers face the same threat from foliar blights every year.  Potato and vegetable growers in Wisconsin have worked closely with University of Wisconsin researchers for decades, to understand the science behind that makes these blights tick.  Through research, we have developed and implemented innovative disease management strategies to both avoid and combat plant disease problems.    (more…)

Behind the Scenes: Central Sands farmers improving biodiversity (and sustainability) on our farms!

Duane Blog 6

Wisconsin potato and vegetable growers have long looked at sustainability as a three legged stool orf responsibility.  One leg is social responsibility, while another is economic.  The third leg, which gets a lot of attention, is environmental responsibility.  These thoughts and practices are second nature to us, in part, because of our relationship with our core researchers at UW-Madison, USDA, Ag Experiment Systems and our County Extension Agents.  Another reason for the prevalence of these practices on our farms is that is makes good business sense, serving us in achieving both our short and long term goals.  Biodiversity is just one component of our environmental responsibility.

Biodiversity tells us the number and variety of different native species found within an ecosystem. This is important to each of us.  A diverse environment of native species compared to similar environments that are dominated by a few non-native and often weedy less desirable species, is more stable ecologically and provides many essential services to communities. These ecosystem services are not always easy to identify.  They include many valuable natural benefits such as: water filtration, maintenance of soil structure and health, habitat for birds and pollinating insects, alternative food sources to preserve beneficial insect predators and habitats for rare and endangered species.  We have all of these things at work in our diverse ecosystem landscape.   (more…)

Tag Cloud