Deficit Irrigation Conserves Water in Agriculture to Aid in Combating Water Stress

Sep 28, 2022

By Sarah Davis

Washington State has nearly 15 million acres of farmland with around 39,000 operating farms, each producing necessary agricultural commodities. A few of the most well-known crops that are produced and distributed from Washington State are apples, cherries, hops, raspberries, and pears. Even when traveling across the country, I can find Chelan apples, which shows just how productive the state is in their cultivation of high value foods. Many of the 39,000 operating farms require irrigation to produce much of the aforementioned fruit that get distributed far and wide, which consumes a large portion of water resources.

As temperatures rise, the impacts of climate change on agriculture become increasingly apparent. For example, higher rates of sunburn due to atmospheric water stress and drought. The excess stress being put on crops and growers as they try to produce high quality crops in the changing climate is only going to become more severe. The increased frequency of drought limits water resources, access, and availability in the arid Western states, which is becoming concerning, especially for beginning and small farmers. Complex water regulations decrease the reliability of irrigation for small producers which can threaten crop cultivation in summer months. Increased temperatures throughout the year create lower snowpack, which then melts earlier, and is not available later in the season when crops and growers need it the most. Even though this stress is more apparent for smaller farms, the issue can be universally seen in all agricultural systems, small and large. Another challenging aspect when considering irrigating the thousands of farms across the state is the cost: cost of water, cost of labor, and cost of irrigation management.

Washington state produce can be found in supermarkets across the world. These Chelan apples were found in Kuala Lumpur. Photo: Flickr user Dennis Sylvester Hurd CC0 1.0 Universal

Washington state produce can be found in supermarkets across the world. These Chelan apples were found in Kuala Lumpur. Photo: Flickr user Dennis Sylvester Hurd CC0 1.0 Universal

Regulated deficit irrigation in Wenatchee, Washington being applied to cider apple trees.

A potential solution that can help conserve water, reduce irrigation costs, and secure irrigation water for small and large producers is regulated deficit irrigation (RDI). This summer in my undergraduate research internship at the WSU Wenatchee Tree Fruit Research and Extension Center, I am conducting an RDI experiment in cider apples. Regulated deficit irrigation is purposeful reduced irrigation that puts stress on trees or the desired crop but does not negatively impact the growth and production of the crop. This can also be beneficial in different crops such as Honeycrisp apples and grapes, as RDI not only decreases vegetative growth but can also improve fruit quality (which I will discuss further in an upcoming article).

Regulated deficit irrigation valves: pink is regulated deficit irrigation, blue is the control

Regulated deficit irrigation valves: pink is regulated deficit irrigation, blue is the control.

Throughout the summer, I have been running irrigation treatments on two different cider apple cultivars: an RDI treatment as well as a control treatment in Nehou and Golden Russet cultivars. The RDI trees are watered at approximately 60% of what the control is watered. For example, the control groups will get a three-hour set twice a week while the RDI groups are getting two-hour sets twice a week. At the end of each week, I have been collecting midday stem water potential—a measure of how much stress the tree is experiencing—of each of the trees to determine their levels of stress and how long to water in the following week. Preliminary results are showing that the RDI trees are experiencing more stress than the control trees, but not so different that they will have drastic differences in appearance. The team will know more about the fruit quality effects of the RDI after harvest in September.

Regulated deficit irrigation practices have the potential to be a useful tool to conserve water, which in turn can help ensure reliable water for both small and large producers. Water conservation is becoming increasingly important as climate change brings longer and more prominent drought seasons and high temperatures. However, it is important to note that changing practices such as irrigation can be difficult. Crops might react differently to deficit irrigation, and it may take more work to monitor tree stress to determine how much deficit is appropriate. There could also be other potential unanticipated drawbacks to using these techniques. However, even with these potential disadvantages, using less water with regulated deficit irrigation could save a significant amount of money, improve fruit quality, and conserve water in the increasing times of water stress, making it all worthwhile.

Source : wsu.edu

Video: Can Gene Editing Give Seeds a Stronger Start?

Reagan Reed has a way of describing his research that might make a plant breeder pause.

“I’m the sort of person who likes to break things to understand them,” he says.

What he breaks are genes involved in seed germination. Reed, a Ph.D. candidate at the University of California, Davis, is investigating whether changing those genes can help seeds establish healthy plants under a wider range of conditions.

Reed recently attended the National Association for Plant Breeding meeting in College Station, Texas, as an NAPB Borlaug Scholar. His work speaks to a question that matters well beyond a research lab: what does it take for a seed to get a crop off to a strong start?

A seed that germinates quickly, alongside the others planted with it, spends less time vulnerable to stresses before seedlings become established.

“If you’re able to bridge that gap between germination to stand establishment, then that’s going to give you the highest probability of having a solid yield that year,” Reed says. “There’s a bunch that can go wrong after that, but it maximises your yield from the start, at least.”

Reed works in Dr. Imtiyaz Khanday’s lab at UC Davis, where his research focuses on seed quality in tomatoes and potatoes. He brings an unusual academic background to the work: at Skidmore College, he studied both biology and Latin.

Reed believes that combination prepared him for research. Translating an ancient text means studying each word, weighing its possible meanings and using context to reach the best interpretation. There is rarely a way to know with complete certainty what an author intended. Science, he says, requires a similar willingness to work through uncertainty.

“Attention to detail and comfortability working with uncertainty,” is how he sums up what Latin taught him.

In the lab, uncertainty can produce a surprise. Reed describes changing one gene and seeing little effect. Changing a second gene also appears to do little. Put both changes in the same genetic background, though, and the result can be substantial.

“I break this gene, nothing really happens. I break this other gene, nothing really happens. I combine them into the same genetic background, and now there’s a massive effect,” he says.

Those interactions matter as researchers gain the ability to edit multiple genes at once. They also complicate any simple account of how a trait works: improving a seed may depend on understanding what several genes do together.

For Reed, the question is whether that knowledge could help seeds germinate reliably when conditions are difficult. Some of the genes he studies prevent germination under certain conditions. That response may serve a plant well in one setting while limiting its usefulness in agriculture. He wants to learn what happens when those genes are changed, and whether the result improves establishment.

Yet a discovery that works in a lab still has a long way to travel before it reaches a field. Reed argues that agricultural biotechnology faces an economic challenge as well as a scientific one. New tools can create value for farmers, he says, but developing them requires a way to support the work in an industry where margins can be thin.

His fellowship with Flagship Pioneering gave him a view across AI, agriculture-related work and human health research. It also reinforced the importance of bringing people with different expertise into the same conversation—a benefit of gatherings such as the NAPB meeting.

“You need to have a team of people with different backgrounds who are willing to work together and approach the same problem in different perspectives and different ways,” he says.

That thinking connects the different parts of Reed’s path. Latin taught him to examine details without expecting a perfect answer. Gene editing lets him test what individual genes do—and what happens when their effects combine. Working with people beyond his own field helps him ask what those findings could become.

He came to agriculture because of its reach: the possibility that work by a small group of researchers could eventually make a difference on a much larger scale. His immediate focus is smaller and more precise. He wants to understand what helps a seed get through its first days and become a healthy plant.