Crop Tech Corner

Weeds Nibble Away at Nitrogen

(DTN photo illustration by Nick Scalise)

Research recently published in the Journal Crop and Pasture Science indicates weeds could be stealing Nitrogen (N) from crops.

The study "investigated the ability of several plant species commonly occurring as weeds in Australian cropping systems to produce root exudates that inhibit nitrification via biological nitrification inhibition (BNI)."

The weeds -- wild radish, great brome grass, wild oats and annual ryegrass -- were considered.

Read the preliminary results of the study here: http://bit.ly/…

Each of the weed species showed the ability to suppress nitrification, which could help them to compete with other plants for nitrogen. "This highlights that increasing our understanding of how plants influence soil microbiota and associated nutrient cycling could open the door to potential novel weed-management strategies," according to the study. Further research is needed to explore whether it is possible to enhance weed-control strategies by manipulating the form and or timing of N supplied to crops.

"Weeds are called weeds for a reason," writes Cathryn O'Sullivan, a researcher with the Commonwealth Scientific and Industrial Research Organization. "They are masters of invasion, and they use sneaky tricks to give them an advantage over our crops. This is very interesting research that could one day give us another tool in our arsenal against our selfish weeds."

PASS THE CORN BELT-RAISED RICE

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The upper reaches of the Corn Belt are known more for ice than rice, but one researcher is hot to use the crop to unlock genetic secrets about cold tolerance.

Rice is ranked as the most valuable agricultural crop in the world. Research by Michael Schlappi, associate professor of biology at Marquette University, is yielding some valuable insight into just how far north rice can grow in the United States and providing a treasure trove of information on how to identify the genetic pathways associated with cold tolerance.

This year his research led to the small-scale harvest of rice in southeastern Wisconsin. While a harvest of 1,200 pounds of rice may not turn any commercial rice producer's head, it proves rice can grow in Wisconsin.

Another mission of Schlappi's research is to show rice can be grown on a more local level. He believes the concept could satisfy consumers with a taste for locally grown foods and producers seeking an alternative crop for acres unsuited for traditional crops.

Wild rice has been harvested in northern extremes for centuries, but it is actually a grass and a distant relative to domesticated rice. Asian-type domesticated rice is more the species Oryza sativa, which gave us the word "rice" (Oryza). The wild rice species found in Wisconsin is called Zizania palustris and a completely different genus.

Ultimately, the big attraction is how cold tolerance research could benefit other crops. "The rice genome is fully sequenced, so we know where the genes are. That allows us to find the genes that deal with cold tolerance and map those pathways," said Schlappi.

"This research can also be used as we work to understand the genetic pathways in other crops. It's not a simple process, but the more we know how these pathways work, the more information we have available to develop crops with specific traits," he said.

Read more about his research here: http://bit.ly/…

MORE NEONICOTINOID NEWS

The topic of neonicotinoid seed treatments (NSTs) continues to keep researchers searching for answers.

A study from the University of Maryland's Department of Entomology concludes that NSTs play an important role in grain crop production and can be a useful tool for insect pest management, but using when pest pressure is low may not increase yield relative to seeds not treated with insecticides.

"When pest pressure is high, NSTs provide a convenient and economical way to protect crops. However, our work demonstrates that the use of NSTs may not always be economically beneficial in the mid-Atlantic region. Producers can make the best use of NSTs where they regularly have high early season insect pest pressure," the researchers wrote.

The three-year study looked at Cruiser (thiamethoxam) and Gaucho (imidacloprid) in a three-year grain crop rotation of full-season soybean, winter wheat, double-crop soybean and corn.

"Farmers growing corn for many years probably know which fields have a history of soil insect activity based on previously encountered problems or the field characteristics and cropping history," said Galen Dively, professor Emeritus of Entomology at the University of Maryland, and one of the study's authors. "Field scouting is possible but requires a trained individual for sampling soil insect populations."

Additional research is under way to study insect pressure and response to seed treatments. "Seed treatments do an excellent job and are our best option for soil pests. We need them to work when there is pressure," said Kelly Hamby, University of Maryland extension specialist. "Using them so widely likely increases the risk of insecticide resistance developing, in addition to other non-target impacts."

Read the study here: http://bit.ly/…

Mark Moore can be reached at talk@dtn.com

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