In water-limited arid and semiarid regions, water needs to be used efficiently for sustaining irrigated crop yields and that efficiency can vary widely with the type of irrigation system used. But what other impacts do these differing systems have on sustainability? For example, how do they impact key soil nutrients such as carbon and nitrogen? And what of the increased use of strip tillage for sugar beet rotations in the MonDak? How do these different irrigation systems impact soil carbon and nitrogen under strip tillage?
These questions and more are the subject of the next presentation in the 2012 BrownBagger series sponsored by the USDA-ARS Northern Plains Agricultural Research Laboratory (NPARL), Sidney. The presentation by NPARL Soil Scientist Upendra Sainju is set for Friday, March 16 from noon-1 p.m., and is entitled “Irrigation System and Crop Rotation Effects on Soil Carbon and Nitrogen Fractions”. The one-hour session is open to the public.
In his research, Dr. Sainju is comparing the effects of two different sprinkler irrigation systems – the conventional Mid-Elevation Spray Application (MESA) system and the highly efficient Low Energy Precision Application (LEPA) system – in both conventional- and strip-tilled sugarbeet-malt barley rotations. He’s interested in knowing how the irrigation, tillage and rotation systems impact carbon and nitrogen in the soil.
In particular, he’s interested in how much of both nutrients are available for uptake by plants, or subject to leaching loss; how much is stored or sequestered in the soil over the long term, and how much is changing rapidly over the growing season under these different irrigation and tillage scenarios. All of these different types or “fractions” of soil carbon and nitrogen have significant impacts on crop yields and soil quality, according to Dr. Sainju.
“We will evaluate these fractions for carbon and nitrogen sequestration, microbial biomass and activity, nitrogen mineralization potential, and soil quality and productivity as influenced by irrigation system and crop rotation,” he notes.
Each component, irrigation and tillage, also have their own set of impacts on crop sustainability, according to Sainju. For example, the MESA applies water through nozzles from a height of 3 feet which results in low water application efficiency (35-80%) and increases loss of water soluble carbon and nitrogen through leaching and surface runoff. In contrast, the highly water-efficient LEPA sprinklers apply water near the soil surface, and can reduce carbon and nitrogen loss through these processes.
As for tillage, multiple tillage operations conducted in conventional sugarbeet and malt barley production can increase soil erosion, fuel costs, and seedling damage caused by windblown soil. Multiple tillage operations can also reduce soil quality due to increased organic matter mineralization, influencing future crop yields, Sainju says. In contrast, reduced tillage, such as strip tillage where only crop rows are tilled with the areas between them left undisturbed, can reduce soil erosion and improve soil quality without influencing crop yields.
So bring your lunch and learn more at another informative presentation in the sixth of our 2012 Friday BrownBagger seminars. Coffee and cookies will be provided. The lab is located at 1500 N. Central Ave. Sidney. All presentations begin at noon. For more information, contact Beth Redlin at 406-433-9427.
Don’t miss these remaining presentations in 2012:
March 30: Tatyana Rand, Entomologist, ARS-Sidney, MT
Factors influencing wheat stem sawfly infestation levels and parasitism by native biocontrol agents
April 6: Kevin Delaney, Entomologist, ARS-Sidney, MT
Wheat stem sawfly – wheat interactions with spring wheat, and classical biocontrol of weeds.
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