Increasing carbon sequestration of working prairie by reducing invasive species in a fire and grazing system

The investigators looked at one method for curbing invasive species that limit carbon sequestration potential for tallgrass prairie stands. They also learned that grasslands dominated by either warm-season, cool-season, or mixed stands are likely equal in their carbon sequestration potential

Winter Cereal Rye Cover Crop Decreased Nitrous Oxide Emissions During Early Spring

Despite differences between the cover crop growth and decomposition phases, few greenhouse gas (GHG) studies have separated these phases from each other. This study’s hypothesis was that a living cover crop reduces soil inorganic N concentrations and soil water, thereby reducing N2O emissions. We quantified the effects of a fall-planted living cereal rye (Secale cereale L.) cover crop (2017, 2018, 2019) on the following spring’s soil temperature, soil water, water-filled porosity (WFP), inorganic N, and GHG (N2O-N and CO2–C) emissions and compared these measurements to bare soil. The experimental design was a randomized complete block, where years were treated as blocks. Rye was fall planted in 2017, 2018, and 2019, but mostly emerged the following spring. The GHG emissions were near-continuously measured from early spring through June. Rye biomass was 1,049, 428, and 2,647 kg ha–1 in 2018, 2019, and 2020, respectively. Compared to the bare soil, rye reduced WFP in the surface 5 cm by 29, 15, and 26% in 2018, 2019, and 2020 and reduced soil NO3–N in surface 30 cm by 53% in 2019 (p = .04) and 65% in 2020 (p = .07), respectively. Rye changed the N2O and CO2 frequency emission signatures. It also reduced N2O emissions by 66% but did not influence CO2–C emissions during the period prior to corn (Zea mays L.) emergence (VE). After VE, rye and bare soils N2O emissions were similar. These results suggest that nitrous oxide (N2O-N) sampling protocols must account for early season impacts of the living cover

Statistical Study of the Geology, Topography, and Pore Fluid Salinity Controls on the Large Slope Failures Observed in North Dakota

A geospatial database of over 24,000 slope failures across the state of North Dakota was developed. The database revealed that nearly 1,500 slopes failures were larger than 100,000 m2 in area posing significant safety concerns and engineering issues. To better understand the influence of various conditioning factors, a statistical study was undertaken in this paper. The slope failures were found to be concentrated in western North Dakota primarily occurring in the Sentinel Butte Formation. Statistical analyses suggest that this is likely due to the steeper topography and the abundance of Sentinel Butte Formation in this region in comparison to eastern North Dakota. The number of slope failures were log-normally distributed with the slope inclination. The mean slope inclination on which slope failures occurred was found to be 9.5° with a standard deviation of 5.7°. Interestingly, despite the presence of high salt concentrations in the soils underlying the majority of the state, the slope failures were found to be concentrated in areas with low salt concentrations. This may be attributed to the lower shear strengths of the soils with lower pore fluid salinity than that of soils with greater concentrations of salinity in the pore fluid.This is a manuscript of a proceeding published as Ajmera, Beena, Aaron Lee M. Daigh, and Kamal Raj Upadhaya. "Statistical Study of the Geology, Topography, and Pore Fluid Salinity Controls on the Large Slope Failures Observed in North Dakota." In Geo-Congress 2023, pp. 491-499. This material may be found at DOI: 10.1061/9780784484654.049. This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. Copyright 2023 American Society of Civil Engineers. Posted with permission

Factors affecting in the use of weather stations data in predicting surface soil moisture for agricultural applications

Weather stations often provide key information related to soil moisture, temperature and evaporation are used by farmers to decide farm operations of nearby agricultural fields. However, the site conditions at the weather stations where data are recorded may not be similar with these nearby fields. The objective of this study was to determine the level of discrepancies in surface soil moisture between weather stations and nearby agricultural fields based on 1) the soil texture, crop residue cover, crop type, growth stages and 2) temporal dependency of soil moisture to recent rainfall and evaporation rates. Soil moisture from 25 weather stations in the North Dakota Agricultural Weather Network (NDAWN) and 75 nearby fields were measured biweekly during the 2019 growing season in Red River Valley. Field characteristics including soil texture, crop residue cover, crop type and growth stages along with rainfall and potential evapotranspiration were collected during the study period. The regression analysis between surface soil moisture at weather station and nearby field showed higher values for corn at V10 stage (r2=0.92) and for wheat at flowering stage (r2=0.68) and opposite was observed with soybean. We found the regression coefficient of soil moisture with four-day cumulative rainfall slightly increased to 0.51 with an increase in percent residue cover resulting in a decreased root mean square error (RMSE) to 0.063 m3 m-3. In general, we observed that surface soil moisture at weather stations could reasonably predict moisture in nearby agricultural fields considering crop type, soil type, weather, and distance from weather station.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Soil temperature and water contents among vertical tillage, strip tillage, and chisel plowing in the Upper Great Plains

Long winters in the Red River Valley (RRV) of eastern North Dakota and western Minnesota result in short growing seasons for corn (Zea mays L.)-soybean (Glycine max L. Merr.) systems. Historically, producers implement aggressive tillage to warm the soil, which has caused hesitation when considering reduced tillage systems. The association between soil warming-drying and crop yields via research at farmer-operated, production-scale systems practicing reduced tillage is lacking. A two-year study was conducted at three producer-operated, corn-soybean fields in the RRV with five soil series ranging from sandy loams to silty clays. Soil temperature (T), soil volumetric water content (θ), and crop yields were measured to evaluate the effects of soil warming and drying and crop performance under reduced tillage practices of vertical till (VT), strip till with shanks (STS), strip till with coulters (STC), and chisel plow (CP). Results showed daytime soil T and θ in the tilled strips for STC and STS (i.e., in the plant rows) were similar to CP and significantly different from VT. The ST treatments demonstrated added benefits of higher soil θ between the tilled strips (i.e., between the plant rows) during the mid-growing season when plant water needs are at their highest. However, daily averaged soil T and θ had little to no significant differences among the tillage treatments. Moreover, crop yields were inconsistent with soil T and θ, indicating weak to no practical association in these on-farm settings.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author