Physical Sciences and Mathematics Commons^™

Soil Aggregate Dynamics, Particulate Organic Matter And Phosphate Under Dryland And Irrigated Pasture, J. T. Scott, L. M. Condron, R. W. Mcdowell

IGC Proceedings (1997-2023)

Soil aggregate formation and turnover affects the rate of occlusion or release of soil organic matter and therefore the availability for mineralisation or stabilisation of soil carbon (C) and phosphorus (P). Furthermore, differences in soil type, management and the quantity and quality of organic inputs can affect aggregate turnover rates (Six et al., 2000). Under pastoral farming the ratio of coarse particulate organic matter (inter-POM) inside macroaggregates but outside microaggregates to fine POM (intra-POM) within microaggregates may provide an indication of physical processes influencing mineralisation and stabilisation of soil C and organic P (Po). Our aim was to determine …

Irrigation Decisions In Response To Groundwater Salinity In Kansas, Juhee Lee, Nathan P. Hendricks

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Understanding the interaction between groundwater salinity and irrigation decision making has important implications for groundwater management. Econometrics models were estimated using observed farmer behavior in response to different groundwater salinity levels in a region of Kansas. Estimation results demonstrate that farmers in the face of groundwater salinity change their irrigation decisions on irrigated acreage (i.e., extensive margin), crop choice (i.e., indirect intensive margin), and water application depth (i.e., direct intensive margin). The empirical results indicate an overall decrease in water use due to higher salinity, primarily through a decrease at the extensive margin.

Analysis Of Soil Change Across Nebraska, Trinity Baker

School of Natural Resources: Dissertations, Theses, and Student Research

The world’s population is growing and an increasing populace requires more resources. These requirements place increasing pressure on the environment and the soil. Soils serve many important functions throughout the world. These functions range from offering a media for food production, providing a sink for organic carbon, nutrient cycling, and improving water quality. It is important to focus on the human impact on soils and their change over time.

For my research I examined how soils across Nebraska have changed over a time period of roughly 65 years. I sampled and analyzed 39 pedons from four Major Land Resource Areas …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Water Resources, Agriculture And Pasture: Implications Of Growing Demand And Increasing Scarcity, M. W. Rosegrant, R. A. Valmonte-Santos, S. A. Cline, C. Ringler, W. Li

IGC Proceedings (1997-2023)

Key points

1. Water availability for irrigation is threatened in many regions by rapidly increasing demand for nonagricultural water uses in industry, households, and the environment. The scarcity of irrigation water will not only impact crop production, but also meat production, as much of the pasture used to feed livestock is irrigated.

2. Grassland is caught between two countervailing forces: a requirement for increasing meat demand that boosts the need for additional pasture to support livestock production, and rapidly increasing water scarcity that makes pasture irrigation uneconomical.

3. The most effective means of dealing with water scarcity is likely to …

Irrigation’S Impact On A Precipitation Event During Grainex In Nebraska, Usa, Daniel Whitesel

School of Natural Resources: Dissertations, Theses, and Student Research

Numerous precipitation events were observed during the Great Plains Irrigation Experiment (GRAINEX). However, the precipitation event that was observed the morning of 23 July 2018 is the focus of this thesis. Six experiments were conducted which involved increasing or decreasing soil moisture by 5% increments over the irrigated cropland. An additional experiment, which changed the irrigated land use to grassland, showed precipitation increases. It was found that regardless of strength of irrigation, average precipitation decreased. Average precipitation decreased by up to 72% when irrigation increased compared to the control simulation and decreased by up to 85% when irrigation decreased compared …

Influence Of Irrigation On Diurnal Mesoscale Circulations: Results From Grainex, C. Phillips, R. Mahmood, R. Pielke Sr.

School of Natural Resources: Faculty Publications

No abstract provided.

Simulation Of Nitrous Oxide Emissions In Zoysia Turfgrass Using Daycent And Dndc Ecosystem Models, Mu Hong, Yao Zhang, Ross Braun, Dale J. Bremer

Kansas Agricultural Experiment Station Research Reports

Nitrous oxide (N₂O) is an important greenhouse gas (GHG) implicated in global climate change. Process-based ecosystem models, such as DAYCENT and DNDC, have been widely used to predict GHG fluxes in agricultural systems. However, neither model has yet been applied to warm-season turfgrasses such as zoysiagrass. This study parameterized, calibrated, and validated the DAYCENT and DNDC models for N₂O emissions from Meyer zoysiagrass (Zoysia japonicaSteud.) using Bayes’ theorem and field data from Braun and Bremer (2018a, 2019) and Lewis and Bremer (2013). Results indicated DAYCENT, but not DNDC, reasonably simulated the impacts of irrigation …