G03-1504 Lime Use for Soil Acidity Management

Soil acidity can reduce crop production by directly affecting roots and changing the availability of essential nutrients and toxic elements. Liming can neutralize soil acidity, but several factors can affect the economic benefits of liming. With continuous cropping, soil pH can decrease (i.e., increase in acidity) because of various factors, including crop removal and leaching of basic cations, application of ammoniabased nitrogen fertilizers, and organic matter decomposition. Adding lime or other materials can raise soil pH to the ideal range for crop production, create an environment for a healthy function of microbes, and increase the levels of calcium or magnesium ions

Temporal changes in the nutrient content of cattle dung in the Nebraska Sandhills ecosystem

Dung excreted by cattle composes a significant portion of the nutrient inputs in a grazed ecosystem and can have wide-ranging effects on soil properties and vegetation. However, little research has been conducted on the nutrient dynamics of excreted dung in situ that has not been disturbed prior to field sampling. In this study, we analyzed 294 dung pats (1–24 days old) collected from a Nebraska Sandhills meadow to determine water-extractable organic carbon (WEOC), water-extractable nitrogen (WEN), water-extractable phosphorus (WEP), and percent dry matter (DM) changes over time. In addition, we investigated if sample handling - frozen storage – and the formation of surface crust during dung field drying affect dung nutrient concentrations. Dung WEOC and WEN both followed exponential decay curves of nutrient loss over time and were modeled as a function of age. In contrast, WEP was poorly correlated with age. The percent dry matter in conjunction with sample WEOC concentration were stronger determinants of WEP than age alone. Freezing samples prior to analysis increased WEOC (37–98%) and WEN (37–123%), but lowered WEP (0.8–65%) compared to the samples from the same dung pat analyzed fresh. The dry surface crusts of dung pats had higher WEOC (98–112%) and WEN (112%) compared to moist interiors (on average, 3 cm from surface). This research provides evidence that dung nutrient concentrations decreased by 73% (WEOC) and 76% (WEN) over 24 days and shows that frozen storage and subsequent thawing for analysis, as well as crust formation during field drying, can significantly affect dung nutrient concentrations and spatial partitioning of dung nutrients

Empowerment and Tech Adoption: Introducing the Treadle Pump Triggers Farmers’ Innovation in Eastern Ethiopia

In 2013, thirty-eight treadle pumps (TPs) were installed as low-cost technology introduction for small-scale irrigation in eastern Ethiopia. This pilot project also trained six farmers on tube well excavation, as well as the installation and maintenance of pumps. In June 2015, researchers visited nine of the thirty-eight TP villages and found only two TPs functioning as originally installed. The rest were replaced with a new technology developed by the trained farmers. Farmers, empowered by training, gained more control in developing technology options tailored to local needs and conditions of their communities. Adopters of the new technology stated that the limited water output and high labor demand of the conventional TP did not optimally fulfil their irrigation water requirements. The new technology had spread quickly to more than one hundred households due to three key factors. First, farmers’ innovative modifications of the initial excavation technique addressed the discharge limitations of the conventional TP by excavating boreholes with wider diameter. Second, local ownership of the new technology, including skills used in well drilling and manufacturing excavation implements, made the modified irrigation technology affordable and accessible to the majority of households. Third, this innovation spread organically without any external support, confirming its sustainability

Identifying and Addressing Soil Property Issues Affecting Roadside Vegetation Establishment

Attaining adequate vegetation cover along highways is important for NDOR to comply with EPA’s stormwater regulations. However, low plant cover is a common problem on shoulders (first 16 feet off the pavement) of many highways in Nebraska. The ultimate goal of this study is to identify cost-effective engineering solutions that assure adequate seed beds (i.e., soil conditions) for establishment of selected seeding mixtures. The objectives of this study are to (1) characterize the soil properties along roadsides where vegetation stands have not developed well, and (2) verify the effects of select soil property parameters on plant germination and establishment. Sampling occurred at multiple locations along the highways near Beaver Crossing and Sargent, NE. At each location, soil samples were collected from a transect of multiple landscape positions, perpendicular to the highway. The soil physical properties measured included cone index, sorptivity, and aggregate stability, while the soil chemical properties measured included EC, pH, organic matters, Na, and Ca. Results show that the soils near the edge of the highway pavement were highly compacted. Also, the soils had higher pH, lower organic matter, and higher salt levels than optimal conditions. In the subsequent greenhouse studies, a factorial design was used to test three factors: soil compaction (i.e., 1.5, 1.7, and 1.9 g cm-3 soil compaction levels as well as sand as control), timing of salt stress (2 pulses of salt treatment applied pre-germination and post-germination as well as no-salt control), and plant species (buffalo grass, tall fescue, and western wheat grass). Results from the greenhouse studies showed that the three plant species exhibited different germination and early survival responses to the soil compaction and salt treatments. Tall fescue is better suited for site re-vegetation especially if salt is present in the soil prior to germination. Statistical analysis show that salt treatment had the most impact on species performance. Finally the project recommends a few engineering remediation strategies for plant establishment. Creating microsites on compacted soil surfaces could potentially alleviate the soil compaction issue by creating local environmental conditions favorable to plant establishment at microsites. To remediate the high salt levels in soil, it is recommended to consider alternative de-icing agents and amend zeolites and organics in soil

Abundance and Diversity of Dung Beetles (Coleoptera: Scarabaeoidea) as Affected by Grazing Management in the Nebraska Sandhills Ecosystem

Dung beetles (Coleoptera: Scarabaeoidea) serve a significant role in regulating ecosystem services on rangelands. However, the influence of grazing management on dung beetle communities remains largely unknown. The purpose of this study was to investigate dung beetle abundance and diversity throughout the grazing season in the Nebraska Sandhills Ecoregion. Grazing treatments included: continuous grazing (CONT), low-stocking rotational grazing (LSR), high-stocking rotational grazing (HSR), and no grazing (NG). The abundance and diversity of dung beetles were measured in the 2014 and 2015 grazing seasons using dung-baited pitfall traps. Dung beetle abundance for each grazing treatment was characterized through four indices: peak abundance, species richness, Simpson’s diversity index, and Simpson’s evenness. A total of 4,192 dung beetles were collected through both years of trapping in this study. Peak abundance and species richness were greater in grazed treatments when compared to NG in both years. Peak abundance in the HSR was 200% (2014) and 120% (2015) higher than in the LSR. Species richness in the HSR was 70% (2014) and 61% (2015) higher than in the LSR, and 89% (2014) and 133% (2015) higher than in CONT. Simpson’s diversity index was lower in the NG and CONT treatments when compared to the LSR or HSR treatments for both years. We conclude that rotational grazing, regardless of stocking density, promoted dung beetle abundance and diversity within the Nebraska Sandhills Ecoregion

Abundance and Diversity of Dung Beetles (Coleoptera: Scarabaeoidea) as Affected by Grazing Management in the Nebraska Sandhills Ecosystem

Dung beetles (Coleoptera: Scarabaeoidea) serve a significant role in regulating ecosystem services on rangelands. However, the influence of grazing management on dung beetle communities remains largely unknown. The purpose of this study was to investigate dung beetle abundance and diversity throughout the grazing season in the Nebraska Sandhills Ecoregion. Grazing treatments included: continuous grazing (CONT), low-stocking rotational grazing (LSR), high-stocking rotational grazing (HSR), and no grazing (NG). The abundance and diversity of dung beetles were measured in the 2014 and 2015 grazing seasons using dung-baited pitfall traps. Dung beetle abundance for each grazing treatment was characterized through four indices: peak abundance, species richness, Simpson’s diversity index, and Simpson’s evenness. A total of 4,192 dung beetles were collected through both years of trapping in this study. Peak abundance and species richness were greater in grazed treatments when compared to NG in both years. Peak abundance in the HSR was 200% (2014) and 120% (2015) higher than in the LSR. Species richness in the HSR was 70% (2014) and 61% (2015) higher than in the LSR, and 89% (2014) and 133% (2015) higher than in CONT. Simpson’s diversity index was lower in the NG and CONT treatments when compared to the LSR or HSR treatments for both years. We conclude that rotational grazing, regardless of stocking density, promoted dung beetle abundance and diversity within the Nebraska Sandhills Ecoregion

Patch Burning: Implications on Water Erosion and Soil Properties

Patch burning can be a potential management tool to create grassland heterogeneity and enhance forage productivity and plant biodiversity, but its impacts on soil and environment have not been widely documented. In summer 2013, we studied the effect of time after patch burning (4 mo after burning [recently burned patches], 16 mo after burning [older burned patches], and unburned patches [control]) on vegetative cover, water erosion, and soil properties on a patch-burn experiment established in 2011 on a Yutan silty clay loam near Mead, NE. The recently burned patches had 29 ± 8.0% (mean ± SD) more bare ground, 21 ± 1.4% less canopy cover, and 40 ± 11% less litter cover than older burned and unburned patches. Bare ground and canopy cover did not differ between the older burned and unburned patches, indicating that vegetation recovered. Runoff depth from the older burned and recently burned patches was 2.8 times (19.6 ± 4.1 vs. 7.1 ± 3.0 mm [mean ± SD]) greater than the unburned patches. The recently burned patches had 4.5 times greater sediment loss (293 ± 89 vs. 65 ± 56 g m-2) and 3.8 times greater sediment-associated organic C loss (9.2 ± 2.0 vs. 2.4 ± 1.9 g m-2) than the older burned and unburned patches. The recently burned patches had increased daytime soil temperature but no differences in soil compaction and structural properties, dissolved nutrients, soil C, and total N concentration relative to older burned and unburned patches. Overall, recently burned patches can have reduced canopy and litter cover and increased water erosion, but soil properties may not differ from older burn or unburned patches under the conditions of this study

Experiential Learning in Soil Science: Evaluating Soil Quality in South Wollo, Ethiopia

This study abroad program provided an opportunity to enhance the international experience and research skills of University of Nebraska-Lincoln (UNL) students within a multidisciplinary team’s research-education goal on improving food security in Ethiopia. The experiential study component of the project included preparatory sessions during the Fall 2015 Semester at the UNL followed by a four- to five-week fieldwork experience in Ethiopia. Teams from the UNL and an Ethiopian university participated in survey data collection and field soil evaluations from farms in the Gerado area of South Wollo, Ethiopia. Having students interact with farmers increased student self-confidence and enhanced their leadership skills. Soil fertility evaluation provided the opportunity for students to apply soil health concepts in a practical setting, thus giving them a fuller understanding of these commonly challenging concepts. Throughout the study experience in Ethiopia, two UNL students wrote reflective journal entries each day and participated in daily wrap-ups. Students also gave permission to staff at Wollo University and to fellow students and faculty at the UNL. In addition they completed a final paper integrating the journal material and the experiential research work in Ethiopia. Students experienced cultural immersion while participating in this ongoing research project