Epiphytic Movement and Survival of Pseudomonas Syringae on Spring Wheat

Field, greenhouse, and growth chamber experiments demonstrated that Pseudomonas syringae, the incitant of bacterial leaf necrosis of wheat, moved from inoculated wheat seed to the seedling and survived as an epiphyte on the leaves. In greenhouse experiments 80-90% relative humidity favored movement of P. Syringae to the coleptile and first true leaf of the seedlings. Movement was not different on wheat cultivars susceptible or resistant to bacterial leaf necrosis. Under 70-98% relative humidity in a growth chamber, P. syringae moved to a significantly higher (P=0.01) percentage of seedlings at 10C than at 16 or 22C. In a field experiment, using serotype VI as a marker, P. syringae was recovered from the first true leaf, but not from upper leaves up to 41 days after emergence. From date of seedling emergence to day 41, total precipitation received was only 1.09 cm. However, after substantial rainfall (3.48cm) on day 42, P. syringae serotypes III, IV, and V in addition to VI, were isolated from upper leaves in both inoculated and control areas. This suggests that other sources of inoculum or bacterial leaf necrosis were also present

Effects of environmental and anthropogenic landscape features on mule deer harvest in Nebraska

Understanding the habitat use of wildlife species is important for effective management. Nebraska has a variety of habitat types, with the majority being covered by rangeland and cropland. These habitat types likely influence the harvest of mule deer (MD; Odocoileus hemionus) in Nebraska, but their specific effects are unknown, and moreover, harvest may also be influenced by the accessibility of deer habitats for hunters. We modeled which environmental and anthropogenic landscape features influenced harvest densities. Spatial analysis in a Geographic Information System was used to determine the mean values of environmental and anthropogenic landscape features at the county level. We then used a generalized linear model to determine which of those factors influenced MD harvest from 2014–2016. We found that NDVI amplitude, hunter effort, road density, terrain roughness, and canopy cover influence MD harvest in Nebraska. According to our model, MD harvest densities are significantly greater areas with NDVI amplitude ∼38, increasing hunter effort, road densities near 1,750 m/km2, increasing terrain roughness, and decreasing canopy cover. Understanding increased harvest densities of MD can be beneficial for wildlife managers, allowing for more efficient allocation of efforts and expenses by managers for population management

Poultry Litter Gasification in a Fluidized Bed Reactor: Effects of Gasifying Agent and Limestone Addition

Air and air-steam gasification of poultry litter was experimentally studied in a laboratory scale bubbling fluidized bed gasifier at atmospheric pressure using silica sand as the bed material. The effects of equivalence ratio (ER), gasifier temperature, steam-to-biomass ratio (SBR), and addition of limestone blended with the poultry litter, on product gas species yields and process efficiency, are discussed. The optimum conditions (maximum carbon conversion, gas yield, heating value, and cold gas efficiency) were achieved at an ER 0.25 and 800 °C, using air (SBR = 0) and poultry litter blended with 8% w/w limestone, yielding a product gas with a lower heating value (LHV) of 4.52 MJ/Nm 3 and an average product gas composition (dry basis) of H 2 : 10.78%, CO: 9.38%, CH 4 : 2.61, and CO 2 : 13.13. Under these optimum processing conditions, the cold gas efficiency, carbon conversion efficiency, and hydrogen conversion efficiency were 89, 73, and 43% respectively. The reported NH 3 measurement at an ER of 0.28 and 750 °C is 2.7% (equivalent to 19,300 mg/Nm 3 ) with 14.7 mg/Nm 3 of HCl observed as the dry product gas. High temperature and steam injection favor production of CO and H 2 , while their effect on CH 4 was almost negligible. It is demonstrated that poultry litter can be gasified by blending with limestone, making it possible to overcome the fluidization problems caused by the mineral composition of poultry litter ash (high K and P content), yielding a gas with a similar heating value compared to gasifying without limestone addition, but with a significantly lower tar content

Assessment of Water Quality and Response Rate of Zooplankton in a Nebraska “Barrow Pit” After Rotenone Application

Understanding the extent and depth of rotenone impacts on all trophic levels is essential to effective aquatic management. We examined changes in water quality tenets and zooplankton communities following the establishment of 3 ppm rotenone concentration in a Nebraska barrow pit. Dissolved oxygen initially decreased 57% and subsequently increased 298% the week following rotenone application. Turbidity decreased from 25.8 FAU ± 0.80 pre-treatment to 6.6 FAU ± 0.98 one year later. Total zooplankton (0.17/L ± 0.03) were limited prior to rotenone application and absent for the following 3 weeks. One year later the total number of zooplankton increased 1024%, and during the same timeframe both pseudo-control barrow pits remained similar or decreased in total zooplankton present. Rotifers were the first taxon to recover. Copepods and their nauplii were absent for 2 months and recovered to levels greater than pseudo-controls three months after the rotenone treatment. Cladocerans were the slowest to re-establish as they were absent for 3 months and did not match those recorded in pseudo-controls until 7 months later. This research can assist aquatic managers in understanding how water quality and zooplankton communities will change following the application of rotenone in a Nebraska barrow pit

\u3ci\u3eDaphnia lumholtzi,\u3c/i\u3e an Exotic Zooplankton, Invading a Nebraska Reservoir

A limnological assessment project by the University of Nebraska at Kearney and the Nebraska Game and Parks Commission collected weekly vertical zooplankton tows during May through September 2002 at Harlan County Reservoir in Nebraska. Beginning on 5 August 2002, the exotic Daphnia lumholtzi (Cladocera: Daphniidae) appeared at a density of 0.04 1.1 in one of fifteen standardized sampling stations. By 6 September 2002, D. lumholtzi was found in all fifteen stations at an average density of 2.17 ± 3.10 1.1 with a site maximum density of 11.43 1.1 • Length measurements of D. lumholtzi ranged from 0.80 mm to 5.66 mm with a mean length of 2.38 ± 1.107 mm. During sampling, the abundance of D. lumholtzi increased relative to the native Daphnia retrocurva from less than 1 % to greater than 45% of all zooplankton collected. Our finding represents the first account in a Nebraska water system of D. lumholtzi, a native of Africa, Asia, and Australia, and shows a northern expansion in the Great Plains of this exotic species