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Tillage And Crop Residue Removal Effects On Evaporation, Irrigation Requirements, And Yield, Simon Van Donk, Norman L. Klocke

West Central Research and Extension Center, North Platte

Irrigators in the western Great Plains and other irrigated regions face water restrictions caused by decreased well capacity, water allocations imposed by water policy, and/or rising energy costs. These growers require water management practices that optimize grain production. When not enough water is available to produce full yields, the goal for water management is to maximize transpiration and minimize nonessential water losses such evaporation of soil water.

It is generally believed that increasing crop residue levels leads to reduced evaporation. However, crop residue that is removed from the field after harvest is gaining value for use in livestock rations and …

True Integrated Weed Management, Stephen L. Young

West Central Research and Extension Center, North Platte

Using the simplest of definitions, integrated weed management has been described as “putting components [of weed control] together, not taking them apart.” Yet, weed science has stopped at the “field edge” in assembling the components into a truly integrated approach. What is keeping weed scientists from developing real integrated weed control regardless of space and time? The answer to this question lies with our colleagues in the engineering and computer science fields, who have made significant advances in developing automated machinery for real-time detection and control of weeds in cropping systems. By using the latest technologies that can quickly identify …

Effects Of Crop Residue Removal On Soil Water Content And Yield Of Deficit-Irrigated Soybean, Simon Van Donk, Timothy M. Shaver, James L. Petersen, Don Davison

West Central Research and Extension Center, North Platte

Reduced tillage, with more crop residue remaining on the soil surface, is believed to conserve water, especially in arid and semi-arid climates. However, the magnitude of water conservation is not clear. An experiment was conducted to study the effect of crop residue removal on soil water content, soil quality, and crop yield at North Platte, Nebraska. The same field plots were planted to soybean (Glycine max) in 2009 and 2010. There were two treatments: residue-covered soil and bare soil. Residue (mostly corn residue in 2009 and mostly soybean residue in 2010) was removed every spring from the same …

Effect Of Growth Promotants On The Occurrence Of Endogenous And Synthetic Steroid Hormones On Feedlot Soils And In Runoff From Beef Cattle Feeding Operations, Shannon L. Bartelt-Hunt, Daniel D. Snow, William L. Kranz, Terry L. Mader, Charles A. Shapiro, Simon Van Donk, David P. Shelton, David Tarkalson, Tian Zhang

West Central Research and Extension Center, North Platte

Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of 16 endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and …

Ecosystem Services: The Significance Of Contributions By Invasive Plant Species, Stephen L. Young

West Central Research and Extension Center, North Platte

A symposium was organized to investigate the area of invasive plant species and ecosystem services and further our understanding of the contributions that invasive plants are making to ecosystem services, which, to date, has received limited attention. The following symposium articles address three important areas of assessing the effects of invasive plant species on ecosystem services. Karie Decker et al., in “Landuse, landscapes, and biological invasions,” introduce the concept of resilience in natural systems and use an analysis of the nonnative plants and land use types in Nebraska to emphasize the importance of predicting and quantifying changes in ecological structure, …