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An Integrated Crop- And Soil-Based Strategy For Variable-Rate Nitrogen Management In Corn, Darrin F. Roberts

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Nitrogen (N) management in cereal crops has been the subject of considerable research and debate for several decades. Historic N management practices have contributed to low nitrogen use efficiency (NUE). Low NUE can be caused by such things as poor synchronization between soil N supply and crop demand, uniform application rates of fertilizer N to spatially variable landscapes, and failure to account for temporally variable influences on soil N supply and crop N need. Active canopy reflectance sensors and management zones (MZ) have been studied separately as possible plant- and soil-based N management tools to increase NUE. Recently, some have …

Effect Of Nitrogen Application Timing On Corn Production Using Subsurface Drip Irrigation, David D. Tarkalson, Simon J. Van Donk, James L. Petersen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The use of subsurface drip irrigation (SDI) in row-crop agriculture is increasing because of potential increases in water and nutrient use efficiency. Research-based information is needed to manage N applications through SDI systems in field corn (Zea-mays L.) production. This study was conducted to assess the effect of different in-season SDI system N application timings on corn production and residual soil N0₃-N at the University of Nebraska-Lincoln West Central Research and Extension Center in North Platte, Neb, on a Cozad silt loam (fine-silty, mixed, mesic Fluventic Haplustoll). We evaluated the effect of three N application timing methods …

Crop Updates 2009 - Cereals, Jeff Baldock, Doug Edmeades, Mark Seymour, Paul Carmody, Ian Pritchard, Alan Meldrum, Michael Robertson, Roger Lawes, Rob Sands, Peter White, Felicity Byrne, Andrew Bathgate, Kedar Adhikari, Tanveer Khan, Stuart Morgan, Alan Harris, P. Gaur, K. M. H. Siddique, H. Clarke, N. C. Turner, W. Macleod, S. Morgan, Chris Veitch, Tony Leonforte, Kith Jayasena, Geoff Thomas, Rob Loughman, Kazue Tanaka, Ravjit Khangura, M. Amjad, Richard Oliver, Dusty Severtson, Peter Mangano, John Botha, Brenda Coutts, Manisha Shankar, Kasia Rybak, Michael Baker, Andrea Hills, Shahajahan Miyan, Peter Portmann, Nicole Rice, Robert Henry, Jeff J. Russell, B. H. Paynter, Linda Price, Brenda Shackley, Vicki Scanlan, Darshan Sharma, Christine Zaicou-Kunesch

Crop Updates

This session covers twenty seven papers from different authors:

PLENARY

1. Building soil carbon for productivity and implications for carbon accounting, Jeff Baldock, CSIRO Land and Water, Adelaide, SA

2. Fact or Fiction: Who is telling the truth and how to tell the difference, Doug Edmeades, agKnowledge Ltd, Hamilton

3. Four decades of crop sequence trials in Western Australia, Mark Seymour,Department of Agriculture and Food

BREAK CROPS

4. 2008 Break Crops survey Report, Paul Carmody,Development Officer, Department of Agriculture and Food

5. Attitudes of Western Australian wheatbelt growers to ‘Break Crops’, Paul Carmody and Ian …

Quantifying Turfgrass-Available N From Returned Clippings Using Anion-Exchange Membranes, Kelly L. K.Opp, Karl Guillard

Plant Science Articles

Returning clippings can provide N to turf, but the amount of plant-available N derived from clippings is not easy to quantify. An accurate estimate of N released by clippings would be useful in guiding turf N fertilizer recommendations. The objective of this study was to determine if anion-exchange membranes (AEMs) could be used to quantify plant-available soil N when clippings are returned. A greenhouse and two field experiments were set out in randomized block designs using a factorial arrangement of 2 clipping practices [removed (CRM) and returned (CRT)] and 4 rates of N fertilization (0 to 392 kg N ha-1 …

Development And Application Of A System For The Analysis Of Atmospheric, Water And Sediment Nitrogen And Carbon, Ann Stavert, Stephen R. Wilson, Dianne F. Jolley

Faculty of Science - Papers (Archive)

Eutrophication and climate change, key environmental concerns, are both linked to the carbon and nitrogen cycles hence the improved understanding of these cycles is essential. Currently, there is no system that simultaneously measures the fluxes of the three key gas phase products of nitrogen and carbon cycling (CO2, CH4 and N2O) in submerged ecosystems with hourly time resolution. A “Lake-in-a-box” (mesocosm) was developed in the laboratory which allowed the monitoring of key components of the carbon and nitrogen cycles within the air, water and sediments. The approach is automated, simple and time efficient and novel in its ability to examine …

Nutrient Limitation Of Phytoplankton By Nitrogen And Phosphorus: Erosion Of The Phosphorus Paradigm, Wayne A. Wurtsbaugh, William M. Lewis Iii

Watershed Sciences Faculty Publications

No abstract provided.

Freshwater Responses To Nitrogen And Phosphorus Pollution And A Case Study Of Cutler And Dingle Marsh Wetlands, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.

Container And Installation Time Effects On Soil Moisture, Temperature, And Inorganic Nitrogen Retention For An In Situ Nitrogen Mineralization Method, Brian J. Wienhold, Gary E. Varvel, Wallace W. Wilhelm

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Mineralization contributes significantly to agronomic nitrogen (N) budgets and is difficult to accurately predict. Models for predicting Nmineralization contributions are needed, and development of these models will require field-based data. In situ mineralization methods are intended to quantify N mineralization under ambient environmental conditions. This study was conducted to compare soil moisture and temperature in intact soil cores contained in cylinders to those in adjacent bulk soil, compare the effect of two resin-bag techniques on water content of soil within cylinders, and assess the effect of installation duration on inorganic N retention by resins. The study was conducted at a …

Hydrologic Control Of Nitrogenremoval, Storage And Export In A Mountain Stream, R. O. Hall Jr., Michelle A. Baker, C. D. Arp, B. J. Koch

Biology Faculty Publications

Nutrient cycling and export in streams and rivers should vary with flow regime, yet most studies of stream nutrient transformation do not include hydrologic variability. We used a stable isotope tracer of nitrogen (¹⁵N) to measure nitrate (NO₃^-) uptake, storage, and export in a mountain stream, Spring Creek, Idaho, U.S.A. We conducted two tracer tests of 2-week duration during snowmelt and baseflow. Dissolved and particulate forms of ¹⁵N were monitored over three seasons to test the hypothesis that stream N cycling would be dominated by export during floods, and storage during low flow. Floods …

Aspen Succession And Nitrogen Loading: A Case For Epiphytic Lichens As Bioindicators In The Rocky Mountains, Usa, Paul C. Rogers, Kori D. Moore, Ronald J. Ryel

Wildland Resources Faculty Publications

Question: Can lichen communities be used to assess shortand long-term factors affecting seral quaking aspen (Populus tremuloides) communities at the landscape scale? Location: Bear River Range, within the Rocky Mountains, in northern Utah and southern Idaho, USA. Method: Forty-seven randomly selected mid-elevation aspen stands were sampled for lichens and stand conditions. Plots were characterized according to tree species cover, basal area, stand age, bole scarring, tree damage, and presence of lichen species. We also recorded ammonia emissions with passive sensors at 25 urban and agricultural sites throughout an adjacent populated valley upwind of the forest stands. Nonmetric multidimensional scaling (NMS) …