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Wortmann C.S.,University of Nebraska - Lincoln | Tarkalson D.D.,Northwest Irrigation and Soils Research Laboratory | Shapiro C.A.,University of Nebraska - Lincoln | Dobermann A.R.,International Rice Research Institute | And 3 more authors.
Agronomy Journal | Year: 2011

Nitrogen use efficiency (NUE) is of economic and environmental importance. Components of NUE were evaluated at in 32 irrigated corn (Zea mays L.) trials conducted across Nebraska with different N rates and where the previous crop was either corn (CC), drybean (Phaseolus vulgaris L.) (CD), or soybean [Glycine max (L.) Merr.] (CS). The mean grain yield with adequate nutrient availability was 14.7 Mg ha kg-1. When non was applied, measured soil properties and irrigation water N accounted for <20% of the variation in plant nitrogen uptake (UN). Mean fertilizer N recovery in aboveground biomass was 74% at the lowest N rate compared with 40% at the highest N rate, a mean of 64% at the economically optimal nitrogen rate (EONR), and least with CD. Agronomic efficiency of fertilizer N averaged 29 kg grain kg-1 N at EONR and was also least with CD. Partial factor productivity of N averaged 100 kg grain kg kg-1 N at EONR, and was greater with CS compared with CC and CD. After harvest, residual soil nitrate nitrogen (RSN) in the 0- to 1.2-m depth ranged from 21 to 121 kg ha kg-1 and increased with N rate. Mean RSN was 88, 59, and 59 kg ha kg-1 for CD, CC, and CS, respectively. High corn yields can be achieved with high NUE and low RSN by management to maximize profitability in consideration of yield potential, and by applying N at the right amount and time. © 2011 by the American Society of Agronomy. Source


Cavigelli M.A.,U.S. Department of Agriculture | Del Grosso S.J.,U.S. Department of Agriculture | Liebig M.A.,U.S. Department of Agriculture | Snyder C.S.,International Plant Nutrition Institute | And 5 more authors.
Frontiers in Ecology and the Environment | Year: 2012

The use of commercial nitrogen (N) fertilizers has led to enormous increases in US agricultural productivity. However, N losses from agricultural systems have resulted in numerous deleterious environmental impacts, including a continuing increase in atmospheric nitrous oxide (N2O), a greenhouse gas (GHG) and an important catalyst of stratospheric ozone depletion. Although associated with about 7% of total US GHG emissions, agricultural systems account for 75% of total US N2O emissions. Increased productivity in the crop and livestock sectors during the past 30 to 70 years has resulted in decreased N2O emissions per unit of production, but N2O emissions from US agriculture continue to increase at a rate of approximately 0.46 teragrams of carbon dioxide equivalents per year (2002 - 2009). This rate is lower than that during the late 20th century. Improvements in agricultural productivity alone may be insufficient to lead to reduced emissions; implementing strategies specifically targeted at reducing N2O emissions may therefore be necessary. © The Ecological Society of America. Source


Lehrsch G.A.,Northwest Irrigation and Soils Research Laboratory | Brown B.,University of Parma | Lentz R.D.,Northwest Irrigation and Soils Research Laboratory | Johnson-Maynard J.L.,University of Idaho | Leytem A.B.,Northwest Irrigation and Soils Research Laboratory
Agronomy Journal | Year: 2015

To maximize recoverable sucrose from sugarbeet (Beta vulgaris L.), producers must effectively manage added N, be it from urea or organic sources such as manure or composted manure. Our study’s objective was to determine the effects of a one-time application of stockpiled and composted dairy cattle (Bos taurus) manure on sugarbeet N uptake, nitrogen recovery (NR) and nitrogen use efficiency (NUE). First-year Site A treatments included a control (no N), urea (202 kg N ha–1), compost (218 and 435 kg estimated available N ha–1), and manure (140 and 280 kg available N ha–1). Site B treatments were a control, urea (82 kg N ha–1), compost (81 and 183 kg available N ha–1), and manure (173 and 340 kg available N ha–1). Compost and manure were incorporated into two silt loams, a Greenleaf (fine-silty, mixed, superactive, mesic Xeric Calciargid) near Parma, ID, in fall 2002 and 2003 and a Portneuf (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid) near Kimberly, ID, in fall 2002 with sugarbeet planted the following spring. At each site, N uptake of sugarbeet tops, but not roots, was similar whether fertilized with urea or organic N, regardless of rate. Incorporating equal organic amendment rates to 0.05 rather than 0.10 mincreased whole-plant N uptake 1.13-fold, to 163.3 kg N ha–1. In general, NR varied among fertilizer sources such that urea >> manure > compost. Where similar available N rates were supplied, NUE ranged from 44.1 to 83.5 kg sucrose kg–1 available N, not differing among inorganic and organic N sources within site-years. © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. Source


Novak J.M.,U.S. Department of Agriculture | Ippolito J.A.,Northwest Irrigation and Soils Research Laboratory | Lentz R.D.,Northwest Irrigation and Soils Research Laboratory | Spokas K.A.,Soil and Water Management Research Unit | And 5 more authors.
Bioenergy Research | Year: 2016

Biochars vary widely in pH, surface area, nutrient concentration, porosity, and metal binding capacity due to the assortment of feedstock materials and thermal conversion conditions under which it is formed. The wide variety of chemical and physical characteristics have resulted in biochar being used as an amendment to rebuild soil health, improve crop yields, increase soil water storage, and restore soils/spoils impacted by mining. Meta-analysis of the biochar literature has shown mixed results when using biochar as a soil amendment to improve crop productivity. For example, in one meta-analysis, biochar increased crop yield by approximately 10 %, while in another, approximately 50 % of the studies reported minimal to no crop yield increases. In spite of the mixed crop yield reports, biochars have properties that can improve soil health characteristics, by increasing carbon (C) sequestration and nutrient and water retention. Biochars also have the ability to bind enteric microbes and enhance metal binding in soils impacted by mining. In this review, we present examples of both effective and ineffective uses of biochar to improve soil health for agricultural functions and reclamation of degraded mine spoils. Biochars are expensive to manufacture and cannot be purged from soil after application, so for efficient use, they should be targeted for specific uses in agricultural and environmental sectors. Thus, we introduce the designer biochar concept as an alternate paradigm stating that biochars should be designed with properties that are tailored to specific soil deficiencies or problems. We then demonstrate how careful selection of biochars can increase their effectiveness as a soil amendment. © 2016 Springer Science+Business Media New York (outside the USA) Source

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