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Title:Demonstration of anaerobic digestion centrate as a nitrogen & water source for corn grain production
Author(s):Schaefer, Michael Tinoco
Department / Program:Agricultural & Biological Engr
Discipline:Technical Systems Management
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):anaerobic digestion
Abstract:In this study, a method to deliver subterreanean nitrogen and water as a strategy to benefit both corn producers and wastewater treatment plants (WTPs) was demonstrated for two growing seasons in 2013 and 2014. Subirrigation (SI)/drainage tiles were installed (approximately 60 cm) and used to deliver either anaerobic digestion (AD) centrate (“SICW”) or dissolved urea (“SIUW”) to growing corn plants. These plots were compared to topically applied urea without SI (“Non-SI U”) and controls (“No N” in 2013 and “Base N” in 2014). The first objective of the study was to evaluate corn grain yield and plant nitrogen uptake with AD centrate or urea through SI. AD centrate or urea was added through the SI pipes in 3 to 5 events during the late vegetative and early reproductive phases of 2013 and 2014. Results indicated that, in 2013, among low rate nitrogen treatments (SICW N+ and SIUW N+), SI enhanced average grain yield by 9% (p = 0.05) and nitrogen uptake by 18% (p < 0.01) compared to unfertilized controls (7803 kg grain/ha and 170 kg N/ha). A high rate nitrogen treatment (SICW N++) enhanced average grain yield by 18% compared to the Champaign county average of 9010 kg grain/ha. Low rate nitrogen SI treatments enhanced average grain yield by 8% (p = 0.18) and nitrogen uptake by 8% (p = 0.06) compared to low rate nitrogen Non-SI U treatment plots (7905 kg grain/ha and 185 kg N/ha). In 2014, a wet growing season, among low rate nitrogen SI treatments, SI enhanced average grain yield by 12% (p = 0.07) and nitrogen uptake by 10% (p = 0.06) compared to controls which received a base nitrogen application (Control Base N) of 140 kg N/ha (4590 kg grain/ha and 110 kg N/ha). Low rate nitrogen SI treatments enhanced average grain yield by 15% (p = 0.22) compared to low rate nitrogen Non-SI U treatment plots (4840 kg grain/ha). Among high rate nitrogen SI treatments (SICW N++ and SIUW N++), SI enhanced average grain by 26% (p < 0.01) and nitrogen uptake by 27% (p < 0.01) compared to controls with a base nitrogen application. High rate nitrogen SI treatments enhanced average grain yield by 14% (p = 0.08) compared to high rate nitrogen Non-SI U (Non-SI U N++) treatment plots (5100 kg grain/ha). The second objective was to assess nitrogen and water movement away from an SI pipe in unsaturated soil conditions. A soil profile box was built and centrate was added. Both soil moisture and NH4-N were measured after 48 hours. Water moved uniformly throughout the soil matrix compared to NH4-N—the standard deviation of 7 measured points’ soil water concentration was 13% of the average, compared to the standard deviation of 7 measured points’ NH4-N concentration which was 174% of the average. In summary, the results indicate that delivering centrate and water through SI is an effective strategy for late vegetative nitrogen and water delivery when N uptake is highest (Bender, Haegele et al. 2012); however, the physical and chemical mechanisms through which water and nitrogen move through the soil vary—as such, the beneficial effect that they can each have on grain yield and nitrogen uptake will change depending upon climatic conditions.
Issue Date:2015-05-01
Rights Information:Copyright 2015 Michael Schaefer
Date Available in IDEALS:2015-07-22
Date Deposited:May 2015

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