NH3 Loss Research Articles

Can Surface-Applied Zeolite Reduce Ammonia Losses from Feedyard Manure? A Laboratory Study

Abstract. Ammonia (NH 3 ) emission from beef cattle feedyard manure results in losses of nitrogen (N), which may negatively affect air, soil, and water quality. The magnitude and rate of NH 3 volatilization from feedyards partially depends on the amount of urinary urea excreted and dissociation of ammonium (NH 4 + ) into NH 3 following urea hydrolysis. Zeolite clinoptilolite is a naturally occurring, porous aluminosilicate mineral that can sorb and sequester cations within its negatively charged framework structure. Zeolite has been used to mitigate NH 3 losses and improve fertilizer value of compost, sewage sludge, and manure in livestock barns; however, few studies have evaluated its efficacy on open-lot beef cattle feedyards. Zeolite application to pen surfaces could be a practical and cost-effective means of reducing NH 3 losses. Objectives of this study were to (1) characterize NH 4 + sorption by zeolites with differing physicochemical properties and (2) evaluate zeolite effects on rates and cumulative losses of NH 3 following application of artificial urine to feedyard manure. Batch incubation studies with four commercially available zeolites revealed that NH 4 + sorption by zeolite was rapid (1 to 2 h) with large differences in sorption potential largely related to zeolite pH. Maximum sorption ranged from 28 to 97 cmol NH 4 + -N kg -1 zeolite. Effects of zeolite application rate [0.5% to 10.0% of manure dry matter (DM)] on sorption and desorption characteristics in a manure/artificial urine matrix were highly variable but tended to be proportional to zeolite application rate: as little as 0.5% zeolite increased NH 4 + -N recovery by up to 19%. In flow-through chamber studies, higher rates of zeolite did not reduce cumulative NH 3 emissions, as 1.0% zeolite reduced cumulative NH 3 emission by 42% and 5.0% zeolite reduced N losses by only 18% compared to unamended manure. Surface application of zeolite has potential for mitigating feedyard NH 3 losses, but specific zeolite properties influenced its effectiveness. Further studies are warranted to evaluate effects of repeated zeolite application, co-application of zeolite and urease inhibitors, and cost:benefit ratios of zeolite application at commercial feedyards.

Ammonia Volatilization from Broiler Litter: Effect of Soil Water Content and Humidity

Broiler litter is commonly applied to grasslands as fertilizer where it undergoes N losses through NH3 volatilization. Ammonia losses represent not only a loss of plant-available N but also a source of environmental contamination. Previous research has shown that NH3 volatilization from broiler litter is affected by environmental conditions, but the effects of atmospheric water and soil water content (WC) are not well understood. We conducted a study at constant 94% relative humidity (RH) to evaluate rewetting of broiler litter and another study at 32% RH to evaluate drying of broiler litter. We also conducted two laboratory studies to evaluate the effect of soil WC (0.03 vs. 0.13 g H2O g−1) at either 32 or 92% RH on NH3 volatilization from surface-applied broiler litter. Results of the drying and rewetting studies showed that broiler litter can absorb or lose water at a relatively fast rate depending on RH. Ammonia volatilization was greater from wet soil (0.13 g g−1 soil WC) than from drier soil (0.03 g g−1 soil WC) under the high RH (92%), with losses of 21 and 11% of total N, respectively. In contrast, NH3 loss was only slightly greater in wet (0.13 g g−1 soil WC) vs. dry (0.03 g g−1 soil WC) soil at 32% RH, with losses of 5.2 and 3.2% of total N, respectively. These findings indicate that both soil WC and RH may play an important role in NH3 volatilization. Further research should evaluate the effect of diurnal RH changes on NH3 loss from surface-applied broiler litter.

Improving the Efficiency of Organic Fertilizer and Nitrogen Use via Air Plasma and Distributed Renewable Energy

Synthesis of reactive forms of nitrogen such as ammonia is important in modern agricultural productivity, but present agricultural technology uses reactive nitrogen inefficiently, leading to numerous and growing environmental problems. Animal, human, and food waste all contain significant quantities of organic nitrogen that are transformed into ammonia (NH3) by bacterial degradation of organic waste. If not captured, this volatile form of reactive nitrogen is lost to the environment, reducing N content and thus the agricultural value of organic waste. Furthermore, ammonia loss to the environment initiates a cascade of environmental problems. Nonequilibrium air plasma technology creates reactive nitrogen that can be readily converted to dilute aqueous nitric acid solutions. If mixed with decaying organic waste, NH3 loss is greatly reduced via the formation of involatile ammonium nitrate, a potent nitrogen fertilizer. Air plasma technology for fixed nitrogen manufacture is currently limited only by the availability of electricity and the energy efficiency of the process. The price of electricity via distributed renewable routes such as solar photovoltaic or wind turbines is rapidly decreasing. Increasingly, inexpensive wind and solar power sources, coupled with recent advances in air plasma energy efficiency, suggest that this technology could have a significant role in improving nitrogen use efficiency and reducing environmental and other threats associated with the current system.

Agronomic Improvements in Corn by Alternating Nitrogen and Irrigation to Various Plant Densities

Increasing water and N use efficiency and lowering environmental pollution are primary concerns for both agricultural production and environmental quality in northwestern China. A 2‐yr field experiment was conducted to assess and model the effects of irrigation, N, and plant density on maize (Zea mays L.) when N fertilizer and irrigation were separated in an alternating furrow irrigation system. Regression modeling (a ternary quadratic equation) showed that N fertilization positively affected yield, water use efficiency, N uptake, soil NO3–N, and NH3 volatilization. Irrigation improved yield, N uptake, and increased soil NO3–N in the deeper soil layer (0.6–2.0 m) but reduced water use efficiency, NH3 volatilization, and soil NO3–N in the 0‐ to 0.6‐m soil layer. Planting density positively affected yield, water use efficiency, and N uptake but negatively influenced NH3 volatilization and soil NO3–N. The combination of 255 kg N ha−1 N fertilizer, 100 mm of irrigation water, and 59,467 plants ha−1 in 2010 and 245 kg N ha−1 N fertilizer, 98 mm of irrigation water, and 58,376 plants ha−1 in 2011 resulted in maximum income for maize yield (7245 kg ha−1 in 2010 and 6972 kg ha−1 in 2011). However, environmental and agronomic objectives did not match. Specifically, the combination of N, irrigation rate, and plant density with maximum yield increased N leaching and NH3 losses, whereas the combination lowering environmental pollution due to N losses caused a reduction in yield. Therefore, the trade‐off in management of N, irrigation, and planting density was emphasized for both environmental and agronomic benefits in our study.

Static Chamber Measurements of Ammonia Volatilization from Manured Soils: Impact of Deployment Duration and Manure Characteristics

Static chambers (SC) are a simple low-cost option for measuring NH₃ volatilization from agricultural soils. However, it is uncertain how their estimates relate to more sophisticated methods. In this study, we compared SCs and wind tunnels (WT) for the field measurement of NH₃ volatilization during 22 d following surface application of seven solid poultry manures to a bare agricultural soil. Our objective was to determine the impact of SC deployment duration and manure characteristics on the emission estimates. Total NH₃ losses measured using SCs were on average 23% lower than using WTs. This bias varied with deployment time as the SC/WT emission ratio increased from a value of 0.2 immediately following deployment to a plateau of 1.6, 8 d later. The performance of SCs was also influenced by manure type, with the SC/WT ratio ranging from 0.40 to 1.30 after 22 d. Globally we found that (i) shortly after deployment, absence of air movement inside SCs results in an underestimation of soil-surface NH₃ volatilization (≈80%) compared with WT; (ii) this initial bias appears independent of the NH₃ source intensity; (iii) the underestimation decreases with deployment duration; and (iv) the cumulative bias after 22 d is impacted by the modified transformations of manure organic N (MON) inside SCs. We conclude that SCs yield biased absolute estimates of NH₃ volatilization rates in most situations. Furthermore, their use for comparing relative emission potential between various surface-applied solid manures is also limited to periods during which the transformation of the manure N is not affected by SC deployment.

Detection and characterization of betamethasone metabolites in human urine by LC-MS/MS.

Glucocorticosteroids are prohibited in sports when administered by systemic routes and allowed using other administrations for therapeutic reasons. Therefore, markers to distinguish between routes of administration through the analysis of urine samples are needed in anti-doping control. As a first step to achieve that goal, the metabolism of betamethasone (BET) was investigated in the present work. Urine samples obtained after BET intramuscular injection were hydrolyzed with β-glucuronidase and subjected to liquid-liquid extraction with ethyl acetate in alkaline conditions. The extracts were analyzed by liquid chromatography coupled to tandem mass spectrometry. Common open screening methods for fluorine containing corticosteroids (precursor ion scan method of m/z 121, 147, 171, and neutral loss (NL) scan methods of 20 and 38 Da in positive ionization, and 46 and 76 Da in negative ionization) were applied to detect BET metabolites. Moreover, an NL method was applied to detect A-ring reduced metabolites of BET, which are ionized as [M+NH4 ](+) (NL of 55, 73, and 91 Da, corresponding to the consecutive losses of NH3 , HF and one, two and three water molecules, respectively). BET and 24 metabolites were detected. Six metabolites were identified by comparison with standards, and for ten, feasible structures were proposed based on mass spectrometric data. Eleven of the characterized metabolites had not been previously reported. Metabolites resulting from 11-oxidation, 6-hydroxylation, C20 or 4-ene-3-one reduction and combination of some of them were detected. Moreover one metabolite resulting from cleavage of the side chain with subsequent oxidation of carbon at C17 was also detected.

Gaseous emissions from management of solid waste: a systematic review.

The establishment of sustainable soil waste management practices implies minimizing their environmental losses associated with climate change (greenhouse gases: GHGs) and ecosystems acidification (ammonia: NH3). Although a number of management strategies for solid waste management have been investigated to quantify nitrogen (N) and carbon (C) losses in relation to varied environmental and operational conditions, their overall effect is still uncertain. In this context, we have analyzed the current scientific information through a systematic review. We quantified the response of GHG emissions, NH3 emissions, and total N losses to different solid waste management strategies (conventional solid storage, turned composting, forced aerated composting, covering, compaction, addition/substitution of bulking agents and the use of additives). Our study is based on a meta-analysis of 50 research articles involving 304 observations. Our results indicated that improving the structure of the pile (waste or manure heap) via addition or substitution of certain bulking agents significantly reduced nitrous oxide (N2O) and methane (CH4) emissions by 53% and 71%, respectively. Turned composting systems, unlike forced aerated composted systems, showed potential for reducing GHGs (N2O: 50% and CH4: 71%). Bulking agents and both composting systems involved a certain degree of pollution swapping as they significantly promoted NH3 emissions by 35%, 54%, and 121% for bulking agents, turned and forced aerated composting, respectively. Strategies based on the restriction of O2 supply, such as covering or compaction, did not show significant effects on reducing GHGs but substantially decreased NH3 emissions by 61% and 54% for covering and compaction, respectively. The use of specific additives significantly reduced NH3 losses by 69%. Our meta-analysis suggested that there is enough evidence to refine future Intergovernmental Panel on Climate Change (IPCC) methodologies from solid waste, especially for solid waste composting practices. More holistic and integrated approaches are therefore required to develop more sustainable solid waste management systems.

Short-term effects of biogas digestate and cattle slurry application on greenhouse gas emissions affected by N availability from grasslands on drained fen peatlands and associated organic soils

Abstract. A change in German energy policy has resulted in a strong increase in the number of biogas plants in Germany. As a consequence, huge amounts of nutrient-rich residues, the by-products of the fermentative process, are used as organic fertilizers. Drained peatlands are increasingly used to satisfy the huge demand for fermentative substrates (e.g., energy crops, grass silage) and the digestate is returned to the peatlands. However, drained organic soils are considered as hot spots for nitrous oxide (N2O) emissions and organic fertilization is additionally known to increase N2O emissions from managed grasslands. Our study addressed the questions (a) to what extent biogas digestate and cattle slurry application increase N2O and methane (CH4) fluxes as well as the mineral nitrogen use efficiency (NUEmin) and grass yield, and (b) how different soil organic matter contents (SOMs) and nitrogen contents promote the production of N2O. In addition NH3 volatilization was determined at one application event to obtain first clues with respect to the effects of soil and fertilizer types. The study was conducted at two sites within a grassland parcel, which differed in their soil organic carbon (SOC) and N contents. At each site (named Corg-medium and Corg-high) three plots were established: one was fertilized five times with biogas digestate, one with cattle slurry, and the third served as control plot. On each plot, fluxes of N2O and CH4 were measured on three replicates over 2 years using the closed chamber method. For NH3 measurements we used the calibrated dynamic chamber method. On an annual basis, the application of biogas digestate significantly enhanced the N2O fluxes compared to the application of cattle slurry and additionally increased the plant N-uptake and NUEmin. Furthermore, N2O fluxes from the Corg-high treatments significantly exceeded N2O fluxes from the Corg-medium treatments. Annual cumulative emissions ranged from 0.91 ± 0.49 to 3.14 ± 0.91 kg N ha−1 yr−1. Significantly different CH4 fluxes between the investigated treatments or the different soil types were not observed. Cumulative annual CH4 exchange rates varied between −0.21 ± 0.19 and −1.06 ± 0.46 kg C ha−1 yr−1. Significantly higher NH3 losses, NUEmin and grass yields from treatments fertilized with biogas digestate compared to those fertilized with cattle slurry were observed. The total NH3 losses following the splash plate application were 18.17 kg N ha−1 for the digestate treatments and 3.48 kg N ha−1 for the slurry treatments (36 and 15% of applied NH4+–N). The observed linear increase of 16 days' cumulative N2O–N exchange or annual N2O emissions, with mean groundwater level and ammonium application rate, reveals the importance of site-adapted N fertilization and the avoidance of N surpluses in Corg-rich grasslands.

The effect of the nitrification inhibitor dicyandiamide (DCD) on nitrous oxide and methane emissions after cattle slurry application to Irish grassland

Application of cattle slurry to grassland can lead to gaseous losses of nitrogen (N). The dynamics of ammonia (NH3) emissions are well documented, but emissions of nitrous oxide (N2O) and other trace gases from land application of cattle slurry, are not as well understood. Nitrification inhibitors such as dicyandiamide (DCD) help to retain soil N in the ammonium (NH4+) form, which is expected to result in reduced N loss and increased N use efficiency. Emissions of methane (CH4) could potentially be affected by DCD, since the enzyme ammonia monooxygenase (AMO), which DCD is thought to inhibit, can oxidise CH4 as well as NH3. The objective of this study was to investigate the impacts of DCD on N2O and CH4 emissions from grassland soils after slurry application. At one experimental site, Johnstown Castle (JC), County Wexford, Ireland, slurry was applied in March, June and October for two years, at a rate of 33m3ha−1, by either bandspread (BS) or splashplate (SP) application methods, with and without DCD. A second site at Hillsborough (HB), County Down, Ireland, was treated in the same way for one year only, using the SP application method. Emissions of N2O and CH4 were measured using static chambers. Over the entire experiment DCD significantly reduced cumulative N2O emissions by 47 and 70% at both sites. Slurry spreading method had no significant effect on direct N2O emissions and there was no effect of DCD on CH4 emissions throughout the experiment. Using an emission factor for indirect N2O emissions of 1%, modelled losses of NH3 through volatilisation, resulted in an estimated 13 times greater indirect than direct N2O emissions. The results suggest that, under typical Irish field conditions, DCD can be used to decrease direct N2O emissions, without increasing CH4 emissions, and bandspreading can be used as a method of decreasing NH3 volatilisation, without increasing direct N2O or CH4 emissions. Since direct N2O emissions were relatively small, targeting indirect N2O emissions through mitigation of NH3 volatilisation and nitrate (NO3−) leaching could be an effective way of decreasing total N2O emissions from slurry application at these sites.

Ammonia volatilization after surface application of laying-hen and broiler-chicken manures.

Ammonia (NH) losses after field application of animal manure are affected by manure characteristics. The objectives of this study were to quantify NH losses from poultry manures obtained from varied handling and storage systems commonly found in eastern Canada and to relate NH emissions to manure characteristics. We measured NH volatilization using wind tunnels for 22 d after soil-surface application of seven solid poultry manures originating from farms varying in production type (laying hens and broiler chickens) and in storage duration and conditions. Cumulative emissions (2.7-7.0 g NH-N m) accounted for 13.6 to 35.0% of the total N applied and 51 to 84% (mean, 70%) of the sum of ammoniacal N, urea N, and uric acid N applied (TAUA). On average, 20% of these losses occurred during the first 4.5 h after application for manures that were not dried in the barn shortly after excretion. Production type and storage durations could not explain differences in NH volatilization between manures. Volatilization losses were linearly related to manure dry matter and to manure-derived NH-N, but sources of N changed with time after application. During the first 7 d, variations in total ammoniacal N applied (TANA) among manures explained most of the variations in cumulative NH losses ( = 0.85 after 26 h and 0.92 after 7 d). After a simulated rainfall (5 mm) on Day 7 that stimulated the decomposition of uric acid in manures, TAUA rather than TANA was related to cumulative emissions ( = 0.77 after 14 and 22 d). Our results indicate that reliable estimates of NH volatilization after land spreading of poultry manures should be based not only on TANA but also on NH-N derived from the decomposition of uric acid, that volatilization losses reported in the literature (including the present study) averaged 50% of TAUA, and that estimates for a given situation also need to account for local environmental conditions.

Volatilização de Amônia Proveniente de Ureia Compactada com Enxofre e Bentonita, em Ambiente Controlado

Nos últimos anos, novas tecnologias têm sido desenvolvidas para reduzir as perdas de N quando se utiliza ureia como fonte desse macronutriente. A utilização de fertilizantes de características ácidas pode reduzir as perdas de amônia por volatilização, quando combinados com a ureia. O objetivo deste trabalho foi avaliar as perdas de amônia provenientes de fontes de N revestidas e, ou, incorporadas com ou sem enxofre e bentonita. Esses foram aplicados na superfície de um Planossolo Háplico contido em bandejas (0,1 m2 de área e 10 cm de profundidade), em dose equivalente a 200 kg ha-1 de N. Foram avaliadas as perdas de N-NH3 por volatilização durante 21 dias, com auxílio de um coletor semiaberto. A adição de diferentes fontes de enxofre e de bentonita no processo de compactação da ureia reduziu as perdas de amônia em até 29 %, quando comparadas com a ureia granulada comercial, comprovando serem alternativas promissoras para aumentar a eficiência da adubação nitrogenada.

High-energy collision-activated and electron-transfer dissociation of gas-phase complexes of tryptophan with Na+, K+, and Ca2+

The structure and reactivity of gas-phase complexes of tryptophan (Trp) with Na+, K+, and Ca2+ were examined by high-energy collision-activated dissociation (CAD) and electron transfer dissociation (ETD) using alkali metal targets. In the CAD spectra of M+Trp (M = Na and K), neutral Trp loss was the primary dissociation pathway, and the product ion of collision-induced intracomplex electron transfer from the indole π ring of Trp to the alkali metal ion was observed, indicating a charge-solvated structure in which Trp is non-zwitterionic. The NH3 loss observed in the CAD spectrum of Ca2+Trp2 is ascribed to a CZ (mixed charge-solvated/zwitterionic)-type structure, in which one Trp is non-zwitterionic and the other Trp adopts a zwitterionic structure with an NH 3 + moiety. The H atom and NH3 losses observed in the ETD spectrum of Ca2+Trp2 indicate the formation of a hypervalent radical in the complex, R–NH3, via electron transfer from the alkali metal target to the NH 3 + group of the CZ-type structure. Ca2+ attachment to Trp cluster induces the zwitterionic structure of Trp in the gas phase, and an electron transfer to the zwitterionic Trp forms the hypervalent radical as a reaction intermediate.

Factors Affecting Ammonia Loss from Pastures Fertilized with Broiler Litter

Broiler litter is commonly surface‐applied to pasture in the southeastern United States as a method of waste management and to provide an inexpensive source of plant nutrients, such as N. However, predicting plant available N derived from litter can be difficult due to losses through NH3 volatilization. We conducted 11 field studies to determine overall NH3 loss as affected by environmental variables and litter characteristics. Ammonia loss as a percentage of the applied total N (TN) ranged from 0.9 to 10.5% in eleven 28‐d studies conducted from April to November in 2011 and 2012. In two studies, a series of small rain events (2–5 mm) combined with elevated soil water content (WC) (>0.2 g H2O g soil−1) decreased overall NH3 losses, potentially due to N movement into the soil. In the remaining nine studies, average vapor pressure (VP) and initial NH4–N plus uric acid‐N (ANUA) explained 79% of the variability in cumulative NH3 loss over 28 d. Our data suggest that elevated concentrations of initial uric acid‐N and NH4–N, as well as, elevated VP increase NH3 losses. The effect of elevated VP on NH3 losses was attributed to the rewetting of the litter, which likely leads to increased N mineralization and NH4–N in solution. The statistical model developed may help estimate NH3 losses from surface‐applied litter and increase the accuracy of estimating available N under field conditions.

Nutrient and sediment losses in snowmelt runoff from perennial forage and annual cropland in the canadian prairies.

An 8-yr field-scale study, 2005 to 2012, investigated effects of agricultural land use on nutrient and sediment losses during snowmelt runoff from four treatment fields in southern Manitoba. In 2005, two fields with a long-term history of annual crop (AC) production were planted to perennial forage (PF), while two other fields were left in AC production. In 2009, the AC fields were converted to PF, while the PF fields were returned to AC. Runoff flow rates were monitored at the lower edge of the fields, and nutrient concentrations of runoff water were determined. The effects of AC and PF on selected variables were similar for the spatial (between-fields) and temporal (within-field) comparisons. The flow-weighted mean concentrations (FWMCs) and loads of particulate N, P, and sediment were not affected by treatment. Soil test N and the FWMC and load of NO (NO + NO) were significantly greater in the AC treatment, but the FWMC and load of NH were greater in the PF treatment. Loads of total dissolved N (TDN) and total N (TN) were not affected by treatment, although the concentrations of TDN and TN were greater in the AC treatment. The PF treatment significantly increased FWMCs and loads of total dissolved P (TDP) and total P (TP). On an annual snowmelt runoff basis, the PF treatment increased the FWMC of TDP by 53% and TP by 52% and increased the load of TDP by 221% and TP by 160% compared with the AC treatment. The greater P and NH losses in the PF treatment were attributed mainly to nutrient release from forage residue due to freezing.

Ammonia volatilization after application of urea to winter wheat over 3 years affected by novel urease and nitrification inhibitors

Ammonia emission from urea application negatively affects both environmental quality and human health, and so it is desirable to minimize nitrogen loss by ammonia volatilization and to improve nitrogen use efficiency. This field study aimed to assess the effects of recently introduced urease (N-(2-nitrophenyl) phosphoric triamide, 2-NPT) and nitrification inhibitors (mixture of dicyandiamide and 1H-1,2,4-triazol) on NH3 emissions following urea application as compared to calcium ammonium nitrate (CAN) in Northern Germany. The measurements were carried out in winter wheat (Triticum aestivum) in the years 2011–2013 covering in total 12 urea application dates. Urea was applied as unamended granulated urea, or combined with urease or nitrification inhibitor or with both inhibitors. Fertilizers were applied in multi-plot field trials with four replications and ammonia losses were measured simultaneously by a combination of a calibrated dynamic chamber and passive samplers. Application date strongly affected relative NH3 loss (% of applied N) due to seasonal variation of soil moisture, temperature, and rainfall. Initial soil moisture showed a strong effect on NH3 emission. Averaged over the three vegetation periods, relative NH3 losses from unamended urea amounted to 8%, with mean emissions of 5%, 4%, and 17% for split N applications in March, April, and early June, respectively. Compared with treatment without urease inhibitor, the urease inhibitor addition reduced emissions by 26–83%, resulting in emissions similar to that from CAN. Analyzing the total data set, no significant effect of the nitrification inhibitor on NH3 emission was observed while at specific applications significantly higher as well as lower emissions compared to unamended urea were detected. The results highlight that NH3 emissions after field application of urea are highly variable under north German climate conditions and simple emission factors should be reevaluated. Urease inhibitor and appropriate application timing are effective measures to reduce NH3 emission from field applied urea.

Contribution of N2O and NH3 to total greenhouse gas emission from fertilization: results from a sandy soil fertilized with nitrate and biogas digestate with and without nitrification inhibitor

Fertilization with biogas residues from the digestion of energy crops is of growing importance. Digestate from silage maize (Zea mays L.) is a new fertilizer with a high potential for ammonia (NH3) and nitrous oxide (N2O) emission. The aim of this study was to determine the effect of different maize fertilization systems [180 kg N ha−1 in form of calcium nitrate (MIN), biogas digestate from maize (DIG) and biogas digestate from maize mixed with the nitrification inhibitor Piadin (DIG + NI)] on the emission of NH3 and N2O from a sandy soil and to assess the total greenhouse gas emission of these fertilization systems. The study is based on a randomized field plot experiment in central Germany and an experimental period of a full year. Annual N2O-N emission was generally low [0.21 (MIN) to 0.37 (DIG) kg N ha−1] without differences between treatments. The application of Piadin reduced N2O emissions by 37 and 62 % during the weeks following digestate application but the annual N2O emission was not affected by the fertilization treatment. NH3 emission was only significant for treatments fertilized with digestate. It was not affected by Piadin and accounted for 27 % (+NI) and 29 % of the applied ammonium. Total greenhouse gas emission was dominated by NH3 losses (reducing the fertilizer value and inducing indirect N2O emissions) for the treatments fertilized with maize digestate. The most important greenhouse gas emission source of the MIN treatment were emissions from fertilizer production. Our results show the high potential of digestate from maize as a new source of NH3 emission. Mitigation measures are essential to save the value of this new fertilizer type and to reduce atmospheric and environmental pollution by direct emission of NH3 and indirect emission of greenhouse gases.

Corrigendum to: Process safety in using NH3 as refrigerant in Indian ice making plants: case studies followed by policy recommendations

Corrigendum to: Process safety in using NH₃ as refrigerant in Indian ice making plants: case studies followed by policy recommendations

Nitrogen and phosphorus loss and optimal drainage time of paddy field under controlled drainage condition

In order to reduce agricultural non-point source pollution and improve water use efficiency, the research on the change in ammonium nitrogen (NH4 + -N), nitrate nitrogen (NO3 � -N) and total phosphorus (TP) load in surface water at eachgrowthstage wasconductedbyuseoflysimeter based on experimental test in flooding paddy field at different leakage rates. Results showed that in the early period of paddy flooding, the nitrogen (N) and phosphorus (P) loads were at a relatively high level, but decreased gradually as the flooding lasted. Compared with the flooding on the first day, the loss of NH4 + -N, NO3 � -N, and TP decreased by 58.90-97.75 %, 14.09-98.06 %, and 39.00-94.28 % respectively at the end of flooding. Different leakage (2 mm day �1 and 4m m day �1 ) had a certain influence onthe changein NH4 + -N, NO3 � -Nand TP load, but the difference was not significant; therefore, drainage should be avoided in the early period of paddy flooding, and immediate drainage should be avoided after rainstorm and surface irrigation. A multi-objective controlled drainage model based on pollution reduction and water saving was established in order to obtain the optimal drainage time at each growth stage and to betterguide the drainage practices of farmers. The optimal time for surface drainage were respectively the fourth, seventh, seventh, and fifth day at the stage of tillering, jointing-booting, heading-flowering, and milking after flooding. The innovative point of this study was to get rid of the concentration of N and P as an only visual angle, but taking the specific amount of N and P loss into consideration illustrated the controlled drainage pollution-reduction effect, taking the cumulative evapotrans- piration as the index of water-use efficiency illustrated the water-saving effect, and considering together the two aspects determined the optimal drainage time.

Water Quality and Nitrogen Mass Loss from Anaerobic Lagoon Columns Receiving Pretreated Influent

Control methods are needed to abate NH losses from swine anaerobic lagoons to reduce the contribution of confined swine operations to air pollution. In a 15-mo meso-scale column study, we evaluated the effect of manure pretreatment on water quality, reduction of N losses, and sludge accumulation in swine lagoons using (i) enhanced solid-liquid separation with polymer (SS) and (ii) solid-liquid separation plus biological N treatment using nitrification-denitrification (SS + NDN). A conventional anaerobic lagoon was included as a control. Concentrations of total Kjeldahl N (TKN), total ammoniacal N (TAN), and NO-N were monitored during the course of the study, and the volumes of column liquid and sludge were used to estimate N mass flows. At the end of the study, TKN and TAN concentrations in the liquid of SS columns were 35 and 37% lower than the control, respectively, and TKN and TAN concentrations in SS + NDN were 97 and 99% lower than the control. The N mass flow analysis revealed that SS reduced total N inflow by 30% and SS + NDN by 82% compared with the control. The SS was ineffective at reducing NH losses compared with the control. Instead, SS + NDN effectively reduced total NH losses by 50%, most of which occurred during the first 6 mo of the study. Although both pretreatments can stop the mass accumulation of total N in sludge, SS + NDN had the advantage of improving water quality and abating NH emissions from treated lagoons. As an additional environmental benefit, SS + NDN effluents could be used for crop irrigation without the risk of NH losses during land application.

Management of Furrow Irrigation and Nitrogen Application on Summer Maize

The efficient use of water and N represents a primary concern to agricultural production in Northwest China. The objective of this study was to assess the impacts of irrigation and fertilization on water and N use, soil volatilized NH3, soil NO3 leaching, and NO3 transfer in soil profiles. A 2‐yr field experiment was conducted to assess the separation of N fertilizer and water with alternating furrow irrigation (SNWAFI) and conventional irrigation and fertilization (CIF) in a maize (Zea mays L.) production system. The yields with SNWAFI were 10 to 16% greater than with CIF. Compared with CIF, SNWAFI increased water use efficiencies (WUEs) by 13 to 33%, agronomic efficiency of fertilizer N by 36 to 56%, and NO3−–N in the upper soil layers (0–60 cm) by 30 to 60%. However, SNWAFI reduced NO3−–N in the deeper soil layers (60–200 cm) by 8 to 44% compared with CIF. The use of SNWAFI also decreased soil NH3 emission with the combination with lower irrigation (40 mm) and N rate (100 kg N ha−1), which indicated that SNWAFI emitted less soil NH3 than CIF. Therefore, compared with CIF, SNWAFI increased maize yield WUE and N use efficiency, reduced N leaching, and curtailed soil NH3 loss with appropriate irrigation and N rates. The use of SNWAFI, leading to better spatial management of irrigation water and N application, can provide both agronomic and environmental benefits.