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Item Exploring in vitro production of colonic microbial metabolites from diverse protein sources using human ileal digesta(Elsevier Ltd, 2025-12-15) van der Wielen N; Zhang H; Schouten PJC; Meulenbroeks E; Stroebinger N; Hodgkinson SM; Mensink M; Hendriks W; Capuano EWe explored the relationship between protein fermentation metabolites and ileal digesta composition, using ileal digesta from ileostomates, who ingested nine different protein sources, incubated in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). NH3, short-chain fatty acids, branched-chain fatty acids (BCFA), H2S, tryptophan derivatives, and biogenic amines were measured in proximal and distal colon vessels. The relative changes in most metabolites were positively correlated with their amino acid precursors in ileal digesta. In both colon vessels, the relative change of NH3 was a good predictor for the production of other metabolites. Indole was strongly associated with oxindole, 5-HT, and tryptamine and the sum of Trp metabolites in the distal colon. Per gram ingested protein, zein and whey may produce the highest levels of NH3 and BCFA in the proximal colon and BCFA in the distal colon, whereas whey and pigeon peas may result in the highest levels of H2S.Item Public response to decarbonisation through alternative shipping fuels(Springer Nature, 2023-06-24) Carlisle DP; Feetham PM; Wright M; Teagle DAlthough shipping is the most energy efficient method of transporting trade goods it is held accountable for 2-3% of global greenhouse gas (GHG) emissions. The shipping industry is exploring pathways to carbon-neutral fuels to help eliminate GHG emissions by 2050. To date research on alternative fuels has not considered public opinion; it remains unclear whether the public will support alternative shipping fuels, or whether public opposition might prevent or defer their deployment. To fill this knowledge gap and help the industry and policy makers arrive at publicly acceptable decisions our research examines UK public perceptions of six shipping fuels using a mixed-method approach. Our findings reveal that biofuels and hydrogen are clearly favoured, owing to biofuel’s perceived low risk and hydrogen’s lack of negative by-products. Perceptions of liquid natural gas are somewhat positive, suggesting that it provides an acceptable near-term option while other fuels are developed. Despite lingering stigma, nuclear is preferred over the incumbent heavy fuel oil, though both are perceived negatively. However, the UK public strongly dislike ammonia, perceiving it as unproven, risky, and lacking availability. A third support use of alternative shipping fuels, with support greater from those living near ports - a “yes in my back yard” (YIMBY) effect. The results demonstrate that different alternative fuels are likely to elicit different public reactions as they become more widely known and show how the overall evaluations arise from specific positive or negative associations with each fuel.Item An investigation into measuring ammonia loss during the operation of a freestall dairy barn : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2020) Malik, KhadijaThe dairy sector in New Zealand (NZ) has undergone rapid intensification and transformation over the past few decades: the traditional pasture based grazing systems are continuously being replaced by high supplement feed input system like feed pads, herd homes and wintering barns. Practising duration controlled grazing; using temporary housing systems (naturally ventilated barns) can reduce urinary load to paddocks and N loss to water. There is concern that ammonia (NH3) loss to the atmosphere during housing, manure storage and re-application to pasture simply results in pollution swapping i.e. decreasing N loss to water while increasing the greenhouse gas emission footprint of dairying. The main objective of this research was to develop cost effective techniques to monitor, mitigate and minimise the NH3 gas emissions from a duration controlled grazing system in the Manawatu region of NZ. The main components of dairy cattle (DC) grazing systems are feed, housing, storage and slurry reapplication to land. The first study focused on developing techniques to identify the hotspots contributing to gas emissions from all stages of the manure management chain. The efficiency of two commonly used techniques namely active and passive NH3 gas sampling was evaluated and modified. Commonly used 7 L dynamic chambers and large vacuum pumps were replaced by small 50 ml PVC tube acid scrubbers and small aquarium pumps. The acid scrubbers were successfully deployed for NH3 gas emission measurements from storage pond and slurry re-application to land. Simple diffusion sampling tubes (DSTs) were also developed and calibrated for long term measurements from storage ponds. The second set of laboratory experiments aimed at studying the losses associated with the feed component. The effect of diet on urine N content excreted by dairy cows and the influence of urea N content of urine on the magnitude of NH3 emissions was studied by simulating excreta deposition on a barn floor in 1 L Agee jars. In NZ dairy cows are fed on pasture based production system, however when the pasture becomes limiting during summers then cows are fed on high supplement feed inputs like maize and hay silage. It was hypothesised that dietary manipulation would impact N excretion and NH3 emissions from excreta. For this experiment, a total of fifty four dairy cows were used. They were split into three groups (each group containing 18 cows) and fed on high crude protein (HCP, 25%), medium crude proteins (MCP, 18.5%) and low crude proteins (LCP, 13.5%) diets. Urine and dung samples were collected separately from each group of the cows. NH3 emissions from the slurry mixture were measured in vitro in a laboratory set up at room temperature (18 ºC - 24 ºC) for 6 days. The laboratory set up consisted of 11 Agee jars (1 L) with passive acid traps (10 ml 0.5 M H2SO4) contained in 50 ml pink tops. The slurry mixture was reconstituted at a standard rate of excretion by dairy cows at a ratio of 1 : 1.3 (dung: urine) by mixing the freshly collected urine and dung [(w/v); wet basis] in urine containers. The cumulative NH3 losses were reported based on the urea N applied and total Kjeldahl N applied to each Agee jar. The results showed that NH3 emissions reduced by 13 - 20% with decrease in dietary crude protein. It was concluded that manipulating the CP level in diet can reduce urinary N excretion from dairy cows and hence lower NH3 emissions. A subsequent series of laboratory experiments were conducted using 1 L Agee jars to quantify NH3 losses from various hotspots in a naturally ventilated dairy cow barn to study the factors affecting NH3 emissions. The main sources of NH3 losses from the barn are excreta deposited on laneways, scraper lanes and slurry collection pits located underneath the barn. In Study 1, aged slurry samples were taken from different positions in the slurry pathway from channel grate to the storage pond. In Experiment 2 of study 1 (Ex-situ measurements), sources of fresh slurry were created (by mixing urine and dung) to represent the different depths of fresh slurry deposited in the free-stall barn’s laneways and under the grates in the transport channel. The NH3 emission rate from all slurry samples were measured in closed chambers. In study 2 (In situ measurements), a 3D sonic anemometer and NH3 acid traps were used to measure airflow rates and NH3 concentrations in the barns ventilation pathways. The barn’s estimated NH3 emissions calculated from the two contrasting studies were compared. There is limited NZ data on NH3 gas emissions from a slurry storage pond receiving slurry from a wintering barn. NH3 gas emissions were monitored in the winter of 2017 (2nd June to 16th August) by modified integrated horizontal flux (IHF) methodology. The gas emission flux was measured using diffusion sampling tubes (DSTs) placed at sampling heights (0.25 m to 3.5 m) on an aluminium tower. The towers were mounted at 4 banks (N, S, E, W) of the pond and DSTs were changed every 72 or 94 h. The gas emission flux was found to be positively correlated to daily evapotranspiration rate (ETR) (R2=0.80) and this relationship was used to predict gaseous emission from a static pond. The slurry is usually stored up-to 3 months before re-application to land. NH3 gas emission from the final stage of manure management was measured on two occasions; Summer 2015 and Autumn 2016. Slurry was incorporated in land through slurry surface spray and injection and losses were measured using IHF methodology. Slurry was applied at 81 kg N ha-1 for surface spray and 73 kg N ha-1 was injected into the soil through injection. Similarly the application rate for autumn application was 252 kg N ha-1 for surface spray and 233 kg N ha-1 for injection application. The percentage NH3-N losses were 2% from slurry surface spray and 1.4% from slurry incorporation through injection for summer application and 3% from slurry surface spray and only 1% from injected application of slurry in autumn. On completion of NH3 loss measurements at all stages of manure management it was possible to construct a partial NH3 loss budget to illustrate the relative NH3 losses associated with the temporary housing of cows in a freestall barn, manure storage and reapplication to land. This simple analysis illustrated that the largest loss of NH3 can occur if there is a long storage phase of effluent in a open pond. Future research to mitigate NH3 losses created by housing cows should focus on the reduction of NH3 loss from ponds.Item Mitigation potential of urease inhibitory compounds in reducing ammonia emissions from cattle urine in dairy-grazed pasture soils : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2019) Adhikari, Kamal PrasadThe excretal deposition by grazing animals, especially urine containing about 80% urea, and urea fertiliser use on pastoral farms are major sources of ammonia (NH₃) emissions in New Zealand (NZ) agriculture. Recent intensification of dairy farming in NZ has resulted in a substantial increase in the use of nitrogen (N) fertiliser, especially urea, and the quantity of urine deposited by grazing dairy cows onto pasture soils, and as a consequence, higher NH₃ emissions. These emissions represent economic and environmental losses. The urease inhibitor (UI) N-(n-butyl) thiophosphoric triamide (nBTPT) has shown effectiveness in reducing emissions when applied with fertiliser urea or cattle urine in NZ dairy-grazed pasture soils. However, the inhibitory effect of nBTPT on reducing NH3 emissions is effective for a relatively short period (7 - 14 days), during which emissions from urea fertiliser is inhibited. But, in the context of grazed pasture, to reduce the NH₃ emitted from deposited urine following each grazing event, regular applications of nBTPT are required, which would be prohibitively expensive. To mitigate NH₃ emissions from cattle urine deposited during more than a single grazing, in dairy-grazed pasture soils, it is necessary to identify alternative longer lasting inhibition approaches to using nBTPT. Therefore, the overall objective of this thesis was to assess the effectiveness and longevity of potentially longer-lasting non-specific inhibitors copper (Cu) and zinc (Zn), and the specific inhibitor N-(2-Nitrophenyl) phosphoric triamide (2-NPT) in reducing NH₃ emissions following cattle urine applied to pasture soils. The study presented in this thesis initially examined the influence of inherent and added Cu and Zn in inhibiting soil urease activity (UA), and the role of soil organic carbon (C) and soil textural and mineralogical properties on influencing the ability of these metals at inhibiting soil UA of dairy pasture soils under laboratory incubations. The study then evaluated the effect of the recently introduced UI 2-NPT on NH₃ emissions, soil microbial biomass C, pasture dry matter yield and N uptake, which was compared with the more commonly used UI nBTPT. This study involved both laboratory and field experiments. The first laboratory experiment assessed the effect of inherent and added Cu and Zn in inhibiting soil UA of dairy-grazed pasture soils. The results showed significant positive correlations between soil total C and N with soil UA for 23 soils from the Waikato region of NZ. However, there were no significant negative correlations between soil UA with inherent Cu and Zn levels. Similarly, the addition of Cu up to 20 mg kg⁻¹ soil and the combination of 5 mg Cu and 5 mg Zn kg⁻¹ soil did not significantly reduce soil UA of 4 dairy-grazed pasture soils, with contrasting organic C levels. In the second laboratory experiment, the influence of the soil C factor (soil organic C, and other related soil properties, such as clay content and cation exchange capacity (CEC)) on the effectiveness of Cu and Zn to inhibit urea hydrolysis in soil supernatants were studied. When Cu was added to 2 different soil supernatants, at rates of 5, 10, and 20 mg Cu kg⁻¹ soil, there was a significant reduction in hydrolysis of urea applied at either 120 or 600 mg urea-N kg⁻¹ soil. Additions of Zn, at a rate of 20 mg kg⁻¹ soil achieved negligible or small reductions in urea hydrolysis after either 120 or 600 mg urea-N kg⁻¹ soil applications to soil supernatants. These results suggest that Cu has a urease inhibitory effect, but its ineffectiveness in C rich pasture soils is caused by reduced bioavailability as a result of high Cu complexation. However, Zn had a negligible inhibitory effect on soil UA at the rate used in this experiment. Overall these results support the conclusion that neither metal is likely to be a practical UI for reducing NH₃ emissions from NZ dairy-grazed pasture soils. The effectiveness and longevity of 2-NPT and nBTPT in reducing NH₃ emissions from cattle urine applied to 2 dairy-grazed pasture soils were evaluated under laboratory conditions. The inhibitors were applied at the start of the experiment and urine was applied at 4 stages; (A) immediately before, (B) 29 days after, (C) 56 days after, and (D) 29 days after and again 60 days after inhibitor application, and NH₃ emissions were measured following each urine application. There were 3 application rates of 2-NPT; 0.025, 0.050, and 0.075% of total urine-N applied at Stage-A, and one rate of nBTPT; 0.025% of total urine-N applied at Stage-A. The application depth of urine applied was 10 mm for Stages A, B and C and 7.2 mm for Stage-D. The % applied urine-N that was emitted as NH₃ at the different stages ranged from 14.2 to 50.5% for the soils studied. Both UIs equally reduced total NH₃ emissions (20.6 - 27.3%), from both of the soil types, when urine was applied immediately before inhibitor application. The inhibitor 2-NPT continued to reduce emissions (5.6 - 7.4%) from urine applied up to 56 days after the inhibitor application, but only for the soil with lower microbial biomass C and UA, suggesting that 2-NPT has slightly greater longevity of efficacy than nBTPT. When urine was applied immediately before inhibitor application, inhibitors had no effect on soil microbial biomass C, measured 31 days after inhibitor application, which suggest specificity of UIs on inhibiting UA. Two field experiments were conducted during summer and autumn to assess whether the differences observed between the inhibitors 2-NPT and nBTPT in the laboratory experiment are also achieved under field conditions. In the summer experiment, the inhibitors were applied at the start of the experiment and urine was applied at 3 stages; (A) 3 hrs before, (B) 28 days after, and (C) 68 days after inhibitor application, and NH₃ emissions were measured following each urine application. The application rates of inhibitors to the urine treatments for all 3 stages were based on the percentage (0.025%) of total urine-N applied at Stage-A. In the autumn experiment, urine was only applied either immediately before or 3 hrs before inhibitor application, also at a rate of 0.025% of total urine-N. The application depth of urine applied in both of the summer and autumn experiments was 10 mm. The NH₃-N emitted in the summer experiment was between 15.3 - 23.6% of the applied urine-N (equivalent to 111 - 142 kg N ha⁻¹), however, in autumn the emissions were only 4.5% (equivalent to 27 kg N ha⁻¹ of the total N applied. In the summer experiment, only 2-NPT significantly reduced total NH3 emissions (19.5% reduction), which was only when urine was applied 28 days after the inhibitor application (Stage B). Both inhibitors significantly reduced emissions in autumn when urine was applied either 3 hrs before or immediately before inhibitor application. However, the effectiveness was greater when urine was applied immediately before inhibitor application (52.3 - 72.7% reduction) compared to urine applied 3 hrs before inhibitor application (35.0 - 41.2% reduction). The reduction was greater with 2-NPT (72.7% reduction) compared to nBTPT (52.3% reduction) when urine was applied immediately before inhibitor application. The field study confirmed the findings of laboratory study that the effectiveness and longevity of 2-NPT, in reducing NH₃ emissions from cattle urine applied to pasture soils, is greater compared to nBTPT. There was no effect of inhibitors on pasture dry matter yield and N uptake in either of the field experiments. The 2-NPT applied up to about a month prior to a grazing event in summer reduced NH3 emissions from urine patch areas at a rate equivalent to 26 kg N ha⁻¹ (based on 19.5 % reduction in summer) at the subsequent grazing. If 3 applications of 2-NPT are applied in summer (period when emissions are typically the highest) following 3 grazings that would reduce losses by 78 kg N ha⁻¹ from 3 subsequent grazings. When these reductions are extrapolated to determine the overall benefit on whole paddock basis, the total reduction in N loss (26 kg N ha⁻¹ x 3% x 3 grazings) is 2.3 kg N ha⁻¹ yr⁻¹, assuming the urine patches cover 3% of the grazed area per grazing. Thus, overall benefit from using 2-NPT is greater than nBTPT in reducing NH₃ emissions from cattle urine deposited in dairy-grazed pastures. However, the size of the reduction from using 2-NPT on whole paddock was low, compared to the amount of N cycling in grazed pastures annually. To further improve the effectiveness of inhibitors, applied after urine application in summer, future research could focus on enhancing the contact between the inhibitor and urine urea by increasing the volume of inhibitor used (>800 L ha⁻¹) and/or by implementing shorter durations (<3 hrs) between urine and inhibitor application. Further changes in volume of inhibitor applied and timing of inhibitor application should consider cost involved and feasibility in dairy farms with the current technology.Item The reaction of carbohydrates with ammonia : a thesis presented in partial fulfilment of the degree of Master of Science in chemistry at Massey University(Massey University, 1969) Giltrap, David JohnA feature of typical carbohydrate/ammonia reactions is the formation of complex mixtures of Unidazoles (among other products). These imidazole mixtures have proven difficult to separate in many cases. A theory for cation exchange chromatography of bases has been developed in this work and applied to the separation of imidazole mixtures. The technique used appears to be capable of separating mixtures of imidazoles more effectively than other previously used. D-Glucosone (D-arabo-hexosulose) was papered by the action of benzaldehyde on giucosazone (d-arabo-hexosephenylosazone; and its reaction with ammonia investigated. It was found that the reaction mixture included a number of imidazoles. These imidazoles were separated by the ion exchange technique developed earlier and a total of sixteen compounds giving a positive reaction with the imidazole-specific. Pauly reagent (diazotisod sulphanilic acid) were detected. Fifteen of these compounds were isolated and six were identified by mass spectrometry and/or nuclear magnetic resovance spectrometry. It was also intended to investigate the reaction of 4-O-methyl-D-glucose and ammonia. It was proposed to prepare this compound by methyletion of methyl-2,3,4-tri-O-acetyl- -D-glucopyranoside with methyl iodide in the presence of silver oxide. Under these conditions an acetyl migration from the 4-0 to 6-0 position occurs with the methylation to give methyl-2,3,6-tri-O-acetyl-4-O-methyl- -D-glucopyranoside which may be hydrolysed to give 4-O-methyl-D-glucose. It was intended to prepare the starting material for this reaction (methyl-2,3,4-tri-O-ecetyl- -D-glucopyranoside) from D-glucose by the following steps. (1) hethanolysis of D-gluoose catalysed by an H* cation exchange resin to give methyl- -D-glucopyrunoside. (2) Blocking of the 6-0 position with triphenylchloromethane. (3) Acetylation with acetic anbydride to give methyl-6-O-triphenytaethyl-2,3,4-tri-O-acetyl- -D-glucopyranoside. (4) Removal of the triphenylmethyl blocking group to give the required methyl-2,3,4-tri-O-acetyl- D-glucopyranoside. In fact at the time of this writing the first three steps had been accomplished but attempts to remove the triphenylmethyl blocking group while leaving the ocetyl groups intact had proved unsuccessful.Item Effect of application times of urease inhibitor (Agrotain®) on NH emissions from urine patches : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Soil Science at Massey University, Manawatu, New Zealand(Massey University, 2014) Rodriguez Gelos, Maria JimenaIn grazed pastures about 80% of urine nitrogen (N) in the form of urea is rapidly hydrolysed and is subjected to ammonia (NH3) losses. The use of urease inhibitors (UI) has been used as a mitigation tool to decrease the rate of NH3 volatilization from fertilizer urea and animal urine. In previous New Zealand trials the UI effect in reducing NH3 emissions from urine has been measured by applying urine mixed with the urease inhibitor to the pasture soil thus increasing the chance to better inhibit the urease enzyme. However, these trials do not represent a realistic grazing scenario where only urine is deposited onto the soil. This current research aimed to identify the best time to spray the Agrotain® above soil pasture to reduce NH3 losses from urine patches. A field experiment was carried out on dairy farm # 4 at Massey University, Palmerston North, New Zealand. The treatments were: a control (without urine and Agrotain®), urine alone at 530 kg N ha–1 and urine plus Agrotain®. The UI was applied to the chambers and soil plots 5 and 3 days prior to urine deposition, on the same day and 1, 3 and 5 after urine deposition in autumn (April 2013). NH3 losses were measured using the dynamic chamber method. After the application of the treatments, NH3(g) volatilization was determined in the acid traps, and soil mineral N (NH4+-N and NO3--N) and pH were measured from soil plots at different times over a period of 30 days. The application of the inhibitor prior to urine deposition reduced NH3 losses with reductions of 27.6% and 17.5% achieved for UAgr-5 and UAgr-3, respectively; and there was also a reduction in both soil NH4+-N concentration and soil pH in comparison with urine alone or with the treatments where Agrotain® was applied after urine deposition. Application of Agrotain® on the same day as urine reduced NH3 losses by 9.6% but this was not statistically significant from treatments when Agrotain® was applied after urine. The application of Agrotain® after urine deposition had no effect on NH3 losses from urine.Item Periphyton and water quality in the Manawatu River, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University(Massey University, 1983) Freeman, Michael ConradThe factors responsible for the establishment and summer proliferation of attached filamentous algae in the Manawatu River were investigated. The life cycle of the dominant alga Cladophora was observed to be closely linked with the seasonal river and climatic changes. The magnitude and frequency of flush events were the major factors responsible for reducing the attached algal biomass. During steady low flow conditions, the results of phosphorus nutrient availability tests demonstrated that phosphorus availability frequently limited the growth rate of the Cladophora proliferations. The concentration of dissolved reactive phosphorus during these periods was 3-4 mg P m-3. Dissolved inorganic nitrogen concentrations during steady low flow conditions were low, compared to overseas rivers that experienced similar filamentous algal proliferations, and the results of nitrogen nutrient availability tests never indicated nitrogen limitation of the Cladophora growth rate. The water quality effects of these proliferations were also investigated. The two effects monitored were; diurnal fluctuations of Dissolved Oxygen (DO) and pH. These could become quite severe and consequently affect the river's ability to adequately assimilate effluent discharges from Palmerston North and its associated food industries. Of the two algal-induced fluctuations, DO was the more important. Frequently, maximum daily DO deficits (DODms) of 3.0 g m-3 were observed and these severely limited the river's ability to satisfy the oxygen demands of all discharges while maintaining the minimum desirable DO concentration. A regression equation was developed using the data from both the 1981/82 and 1982/83 seasons to predict the daily DODm. The largest contribution to the total predicted DODm was from the total river community respiration followed by a seasonal effect, the river flow, the regression constant and the terrestrial insolation. The regression equation accounted for 72% of the observed variation in the daily DODm during the two seasons. Fluctuations in the pH of the Manawatu River were also important, as a component of the effluent discharges is ammonia, the toxicity of which increases exponentially with a linear rise in pH. However, algal-induced pH fluctuations were reduced downstream of the discharges by bacterial respiration associated with the oxygen-demanding effluents. This phenomenon and the timing of both pH and ammonia fluctuations meant that toxic concentrations were not observed, although the temporal variation of ammonia was often erratic. However, future discharge changes may alter this situation, and continued surveillance of downstream pH and ammonia is warranted.Item The action of ammonia on carbohydrates and related carbonyl compounds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University of Manawatu, Palmerston North, New Zealand(Massey University, 1965) Grimmett, Murray RossThe chromatography of imidazoles has been studied and a method developed for their quantitative estimation. The following facts have been brought to light:- (i) Formaldehyde does not form imidazoles at room temperature in ammoniacal solution. (ii) From the complex mixture resulting from the interaction of glyoxal with aqueous ammonia imidazole and 2,2'-bis-imidazole have been isolated and identified, while 2-formylimidazole has been tentatively identified. (iii) Glycolaldehyde reacts with aqueous ammonia to form imidazole and 2-hydroxymethylimidazole. (iv) DL-Glyceraldehyde reacts with aqueous ammonia to form a complex mixture of neutral and basic compounds. Dihydroxyacetone, glucose, fructose, mannose, arabinose, lyxose and xylose have been tentatively identified by paper chromatography while ribose was suspected in low concentration. 2-Hydroxymethyl-4(5)-methylimidazole, 4(5)-methylimidazole, 4(5)-(2-hydroxyethyl)imidazole and 4(5)-hydroxymethylimidazole have been isolated and characterised, and their orders and rates of formation studied. (v) Pyruvaldehyde reacts exothermically with concentrated ammonia solution to form four imidazolic compounds. Three of these have been isolated and characterised as 2-acetyl-4(5)-methylimidazole, 2,4(5)-dimethylimidazole and 4(5)-methylimidazole. The latter two compounds were formed in approximately equimolecular proportions. These results fail to confirm Bernhauer's finding that pyruvaldehyde cannot act as a source of formaldehyde in imidazole formation. (vi) Hydroxypyruvaldehyde browns rapidly in aqueous ammonia forming 2-hydroxymethyl-4(5)-methylimidazole, 4(5)-methylimidazole and 4(5)-hydroxymethylimidazole. The yields of the latter two compounds have been found to be higher than from a similar mixture of dihydroxyacetone with ammonia. (vii) Both diacetyl and acetoin react with ammonia to form 2,4,5-trimethylimidazole. (viii) 4(5)-(2-Hydroxyethyl)imidazole has been tentatively identified from the mixture resulting from the interaction of 1,4-dihydroxybutan-2-one with aqueous ammonia. (ix) Arabinose reacts with aqueous ammonia to form a complex mixture of imidazoles from which 4(5)-methylimidazole has been isolated and identified. (x) A chromatographic study has been carried out to determine the orders of formation of imidazoles resulting from the interactions of a number of carbohydrates and their degradation products with aqueous ammonia. Arising from this study have come the following main results:- (a) It appears that, contrary to the findings of Komoto, a number of imidazoles with low Rf values (probably polyhydroxyalkyl-substituted) are formed more rapidly than 4(5)-methylimidazole from hexose sugars with ammonia. (b) Differently linked reducing disaccharides give markedly different patterns of imidazoles under ammoniacal conditions. (xi) As a result of (b) above, a micro-method has been developed for determination of the position of the glycosidic link in reducing hexose disaccharides and homogeneously-linked oligosaccharides.Item Copper induces nitrification by ammonia-oxidizing bacteria and archaea in pastoral soils(Wiley, 12/12/2022) Matse D; Jeyakumar P; Bishop P; Anderson CCopper (Cu) is the main co-factor in the functioning of the ammonia monooxygenase (AMO) enzyme, which is responsible for the first step of ammonia oxidation. We report a greenhouse-based pot experiment that examines the response of ammonia-oxidizing bacteria and archaea (AOB and AOA) to different bioavailable Cu concentrations in three pastoral soils (Recent, Pallic, and Pumice soils) planted with ryegrass (Lolium perenne L.). Five treatments were used: control (no urine and Cu), urine only at 300 mg N kg-1 soil (Cu0), urine + 1 mg Cu kg-1 soil (Cu1), urine + 10 mg Cu kg-1 soil (Cu10), and urine + 100 mg Cu kg-1 soil (Cu100). Pots were destructively sampled at Day 0, 1, 7, 15, and 25 after urine application. The AOB/AOA amoA gene abundance was analyzed by real-time quantitative polymerase chain reaction at Days 1 and 15. The AOB amoA gene abundance increased 10.0- and 22.6-fold in the Recent soil and 2.1- and 2.5-fold in the Pallic soil for the Cu10 compared with Cu0 on Days 1 and 15, respectively. In contrast, the Cu100 was associated with a reduction in AOB amoA gene abundance in the Recent and Pallic soils but not in the Pumice soil. This may be due to the influence of soil cation exchange capacity differences on the bioavailable Cu. Bioavailable Cu in the Recent and Pallic soils influenced nitrification and AOB amoA gene abundance, as evidenced by the strong positive correlation between bioavailable Cu, nitrification, and AOB amoA. However, bioavailable Cu did not influence the nitrification and AOA amoA gene abundance increase.Item Nitrification rate in dairy cattle urine patches can be inhibited by changing soil bioavailable Cu concentration(Elsevier, 17/01/2023) Matse D; Jeyakumar P; Bishop P; Anderson CAmmonia oxidation to hydroxylamine is catalyzed by the ammonia monooxygenase enzyme and copper (Cu) is a key element for this process. We investigated the effect of soil bioavailable Cu changes induced through the application of Cu-complexing compounds on nitrification rate, ammonia-oxidizing bacteria (AOB) and archaea (AOA) amoA gene abundance, and mineral nitrogen (N) leaching in urine patches using the Manawatu Recent soil. Further, evaluated the combination of organic compound calcium lignosulphonate (LS) with a growth stimulant Gibberellic acid (GA). Treatments were applied in May 2021 as late-autumn treatments: control (no urine), urine-only at 600 kg N ha-1, urine + dicyandiamide (DCD), urine + co-poly-acrylic-maleic acid (PA-MA), urine + LS, urine + split-application of LS (2LS), and urine + combination of GA plus LS (GA + LS). In addition, another four treatments were applied in July 2021 as mid-winter treatments: control, urine-only at 600 kg N ha-1, urine + GA, and urine + GA + LS. Soil bioavailable Cu and mineral N leaching were examined during the experimental period. The AOB/AOA amoA genes were quantified using quantitative polymerase chain reaction. Changes in soil bioavailable Cu across treatments correlated with nitrification rate and AOB amoA abundance in late-autumn while the AOA amoA abundance did not change. The reduction in soil bioavailable Cu induced by the PA-MA and 2LS was linked to significant (P < 0.05) reduction in mineral N leaching of 16 and 30%, respectively, relative to the urine-only. The LS did not induce a significant effect on either bioavailable Cu or mineral N leaching relative to urine-only. The GA + LS reduced mineral N leaching by 10% relative to LS in late-autumn, however, there was no significant effect in mid-winter. This study demonstrated that reducing soil bioavailable Cu can be a potential strategy to reduce N leaching from urine patches.
