Massey Documents by Type
Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294
Browse
6 results
Search Results
Item An evaluation of greenhouse gas emissions reduction potential of plantain (Plantago lanceolata L.) in pastoral dairy production systems : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Agriculture Systems Management at Massey University, Manawatu, New Zealand(Massey University, 2025-05-16) Sivanandarajah, KomahanThere is increasing interest in the ability of plantain (PL) to reduce nitrogen (N) leaching losses and mitigate nitrous oxide (N₂O) emissions, while maintaining milk and pasture production. While PL’s role in lowering urinary N concentration is well established, the results regarding the effect of PL on N₂O emissions have been inconsistent. Furthermore, evidence has shown that cows fed pure PL produce less methane (CH₄) emissions compared to those fed ryegrass. However, whether this CH₄ reduction can be achieved with PL in mixed pasture, along with a clear understanding of the mechanism(s) behind those reductions, are still to be determined. This thesis evaluates PL’s potential to mitigate CH₄ and N₂O emissions through a series of in vitro and a field experiment, focusing on mixed pastures with moderate PL levels. When pastures, either a conventional ryegrass-white clover (RWC) or an RWC mix containing ~40% of PL (PLM), were collected during different seasons and tested in an in vitro rumen batch culture system, differences in their chemical composition led to significant differences in CH₄ and rumen ammonia (NH₃) production. Compared to RWC, PLM had lower fibre (neutral detergent fibre and acid detergent fibre), higher lignin, more fermentable carbohydrates (non-structural carbohydrates), and plant secondary metabolites (PSM, acteoside and aucubin) detected only in PLM, while maintaining similar digestibility and crude protein (CP) levels. Consequently, PLM produced up to 27% less net NH₃ in spring, up to 19% less CH₄ in summer, and 17% less net NH₃ in autumn compared to RWC (p<0.05) in vitro. Plant secondary metabolites found in PL, have been associated with reducing N losses from grazed pastures. However, their influence on enteric CH₄ emissions remains unexplored. Additionally, the dose-response relationship between CH₄ and NH₃ production at different concentrations of PSM needs to be established. To address this, purified compounds (>99% purity) of acteoside and aucubin were incubated with perennial ryegrass (RG) as a basal substrate, and gas and CH₄ production were measured in vitro. The addition of acteoside to RG increased gas production (GP) by up to 12%, with a similar quantity of CH₄ production, but a 5–15% lower proportion of CH₄ in gas (%CH₄), compared to the control. Aucubin addition resulted in a longer lag phase for GP and CH₄ production. On addition of aucubin, it took up to 15% more time to reach the halftime (T1/2) GP and up to 20% longer to reach the T1/2 CH₄ production. The combined treatments of acteoside and aucubin produced up to 13% greater GP with similar CH₄ production and reduced %CH₄ by around 9%. These reductions are attributed to the modification of the hydrogen utilisation pathway (less hydrogen to produce CH₄) affected by acteoside. Aucubin reduced rumen net NH₃ production by up to 46%, with a similar reduction observed when acteoside was combined with aucubin. These reductions are attributed to the possible antimicrobial activity of aucubin. These results suggest that PL influences rumen fermentation in vitro, resulting in lower CH₄ and NH₃ production. Since higher rumen NH₃ correlates with greater urinary N excretion into the environment, reducing NH₃ levels in the rumen is advantageous. Previous studies have shown that N₂O emissions from PL pastures may be reduced due to smaller N concentrations in urine and/or biological nitrification inhibition (BNI) activity. In this study, urine collected from cows fed diets containing 0% PL, ~20% PL, and diluted urine from PL-fed cows, was applied to pastures containing 0% PL, 30% PL, and 40% PL during spring. The N₂O emissions were measured over 55 days. Results indicated a trend toward lower N₂O emissions as assessed using the emission factor (EF₃) metric, with increasing PL content (p<0.09), with an average reduction of around 28% for pastures containing 30–40% PL compared to RWC pastures (p=0.03). This reduction in N₂O emissions from PL pastures was attributed to BNI activity rather than differences in urine-N concentrations per se. These results enhance our understanding of PL’s role in mitigating environmental impacts from grazing ruminants in temperate systems. This thesis concludes that medium PL pastures (30–40% PL) exhibit significant environmental benefits compared to RWC pastures in vitro, with reductions in CH₄ and rumen NH₃ influenced by PSM in PL and the seasonal variability in chemical composition. Moreover, under conditions conducive to higher N₂O emissions (in spring), maintaining 30–40% PL in the pasture could reduce N₂O emissions more effectively than excluding PL.Item An investigation on the stability of biochar-C in soils and its potential use to mitigate non-CO₂ greenhouse gases using near-infrared (NIR) spectroscopy : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University, Manawatu, New Zealand(Massey University, 2020) Mahmud, Ainul FaizahThe global interest in using biochar for C sequestration-climate mitigation and soil improvement has driven rapid expansion in biochar research to understand its properties and application impacts. The potential for biochar application to increase soil organic carbon (SOC) stocks and its potential agronomic and additional environmental benefits, such as reducing soil nitrous oxide (N₂O) emission, are determined by its stability in the soil, which is dependent on its intrinsic properties and the soil conditions. The inherent properties of biochar are highly influenced by feedstock type and pyrolysis temperature hence, the use of various types of feedstock and pyrolysis technologies leads to uncertainties in predicting the effect of biochar addition to soils. Previous research has established a general assumption that biochar stability is strongly influenced by the type of feedstock used and maximum pyrolysis temperature. Research is required, however, to produce practical and reliable techniques that can be used to verify the reported maximum pyrolysis temperature, regardless of the type of feedstock used and predict the likely stability of the biochar. In addition to the pyrolysis process, the final particle size of the biochar and the method of incorporation into the soil may also influence the ability of the biochar to moderate soil properties and function. With previous research, there is general lack of attention given to these potentially influential parameters when assessing the impact of biochar application to soil. Therefore this thesis evaluates (i) the use of near-infrared (NIR) spectroscopy technique for predicting the maximum pyrolysis temperature of biochar as it is a well-known, non-destructive, and rapid technique for analyzing organic material; (ii) the effect of biochar application, with special attention to biochar particle size and depth of placement, on N₂O soil emission and SOC stocks; and (iii) the integrated use of NIR spectroscopy for SOC measurement. In the first study, we hypothesized that NIR spectroscopy can be used to predict the maximum pyrolysis temperature achieved during biochar production. Eighty-two carbonized materials produced from various feedstock types and pyrolysis conditions with the reported pyrolysis temperature ranged between 220 to 800 °C, were scanned using NIR spectrometer and were used as the calibration set. The NIR calibration model was built by correlating the NIR spectral data with the reported pyrolysis temperature using partial least squares regression (PLSR). A separate sample set (n=20) was compiled using laboratory-produced biochar made from pine wood at pyrolysis temperature ranged from 325 to 723 °C. The calibration model validated using (i) leave-one-out cross-validation (LOO-CV) and (ii) the prediction set, yielded good accuracy (LOO-CV: r²=0.80 and RMSECV:48.8 °C; prediction: r²=0.82 and RMSEP: 57.7 °C). Results obtained in this study have shown that NIR spectroscopy can be used to predict the maximum pyrolysis temperature of biochar and has the potential to be used as a monitoring tool for biochar production. In addition to the first study, the predictive ability of the NIR model was evaluated further. We hypothesized that the variation in feedstock types and pyrolysis processes may affect the predictive performance of the NIR model in predicting the maximum pyrolysis temperature of biochar. Therefore, three sample sets were generated from a total of 82 carbonized materials and its subsets (Set A: n=82; Set B: n=68; Set C: n= 48) and were used for developing three calibration models. The selection of samples for Set B and C was made by reducing the variability associated with production conditions and feedstock type i.e. Set B consist of samples produced by slow pyrolysis and using the same pyrolyzer unit, while for Set C (a subset of Set B), samples produced from “processed feedstocks” were excluded. A separate sample set (n=18) consists of samples produced from animal manure, crop residue, and woody materials were used as the prediction set. This biochar was produced using the slow pyrolysis technique in a laboratory or under relatively high production controlled conditions at temperature ranged from 250 to 550 °C. These calibration models were validated using (i) leave-one-out cross-validation (LOO-CV) and (ii) a prediction set, with the model based on set C gave the best prediction (R2: 0.941; RMSEP: 27.3 °C), followed by the model based on set A (R2: 0.896; RMSEP: 35.6 °C), and set B (R2: 0.928; RMSEP: 37.3 °C). These results indicate that feedstock types have a considerable effect on the performance of the NIR model while the effect of pyrolysis conditions was less pronounced. Thus, data variability from samples needs to be taken into account in developing the NIR calibration model for predicting the maximum pyrolysis temperature of biochar. Before studying the effect of biochar on N₂O soil emission and SOC stocks, the maximum pyrolysis temperature of biochar to be used in the experiment was predicted using the NIR spectroscopy technique. The estimated pyrolysis temperature – after scanning the 3-year old pine wood biochar and using the NIR model developed – was 500 °C, while the reported temperature was 550 °C. A controlled glasshouse study was conducted to investigate the effect of biochar particle size and the impact of soil inversion (through simulated mouldboard ploughing) on N₂O emissions from soils to which cattle urine was applied. We hypothesized that the application of biochar may (i) affect N₂O emissions through changes in soil physical properties, specifically soil aeration and water retention; and (ii) the effects of biochar addition on these properties may differ depending on their particle size (e.g., a larger particle size may increase soil aeration whereas a smaller particle size may clog pores), and their placement in soil (e.g., the incorporation of a large particle size-biochar at depth may promote water movement from the top layer and increase the overall drainage of the soil). Pine biochar (550 °C) with two different particle sizes (<2 mm and >4 mm) was mixed either into the top soil layer at the original 0–10 cm depth in the soil column or at 10–20 cm depth by inverting the top soil to simulate ploughing. Nitrous oxide emissions were monitored every two to three days, up to seven weeks during the summer trial, and measurements were repeated during the autumn trial. The use of large particle size biochar in the inverted soil had a significant impact on increasing the cumulative N₂O emissions in the autumn trial, possibly through changes in the water hydraulic conductivity of the soil column and increased water retention at the boundary between soil layers. Thus, the importance of the role of biochar particle size and the method of biochar placement on soil physical properties and the implications of these on N₂O emissions was highlighted. In the same glasshouse study, the effect of biochar particle size and depth of placement was further evaluated in relation to soil organic C. We hypothesized that (i) the large-particle size biochar may affect soil aeration and accelerate soil C decomposition rate with increased oxygen availability, and this effect is greater when biochar is incorporated at depth due to the more compacted soil at deeper layer with poorer aeration compared to the surface layer; and (ii) the NIR spectroscopy technique can be used to predict the SOC concentration and SOC stocks in biochar-amended soil. Carbon stocks were estimated using NIR spectroscopy coupled with partial least-squares regression analysis (NIR/PLSR) and direct organic C measurements using an elemental analyzer. The NIR spectra of the soil were acquired by scanning intact soil cores using the NIR spectrometer. By the end of the glasshouse trial (327 days), the large-particle size biochar applied at depth had induced significant soil C loss (9.20 Mg C ha⁻¹ (P < 0.05), possibly through the combination of enhanced soil aeration, and the interrupted C supply from new plant inputs at that depth due to soil inversion. This C loss did not occur in the treatment with the small-particle size biochar. Near-infrared (NIR) spectroscopy was able to predict the SOC concentration, however, the prediction accuracy may be negatively affected by an increasing biochar particle size and soil inversion, thus may affect the subsequent SOC estimates. The information obtained in this thesis will inform the future use of biochar and contribute to the knowledge of possible factors affecting soil N₂O emission from biochar-amended soil, the mineralization of native SOC, and the changes in SOC stocks over time, particularly in the pastoral soils of New Zealand. Also, based on this study, the use of NIR spectroscopy technique may potentially be integrated as part of the methodology for SOC estimation.Item The effect of early life nutrition on rumen microbial community development and impact on lifetime performance in ruminants : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Sciences at Massey University, Palmerston North, New Zealand(Massey University, 2019) Cristobal Carballo, OmarManipulation of the rumen microbiota in adult ruminants has been intended to improve animal performance and decrease greenhouse gas emissions, but results have only shown a short- or non-lasting effect after intervention. Changes in the ruminal microbiota during rumen development have recently shown promising results in the short-term. Therefore, the purpose of the present body of work was to determine how dietary management and chemical interventions, during rumen development, modify the ruminal microbial community composition, and whether these changes affect rumen fermentation and development, and consequently, performance in the young ruminants. The objectives of this thesis were to: (i) evaluate the impact of early weaning on rumen development and function in artificially-reared lambs; (ii) characterize the impact of early weaning in lambs on the rumen microbiota in the first 16 weeks of life and examine the relationships between rumen microbiota composition and rumen fermentation profiles, rumen development and blood metabolites; (iii) assess whether contrasting feeding regimes in the first 7 months of life lead to an imprint in the rumen microbial community structure, fermentation profiles and methane emissions in the rumen of calves; (iv) and evaluate the effect of methane inhibitors on the rumen microbial community composition, fermentation pathways, and gas emissions in calves. A series of three experiments were carried out in young ruminants separated from their mothers after colostrum intake, to address the objectives of this thesis. In experiment one, 3-5-day-old lambs were euthanized at weeks 0, 4 and 16 of rearing to investigate objectives (i) and (ii). Early weaning of lambs increased plasma hydroxybutyrate at week 4 of rearing, while dry matter intake, fermentation profiles and rumen morphology were similar between groups. Papillae morphology and muscular thickness differed between ruminal sites at 4 and 16 weeks of rearing, but not between treatments. Diversity and relative abundance of ruminal bacteria was affected by feeding management, whilst the archaea community showed few changes. Changes in the proportions of abundant bacteria genera from Bacteroidetes and Firmicutes were associated with fermentation profiles, rumen morphology and blood metabolites; however, further investigations are required to explain these associations. In experiment two, ~1-week-old calves were reared with two divergent feeding systems and different post-weaning forage quality with a common pasture diet after 7 months of age to investigate objective (iii). Consumption of pre-weaning concentrate compared to forage produced lower methane yields and greater total short chain fatty acids (SCFA) concentrations and propionate proportions; whist ruminal microbes showed greater proportions of saccharolitic bacteria and Methanobrevibacter boviskoreani, but lower hemicellulolytic and cellulolytic bacteria, and Mbb. gottschalkii. Post-weaning, high-quality forage produced greater total SCFA concentration and propionate proportions than low-quality forages, while methane yield was similar. Hemicellulolytic bacteria and Methanosphaera spp. were greater in high-quality forages, while cellulolytic bacteria and Methanomassiliicoccales spp. were greater in low-quality forages. No pre-weaning effect was observed. Finally, the consumption of a common diet after 7 months of age resulted in similar methane emissions, fermentation profiles and microbial communities. In experiment three, ~1-week-old calves fed either concentrate starter diets or starter diets plus methane inhibitors were tested to evaluate objective (iv). Inhibitor intake decreased methane yield, but increased hydrogen yield and the proportion of propionate and had no effect on dry matter intake, total SCFA concentrations or animal growth. Within the abundant bacteria, the proportions of hydrogen utilizing and producing bacteria increased and decreased, respectively. Archaea diversity and proportions were affected during the period of methane inhibitor intake. However, similar gas emissions, fermentation profiles, and microbial communities were observed between groups at 24 and 49 weeks of age. Collectively, these results showed that reducing the age at weaning and introducing the solid feed to lambs at ~1 week of life accelerated some aspects of rumen morphology and function. Dietary management and methanogen inhibitor interventions affected the composition of the ruminal microbiota and fermentation profiles during treatment, however, no permanent changes in the microbial community and resulting ruminal fermentation were observed post-treatment in young ruminants.Item The effect of an integrated catchment management plan on the greenhouse gas balance of the Mangaotama catchment of the Whatawhata Hill Country Research Station : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Ecology at Massey University, Manawatu, New Zealand(Massey University, 2012) Smiley, DanielAn integrated catchment management plan implemented in the Mangaotama catchment of the Whatawhata Research Station in 2001 demonstrated that Pinus radiata forestry on marginal land, along with conservation measures and intensification could produce a win-win outcome for economic output and the environment. However, greenhouse gas mitigation was never fully considered. This research investigated the effect of the plan on the land’s greenhouse gas balance and carbon stocks between 2000 and 2011. Historical records, modelling with OVERSEER and CenW, literature values and field measurements were used to account for CO2, CH4, and N2O from the four main land-use types: pasture, native forest, pine, and native plantings. The original land-use would have emitted a net 10.99 Gg CO2e over 10yrs, whereas the new land-use sequestered a net 47.26 Gg CO2e in its first 10yrs. The total carbon stocks rose by 15.9 Gg C. Forestry conversion of almost half the area explained most of this effect. Agricultural intensification increased per hectare emissions from pasture, but overall pasture emissions were lowered by over half due to the reduction in livestock numbers. The native plantings had a small impact due to the small area planted and their slower growth compared with pines. Soil carbon was lost under all land-uses, except possibly in grazed native forests, but these conclusions were hampered by a scarcity of samples. Uncertainty also surrounded the modelling of the pine forest in complex terrain, which is not yet adequately captured in CenW. A preliminary look at carbon trading suggested that it could strongly undermine the viability of the original farm system, but it could also help to fund the expensive transition to the new land-use. Overall, it was found that in addition to the benefits already shown by the integrated catchment management plan, it was also an effective way of mitigating climate change.Item Emissions and removals of greenhouse gases at an institution level : a case study of Massey University Turitea campus : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Natural Resource Management, Institute of Natural Resources, Massey University, Palmerston North, New Zealand(Massey University, 2009) Butt, Zulfiqar HaiderThe first commitment period of the Kyoto Protocol (2008-2012) has started. Being a signatory to the protocol, New Zealand is committed to reduce its greenhouse gas (GHG) emissions down to 1990 levels by the end of the first commitment period, or to take responsibility for any emissions above this level if it cannot meet this target. Although the inventory of New Zealand's GHG emissions is made at a national level, the actual reductions in GHG emissions required under the Kyoto Protocol will need to be made by individuals and institutions in society. Little attempt has yet been made at an institution level, especially by the Universities in New Zealand, to determine their aggregated net emissions of the major GHGs: carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). In order to help Massey University to prepare its own emission budget, estimates of current emissions were made in four major sectors - energy, agriculture, waste and forestry - at the Turitea campus and the associated 2200 hectares of the University's farms. Greenhouse gas emissions from these sectors in 1990 were also estimated to compare the current emissions with the base year of the Kyoto protocol. An introduction to the major GHGs, their emissions, the effect of these emissions on climate change, and an overview of the approach to calculate these emissions is provided. Total emissions from the energy sector included emissions from the electricity, gas, coal, vehicles and aviation sub-sectors, that were calculated with the help of national and international emission factors. Greenhouse gas emissions from solid waste and wastewater were calculated using the Intergovernmental Panel on Climate Change (IPCC) tier 1 approach. Emissions from the agriculture sector were calculated using a combination of New Zealand national and IPCC default emission factors. This sector accounts for emissions resulting from enteric fermentation, animal manure management and agricultural soils. An overview of Massey University's forest estate has also been provided. At present, forestry is the only sector contributing toward the mitigation of GHGs at Massey University through Kyoto-defined plantation forests. The amounts of C sequestered by the native and exotic tree plantations, and the total amount of CO2 absorbed by these plantations are presented. Although an assessment of C sequestered by all Massey University's tree plantations was made, only plantations established in 1990 and after were considered for inventory purposes. In the conclusions, some suggestions to reduce GHG emissions from Massey University and to improve future inventories are given. The annual gross GHG emissions in terms of CO2 equivalents (CO2e) in 2004 were 26,696±2,674 Mg which were about 7.9% above the level of 1990 emissions. It was estimated that the forestry sector removed about 4,094±439 Mg of CO2e and therefore the overall net emissions in 2004 were 8.6% below the base-line GHG emissions of 1990. At present the major contributing sector to GHG emissions at Massey University's Turitea campus is the energy sector. This contributes 71.4% of the gross emissions, whereas the agriculture and waste sectors are producing 26.2% and 2.4% respectively of the total gross emissions. About 37% of the total GHG emissions from the energy sector were contributed by commuting traffic, whereas electricity and gas collectively produced 33% of the total 19,064±1,324 Mg CO2e energy emissions. The largest absolute uncertainties in emission estimates were in the energy sector and some suggestions have been made as to how Massey University might reduce these uncertainties and improve the overall accuracy of the estimates of GHG emissions.Item Methane emissions and mitigation technologies in cattle, sheep and red deer : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand(Massey University, 2011) Swainson, Natasha MadeleineEnteric fermentation of ingested feed by ruminant livestock is an important source of methane (CH4), a potent greenhouse gas (GHG). Ruminant CH4 emissions contribute approximately 31% of New Zealand‟s total GHG inventory; therefore reducing CH4 emissions from ruminant livestock is a national priority. The aims of this research were to investigate the effectiveness of potential mitigation technologies on the CH4 emissions in sheep. This included the supplementation of monensin and coconut oil, individually or in combination, and the feeding of chicory as an alternative forage to perennial ryegrass-based pasture (pasture). The influence of ruminant age (grazing red deer) and ruminant species (housed cattle, sheep and red deer) on CH4 yield were also explored. This research showed that the supplementation of monensin to sheep may provide reductions in CH4 yield (g CH4/kg dry matter intake, DMI) of up to 30%, but this was not consistent between experiments. Sheep fed chicory yielded less CH4 (17%) compared with sheep fed pasture, which was suggested to be due to faster degradation rates of chicory, leading to the increased outflow rate of digesta from the rumen; this theory needs to be tested. Neither, the supplementation of coconut oil or the combination of mitigation technologies resulted in a significant reduction in CH4 yield. Nevertheless, as the power to detect a significant difference between treatments was reduced, due to the high variability of estimated CH4 production, it is recommended that the effects of combined mitigation technologies be retested. Methane yield was influenced by deer age, but only at 4.5 months of age as CH4 yields of deer aged 6.5 to 11.5 months did not differ and may be an artefact of the method used to estimate DMI. Mean differences of CH4 yield (up to 32%) between ruminant species was found when animals were offered the same diet and constant feeding levels; cattle > sheep > deer. This study indicates that the use of a single ruminant species to model potential CH4 mitigation technologies may not represent all target populations due to differences of age or species found in this study. Research is required to confirm if differences between ruminant species persist when animals are fed fresh forages and to determine if responses to potential mitigation technologies are similar with age or between ruminant species.