Massey Documents by Type
Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294
Browse
8 results
Search Results
Item Comparing nitrate leaching between contemporary and regenerative dairy pasture management : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science, Agricultural Science at Massey University, Manawatū, Palmerston North, New Zealand(Massey University, 2025) Wittahachchi, Udara DilhaniNew Zealand’s dairy industry is crucial to the national economy, yet it faces significant environmental challenges, particularly nitrate (NO₃⁻) leaching from intensive pasture-based farming systems. The concentrated nitrogen (N) in urine patches left by grazing cows is the primary contributor to NO₃⁻ leaching in dairy pastures. While various mitigation strategies have been explored, many have come with limitations. Lower N input regenerative management has emerged as a potential approach to reduce NO₃⁻ leaching, particularly when combined with diverse pasture. More diverse pasture swards that include deeper-rooted species and herbs already known to reduce leaching have the potential to mitigate NO₃⁻ -N loss from NZ dairy systems. The measurement of NO₃⁻ leaching in free-draining soils is challenging due to the lack of methods that can accurately collect drainage at a scale representing the variability in a pasture paddock. Therefore, the objectives of this research were to 1) assess the effectiveness of trench lysimeters to measure drainage and NO₃⁻ leaching in a free-draining Manawatū sandy loam soil, 2) compare NO₃⁻ concentrations measured using trench lysimeters with a suction cup array, and 3) evaluate and compare NO₃⁻ leaching under three pasture management systems: standard pasture with contemporary management (Std-Con), diverse pasture with regenerative management (Div-Reg), and diverse pasture with contemporary management (Div-Con). The research was conducted over a period of two years (2023 and 2024) at Dairy One farm at Massey University near Palmerston North, utilising 12 trench lysimeters and 90 suction cups on three different pasture treatments, namely Std-Con, Div-Reg and Div-Con. Contemporary management follows DairyNZ best practices with lower post-grazing residuals and uses mineral/synthetic fertilisers and chemical sprays as needed. Regenerative management involves longer grazing intervals, higher post-grazing residuals, and reduced use of mineral/synthetic fertilisers and chemical sprays. The four trench lysimeters per treatment reliably measured drainage depths with generally low standard errors across different drainage events, indicating their reliability for measuring drainage in free-draining soils. Compared to trench lysimeters, suction cups were less effective, recording significantly lower NO₃⁻-N concentrations with higher variability. In cases where suction cup NO₃⁻ -N concentrations were high; this was likely due to individual urine patches resulting in large variability between replicates. In both years, the Div-Con treatment had the highest NO₃⁻- N load, followed by Std-Con and Div-Reg; however, unusually elevated NO₃⁻-N concentrations in two lysimeters associated with the Div-Con treatment were responsible for this effect. Therefore, further investigation is required to verify the results from this treatment. In 2023, NO₃⁻ N loads were 3 and 14 kg N/ha for Div-Reg and Std-Con, respectively. In 2024, the values increased to 5 and 24 kg N/ha. Both methods indicated a declining trend in NO₃⁻-N concentrations across all treatments as the drainage season progressed. Compared to the Std-Con treatment, the Div-Reg treatment consistently measured only 21.4% and 20.8% of NO₃⁻-N leaching in 2023 and 2024, respectively, but further monitoring is needed to address the challenges identified in this study and to more thoroughly assess differences between treatments.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 Understanding phenotypic and epigenetic drought responses in Trifolium repens (white clover) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy at Massey University, Palmerston North, New Zealand(Massey University, 2024) Hodgkinson, Hannah ElizabethTrifolium repens (white clover) is an allopolyploid species belonging to the clover genus (Trifolium). White clover is very important in New Zealand agriculture as feed for livestock. Yet this species is facing challenges due to drought, an abiotic stress that has impacted New Zealand’s economy in the past and is predicted to have increased effects in the future due to climate change. Therefore, analysing plant phenotypic and epigenetic responses to drought is an important area of research because it will broaden understanding of drought resistance/tolerance and mechanisms that plants use to survive drought stress. An epigenetic mechanism of interest is DNA methylation, which has a role in gene expression in response to drought. There is also evidence that DNA methylation is involved in plant memory and ‘priming’ which assists in subsequent stress responses. However, this response has not been explored in depth in white clover. In other species there has been evidence of transgenerational inheritance of DNA methylation marks associated with stress. Therefore, research into stress-related DNA methylation in white clover is important as it may be able to be incorporated into the plant breeding process in the future to breed more drought tolerant varieties. In this study, a drought trial with two subsequent drought stress periods was run on white clover varieties and related species. A range of phenotypes were measured throughout the drought trial, including relative water content and leaf area. There was evidence that these phenotypes were significantly impacted by drought stress. The relative water content measurements revealed significant differences in drought response depending on whether plants were experiencing their first or second drought, suggesting that some aspect of plant stress memory was involved. Subsequently, DNA methylation analysis was run on a subset of the white clover plants involved in the drought trial. It was found that DNA methylation played a role in the plant drought response and that there were differences in methylation patterns between plants that were experiencing their first and second drought exposures. Further investigation into genomic regions with DNA methylation profiles retained after drought stress revealed examples of stress-related genes. This supported the hypothesis that areas of differential methylation had a role in the stress response. This study revealed insights into white clover’s drought response and provides a starting point for further research into how these findings can be incorporated into plant breeding/generating more drought tolerant varieties in the future.Item Investigating the impact of abiotic stresses on the growth and persistence of plantain (Plantago lanceolata L.) within grazed mixed pastures : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Palmerston North, New Zealand(Massey University, 2025-02-26) Wilson, SamuelThe New Zealand dairy industry has identified plantain (Plantago lanceolata L.) as a tool to mitigate nitrogen losses from perennial ryegrass (Lolium perenne L.) based pastures, however reports of variable pasture plantain contents (dry matter basis) and poor persistence within grazed mixed pastures have led to industry concern over its viability. There is anecdotal evidence that the persistence of plantain within dairy pastures is negatively impacted by waterlogging and treading damage from livestock, however there is little scientific literature relevant to these issues. This research aimed to answer the following research question: What are the impacts of waterlogging and treading damage on plantain growth and survival within mixed dairy pastures? This thesis includes a series of experiments conducted between 2021 and 2024. In a glasshouse, the performance of plantain under waterlogging was evaluated against perennial ryegrass. Plantain growth was particularly sensitive to waterlogging, however the survival of plantain under waterlogging suggested that plantain possesses some waterlogging tolerance. In contrast, perennial ryegrass proved to have an enhanced ability for coping with, and recovering from, waterlogging stress. These findings suggest that while waterlogging may cause limitations to plantain growth, there is no evidence to suggest that waterlogging alone could cause a major decline in plantain density within mixed pastures. Rather, waterlogging could undermine the ability of plantain to compete with perennial ryegrass in mixed pastures. The impact of treading damage on plantain regrowth and survival was investigated in two field experiments. In a small-plot study, treading damage was simulated on separate plantain and perennial ryegrass pastures using a novel treading device. Damage by the treading device, in late spring, immediately reduced the herbage accumulation rate of both plantain and perennial ryegrass pastures by 30%, however neither plantain content nor density were reduced as a consequence of the damage. In a larger, two-year experiment, on a mixed plantain + perennial ryegrass pasture, early spring treading damage by dairy cows reduced pasture growth by 50% and 75% during the early spring periods of year one and two, respectively. Plantain content tended to be lower in damaged plots during early spring in both years, before recovering throughout summer, although this effect was more pronounced during year one. Treading damage caused a reduction in plantain shoot yield (leaf + petiole) and density in year one, however the negative effects of the damage on plantain growth were short-lived and subsided throughout the first year of the experiment. Treading damage in early spring in year two did not significantly impact plantain content or density. An observed reduction in plantain shoot density in late spring in year two was possibly caused by shading from perennial ryegrass. Taken together, these results suggest that treading damage in early spring is unlikely to be a primary cause of plantain content decline within mixed pastures, although it might contribute to temporary reductions in plantain content during spring, particularly in newly established swards. It is possible that treading damage could reduce the ability of plantain to compete with perennial ryegrass in mixed pastures.Item An investigation of pasture legume root and shoot properties that influence their rate of decomposition in soil : 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, 2021) Walker, HelenAgriculture is the largest source of GHG emissions (47.8 %) in New Zealand. Emissions are increasing annually, driven by increasing relative productivity. Irrespective of the climate regime, grassland soils have historically sequestered large amounts of atmospheric C into SOM (soil C) raising interest in the potential for agricultural emissions to be mitigated through acceleration of soil C sequestration. Soil C sequestration is a direct result of the rate of deposition (excreta, plant litter, and roots) exceeding the rate of decomposition and can be raised by: 1) increasing the rate of input (manipulating the drivers of vegetation); or 2) increasing the longevity of C in the system. This PhD study tests the hypothesis that C sequestration in pasture soils can be accelerated, by selecting pasture species that contribute slower decomposing litter to soil. A series of laboratory incubation studies were conducted to measure the decomposition rate (CO₂ emissions) of plant shoots and roots with high (Lotus pedunculatus) and low (Trifolium repens) tannin contents. In addition the effects of residue management (fresh and freeze dried), application to soil (fresh - surface, freeze dried - surface, and freeze dried - mixed) and rate of application (2, 5, 10 mg C. g⁻¹ soil) were evaluated. The effect of species, plant management, plant part, and rate of application on C emissions were all statistically significant (P < 0.05), with large variance in CO₂ emissions associated with all treatments. Plant species and plant part influenced the amount of C retained in the soil, although not entirely as expected. Lotus pedunculatus shoot material retained significantly more C than Trifolium repens shoot material at all rates of application (2, 5, 10 mg C. g⁻¹ soil); whereas Trifolium repens root material retained significantly more C than Lotus pedunculatus root material at all rates of application (P < 0.05). Notably plant roots and particularly Trifolium repens roots had slow decomposition rates compared to shoot materials. Research showed that soil and plant residue preparation greatly influenced the total amount of C retained for both shoot and root treatments, with more C retained under conventional incubation techniques (dried - mixed application) than with fresh applications. This indicates that CO₂-C retention in a field situation may be overestimated if predicted using conventional laboratory incubation techniques. However from a research perspective it is infinitely easier to work with pre-dried incubation materials (timing, handling, chemical analysis) so it is highly likely that this style of incubation practice will continue to be the preferred method of research. Care must therefore be taken when extrapolating the results from such incubation studies. A four compartment (2 soil C pools, persistent and labile; and 2 plant C residue pools, fast and slow) computer simulation model was developed and provided an excellent explanation of the CO₂ emissions from the incubation of fresh shoot and root material. The measurement of the metabolisable energy (ME) or lignin contents of plant shoot and root were successful in parameterising (allocating C to) the fast and slow plant residue pools. Plant tannin content was not able to explain CO₂ emission rates. The experimental and modelling studies provide evidence that grazed pasture rotations in mixed farming systems could be manipulated, by careful plant pasture species selection, to accelerate soil C sequestration. Litter and root metabolisable energy (ME) or lignin contents could be useful in species selection, but further research into other pasture species and pasture management techniques is required. Field studies should focus on the role of clover (Trifolium repens) roots in building pasture soil C content.Item Genotypic variation among a diverse collection of red clover (Trifolium pratense L.) germplasm and in-vitro techniques for screening resistance to Sclerotinia trifoliorum Erikks in red clover : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Plant Breeding at Massey University, Palmerston North, New Zealand(Massey University, 2020) Wera, BoneyRed clover (Trifolium pratense L.) is the world’s second-ranking most important forage species after alfalfa (Medicago sativa L.) based on seed volumes produced, marketed and cultivar availability. In New Zealand, red clover account for 23% of legume sales by volume after white clover (62%) and contributes significantly to primary industries by providing high quality feed for livestock. However, production is currently constrained by several limiting factors. In order to address some of these limitations, there is a need to broaden the genetic base of existing cultivars through breeding by introducing sources of genetic diversity from germplasm representing different geographical regions. In the study presented, two major experiments were carried out aiming to investigate: 1. The genetic diversity among 40 selected world source of red clover germplasm together with 3 local cultivars for ten important morphological traits under field condition across three seasons. Univariate and multivariate analysis were used to estimate genotypic variation for each trait and assess inter-relationships for a range of traits respectively so as to identify distinct germplasm accessions based on seasonal morphological measurements. Results from variance component analysis indicate significant genotypic variation as well as moderate to high repeatability among the yield related traits. This indicates potential underlying additive genetic variation among the 40 germplasm accessions for yield related morphological traits. 2. The response of eleven selected New Zealand commercial cultivars to clover rot disease (Sclerotinia trifoliorum Erikss) through artificial inoculation under high disease pressure in glasshouse to identify source of resistance for further breeding purposes. In order to facilitate the glasshouse artificial inoculation and identify the sources of resistance, this experiment used the in-vitro culturing procedures for production of S. trifoliorum ascospores to inoculate red clover plants using two locally sourced S. trifoliorum isolates. Although in-vitro production of sclerotia has been successful, our attempt to produce ascospores was not possible leading to delay in artificial inoculation of plants in glasshouse. This result suggests the need to improve on in-vitro techniques for ascospore production, understand appropriate culture condition and determine right choice of S. trifoliorum isolate to facilitate fertilization. Generally, both experiments under this study has provided valuable source of information and identify potential untapped germplasm material for future prospects of red clover breeding to develop new cultivars with improved yield, persistence and other desirable traits suitable for New Zealand condition.Item Pursuing pasture tolerance and resilience through species with different functional traits and soil-plant-water interactions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Manawatu, New Zealand(Massey University, 2020) Ordóñez Vásquez, Iván PabloHigher stability, persistence and yield can be achieved through increasing the biodiversity of pasture plants. The combination of species with different functional traits confers niche differentiation (e.g. different root depth). Otherwise species compete for the same resources in the same location and time. In diverse pasture, agricultural needs should overlap between species, enhancing species survival during critical periods. Productive ecosystems with low complexity (low plant functional diversity) show more the negative impacts of climate change, being less stable through the stress periods. Bromus valdivianus Phil. is regarded as having high potential for grazing systems, due to its high yield and good nutritive quality. It also has high tolerance to periods of soil water restriction, maintaining a higher growth rate during summer in comparison to Lolium perenne L. Alongside L. perenne, B. valdivianus co-dominates permanent perennial pastures in the South of Chile, indicating that it is a good competitor in mixed cool-temperate pastures. However, key parameters associated with recovery from defoliation, such as watersoluble carbohydrate (WSC) reserves, growth rate, tiller number and persistence, are unknown for B. valdivianus. Therefore, the first step in this thesis was to determine these defoliation criteria in relation to similar defoliation criteria of other highly productive species, L. perenne and Plantago lanceolata, to determine if and when any overlap occurred. This thesis consisted of three main experiments, which cover the physiological, morphological and competitive traits of B. valdivianus. The first experiment was designed to determine a theoretical optimum defoliation interval for B. valdivianus, and it was concluded that defoliation at leaf stage 4 (LS-4) was the optimum defoliation in terms of highest shoot and root growth rates, and accumulation of WSC. The second experiment was designed to determine the resilience and tolerance between monocultures and mixtures of B. valdivianus, L. perenne and P. lanceolata. All three species were defoliated when B. valdivianus reached LS-4, which coincided with approximately 3.5 regrowth leaves/tiller for L. perenne, and over 6 leaves/plant for P. lanceolata. Measurements included biomass production across critical periods, botanical composition, physiological response against water stress (waterlogging and soil water restriction) and water uptake at different depths, and it was concluded that a more diverse pasture (B. valdivianus + L. perenne + P. lanceolata) maintained higher biomass under soil water restriction and also had a more effective water uptake from the soil profile. The third experiment was designed to determine the tiller population dynamics, photosynthetic carbon fixation capacity (PCFC) and competitive ability of B. valdivianus in relation to L. perenne. It was concluded that L. perenne was a better competitor than B. valdivianus, however, B. valdivianus was able to recover its tiller population during a period of soil water restriction and reached a full recovery at the end of the experimental period. Also, a B. valdivianus + L. perenne mixed pasture had the highest values for PCFC during the waterlogging and soil water restriction periods. Pasture plants such as B. valdivianus and P. lanceolata can access water from deeper in the soil than L. perenne, having a direct effect on their physiological traits. Water accessibility (root depth) plays a key role in maintaining their photosynthesis, production, and improving their survival, during periods of soil water restriction, relative to L. perenne. On the other hand, L. perenne tolerate waterlogging and maintain a relatively high growth rates during winter. Pasture establishment and performance, in a climate with dry and wet seasons and in soils with a high percentage of silt and/or clay (low gas permeability), is related to species tolerance to drought and waterlogging conditions. Thus, increasing species diversity is a good strategy that confers stability to the pastoral ecosystem, especially when global warming has enhanced droughts and unpredictable rain events. Mixtures of L. perenne + T. repens + P. lanceolata or L. perenne + T. repens + B. valdivianus can reach higher growth rates during water restriction periods, in comparison to L. perenne + T. repens pastures, along with relatively high growth rates during winter. Therefore, combining species with the aim of complementary resources uptake, and depending on the contribution of each species within the pasture, will change the seasonal herbage growth rate under the stress periods. However, to keep a great contribution of the desirables pasture species it is essential to use a defoliation criterion that allow them to replenish its water soluble carbohydrates, only then, the persistence, survival and yield of the pasture and the desirables species within it will be maximized.Item The effect of nitrogen fertiliser on the sensometabolomic profile of steamed potatoes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, Manawatu, New Zealand(Massey University, 2020) Ross, Sarah BeatrixFor growers of high-value potatoes (Solanum tuberosum L.), flavour is an important product characteristic to consider, as a driver of consumer purchasing behaviour. Recent potato flavour research has focused on combining sensory and analytical techniques to better understand flavour. However, there is a lack of understanding around the relationship between consumer flavour preferences and flavour-related composition. In addition, there is very little known about the impact of agronomic factors on these aspects combined. For nitrogen, a nutrient of concern in New Zealand because of its environmental implications, understanding on how different rates of nitrogen fertiliser affect flavour is limited. Therefore, this study used a combined approach of consumer sensory evaluation with metabolite testing (sensometabolomics) to determine if nitrogen fertiliser affects the perception of steamed gourmet potato flavour and composition. Two potato varieties, ‘Annabelle’ and ‘Andean Sunside’, were treated with three different rates of nitrogen fertiliser during crop growth: 0 kg N ha⁻¹, 150 kg N ha⁻¹, and 300 kg N ha⁻¹. One hundred and eleven regular potato consumers assessed steamed potato samples for liking, using a labelled affective magnitude scale, and flavour, using rate-all-that-apply, across 14 flavour attributes. The levels of key flavour-related metabolites and variables were measured in the same potatoes, including dry matter, sugars, glycoalkaloids, polyphenols, umami amino acids, total nitrogen, nitrate, and volatile compounds. Principal component analysis was used to assess the association between changes in composition and flavour. Nitrogen fertilisation significantly affected composition and flavour in Annabelle and Andean Sunside, and ranked liking in Andean Sunside. In both Annabelle and Andean Sun- side, total nitrogen, asparagine, and glutamine levels significantly increased with the rate of nitrogen fertiliser applied, from 0 kg N ha⁻¹ to 300 kg N ha⁻¹. In Annabelle alone, nitrate, 2- butanone, 2-methyl-2-(E)-butenal, methional, and benzaldehyde increased with nitrogen, while dry matter and both α-solanine and α-chaconine concentrations decreased. The effect of fertiliser on β-ocimene was variable. In Andean Sunside, α-solanine, β-ocimene, and phenethyl alcohol all increased with nitrogen supply, while glucose and fructose con- centrations significantly decreased. Levels of (Z)-hex-3-en-1-ol, linalool, and benzyl alcohol significantly increased between 0 and 150 kg N ha⁻¹ treatments. The effect of nitrogen on quercetin-3-rutinoside was inconsistent in Andean Sunside. While average liking was not significantly affected by nitrogen, Andean Sunside 0 kg N ha⁻¹ samples were ranked significantly higher in liking compared to 300 kg N ha⁻¹ samples. Overall, nitrogen fertilisation appeared to slightly, but significantly, increase the intensity of attributes with more negative associations. Annabelle 300 kg N ha⁻¹ samples contained significantly higher intensities of nutty, musty, and sour attributes, while Andean Sunside 0 kg N ha⁻¹ samples were significantly more buttery, and less cardboard and green grass- flavoured, compared to 150 kg N ha⁻¹ samples. Therefore, for Annabelle, either 0 and 150 kg N ha⁻¹ treatments were recommended to reduce the intensity of off-flavoured attributes. For Andean Sunside, decreasing the rate of nitrogen applied was recommended to reduce the intensity of off-flavours and increase the intensity of buttery flavour, as observed in 0 kg N ha⁻¹ samples. Changes in composition could not be associated with changes in perceived flavour, within the varieties and treatments used in this study.