Massey Research Online - Browsing by Author "Burkitt L"

Browsing by Author "Burkitt L"

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A Framework for Reviewing Silvopastoralism: A New Zealand Hill Country Case Study
(MDPI (Basel, Switzerland), 2021-12-14) Mackay-Smith TH; Burkitt L; Reid J; López IF; Phillips C
Silvopastoral systems can be innovative solutions to agricultural environmental degradation, especially in hilly and mountainous regions. A framework that expresses the holistic nature of silvopastoral systems is required so research directions can be unbiased and informed. This paper presents a novel framework that relates the full range of known silvopastoral outcomes to bio-physical tree attributes, and uses it to generate research priorities for a New Zealand hill country case study. Current research is reviewed and compared for poplar (Populus spp.), the most commonly planted silvopastoral tree in New Zealand hill country, and kānuka (Kunzea spp.), a novel and potentially promising native alternative. The framework highlights the many potential benefits of kānuka, many of which are underappreciated hill country silvopastoral outcomes, and draws attention to the specific outcome research gaps for poplar, despite their widespread use. The framework provides a formalised tool for reviewing and generating research priorities for silvopastoral trees, and provides a clear example of how it can be used to inform research directions in silvopastoral systems, globally.
Co-production of insights for place-based approaches to revitalise te taiao in Aotearoa New Zealand
(John Wiley and Sons Australia, Ltd on behalf of New Zealand Geographical Society, 2024-11-16) Turner JA; Stokes S; Jones RTH; Hemi M; Collins H; Vannier C; Burkitt L; Bradley C; Doehring K; Macintosh KA; Young J; Roskruge N; Perry-Smith P; Iosefa RK; Walker N; Young F; Bell A; McDermott A; Wood C
Communities across Aotearoa New Zealand are collaborating to reverse ecological decline, but little attention has been given to understanding the deeper relationship required with our physical and socio-cultural landscapes. We used knowledge co-production to develop 11 insights to support place-based strategies that nurture a collective responsibility to revitalise both people and place. Twenty-five subject matter experts across communities, government, industry and research drew from their collective expertise and the review of 63 local-to-global case study examples of farm-to-community-scale place-based approaches. A key output from this work is an Aotearoa New Zealand framework that diagrammatically represents the interdisciplinary nature of the 11 insights.
Correction to: A Framework for Reviewing Silvopastoralism: A New Zealand Hill Country Case Study (Land, (2021), 10, 12, (1386)
(MDPI (Basel, Switzerland), 2023-03-22) Mackay-Smith TH; Burkitt L; Reid J; López IF; Phillips C
The authors would like to make the following correction to the published article [1]. There was a miscommunication with the journal editors regarding the formatting of the table. Individual points within table boxes were removed for the final manuscript so there were duplicate references in each table box. The following changes were made to the references in Table 2: “McIvor et al. [42]” was removed from Page 8; “Charlton et al. [25]” was removed from Page 10; “Marden and Phillips [49]”, “Charlton et al. [25]” and “Boffa Miskell Limited [50]” × 2 were removed from Page 11 and from Page 10. Additionally, colons were added between references where necessary. Other changes include the following: “survivial” was changed to “survival” on Page 11; “Quantatiative” was changed to “quantitative” on Page 11; to was removed on Page 11; “precence” was changed to “presence” on Page 13; “11.5 year old” was changed to “11.5-year-old” on Page 8; “16 year-old” was changed to “16-year-old” on Page 8; “32.0-year-old” was changed to “32-year-old” on Page 8; and “5.0, 7.0 and 9.5 year old” changed to “5, 7, and 9.5 years old”. Finally, “≥25 m” was changed to “>30 m” and “10–20 m” was changed to 8–20 m” on Page 7 due to ongoing research refining the sizes of the tree. The corrected Table 2 appears below. Tree attributes for poplar (Populus spp.) and kānuka (Kunzea spp.) in a New Zealand hill country silvopastoral system. Tree attributes have been adapted from Wood [15]. The photographs were taken by the lead author. The following changes were made to the references in Table 3: “Guevara-Escobar et al. [26]” and “Wall [27]” were removed from Page 14, and “Guevara-Escobar et al. [26]” was removed from Page 16. Additionally, the Table 3 header was moved to the left and the font size of Table 3 was adjusted to size 8. The corrected Table 3 appears below. Silvopastoral outcomes for poplar (Populus spp.) and kānuka (Kunzea spp.) in a New Zealand hill country silvopastoral system. Tree outcomes have been adapted from Wood [15]. There was an error in the original publication. “Forst.” should be “(G. Forst.) Oerst.” A correction has been made to Section 1. Introduction, paragraph 1: Page 1. There was an error in the original publication. “>15” has been changed to “> 15”. A correction has been made to Section 1. Introduction, paragraph 3: Page 1. There was an error in the original publication. “(Populus spp.)” and “(Salix spp.)” have been removed. A correction has been made to Section 3.1. Poplar and Willow, paragraph 1: Page 5. There was an error in the original publication. “40 year” has been changed to “40-year”. A correction has been made to Section 3.1. Poplar and Willow, paragraph 2: Page 5. There was an error in the original publication. “serotine” should be “serotina”. A correction has been made to Section 3.2. Kānuka, paragraph 1: Page 6. There was an error in the original publication. “(Leptospermum scoparium)” has been removed. A correction has been made to Section 3.2. Kānuka, paragraph 2: Page 6. There was an error in the original publication. The reference “[23,24,25]” should be “[25]”. A correction has been made to Section 4.1. The interaction of Poplar and Kānuka with the Pasture and Soil, paragraph 5: Page 21. There was an error in the original publication. “400-years-old” should be “400 years old”. A correction has been made to Section 4.2. Longevity, paragraph 1: Page 21. There was an error in the original publication. Reference [80] should be removed after kiwi-fruit orchards. A correction has been made to Section 4.6. Bird biodiversity, paragraph 2: Page 22. There was an error in the original publication. “2 year” should be “2-year”. A correction has been made to Section 4.6. Bird biodiversity, paragraph 2: Page 22. There was an error in the original publication. “(Leptospermum scoparium)” has been removed. A correction has been made to Section 4.7. Additional Income, paragraph 1: Page 23. There was an error in the original publication. “7-years-old” should be “7 years old”. A correction has been made to Section 4.7. Additional Income, paragraph 3: Page 23. There was an error in the original publication. Reference [46] has been changed to [52]. A correction has been made to Section 4.7. Additional Income, paragraph 4: Page 23. There was an error in the original publication. reference [52] should be “Ministry for Primary Industries. Forest land in the ETS. Available online: https://www.mpi.govt.nz/forestry/forestry-in-the-emissions-trading-scheme/forest-land-in-the-ets/ (accessed on 8 May 2020)”. A correction has been made to References section: Page 27. The authors apologize for any inconvenience caused and state that the scientific conclusions are unaffected. The original publication has also been updated.
Exploring Phosphorus Dynamics in Submerged Soils and Its Implications on the Inconsistent Rice Yield Response to Added Inorganic Phosphorus Fertilisers in Paddy Soils in Sri Lanka
(2024-03-01) Palihakkara J; Burkitt L; Jeyakumar P; Attanayake CP
Rice is the primary energy source of more than half of the global population. Challenges persist in managing phosphorus (P) in paddy soils of tropical rice-growing countries. In Sri Lanka, one specific challenge is the inconsistent yield response observed when inorganic P fertilisers are applied to paddy soils. Previous research conducted in Sri Lanka has shown that the rice yield response to added P fertilisers cannot be adequately explained by factors such as soil available P, irrigation schemes, soil texture, pH, electrical conductivity, total carbon content and available Fe and Mg concentrations. Due to the submerged conditions in which rice is grown for a significant portion of its lifespan, a unique environment controlled by redox-driven processes is developed in paddy soils. Therefore, releasing P from submerged soils is an outcome influenced by complex hydrological and biogeochemical processes, strongly influenced by inherent soil characteristics. The present review paper aimed to critically examine existing literature on soil P behaviour in submerged paddy soils of Sri Lanka, to clarify the behaviour of P under submergence, identify the factors affecting such behaviour and highlight the research gaps that need to be addressed, in order to effectively manage P in the paddy soils of Sri Lanka.
Phosphorus Release and Transformations in Contrasting Tropical Paddy Soils Under Fertiliser Application
(Springer Nature on behalf of the Sociedad Chilena de la Ciencia del Suelo, 2025-04-11) Palihakkara J; Attanayake CP; Burkitt L; Jeyakumar P
Purpose: Inconsistent yield responses to inorganic phosphorus (P) fertilisers in tropical rice paddy soils remain a challenge. This study investigated the contributions of applied P fertilisers to soluble soil P and P transformation mechanisms in P-added paddy soils. Methods: An incubation study was conducted on three rice-growing soils (Ultisol, Alfisol, and Entisol) in Sri Lanka with and without single superphosphate (SSP), triple superphosphate (TSP), and urea. Dissolved reactive phosphorus (DRP) was measured over 112 days of submergence. Thermodynamic modelling and chemical P fractionation were employed to assess soil P transformations. Results: Phosphorus-fertilised soils had significantly higher DRP concentrations (1.1–8.0 mg L−1) compared to controls at 7 days after submergence but DRP declined beyond 21 days (0.024–0.300 mg L−1). Single superphosphate increased DRP more than TSP, short-term. Urea did not affect DRP concentration. Ultisols exhibited the lowest DRP, while Alfisols maintained higher DRP than Ultisol which was near or above the critical concentration for rice (0.1 mg L⁻1) after 28 days. In Entisol, only SSP maintained DRP above 0.1 mg L−1. Modelling suggested Ca phosphates and Fe oxy(hydr)oxides dissolved during submergence. Released P may be resorbed by Fe/Al oxy(hydr)oxides and Ca minerals, with evidence of downward movement of dissolved P and its resorption onto Fe/Al and Ca minerals possibly due to saturation of P sorption sites in the topsoil layer. Conclusion: Low dissolved P in porewater may be linked to inherent soil characteristics, including low organic matter and high amorphous Fe and Al oxides.
Phosphorus release under short-term submergence of pasture soils in critical source areas.
(Elsevier, 2025-01-29) Palihakkara J; Burkitt L; Jeyakumar P; Attanayake CP
Critical source areas (CSAs) can act as a source of phosphorus (P) in surface waters by releasing soil P to porewater during frequent rainfall events. The extent of P release under short-term, frequent submergence has not been systematically studied in CSAs in New Zealand. A study was conducted to explore the potential of three contrasting dairy and sheep/beef farm soils (Recent, Pallic and Allophanic soils) to release P to porewater and pondwater under short-term and frequent submergence. Five undisturbed soil blocks (20 × 20 × 15 cm) were sampled from each soil. Porewater samplers and half-cell platinum electrodes for in-situ redox potential measurements were installed at 2 and 10 cm depths from the soil surface. Six submerged events were created by maintaining a 5 cm waterhead. Porewater and pondwater samples were collected immediately and three days after each submergence event. After three days of submergence, the soil blocks were drained and maintained at 70% of water holding capacity for 10 days before the next submergence event. Dissolved reactive phosphorus (DRP), pH, dissolved organic carbon, cations, anions, and alkalinity of the water samples were measured. Soil chemical P fractions were assessed in initial soils and soils in the middle and end of the experiment. Thermodynamic modelling was used to infer dissolution and formation of P and P-associated minerals. The Recent soil released P to porewater at both depths and to pondwater. The Pallic soil released P to porewater at both depths but did not change pondwater DRP. Allophanic soil sorbed P and did not increase DRP either in porewater or pondwater. The average pondwater DRP of the three soils during submergence were 17 to 65-fold higher than the New Zealand lowland river target DRP concentration (0.01 mg/L). The mechanisms of P release from the Recent and Pallic soils were desorption and reductive dissolution of Mn(Ⅱ) minerals. Reductive dissolution of Fe(Ⅱ) minerals was not supported by fractionation or modelling results. Decreases in labile, moderately labile and stable P fractions contributed to P release in the Recent soil, while increases in the labile and moderately labile P fractions contributed to P retention in the Pallic and Allophanic soils. This study highlighted that the Recent soil is riskier than the other two soils in releasing P upon short-term submergence and the potential use of Allophanic soil as a P sorbing material in CSAs to mitigate P loss.
Redox-induced phosphorus release from critical source areas following rainfall events in New Zealand
(Elsevier Ltd, United Kingdom, 2025-02) Palihakkara J; Burkitt L; Jeyakumar P; Attanayake CP
Critical source areas (CSAs) can act as a source of phosphorus (P) during intermittent rainfall events and contribute to dissolved P loss via runoff. Dissolved forms of P are readily accessible for plant and algal uptake; hence it is a concern in terms of the eutrophication of freshwater bodies. The potential of CSAs to release dissolved P to surface runoff upon intermittent short-term submergence caused by different rainfall events has not been studied at a field-scale in New Zealand previously. A field study was conducted to investigate the potential of two different pastoral soil CSAs (Recent and Pallic soil) to release soil P over five rainfall events during winter and to explore the mechanisms of P release in these soils. Ten sampling stations were installed within each CSA in an area of 6 × 2 m2. Each sampling station had two porewater samplers installed at two depths (2 and 10 cm) below the soil surface. Two platinum half-cell electrodes were installed at the same two depths. Porewater and floodwater samples were collected following five rainfall events. Redox potentials were measured in-situ. Dissolved reactive phosphorus (DRP), pH, dissolved organic carbon, cations, anions, and alkalinity of the water samples were measured. Soil chemical P fractions were assessed at the beginning, middle and end of the experiment. Thermodynamic modelling was used to infer dissolution and formation of P and P-associated minerals. The average porewater DRP at the two depths during the rainfall events of the Recent and Pallic soils were 0.32-1.3 mg L-1 and 0.26-2.31 mg L-1, respectively. The average floodwater DRP concentrations of the Recent and Pallic soils were 35 and 43-fold higher than the target DRP concentration (0.01 mg L-1) for the Manawatū River. The study highlights the substantial risk of P loss from CSAs to surface water, driven primarily by the reductive dissolution of Fe and Mn oxy(hydr)oxides. The findings underscore the importance of targeted management strategies to mitigate dissolved P runoff, particularly in high-risk CSAs frequent submerged during rainfall events. This study developed an effective method for monitoring soil porewater P and redox conditions, offering valuable insights and practical tools for resource managers seeking to reduce P contamination.
The Behaviour of Sheep around a Natural Waterway and Impact on Water Quality during Winter in New Zealand
(MDPI (Basel, Switzerland), 2023-04-25) Bunyaga A; Corner-Thomas R; Draganova I; Kenyon P; Burkitt L; Giuseppe P
Access of livestock, such as cattle, to waterways has been shown to be a cause of poor water quality due to pugging damage and excretion entering the water. In New Zealand, regulations require that cattle, deer, and pigs are excluded from accessing waterways, but there are no such requirements for sheep. The current study utilised 24 h video cameras, global positioning system units, and triaxial accelerometers to observe the interaction of Romney ewes (n = 40) with a natural waterway. Ewes were either restricted (week 1) or given access to a reticulated water trough (week 2). Proximity data showed that ewes spent more time within 3 m of the waterway when the trough was unrestricted than when restricted (14.1 ± 5.7 and 10.8 ± 5.1 min/ewe/day, respectively; p < 0.05). Ewes travelled shorter distances on the steeper areas of paddock than flatter areas. Similarly, ewes showed a spatial preference for the flat and low sloped areas of the paddock. Concentrations of suspended sediment and total phosphorus were higher during access to a reticulated water trough which coincided with the week with more rainy days. Phosphorus and E. coli concentrations in the stream water samples were the above recommended Australian and New Zealand Environment and Conservation Council water quality guidelines, especially after rainy days, but did not appear to be directly related to sheep activity. Overall, the results suggest that during winter, ewes interacted very little with the waterway and were thus unlikely to influence the levels of nutrient and pathogens in the waterway.
The effects of pastoral hill country natural landscape features and land management practices on nitrate losses and its potential attenuation for improved water quality
(Global Initiative of Sustainable Agriculture and Environment and John Wiley and Sons Australia, Ltd, 2024-03-22) Chibuike G; Singh R; Burkitt L
Pastoral farming on hill country landscapes influences nitrogen (N) dynamics and its losses to freshwater. This study reviewed the current literature identifying key effects of pastoral hill country landscape features and land management practices on nitrate losses to receiving waters. The review also highlighted the potential effects of inherent landscape features on nitrate attenuation pathways for better water quality outcomes. Intensive land use activities involving high rates of fertiliser application, higher stocking rates and cattle grazing, relative to sheep grazing, are more likely to increase nitrate loss, especially on lower slopes. However, soils with a high carbon (C) storage capacity such as allophanic soils potentially limit nitrate loss via denitrification in subsoil layers. Hill country seepage wetlands also offer an opportunity to attenuate nitrate loss, though their efficacy is largely impacted by hydrological variations in their inflows and outflows. By enhancing the natural nitrate attenuation capacity of seepage wetlands, mapping and strategic use of high subsoil denitrification potential, effective riparian management, efficient fertiliser and grazing practices and the incorporation of these farm management strategies into Freshwater Farm Plans (FWFPs), wider environmental and farm productivity/profitability goals, including improved water quality, would be achieved on pastoral hill country landscapes.
The importance of incorporating geology, soil, and landscape knowledge in freshwater farm planning in Aotearoa New Zealand
(2/09/2022) Bretherton M; Burkitt L
Over half of Aotearoa New Zealand’s (NZ’s) land area is under agriculture or forestry production. Long term monitoring has shown declines in freshwater quality in regions with the most intensive agriculture. The New Zealand government has historically focused on reducing the impact of agriculture on water quality through its Resource Management Act 1991. Lack of improvement in freshwater quality has resulted in the 2020 Essential Freshwater package of reforms which will require all pastoral farms >20 ha in size and all arable farms > 5 ha in size to develop a Freshwater Farm Plan (FFP) by a certified Freshwater Farm Planner. As far as we are aware, New Zealand is the first country in the world to mandate compulsory FFPs. This paper describes the key geological, soil, and landscape factors that need to be considered in an FFP for it to be successful in meeting the 2020 Essential Freshwater objectives. We argue that a greater emphasis should be placed on understanding a farm’s natural resources, as they provide the physical interface between the farming system and both the freshwater and atmospheric ecosystems. Documenting our learning in this area could assist other countries considering Freshwater Farm Planning as a strategy to reduce the impact of agriculture on freshwater quality.

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