Browsing by Author "Horne D"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
- ItemDairy Cows Grazing Plantain-Based Pastures Have Increased Urine Patches and Reduced Urine N Concentration That Potentially Decreases N Leaching from a Pastoral System(MDPI (Basel, Switzerland), 2023-02-02) Nguyen TT; Navarrete S; Horne D; Donaghy D; Bryant RH; Kemp P; De La Fuente GThe objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass-white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems.
- ItemEffects of alternative forages on nitrate leaching under intensive sheep grazing(NZ Society of Animal Production, 2021) Maheswaran S; Cranston LM; Millner J; Horne D; Hanly J; Kenyon P; Kemp P
- ItemEffects of Plantain (Plantago lanceolata L.) Metabolites Aucubin, Acteoside, and Catalpol on Methane Emissions In Vitro(American Chemical Society, 2025-05-21) Sivanandarajah K; Donaghy D; Kemp P; Navarrete S; Horne D; Ramilan T; Molano G; Pacheco DPlantain (PL) contains plant secondary metabolites (PSM), such as acteoside, aucubin, and catalpol, known for their bioactive properties. While acteoside and aucubin have been linked to reducing nitrogen losses in grazed pastures, their effects on enteric methane (CH4) emissions remain unexplored. Three in vitro batch culture experiments were conducted to assess the effects of PSM on rumen fermentation, using PL pastures with varying PSM concentrations, purified PSM compounds, and/or their combinations added to ryegrass (Lolium perenne, RG), which does not contain these PSM. Aucubin addition to RG extended the time to reach halftime for gas production (GP) and CH4 by 15-20% due to its antimicrobial effects. Acteoside, alone or with aucubin, promoted propionate production, an alternative hydrogen sink, which reduced the acetate to propionate ratio, increased GP by up to 13%, and decreased CH4 proportion in gas by 5-15%. Aucubin reduced ruminal net ammonia (NH3) production by up to 46%, with a similar reduction observed when combined with acteoside. This study highlights the potential of PSM to mitigate CH4 emissions and reduce nitrogen losses from dairy cows, warranting in vivo evaluation of PSM and targeted breeding of PL pastures with increased PSM content.
- ItemExpansion of Lifestyle Blocks in Peri-Urban New Zealand: A Review of the Implications for Environmental Management and Landscape Design(MDPI (Basel, Switzerland), 2025-07-11) Xie H; Pearson D; McLaren SJ; Horne DLifestyle blocks (LBs) are small rural holdings primarily used for residential and recreational purposes rather than commercial farming. Despite the rapid expansion of LBs over the last 25 years, which has been driven by lifestyle amenity preference and land subdivision incentives, their environmental performance remains understudied. This is the case even though their proliferation is leading to an irreversible loss of highly productive soils and accelerating land fragmentation in peri-urban areas. Through undertaking a systematic literature review of relevant studies on LBs in New Zealand and comparable international contexts, this paper aims to quantify existing knowledge and suggest future research needs and management strategies. It focuses on the environmental implications of LB activities in relation to water consumption, food production, energy use, and biodiversity protection. The results indicate that variation in land use practices and environmental awareness among LB owners leads to differing environmental outcomes. LBs offer opportunities for biodiversity conservation and small-scale food production through sustainable practices, while also presenting environmental challenges related to resource consumption, greenhouse gas (GHG) emissions, and loss of productive land for commercial agriculture. Targeted landscape design could help mitigate the environmental pressures associated with these properties while enhancing their potential to deliver ecological and sustainability benefits. The review highlights the need for further evaluation of the environmental sustainability of LBs and emphasises the importance of property design and adaptable planning policies and strategies that balance environmental sustainability, land productivity, and lifestyle owners’ aspirations. It underscores the potential for LBs to contribute positively to environmental management while addressing associated challenges, providing valuable insights for ecological conservation and sustainable land use planning.
- ItemNitrogen Excretion by Dairy Cows Grazing Plantain (Plantago lanceolata) Based Pastures during the Lactating Season(MDPI (Basel, Switzerland), 2022-02-14) Navarrete S; Rodriguez M; Horne D; Hanly J; Hedley M; Kemp PThe use of plantain pasture in dairy systems can potentially reduce nitrogen (N) leaching losses via the lower N concentration in the urine (UNc) of cows. Reducing the urinary N load while cows graze pastures can reduce the risk of N leaching losses from urine patches. Research needs to demonstrate that these environmental benefits are not at the expense of milk production and farm profit. Three groups of 20 cows grazed in the following three pasture treatments: (i) plantain, (ii) plantain-clover mix (plantain, red [Trifolium pratense] and white clover), or (iii) ryegrass-white clover (wc) pastures, from spring to autumn for two years. Each year, pasture intake, diet quality, milk production and animal N (milk and urine) excretion were evaluated in spring, summer, and autumn. The cows grazing the plantain and plantain-clover mix pastures produced similar milk solids as cows grazing ryegrass-wc pasture but reduced their UNc during summer and autumn, when compared to those grazing the plantain-clover mix and ryegrass-wc pastures. Plantain reduced urinary N loads onto pastures by a greater number of urine patches with lower urinary N loading rates. The results demonstrate that plantain pastures do not diminish milk solids production from cows, and the lower UNc from summer to autumn could reduce N being lost to the environment.
- ItemQuantification of denitrification rate in shallow groundwater using the single-well, push-pull test technique(Elsevier BV, Amsterdam, 2025-02) Rivas A; Singh R; Horne D; Roygard J; Matthews A; Hedley MDenitrification has been identified as a significant nitrate attenuation process in groundwater systems. Hence, accurate quantification of denitrification rates is consequently important for the better understanding and assessment of nitrate contamination of groundwater systems. There are, however, few studies that have investigated quantification of shallow groundwater denitrification rates using different analytical approaches or assuming different kinetic reaction models. In this study, we assessed different analytical approaches (reactant versus product) and kinetic reaction (zero-order and first-order) models analysing observations from a single-well, push-pull tests to quantify denitrification rates in shallow groundwater at two sites in the Manawatū River catchment, Lower North Island of New Zealand. Shallow groundwater denitrification rates analysed using the measurements of denitrification reactant (nitrate reduction) and zero-order kinetic models were quantified at 0.42-1.07 mg N L-1 h-1 and 0.05-0.12 mg N L-1 h-1 at the Palmerston North (PNR) and Woodville (WDV) sites, respectively. However, using first-order kinetic models, the denitrification rates were quantified at 0.03-0.09 h-1 and 0.002-0.012 h-1 at the PNR and WDV sites, respectively. These denitrification rates based on the measurements of denitrification reactant (nitrate reduction) were quantified significantly higher (6 to 60 times) than the rates estimated using the measurements of denitrification product (nitrous oxide production). However, the denitrification rate quantified based on the nitrate reduction may provide representative value of denitrification characteristics of shallow groundwater systems. This is more so when lacking practical methods to quantify all nitrogen species (i.e., total N, organic N, nitrite, nitrate, ammoniacal N, nitrous oxide, nitric oxide, and nitrogen gas) in a push-pull test. While estimates of denitrification rates also differed depending on the kinetic model used, both a zero-order and a first-order model appear to be valid to analyse and estimate denitrification rate from push-pull tests. However, a discrepancy in estimates of denitrification rates using either reactant or product and using zero- or first-order kinetics models may have implications in assessment of nitrate transport and transformation in groundwater systems. This necessitates further research and analysis for appropriate measurements and representation of spatial and temporal variability in denitrification characteristics of the shallow groundwater system.
- ItemQuantification of nitrate-N losses under intensive vegetable production systems in New Zealand(Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2025-07-03) Avendaño F; Horne D; Singh R; Palmer A; Cichota R; Bloomer DNitrogen leaching under intensive vegetable production is a major concern in New Zealand, yet measurements remain scarce. The main aim of this study was to quantify the amount of nitrate-N leached from representative soils and vegetable crops of the Lower North Island of New Zealand. Nitrate-N concentrations in soil and drainage losses were measured from 2020 to 2022 at two vegetable crop sites. One site had a potato-fallow rotation with six N fertiliser treatments: control, standard practice, split liquid, controlled release, good practice, and excess fertiliser. The second site, a lysimeter study, evaluated a beetroot-Pak choi rotation under similar treatments, including a reduced rate and chicken manure. High nitrate-N concentrations were observed in topsoil (9.3–18.3 mg kg−1), subsoil (7.3–9.6 mg kg−1), and drainage water (33.8–61.9 mg L−1), with leaching losses reaching 225 kg N ha−1, particularly during fallow periods. Alternative fertiliser strategies reduced soil nitrate-N but did not consistently maintain or increase yields. Excess fertilisation did not significantly increase potato yields but greatly increased nitrate-N losses. This study provides essential data on soil nitrate-N concentration and leaching from intensive vegetable farms.
- ItemShort-term effects of deep ploughing on soil C stocks following renewal of a dairy pasture in New Zealand(14/08/2018) Calvelo Pereira R; Hedley MJ; Hanly J; Bretherton M; Horne D; Bishop P; Beare M; McNally SIn New Zealand’s high producing permanent pastures the topsoil constitutes a large reservoir of soil organic carbon (SOC), which shows a marked stratification with depth. As consequence, sub-surface layers can contain 10 times less carbon than the surface soil. In permanent pastures with high carbon inputs, the formation and decomposition of these surface SOC stocks are often at equilibrium and C storage shows little change over time. Pastoral based dairy systems utilising ryegrass plus clover cultivars require renewal every 7-10 years to avoid reversion to less productive grasses. This may involve spring cultivation (either no-till, shallow till or full cultivation), summer forage cropping and autumn re-grassing. It has been hypothesised that SOC stocks can be increased by inverting the soil profile at pasture renewal through infrequent (once in 25-30 years) deep mouldboard ploughing (up to 30 cm depth). Increased C sequestration occurs when the new grass quickly rebuilds SOC stocks in the new topsoil (exposed low C sub-soil) at a rate faster than the decomposition of SOC in the rich former topsoil transferred to depth (now below 15 cm). However, benefits form accelerated C storage may be offset if crop and pasture production is adversely affected by the ploughing event (e.g., as result of compaction or excessive drainage). Hence, the aim of this work was to assess the short-term effects of infrequent inversion tillage of long-term New Zealand pastoral-based dairy soils under summer crop management and autumn re-grassing. An imperfectly drained Typic Fragiaqualf under dairy grazing was deep ploughed (approx. 25 cm) and re-sown with turnip in October 2016; other treatments included were shallow (< 10 cm) cultivation and no-till. The site was core sampled (0-40 cm) before cultivation and after 5 months of turnip growth to assess changes in SOC. Plant growth, herbage quality, and nutrient leaching were monitored during the 5-month period; root growth was assessed at the end of the crop rotation. Full cultivation transferred SOC below 10 cm depth, as expected. Soil bulk density decreased whereas root mass increased (10-20 cm depth; P < 0.05) under deep cultivation only. Besides, losses of mineral N were attenuated under deep tillage, resulting in a relative increase in crop yield. The potential for infrequent inversion tillage increasing soil C sequestration as a greenhouse gas (GHG) mitigation tool is currently being tested at other sites in New Zealand.
