Browsing by Author "López IF"

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    18O isotopic labelling and soil water content fluctuations validate the hydraulic lift phenomena for C3 grass species in drought conditions
    (Elsevier B.V., 2024-02-29) Oliveira BA; López IF; Cranston LM; Kemp PD; Donaghy DJ; Dörner J; López-Villalobos N; García-Favre J; Ordóñez IP; Van Hale R
    Hydraulic lift is a functional characteristic observed in some plant species, often associated with their ability to withstand drought conditions. It involves capturing water from deep soil layers and redistributing it to shallower soil layers through the plant's roots. Bromus valdivianus Phil., Dactylis glomerata L., and Lolium perenne L. may perform hydraulic lift at varying rates. Using both direct (isotopic labelling - δ18O) and indirect (soil water content sensors) techniques, the study assessed and validated the hydraulic lift under extreme drought conditions on the soil top layer (below permanent wilting point), maintaining the bottom layer at high (20–25% filed capacity [FC]) and low (80–85% FC) levels of soil water restriction. Above- and below-ground biomass growth and morpho-physiological responses were evaluated. All species displayed some degree of hydraulic lift, with significant differences observed in the isotopic analysis and soil water content (p > 0.05). This illustrates that water was redistributed from the deep to shallower soil layer and validates that the hydraulic lift phenomenon is occurring in these C3 grasses. Bromus valdivianus presented the highest δ18O values (25.05‰) and highest increases in soil water content (µ=0.00626 m3 m−3; five events). Bromus valdivianus had a dry matter ratio of approximately 4:1 (0–20cm:20–40 cm). In contrast, L. perenne and D. glomerata had approximately 6:1 and 5:1, respectively. This difference in root morphology may explain the higher rate of hydraulic lift observed in B. valdivianus relative to L. perenne and D. glomerata. This paper validates the occurrence and provides initial insights into the hydraulic lift process occurrence of temperature grass species.
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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.
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    Aboveground Structural Attributes and Morpho-Anatomical Response Strategies of Bromus valdivianus Phil. and Lolium perenne L. to Severe Soil Water Restriction
    (MDPI (Basel, Switzerland), 2023-12-01) Zhang Y; García-Favre J; Hu H; López IF; Ordóñez IP; Cartmill AD; Kemp PD; Głab T
    Grass species have a range of strategies to tolerate soil water restriction, which are linked to the environmental conditions at their site of origin. Climate change enhances the relevance of the functional role of anatomical attributes and their contribution as water stress tolerance factors. Morpho-anatomical traits and adjustments that contribute to drought resistance in Lolium perenne L. (Lp) and Bromus valdivianus Phil. (Bv), a temperate humid grass species, were analysed. The structure of the leaves and pseudostems (stems only in Lp) grown at 20–25% field capacity (FC) (water restriction) and 80–85% FC (control) were evaluated by making paraffin sections. In both species, water restriction reduced the thickness of the leaves and pseudostems, along with the size of the vasculature. Bv had long and dense leaf hairs, small and numerous stomata, and other significant adaptive traits under water stress, including thicker pseudostems (p ≤ 0.001), a greatly thickened bundle sheath wall (p ≤ 0.001) in the pseudostem to ensure water flow, and a thickened cuticle covering on leaf surfaces (p ≤ 0.01) to avoid water loss. Lp vascular bundles developed throughout the stem, and under water restriction the xylem vessel walls were strengthened and lignified. Lp leaves had individual traits of a ribbed/corrugated-shaped upper surface, and the stomata were positioned to maintain relative humidity outside the leaf surface. Water restriction significantly changed the bulliform cell depth in Lp (p ≤ 0.05) that contributed to water loss reduction via the curling leaf blade. This study demonstrated that the two grass species, through different morphological traits, were able to adjust their individual tissues and cells in aboveground parts to reach similar physiological functions to reduce water loss with increased water restriction. These attributes explain how both species enhance persistence and resilience under soil water restriction.
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    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.
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    Decreasing Defoliation Frequency Enhances Bromus valdivianus Phil. Growth under Low Soil Water Levels and Interspecific Competition
    (MDPI (Basel, Switzerland), 2021-07-01) García-Favre J; Zhang Y; López IF; Donaghy DJ; Cranston LM; Kemp PD
    Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.
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    Effects of combined nitrogen and phosphorus application on soil phosphorus fractions in alfalfa (Medicago sativa L.) production in China.
    (Frontiers Media S.A., 2024-05-28) Yang K; Li S; Sun Y; Cartmill AD; López IF; Ma C; Zhang Q; Nazir R
    Nitrogen (N) and phosphorus (P) fertilizers change the morphological structure and effectiveness of P in the soil, which in turn affects crop growth, yield, and quality. However, the effects and mechanism of combined N and P application on the content of P fractions and the transformation of effective forms in alfalfa (Medicago sativa L.) production is unclear. This experiment was conducted with four levels of N: 0 (N0), 60 (N1), 120 (N2) and 180 kg·ha-1 (N3); and two levels of P (P2O5): 0 (P0) and 100 kg·ha-1 (P1). The results indicated that, under the same N level, P application significantly increased soil total N, and total P, available P, and content of various forms of inorganic P when compared to no P application, while decreasing the content of various forms of organic P and pH value. In general, under P0 conditions, soil total N content tended to increase with increasing N application, while total P, available P content, pH, inorganic P content in all forms, and organic P content in all forms showed a decreasing trend. When compared to no N application, insoluble P (Fe-P, O-P, Ca10-P) of the N application treatments was reduced 2.80 - 22.72, 2.96 - 20.42, and 5.54 - 20.11%, respectively. Under P1 conditions, soil total N and O-P tended to increase with increasing N application, while, pH, Ca2-P, Al-P, Fe-P, Ca10-P, and organic P content of each form tended to decrease. Total P, available P, and labile organic P (LOP) of N application reduced 0.34 - 8.58, 4.76 - 19.38, and 6.27 - 14.93%, respectively, when compared to no application. Nitrogen fertilization reduced the soil Ca2-P ratio, while P fertilization reduced soil Fe-P, moderately resistant organic P (MROP), and highly resistant P (HROP) ratios, and combined N and P elevated the Ca8-P to LOP ratio. The results of redundancy analysis showed that soil total N content, available P content, and pH were the key factors affecting the conversion of P fractions in the soil. Nitrogen and P reduced the proportion of soil insoluble P, promoted the activation of soil organic P, resulting in accumulation of slow-acting P in the soil, thereby improving the efficiency of soil P in alfalfa production.
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    Hill country pastures in the southern North Island of New Zealand: an overview
    (New Zealand Grassland Association, 26/04/2016) López IF; Kemp PD
    The 4 million ha of hill country pastures in New Zealand grow mostly on steep slopes and soils of naturally low soil fertility. Pastures are based on approximately 25 exotic species introduced within the last 130 years after the forest was cleared and burnt. Despite the environmental constraints and naturalised species, hill country is a major contributor to agricultural exports. The landscape and the pastures are spatially diverse, with slope and aspect strongly influencing the abundance and production of pasture species. The number of pasture species present is relatively stable, but the relative abundance of high fertility grass species (e.g. perennial ryegrass, Lolium perenne), low fertility grass species (e.g. browntop, Agrostis capillaris) and legumes (e.g. white clover, Trifolium repens) can be shifted towards high fertility grass species and legumes through the interaction of phosphate fertiliser application and grazing decisions (that is, sheep versus cattle, stocking rate, grazing management). Increased proportions of desirable species and improved soil fertility and structure can support sustainable farming systems. There are challenges such as soil erosion and nutrient loss into waterways, but these are more readily managed when the pastoral system is productive and profitable
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    Kānuka Trees Facilitate Pasture Production Increases in New Zealand Hill Country
    (MDPI (Basel, Switzerland), 2022-07) Mackay-Smith TH; López IF; Burkitt LL; Reid JI
    ‘Tree-pasture’ silvopastoral systems have the potential to become transformative multifunctional landscapes that add both environmental and economic value to pastoral farms. Nevertheless, no published study has found increased pasture production under mature silvopastoral trees in New Zealand hill country. This study takes a novel approach to silvopastoral research in New Zealand, and investigates a genus that has similar bio-physical attributes to other global silvopastoral trees that have been shown to increase pasture production under their canopies, with the aim of finding a silvopastoral genera that can increase pasture production under tree canopies compared to open pasture in New Zealand. This study measures pasture and soil variables in two pasture positions: under individually spaced native kānuka (Kunzea spp.) trees (kānuka pasture) and paired open pasture positions at least 15 m from tree trunks (open pasture) at two sites over two years. There was 107.9% more pasture production in kānuka pasture positions. The soil variables that were significantly greater in kānuka pasture were Olsen-P (+115.7%, p < 0.001), K (+100%, p < 0.001), Mg (+33.33%, p < 0.01), Na (+200%, p < 0.001) and porosity (+8.8%, p < 0.05), and Olsen-P, porosity and K best explained the variation between kānuka pasture and open pasture positions. Volumetric soil moisture was statistically similar in kānuka pasture and open pasture positions. These results are evidence of nutrient transfer by livestock to the tree-pasture environment. Furthermore, as there was a significantly greater porosity and 48.6% more organic matter under the trees, there were likely other processes also contributing to the difference between tree and open pasture environments, such as litterfall. These results show that kānuka has potential to increase pasture production in New Zealand hill country farms and create multifunctional landscapes enhancing both production and environmental outcomes in pastoral farms.
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    Pasture brome and perennial ryegrass characteristics that influence ewe lamb dietary preference during different seasons and periods of the day
    (Elsevier BV on behalf of the Animal Consortium, 2023-07) García-Favre J; Cranston LM; López IF; Poli CHEC; Donaghy DJ; Caram N; Kemp PD
    Under the current scenario for climate change, Bromus valdivianus Phil. (Bv), a drought-resistant species, is an option to complement Lolium perenne L. (Lp) in temperate pastures. However, little is known about animal preference for Bv. A randomised complete block design was used to study ewe lamb's preference between Lp and Bv during morning and afternoon grazing sessions in winter, spring, and summer by assessing the animal behaviour and pasture morphological and chemical attributes. Ewe lambs showed a higher preference for Lp in the afternoon in winter (P < 0.05) and summer (P < 0.01), while no differences were found in spring (P > 0.05). In winter, Bv, relative to Lp, had both greater ADF and NDF (P < 0.001), and lower pasture height (P < 0.01) which negatively affected its preference. The lack of differences in spring were due to an increase in ADF concentration in Lp. In summer, ewe lambs showed the typical daily preference pattern, selecting Lp in the morning to ensure a greater quality and showing no preference during the afternoon to fill the rumen with higher fibre content. In addition, greater sheath weight per tiller in Bv could make it less desirable, as the decrease in bite rate in the species was likely due to a higher shear strength and lower pasture sward mass per bite which increased foraging time. These results provided evidence on how Bv characteristics influence ewe lamb's preference; but more research is needed on how this will affect preference for Lp and Bv in a mixed pasture
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    Pasture production–diversity relationships in a kānuka silvopastoral system
    (John Wiley & Sons Ltd on behalf of British Ecological Society, 2023-04-09) Mackay-Smith TH; López IF; Burkitt LL; Reid JI; Wagg C
    Silvopastoral systems have great potential for forming multifunctional landscapes that provide a range of economic and environmental benefits to pastoral land. However, pasture production–diversity relationships in silvopastures require further exploration. This study measures how pasture functional group production, pasture species diversity and pasture functional diversity (FD) are impacted by trees in a novel native silvopastoral system in New Zealand hill country with kānuka (Kunzea spp.). Silvopastoral trees facilitated the growth of fast-growing competitor functional groups (Lolium perenne, Dactylis glomerata and high fertility annuals: Bromus hordeaceus and Critesion murinum), because of positive impacts on soil fertility, organic matter and porosity. Shannon diversity, species richness and species evenness were significantly less in the more productive pastoral environment under the trees, but functional richness, functional evenness and functional dispersion were similar between kānuka pasture and open pasture. These results show that silvopastures can increase pasture production by promoting the growth of competitive pasture functional groups, and that reduced species diversity under silvopastoral trees does not necessarily impact FD in the context of production. Moreover, species indices overestimated diversity reductions under the trees compared to functional indices. Thus, considering FD in silvopastoral systems is integral for not misinterpreting diversity outcomes.
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    Physico-Chemical Characteristics and In Vitro Gastro-Small Intestinal Digestion of New Zealand Ryegrass Proteins
    (MDPI (Basel, Switzerland), 2021-02-04) Kaur L; Lamsar H; López IF; Filippi M; Ong Shu Min D; Ah-Sing K; Singh J; Moreno FJ
    Being widely abundant, grass proteins could be a novel source of plant proteins for human foods. In this study, ryegrass proteins extracted using two different approaches-chemical and enzymatic extraction, were characterised for their physico-chemical and in vitro digestion properties. A New Zealand perennial ryegrass cultivar Trojan was chosen based on its higher protein and lower dry matter contents. Grass protein concentrate (GPC) with protein contents of approximately 55 and 44% were prepared using the chemical and enzymatic approach, respectively. The thermal denaturation temperature of the GPC extracted via acid precipitation and enzymatic treatment was found to be 68.0 ± 0.05 °C and 66.15 ± 0.03 °C, respectively, showing significant differences in protein's thermal profile according to the method of extraction. The solubility of the GPC was highly variable, depending on the temperature, pH and salt concentration of the dispersion. The solubility of the GPC extracted via enzymatic extraction was significantly lower than the proteins extracted via the chemical method. Digestion of raw GPC was also studied via a gastro-small intestinal in vitro digestion model and was found to be significantly lower, in terms of free amino N release, for the GPC prepared through acid precipitation. These results suggest that the physico-chemical and digestion characteristics of grass proteins are affected by the extraction method employed to extract the proteins. This implies that selection of an appropriate extraction method is of utmost importance for achieving optimum protein functionality during its use for food applications.
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    Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development
    (MDPI (Basel, Switzerland), 2021-10-13) Ordóñez IP; López IF; Kemp PD; Donaghy DJ; Zhang Y; Herrmann P
    first_pagesettingsOrder Article Reprints Open AccessArticle Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development by Iván P. Ordóñez 1,2,3ORCID,Ignacio F. López 1,3,*,Peter D. Kemp 1,3ORCID,Daniel J. Donaghy 1,Yongmei Zhang 4ORCID andPauline Herrmann 5 1 School of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North 4440, New Zealand 2 Instituto de Investigaciones Agropecuarias, INIA, Kampenaike, Punta Arenas 6212707, Chile 3 Centro de Investigación en Suelos Volcánicos, Universidad Austral de Chile, Valdivia 5091000, Chile 4 Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China 5 Ecole Nationale Supérieure d’Agronomie et des Industries Alimentaires, ENSAIA, 54505 Nancy, France * Author to whom correspondence should be addressed. Agronomy 2021, 11(10), 2058; https://doi.org/10.3390/agronomy11102058 Submission received: 16 September 2021 / Revised: 8 October 2021 / Accepted: 8 October 2021 / Published: 13 October 2021 Downloadkeyboard_arrow_down Browse Figures Review Reports Versions Notes Abstract The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.