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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    Alfalfa adapts to soil nutrient surplus and deficiency by adjusting the stoichiometric characteristics of main organs and nutrient reabsorption
    (BioMed Central Ltd, 2025-12-01) Sun Y; Hui J; Yang K; Wei K; Wang X; Cartmill AD; López IF; Qi Y; Ma C; Zhang Q
    Accurate nutrient diagnosis is essential for simulating alfalfa (Medicago sativa L.) yield and optimizing resource-use efficiency under diverse soil nutrient conditions. However, limited knowledge exists about how fertilization impacts soil–plant nutrient stoichiometric constraints, especially in nutrient-deficient gray desert soils. This study conducted a field experiment with four nitrogen (N) application rates: 0, 60, 120, and 180 kg N∙ha−1 and four phosphorus (P) application rates: 0, 50, 100, and 150 kg P2O5∙ha−1. We assessed changes in the nutrient limitation characteristics of alfalfa and identified its primary driving factors, focusing on soil nutrient perspectives, nutrient distribution in main organs (leaves, shoots, and roots) and nutrient resorption. The results demonstrated that fertilization increased N and P concentrations in various alfalfa organs while reducing carbon (C) content. A strong synergy was observed in nutrient concentrations across the different alfalfa organs. With increasing application of single-nutrient fertilizers, the C:N and C:P ratios in alfalfa organs decreased, while the N:P ratio stabilized under conditions of sufficient or co-limiting soil N and P. Alfalfa N:P ratios under different fertilization treatments were 4.89–5.46 in roots, 6.19–8.45 in stems, and 9.10–15.16 in leaves. The C:N and C:P ratios were significantly negatively correlated with alfalfa yield, but the relationship between the N:P ratio and yield was not statistically significant. Soil nutrient status positively influenced N and P concentrations in leaves, stems, and roots, however, their effect on stoichiometric ratios was primarily mediated through indirect effects on corresponding organ-level nutrients. Moreover, soil nutrients directly or indirectly explained 98% of the variation in nutrient resorption in leaves. In conclusion, fertilization indirectly affects the stoichiometric characteristics of alfalfa organs via soil nutrients. Adjusting fertilizer nutrient ratios can mitigate nutrient limitations in both soil and alfalfa, providing valuable insights for fertilizer formulation, timing of fertilizer application, and fertilization application strategies. Highlights 1.Fertilization alters the C-N-P stoichiometry of the soil–plant system. 2.The stoichiometric characteristics and ratios of different organs exhibit a certain degree of synergy. 3.Stoichiometric ratios can represent nutrient limitation to a certain extent. 4.Soil nutrient changes affect the stoichiometric characteristics and ratios of alfalfa.
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    Belowground Structural Attributes and Morpho-Anatomical Response Strategies of Bromus valdivianus Phil and Lolium perenne L to Soil Water Restriction
    (MDPI (Basel, Switzerland), 2025-05) Zhang Y; García-Favre J; Hu H; López IF; Ordóñez IP; Cartmill AD; Symonds V; Kemp PD; Vergine M
    The effect of soil water restriction on the root structure and morpho-anatomical attributes of Lolium perenne L. (Lp) and Bromus valdivianus Phil. (Bv) was investigated. The anatomical structure of roots from plants grown under two water restriction conditions (20–25% and 80–85% field capacity (FC)) were assessed using paraffin embedding and thin sections. These sections were examined to assess anatomical traits, including root diameter (root D), stele diameter (stele D) and cortex thickness (cortex T), and xylem vessel of Lp and Bv roots. Tiller population, shoot herbage mass, and the shoot-to-root ratio were also determined. Under water restriction, biomass and tillers were significantly decreased (p < 0.001), while the root-to-shoot ratio significantly increased, indicating a higher proportion of Bv roots than shoots when compared to Lp. The root D and stele D, and cortex T, were larger in Bv than in Lp (p < 0.001), indicating a greater adaptation of Bv for water uptake and storage compared to Lp. Xylem vessels were wider in Lp when compared to Bv (p < 0.01), indicating greater water flow within the plant. Water restriction generated a decrease in root D, stele D, and cortex T (p < 0.01). Canonical variate analysis showed that the pith cell wall had a strong positive relationship with water restriction in both Bv and Lp; lignified xylem and the endodermis wall had a close relationship with Lp under water restriction. The findings demonstrate that Lp and Bv have individual structural and morpho-anatomical response strategies to increasing 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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    Effect of Water Restriction and Supplementary Nitrogen on the Growth Dynamics of Bromus valdivianus Phil
    (MDPI (Basel, Switzerland), 2025-09) López IF; Rodríguez A; Cartmill AD; Dörner J; Calvache I; Balocchi O; Sanders D; Liu Y
    Decreasing summer precipitation is negatively affecting global productivity of grassland plant species. This study evaluated the effect of three levels of soil plant available water [80–90% PAW-H (high), 50–60% PAW-M (medium), and 20–30% PAW-L (low), which were soil water restriction (SWR) equivalent to (v/v%) 10–20%, 40–50%, and 70–80%, respectively] and nitrogen (N 0 and 110 kg ha−1) on growth and nutritional quality of Bromus valdivianus Phil. (Bv) mini-swards (MS; 125 L containers), arranged in three blocks. Total lamina length (TLL), leaf expansion rate (LER; cm d−1), phyllochron (Phy) expressed as “days” and “°C day”, tiller mass (TM, g tiller−1), number of live leaves (NLL), number of dead leaves (NDL), and accumulated herbage mass [AHM, g DM (dry mass) m2] were measured. Defoliation events, leaving 5 cm residual height, were carried out every 320 GDD (using a base growth temperature of 5 °C), and foliage samples for nutritive quality [DM, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), water-soluble carbohydrates (WSC), and metabolic energy (ME)] were collected. Reducing PAW to 20–30% decreased the AHM by 60.7%, TLL by 52.7%, LER by 50%, and TM by 50%, with significant interaction between the main effects for AHM, TLL, and LER. The addition of N increased the AHM by 31.6%, LER by 21.6%, and TLL by 19.6%. The Phy remained undisturbed by decreasing PAW and increasing the N rate. Nutritive quality was generally not statistically different for the interaction or between N levels. However, low PAW levels resulted in statistically (p < 0.05) lower ME and higher concentrations of NDF. In general, growth, AHM, and nutritional quality of Bv during the summer period were driven by PAW levels and by the availability of N. Plant available water levels of 50% to 60% at 20 cm soil depth, with the addition of N, allowed Bv to reach its highest production.
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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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    Enhancing alfalfa photosynthetic performance through arbuscular mycorrhizal fungi inoculation across varied phosphorus application levels
    (Frontiers Media S.A., 2023-10-20) Xia D; An X; López IF; Ma C; Zhang Q; Mundra S
    This study evaluated the effects of arbuscular mycorrhizal fungi inoculation on the growth and photosynthetic performance of alfalfa under different phosphorus application levels. This experiment adopts two-factors completely random design, and sets four levels of fungi application: single inoculation with Funneliformis mosseae (Fm, T1), single inoculation with Glomus etunicatum (Ge, T2) and mixed inoculation with Funneliformis mosseae × Glomus etunicatum (Fm×Ge, T3) and treatment uninfected fungus (CK, T0). Four phosphorus application levels were set under the fungi application level: P2O5 0 (P0), 50 (P1), 100 (P2) and 150 (P3) mg·kg-1. There were 16 treatments for fungus phosphorus interaction. The strain was placed 5 cm below the surface of the flowerpot soil, and the phosphate fertilizer was dissolved in water and applied at one time. The results showed that the intercellular CO2 concentration (Ci) of alfalfa decreased at first and then increased with the increase of phosphorus application, except for light use efficiency (LUE) and leaf instantaneous water use efficiency (WUE), other indicators showed the opposite trend. The effect of mixed inoculation (T3) was significantly better than that of non-inoculation (T0) (p < 0.05). Pearson correlation analysis showed that Ci was significantly negatively correlated with alfalfa leaf transpiration rate (Tr) and WUE (p < 0.05), and was extremely significantly negatively correlated with other indicators (p < 0.01). The other indexes were positively correlated (p < 0.05). This may be mainly because the factors affecting plant photosynthesis are non-stomatal factors. Through the comprehensive analysis of membership function, the indexes of alfalfa under different treatments were comprehensively ranked, and the top three were: T3P2>T3P1>T1P2. Therefore, when the phosphorus treatment was 100 mg·kg-1, the mixed inoculation of Funneliformis mosseae and Glomus etunicatum had the best effect, which was conducive to improving the photosynthetic efficiency of alfalfa, increasing the dry matter yield, and improving the economic benefits of local alfalfa in Xinjiang. In future studies, the anatomical structure and photosynthetic performance of alfalfa leaves and stems should be combined to clarify the synergistic mechanism of the anatomical structure and photosynthetic performance of alfalfa.
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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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    Lactation curves for milk, fat and protein in dairy cows under regenerative versus conventional farming practices
    (Taylor and Francis Grou, 2024-11-10) Moreno-Gónzalez Y; López-Villalobos N; Donaghy D; López IF; MacGibbon A; Holroyd SE
    Regenerative agriculture aims to utilise more diverse pasture species and enhance animal performance through sustainable soil management and pasture quality. This study evaluated the influence of regenerative and conventional farming on dairy cow performance and milk production under different pasture mixes and management strategies. Monthly herd test records were used to model individual lactation curves for daily milk, fat, and protein yield for the 2022–2023 season using random regression with third-order orthogonal polynomials. Total yields were calculated from predicted daily yield. Treatments were SPCM: Standard pasture under conventional management, DPCM: Diverse pasture mix under conventional management, and DPRM: Diverse pasture mix under regenerative management. Total milk yield was similar across treatments, averaging 3370 kg (SPCM), 3649 kg (DPCM), and 3626 kg (DPRM) for the 2022–2023 season. No significant differences were observed in fat, protein, milk solids yield, or milk composition. Cows on diverse pastures, regardless of management approach, showed heavier liveweights than those on standard pastures. DPCM and DPRM cows averaged 474 kg, significantly greater than SPCM cows at 464 kg (P < 0.0001), likely due to longer grazing rotation and higher post-graze mass. These findings suggest that pasture species diversity, regardless the management, enhances liveweight without affecting milk composition.
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    Long-term effects of nitrogen and phosphorus fertilizers on rhizosphere physicochemical characteristics and microbial composition in alfalfa
    (Elsevier BV, 2025-05) Wei K; Sun Y; Cartmill AD; López IF; Ma C; Zhang Q
    Repeated fertilizer applications to different monoculture cropping systems can alter soil nutrients and microbial community structure. Here we investigate the impact of long-term (4 year) distinct nitrogen (N) and phosphorus (P) fertilizer treatments on rhizosphere physicochemical characteristic and soil microbial community composition in an alfalfa (Medicago sativa L.) cropping systems. N and P fertilizer significantly influenced the physicochemical properties and stoichiometry of alfalfa rhizosphere soil. Nevertheless, N and P fertilizers application on the rhizosphere bacterial and fungal community structures were inconsistent. Fertilizer application minimally metamorphose the rhizosphere bacteria and fungi richness (Sobs index) and diversity (Shannon index). Non-metric multidimensional scaling analysis (NMDS) revealed that fertilizer treatments have no significant influence the fungal community, however, they significantly altered the bacterial community. Bacterial dominant phyla, Actinobacteriota, Acidobacteriota, Chloroflexi, and Gemmatimonadota changed significantly, indicating that the composition of the bacterial community was more responsive to fertilizer application when compared to fungal community composition. Spearman correlation analysis demonstrated no significant correlation amidst soil factors and bacterial diversity, conversely, bacterial richness, fungal diversity and richness were significantly modified by soil factors (AP, AN, and C/N). Network analysis indicated that N application reduced the positive associations between bacteria and fungi, whereas P application enhanced the positive associations. In conclusion, fertilization changes soil fertility of alfalfa fields and the bacterial community composition. Additionally, tests on phosphate solubilizing bacteria (PSB) isolated from the rhizosphere soil of alfalfa demonstrated that these bacteria could significantly enhance the biomass of alfalfa.
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    Nitrogen and phosphorus fertilizer use efficiency improves alfalfa (Medicago sativa L.) production and performance in alkaline desert soil.
    (Frontiers Media S.A., 2025-02-18) Sun Y; Sun J; Wang X; Cartmill AD; López IF; Ma C; Zhang Q; Srivastava AK
    The deficiency of nitrogen and phosphorus is a primary constraint on the normal growth of alfalfa (Medicago Sativa L.) in the alkaline desert soils of northern Xinjiang. Optimizing the combination of nitrogen and phosphorus fertilizers can maximally significantly enhance farmers' economic returns while concurrently mitigate soil environmental pollution. For this purpose, a field experiment based on a randomized complete block design was conducted over two consecutive years (2019 and 2020) in Shihezi, Xinjiang province, China. The WL366HQ variety of alfalfa was evaluated with four levels each of urea and monoammonium phosphate. The effects of fertilizer treatments were assessed on alfalfa yield, growth traits, nutritional quality, fertilizer use efficiency, and economic benefit. Application of nitrogen (N), phosphorus (P), and their interaction significantly (P< 0.05) affected cumulative alfalfa dry matter (DM) yield. In general, compared to no-fertilization treatment, the application of N and P fertilizers resulted in increased plant height, stem thickness, crude protein, and ether extract of alfalfa, while neutral detergent fiber (NDF) and acid detergent fiber (ADF) exhibited a decreasing trend. Additionally, while N and P fertilizer application reduced corresponding fertilizer use efficiency, it increased non-corresponding fertilizer use efficiency. During the two-year experimental period, the treatment involving the application of urea at 286.3 kg·ha-1 combined with monoammonium phosphate at 192 kg·ha-1 achieved the highest evaluation scores for production performance, fertilizer use efficiency, and total net profit, resulting in a net profit increase of 44.18% compared to the no-fertilizer treatment. These findings lay the groundwork for nuanced fertilization strategies in future alfalfa cultivation.
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    Optimizing irrigation and fertilization management enhances alfalfa seed yield components through improved soil nutrient availability and leaf photosynthetic efficiency
    (Frontiers Media S.A., 2025-08-29) Hui J; Sun Y; Wei K; Cartmill AD; López IF; Ma C; Zhang Q; Liu K
    Introduction: Addressing the challenges of inefficient water-fertilizer utilization and suboptimal seed yield in alfalfa (Medicago sativa L.) seed production systems, we investigated the effects of differential irrigation-fertilization regimes on soil nutrient dynamics, photosynthetic performance, and yield parameters. This study aims to optimize seed production while elucidating the response mechanisms linking soil nutrient availability, foliar photosynthetic efficiency, and seed yield outcomes. This experiment employed drip irrigation to address production constraints in alfalfa seed cultivation. Methods: Using ‘WL354HQ’ and ‘Xinmu No.4’ as the experimental materials, a two-factor randomized block design was adopted, with three fertilization levels: F0 (no fertilizer), F1 (90 kg·ha-1 N 75 kg·ha-1 P2O5, 12 kg·ha-1 K2O), and F2 (120 kg·ha-1 N, 100 kg·ha-1 P2O5, 15 kg·ha-1 K2O), and combined with three irrigation levels W1 (1650 m3·ha-1), W2 (2500 m3·ha-1), and W3 (3350 m3·ha-1). Results: Water and fertilizer management is a prerequisite for high yield of alfalfa seeds, and the impact of fertilization on seed yield is greater than that of irrigation. Compared to the non-fertilized control (F0W1), the F2W2 treatment significantly increased soil nutrients in the 0–20 cm layer: soil total nitrogen content (+52.17%), total phosphorus content (+18.72%), and organic carbon content (+16.85%), and available phosphorus content (+37.34%), and alkali-hydrolyzable nitrogen content (+17.45%). Notably, F2W2 enhanced net photosynthetic rate by 35.04% despite reduced stomatal conductance (-2.14%) and intercellular CO2 concentration (-9.50%), thereby promoting assimilate partitioning to reproductive organs. Consequently, seed dimensional parameters (width: +53.02%; thickness: +21.75%) and germination rate (+23.11%) were significantly improved (P < 0.05), increasing the seed yields of WL354HQ and Xinmu No.4 by 42.76% and 49.81% respectively. Correlation analysis revealed significant (P < 0.01) positive associations between seed yield and seed length, seed width, seed thickness, chlorophyll a, carotenoids, total chlorophyll content, and net photosynthetic rate. Principal component analysis showed that the optimal fertilization level was N 120 kg·ha-1; P2O5–100 kg·ha-1; K2O 15 kg·ha-1, with an irrigation level of 2500 m3·ha-1 (F2W2) as the optimal model. Discussion: This optimized model significantly enhanced alfalfa seed yield formation, photosynthetic characteristics, and soil nutrient availability, which provided a theoretical basis for high yield cultivation of alfalfa seed production in arid areas.
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    Optimizing nitrogen and phosphorus application to improve soil organic carbon and alfalfa hay yield in alfalfa fields
    (Frontiers Media South Africa, 2023) Wei K; Zhao J; Sun Y; López IF; Ma C; Zhang Q; Wang LI
    Soil organic carbon (SOC) is the principal factor contributing to enhanced soil fertility and also functions as the major carbon sink within terrestrial ecosystems. Applying fertilizer is a crucial agricultural practice that enhances SOC and promotes crop yields. Nevertheless, the response of SOC, active organic carbon fraction and hay yield to nitrogen and phosphorus application is still unclear. The objective of this study was to investigate the impact of nitrogen-phosphorus interactions on SOC, active organic carbon fractions and hay yield in alfalfa fields. A two-factor randomized group design was employed in this study, with two nitrogen levels of 0 kg·ha-1 (N0) and 120 kg·ha-1 (N1) and four phosphorus levels of 0 kg·ha-1 (P0), 50 kg·ha-1 (P1), 100 kg·ha-1 (P2) and 150 kg·ha-1 (P3). The results showed that the nitrogen and phosphorus treatments increased SOC, easily oxidized organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC), microbial biomass carbon (MBC) and hay yield in alfalfa fields, and increased with the duration of fertilizer application, reaching a maximum under N1P2 or N1P3 treatments. The increases in SOC, EOC, DOC, POC, MBC content and hay yield in the 0-60 cm soil layer of the alfalfa field were 9.11%-21.85%, 1.07%-25.01%, 6.94%-22.03%, 10.36%-44.15%, 26.46%-62.61% and 5.51%-23.25% for the nitrogen and phosphorus treatments, respectively. The vertical distribution of SOC, EOC, DOC and POC contents under all nitrogen and phosphorus treatments was highest in the 0-20 cm soil layer and tended to decrease with increasing depth of the soil layer. The MBC content was highest in the 10-30 cm soil layer. DOC/SOC, MBC/SOC (excluding N0P1 treatment) and POC/SOC were all higher in the 0-40 cm soil layer of the alfalfa field compared to the N0P0 treatment, indicating that the nitrogen and phosphorus treatments effectively improved soil fertility, while EOC/SOC and DOC/SOC were both lower in the 40-60 cm soil layer than in the N0P0 treatment, indicating that the nitrogen and phosphorus treatments improved soil carbon sequestration potential. The soil layer between 0-30 cm exhibited the highest sensitivity index for MBC, whereas the soil layer between 30-60 cm had the highest sensitivity index for POC. This suggests that the indication for changes in SOC due to nitrogen and phosphorus treatment shifted from MBC to POC as the soil depth increased. Meanwhile, except the 20-30 cm layer of soil in the N0P1 treatment and the 20-50 cm layer in the N1P0 treatment, all fertilizers enhanced the soil Carbon management index (CMI) to varying degrees. Structural equation modeling shows that nitrogen and phosphorus indirectly affect SOC content by changing the content of the active organic carbon fraction, and that SOC is primarily impacted by POC and MBC. The comprehensive assessment indicated that the N1P2 treatment was the optimal fertilizer application pattern. In summary, the nitrogen and phosphorus treatments improved soil fertility in the 0-40 cm soil layer and soil carbon sequestration potential in the 40-60 cm soil layer of alfalfa fields. In agroecosystems, a recommended application rate of 120 kg·ha-1 for nitrogen and 100 kg·ha-1 for phosphorus is the most effective in increasing SOC content, soil carbon pool potential and alfalfa hay yield
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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.