Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Effect of Varying Dairy Cow Size and Live Weight on Soil Structure and Pasture Attributes(MDPI (Basel, Switzerland), 2025-10) Negrón M; López IF; Dörner J; Cartmill AD; Balocchi OA; Saldivia E; Bellocchi GGrazing systems’ production efficiency is a dynamic interaction between soil, pasture, livestock, and climate. The magnitude of the changes is related to the mechanical stress applied by the livestock and their feeding behaviour. In Southern Chile, dairy cattle present a high heterogeneity in breeds, size, live weight, and milk production. This study investigated whether cows of contrasting size/live weight can improve degraded pasture and positively modify soil (Andosol-Duric Hapludand) physical features. Three pasture types were used as follows: (i) cultivated fertilised Lolium perenne L. (perennial ryegrass) and Trifolium repens L. (white clover) mixture (BM); (ii) cultivated fertilised L. perenne, T. repens, Bromus valdivianus Phil. (pasture brome), Holcus lanatus L. (Yorkshire fog), and Dactylis glomerata L. (cocksfoot) mixture (MSM); and (iii) naturalised fertilised pasture Agrostis capillaris L. (browntop), B. valdivianus, and T. repens (NFP). Pastures were grazed with two groups of dairy cows of contrasting size and live weight: light cows (LC) [live weight: 464 ± 5.4 kg; height at the withers: 132 ± 0.6 cm (average ± s.e.m.)] and heavy cows (HC) [live weight: 600 ± 8.7 kg; height at the withers: 141 ± 0.9 cm (average ± s.e.m.)]. Hoof area was measured, and the pressure applied by cows on the soil was calculated. Soil differences in penetration resistance (PR) and macro-porosity (wCP > 50 μm) between pastures were explained by tillage and seeding, rather than as a result of livestock presence and movement (animal trampling). The PR variation during the year was associated with the soil water content (SWC). Grazing dairy cows of contrasting live weight caused changes in soil and pasture attributes, and they behaved differently during grazing. Light cows were linked to more intense grazing, a stable soil structure, and pastures with competitive species and greater tiller density. In MSM, pasture consumption increased, and the soil was more resilient to hoof compression. In general, grazing with heavy cows in these three different pasture systems did not negatively impact soil physical properties. These findings indicate that volcanic soils are resilient and that during renovation, the choice of pasture type has a greater initial impact on soil structure than the selection of cow size, but incorporating lighter cows can be a strategy to promote denser pasture swards in these grazing systems.Item Measuring Herbage Mass: A Review(MDPI (Basel, Switzerland), 2025-10-01) Susruthan V; Donaghy DJ; Kenyon PR; Sneddon NW; Cartmill AD; Bellocchi GThe accurate measurement of herbage mass is essential for feed budgeting and the management of sustainable and profitable grazing systems. There are many techniques available to estimate herbage mass in pastoral systems, and these vary in accuracy, cost, and time taken to implement. In situ and remote sensing techniques are both associated with moderate to high error, as herbage mass is affected by a number of dependent and independent factors, including sward composition, soil structure, chemical characteristics and moisture levels, climatic conditions, and grazing management, which must be considered in the development of an accurate local calibration model for precise estimation of herbage mass. This review provides an overview of commonly used herbage mass assessment techniques and describes their limitations, synergies, and trade-offs, and also covers the integration of new technologies which have the potential to monitor pastures at scale. This review highlights the need for further research and to integrate new technologies for accurate and precise measurement of herbage mass, noting the lack of calibration with in situ methods, the need for development of new protocols for assessment, variance in equipment and software compatibility, and the need to evaluate the effectiveness of methods/techniques on a variety of livestock operations for extended periods.Item 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 QAccurate 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.Item 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 YDecreasing 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.Item 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 KIntroduction: 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.Item Daily Light Integral and Nutrient Solution Electrical Conductivity for Tomato and Bell Pepper Seedling Production in an Indoor Vertical Farm with Artificial Lighting(MDPI (Basel, Switzerland), 2025-05-01) Adame-Adame DY; Alvarado-Camarillo D; Valdez-Aguilar LA; Cartmill AD; Cartmill DL; Soriano-Melgar LDAA; Yang QIndoor vertical farms (IVFs) provide the conditions for producing seedlings of good quality. However, their effectiveness depends on the daily light integral (DLI) and nutrient management. This study examined the effects of DLI and nutrient solution electrical conductivity (EC) on tomato and bell pepper seedlings produced in an IVF or a greenhouse. Seedlings in the greenhouse were harvested 45 (tomato) and 55 (bell pepper) days after sowing, while those in the IVF were harvested after 30 and 40 days, respectively. The optimal EC was 2.0 for tomato and 2.4 dS m−1 for bell pepper. Tomato seedlings showed a decreased shoot-to-root ratio in the IVF. Tomatoes in the IVF reached 241% higher total biomass than greenhouse seedlings at 31.7 mol m−2 d−1, while bell peppers had an increase of 333% at 39.6 mol m−2 d−1; however, a DLI of 23.7 mol m−2 d−1 was enough to cause an increase of 153% and 264%, respectively. Nutrient concentration decreased in IVF seedlings, which was attributed to a dilution effect; in contrast, the nutrient content of tomato and bell pepper were highest when grown in the IVF when irrigated with solutions at 2.0 dS m−1 and a DLI of 31.7 mol m−2 d−1.Item 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 MThe 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.Item Make African grasslands climate-change resilient(Springer Nature Limited, 2025-02-14) Akpensuen TT; Cartmill AD; Pérez-Márquez S; Sheridan H; Lee MRF; Rivero MJClimate change has negatively impacted grassland productivity in Africa. Climate-smart technologies such as forage grass, legume, and herb mixtures could enhance grassland productivity and resilience, offering a sustainable solution for African pasture-based livestock systems.Item 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 AKThe 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.Item 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 QRepeated 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.