Internal Cycling Research Articles

ТИПОЛОГІЯ ІНТЕРТЕКСТУАЛЬНИХ ЗВ’ЯЗКІВ У ПОСТМОДЕРНІСТСЬКОМУ ДИСКУРСІ: ТЕКСТУАЛЬНІ, КОНТЕКСТУАЛЬНІ Й МЕТАТЕКСТУАЛЬНІ ВПЛИВИ

Artistic texts as products of individual authorial creative work, formed as a result of interaction with previous texts – with literary and cultural heritage, require a systematic linguistic study. They enter into a dialogue with the semiosphere both at the moment of generation, and in the process of their reading, perception and understanding. The organization of the artistic text structure occurs with the help of intertextual connections in conceptual and linguistic forms. Thus, the study and understanding of the artistic text involves the research of the conceptual and language picture of the writer’s world, the linguistic representation of intertextual connections. In postmodern artistic texts, pretexts are recoded, instead, intertextual forms, harmoniously combined and mutually rethought, create the idiostyle profile. Each writer has his own vocabulary, favorite themes and images that define internal cycles in his creative work, which cannot be contained within precise chronological boundaries. Currently, there is a revival of attention to the scientific study of intertextual relations specifics in postmodern discourse, as well as a general gravity tendency of the humanitarian paradigm of knowledge to the cognitive and communicative analysis of textual communication, in particular, the influence of postmodernism on modern post-industrial communicative culture, which finds expression in the artistic speech aesthetics. The use of the concept “the author’s consciousness” is necessary in the study of the communicative, cognitive, informative and emotional integrity of the text. The modeling of the writer’s consciousness with the help of intertextual connections with other texts is based on the ideas of cognitive linguistics.

Are bog plant/lichen tissue concentrations of Ca, Mg, K, and P affected by fugitive dust released from oil sands development in the Fort McMurray region of Alberta?

Bogs are ombrotrophic, relying solely on atmospheric deposition for new inputs of elements. Increased element deposition through anthropogenic activities has the potential to alter nutrient availability, and hence ecosystem function, in bogs. Further, because of efficient element retention, bogs may function as effective monitors of element deposition. To assess the potential effects of particulate fugitive dust from oil sands development in Alberta, Canada, we quantified plant/lichen tissue Ca, Mg, K, and P concentrations in 6 bogs ranging from 12 to 77 km from the oil sands industrial center. Deposition of Ca and Mg, but not K or P, quantified using ion exchange resin collectors, to bogs decreased with distance from the oil sands industrial center. Concentrations of Ca and Mg, but not K or P, in tissues of lichens (Cladonia mitis, Evernia mesomorpha) and Sphagnum (S. capillifolium, S. fuscum) decreased with distance from the oil sands industrial center. Tissue Ca concentrations were positively correlated with growing season Ca and Mg deposition in all species except Vaccinium oxycoccos, Rhododendron groenlandicum, and Picea mariana; leaf Mg concentrations were positively correlated with growing season Mg deposition for all species except P. mariana. Tissue concentrations of K and P were not correlated with growing season K and P deposition. For each species, receptor modeling identified two distinct sources, one dominated by Ca and Mg, presumed to represent particulate fugitive dust from oil sands activities, and a second dominated by K and P, which may reflect tight internal cycling and upward translocation of K and P in peat and/or K and P deposition as particulates generated in wildfires. Increasing Ca2+ and Mg2+ deposition may acidify bog porewaters through cation exchange in peat.

Strategy for Improving the Quality of Islamic Religious Education Study Programs with Total Quality Management

This article aims to find a strategy to improve the quality of the Islamic Religious Education Study Program with Total Quality Management at Islamic Religious Colleges. The method used in this article is qualitative descriptive by describing the existing phenomena. The results showed that the strategy for implementing Total Quality Management in the Islamic Religious Education Study Program, University of Muhammadiyah Malang, began with improving the learning program, providing an Education Laboratory, Arabic and English laboratory, both manual and digital libraries, revamping and repairing ideal infrastructure and facilities, learning facilities. complete, innovative, creative, and fun learning methods, training for lecturers and students, as well as distribution of graduates through the job market. Improvements were made based on data from a questionnaire to students. The strategy for improving the quality of the Islamic Religious Education Study Program with Total Quality Management is for the leaders of the University of Muhammadiyah Malang who are quality-oriented, both input, process, and output by relying on cooperation, stakeholders, both staff and staff lecturers, human resource development, strengthening the body. Quality assurance, implementation of the internal quality audit cycle, management review in Management Review Meetings, formulation and updating of strategic plans and operational plans. Thus the Islamic Religious Education Study Program, University of Muhammadiyah Malang has implemented Total Quality Management to improve quality. This can be seen from various achievements and accreditations at regional, national and international levels.

Redeploy manure resources to enhance the agro-pastoral cycle

Returning manure to the land is a critical link in the internal cycle of agricultural systems, but excess manure leads to water eutrophication. The traditional manure re-use method brings pathogenic microorganisms, heavy metals, antibiotic resistance genes (ARGs), insect eggs, and other contaminants into the soil, posing a great threat to the ecological environment and human health. Clarifying the spatial distribution patterns of manure nutrient supply and farmland nutrient demand can help guide a more efficient and harmless way to return manure to farmland. This work counted data on cultivation and breeding in 356 cities on the Chinese mainland from 2015 to 2019 and calculated the livestock breeding volume (LB), total environmental capacity (C), and remaining environmental capacity (RC) accordingly. The Spatial Autocorrelation Model (SAC) was used to analyze the distribution patterns of the three. Data results show that China currently has the potential to double LB, but most cities in the west have excess manure due to the mismatched distribution of LB and C. The hot spot analysis results demonstrate the priority/general areas of manure management and the export/import areas of manure resources. The results of the outlier analysis show that some cities located at the boundary of RC Cold/Hot spot areas (e.g., Chengdu City) can perform resource replacement nearby to relieve local environmental pressure. This study analyzes the potential and realistic resistance to utilizing manure as an organic nutrient resource and provides a reference for developing manure management links.

Seasonally driven internal P and N nutrient (re)cycling strategies of beech saplings are element specific

Excessive N deposition leads to the conversion of previously N limited to N saturated forest ecosystems. The input of N can result in severe N/P imbalance and N-induced P deficiency. The present study investigates whether N addition induces P deficiency in beech saplings or if this can be counteracted by enhanced internal P (re)cycling. Furthermore, it was tested whether addition of P can mitigate N induced P deficiency. In addition, higher need of P due to enhanced growth may be realized either by enhanced P uptake or by improved internal P (re)cycling. This assumption was tested with beech saplings growing at higher light intensity. Therefore, a mesocosm approach with beech saplings and soil (O and A horizon) originating from a P-poor forest was conducted. Mesocosms were cultivated for two growing seasons in a garden. Addition of N, P, or combined addition of N and P took place during the first year and another group of saplings was exposed to higher light intensity to enhance CO 2 assimilation and growth. Soil horizons and beech saplings were harvested during the second year of growth in spring, summer, autumn, and winter. The results show that internal (re)cycling of N and P is different and mostly determined by the season. The seasonal (re)cycling of P was driven by the metabolic P demand of tissues/organs characterized by shifting P between the perennial tissues bark and wood of branches and coarse roots and deciduous leaves, fine roots and long-distance transport paths without using major storage resources. In contrast, seasonal (re)cycling of N is characterized by N storage in perennial tissues during dormancy and by N mobilization from the entire trunk, i.e. branch, stem and coarse roots, in spring. Furthermore, these seasonal dynamics were found to be independent of the treatment. • P (re)cycling comprises the shift of P to the places of demand without P storage. • N storage and re-mobilization characterizes saplings seasonal (re)cycling of N. • High light induces N deficiency but sufficient P supply sustained by P (re)cycling. • N/P ratios used as indicator of nutrient imbalance show large seasonality. • Missing root establishment in the Of+Oh prevents P improvement of saplings.

Contribution of the Precipitation‐Recycling Process to the Wetting Trend in Xinjiang, China

AbstractXinjiang, China has experienced a significant wetting trend since the mid‐1980s in the context of climate warming. However, the features and mechanism associated with the water cycles in this region remain unclear. In this study, the contributions of the precipitation‐recycling process to the wet‐season (May‐August) wetting trend are investigated using a dynamic recycling model and the Modern Era Retrospective analysis for Research and Application version 2 reanalysis product from 1982 to 2020. The results show that the mean precipitation recycling ratio is 37.91%, implying that Xinjiang precipitation is mainly contributed by external moisture. Moreover, the recycling ratio exhibits a significantly increasing trend of 2.29% per decade, and this increased recycled precipitation contributes 55.55% to the wet‐season wetting trend in Xinjiang. The amount of externally advected moisture transported to Xinjiang has also increased in recent decades, accounting for 44.45% of the wetting trend. Further analysis reveals that a deepening anomalous trough over Central Asia accompanied by strengthening moisture inflow through the southwest and south boundaries induce the increased inflow of moisture to Xinjiang, thereby increasing external‐cycle precipitation in Xinjiang. Along with the strengthened ascending movement in the lower troposphere, the increasing atmospheric moisture content induced by enhanced evapotranspiration is beneficial for recycling precipitation in Xinjiang. These results imply that both the internal and external water cycles deserve further attention when exploring the wetting phenomenon in Xinjiang.

Drainage Ditch Cleaning Has No Impact on the Carbon and Greenhouse Gas Balances in a Recent Forest Clear-Cut in Boreal Sweden

Ditch cleaning (DC) is increasingly applied to facilitate forest regeneration following clear-cutting in Fennoscandinavia. However, its impact on the ecosystem carbon and greenhouse gas (GHG) balances is poorly understood. We conducted chamber measurements to assess the initial DC effects on carbon dioxide (CO2) and methane (CH4) fluxes in a recent forest clear-cut on wet mineral soil in boreal Sweden. Measurements were conducted in two adjacent areas over two pre-treatments (2018/19) and two years (2020/21) after conducting DC in one area. We further assessed the spatial variation of fluxes at three distances (4, 20, 40 m) from ditches. We found that DC lowered the water table level by 12 ± 2 cm (mean ± standard error) and topsoil moisture by 0.12 ± 0.01 m3 m−3. DC had a limited initial effect on the net CO2 exchange and its component fluxes. CH4 emissions were low during the dry pre-treatment years but increased particularly in the control area during the wet years of 2020/21. Distance to ditch had no consistent effects on CO2 and CH4 fluxes. Model extrapolations suggest that annual carbon emissions decreased over the four years from 6.7 ± 1.4 to 1.6 ± 1.6 t-C ha−1 year−1, without treatment differences. Annual CH4 emissions contributed <2.5% to the carbon balance but constituted 39% of the GHG balance in the control area during 2021. Overall, our study suggests that DC modified the internal carbon cycling but without significant impact on the carbon and GHG balances.

Internal Heat Exchanger Influence in Operational Cost and Environmental Impact of an Experimental Installation Using Low GWP Refrigerant for HVAC Conditions

The use of an internal heat exchanger in vapor compression refrigeration systems of one stage is a common practice because it helps to increase the cooling capacity in the evaporator. Furthermore, the use of refrigerants with low global warming potential is becoming more frequent due to environmental regulations worldwide. Thus, this paper presents an evaluation of the improvement produced by the inclusion of an internal heat exchanger cycle (IHXC) in an experimental installation from the viewpoint of exergy, economic and environmental through to exergy, exergoeconomics, and Specific Life Cycle Climate Performance (SLCCP) studies. The tests were conducted using R1234ze(E) as a replacement alternative to R134a in three evaporating temperature conditions: 4 °C, 9 °C, and 14 °C. Comparisons were made considering R134a in BRC mode versus R1234ze(E) in BRC and IHXC modes. Results show that a lower environmental impact is produced by an evaporating temperature of 14 °C with a reduction in SLCCP of 13.3% using IHXC and R1234ze(E). Moreover, the highest increase in exergy efficiency was observed for an evaporating temperature of 4 °C, with this increase being 9%, while the lowest increase in the total cost rate was observed for the same evaporating temperature, being 12.3% and 21.2% for BRC and IHXC modes using R1234ze(E), respectively.

Effect of Carbon-Coating on Internal Resistance and Performance of Lithium Iron Phosphate Batteries

In this paper, the LiFePO4 material was modified by carbon coating using polyvinyl alcohol (PVA) and Ketjen black as the composite carbon sources. Firstly, the structure, electron and ion transport properties of LiFePO4 and carbon-coated LiFePO4 were calculated by first-principles and density functional theory. The calculation results show that after carbon coating, the coating system will change from semiconductor properties to conductor properties, and its electronic conductivity will be significantly improved. Then, different proportions of Ketjen black and PVA (polyvinyl alcohol) were mixed to prepare a composite carbon source, which was then coated with carbon on the surface of the LiFePO4 cathode material. The prepared LiFePO4/C samples were characterized by XRD, SEM, physical properties and electrochemical properties. The 14500 cylindrical steel shell battery was prepared by using lithium iron phosphate materials coated with different carbon sources. By testing the internal resistance, rate performance and cycle performance of the battery, the effect of carbon coating on the internal resistance of the battery and the electrochemical performance of the full battery was studied and analyzed. The experimental results show that when Ketjen Black:PVA = 2:1, the synthesized LiFePO4/C cathode material exhibits the best rate performance and cycle stability. The compaction density of the pole piece is reduced, the internal resistance of the battery is reduced, and the electrochemical performance of the battery is improved.

Optimal thermal management of server cooling system based cooling tower under different ambient temperatures

• A new model is introduced to analyze year-round cooling system power consumption. • Optimal water operation conditions under different ambient temperatures are given. • Year-round energy consumption analysis is done by taking Tianjin as a study case. • Significant year-round cooling power can be saved by optimizing thermal parameters. To develop a highly efficient and energy-saving cooling system in a data center, this study investigates the optimal thermal management both on the internal server cooling cycle and external cold source water cycle under different ambient temperatures based on the principle of minimal power consumption. Taking a server cabinet of 4.8 kW as the case, an internal indirect water-cooled heat sink cycle and an external cooling tower cold source cycle are constructed. A hybrid thermal management model combined with a heat dissipation model and a power consumption model was developed with the aid of MATLAB and TRNSYS. Using this model, the relationship between the chip dissipation performance attached to the fin-type heat sink and the energy consumption performance of the cooling system under different water working conditions and ambient temperatures was analyzed. Finally, to achieve minimal system energy consumption, the optimized inlet temperature and water flow rates corresponding to different ambient temperatures were obtained by fitting expressions that can better serve the optimal design of data center cooling systems. Furthermore, when the optimal value was applied using the year-round temperature of Tianjin, China in the case study, a 21.3% reduction in power consumption and a 4.43% decrease in the power usage effectiveness can be achieved compared to the case without optimization. Therefore, significant power can be saved in a data center cooling system through thermal management optimization.

Vertical Flux of Trace Elements Associated With Lithogenic and Biogenic Carrier Phases in the Southern Ocean

AbstractTrace elements (TE) are tracers of multiple biotic and abiotic processes in the ocean and some of them are essential for marine life. Vertical export by particles is a major removal process of a large fraction of TE from the surface ocean. However, the seasonal export dynamics and its controlling factors, critical for the understanding of the internal TE cycling, remain poorly constrained. Here, we report and discuss the seasonal export of 15 TE in sinking particles collected by a sediment trap deployed in a highly productive region of the Southern Ocean. Basalt material was the main carrier phase for the export flux of 9 TE, and its dynamic was characterized by a strong decrease over time. TE export driven by biological carriers such as diatom spores and vegetative cells added pulsed seasonal dynamics to the lithogenic signal, while the contribution of fecal pellets was less variable over the season. For each TE, we were able to decipher the biological carrier phases that represent the most dominant export pathway. We discuss this partitioning with regards to the known metabolic functions of the different trace metals or TE of biological interest.

Measuring the Intermediate Goods’ External Dependency on the Global Value Chain: A Case Study of China

In the face of the anti-globalization trend and the shrinking of the global value chain, ensuring the safety of the global layout of the industrial chain and the sustainability of each country’s internal intermediate product production cycle has become an important new development strategy for all countries. The sustainability of the internal and external cycles of production systems is closely related to global value chains. Based on the world input-output model, we define the trade pattern of intermediate goods in various countries from the perspective of trade intermediary attributes, and propose two indicators by which to measure the dependence of China on the global value chain in the process of “dual circulation” development: the degree of vertical specialization (VSD) and the import share of domestic total consumption (IMS); China’s super-large market leads to low values of both VSD and IMS. China’s high-tech industry has the highest degree of external dependence in the process of participating in dual circulation, and there has been a fluctuation cycle since 2009. The external dependence of different industries shows heterogeneity.

Bottom boundary layer mixing processes across internal seiche cycles: Dominance of downslope flows

AbstractIn a stratified lake, where an internal seiche maintained an oscillating bottom boundary layer (BBL), processes including strain‐induced periodic stratification (SIPS), a downslope mean flow, and upslope‐propagating internal waves controlled fluctuating BBL mixing rates. To investigate these processes, high‐resolution temperature and velocity profiles were measured within 2 m of the sloping bed, through more than 100 cycles of upslope and downslope flows. The associated seiche‐induced velocity reversals coincided with the arrival of upslope‐propagating cold fronts. Although fronts are sometimes associated with internal wave breaking, in this lake the measured frontal slopes were small and breaking did not occur. When fronts were not propagating past instruments, near‐bed stratification was consistent with SIPS, being intensified by downslope flows and reduced by upslope flows. Owing to a downslope near‐bed mean flow, which was previously shown to cancel an upslope internal‐wave Stokes drift, peak downslope velocities regularly exceeded peak upslope velocities. Given these strong downslope velocities, turbulent dissipation rates were most intense during downslope phases. Therefore, during downslope flow, creation of stratification by SIPS coincided with elevated dissipation, creating conditions for effective mixing. Correspondingly, two simple parameterizations for mixing efficiency suggest that most of the total near‐bed buoyancy flux (≥ 82%), and most of the irreversible flux (87%), occurred during the downslope‐flow phase of internal seiche cycles. The observed mechanism for dominant mixing during downslope flow has potential to act in other environments where internal waves propagate up sloping beds.

River-Lake States in the Tributary of the Three Gorges Reservoir Area and Their Effects on the Phosphorus Content of Different Forms in the Sediment

The unique operation mode of the Three Gorges Dam has determined that the tributaries of the Three Gorges Reservoir (TGR) are significantly different from natural rivers in terms of hydrodynamics. The aim of this study was to explore the dynamic changes of internal phosphorus in tributary sediments under special water transfer mechanisms in the reservoir area. In 2016, we conducted samplings eight times (January, March-August, and October, once a month) in the Gaoyang Lake, which is located in the middle section of the Pengxi River, the largest tributary in the northern bank of the TGR. Samples of the adjacent overlying (AOL) water and sediment were collected, and a series of analyses were carried out on the flow velocity, water depth, and alkaline phosphatase activity (APA) of sediments. The results indicated that the waterbody types of the Gaoyang Lake can be divided into two hydrological states:deep lakes before May and June and typical rivers from May and June until the Three Gorges Dam re-flooding in autumn. The concentration of dissolved phosphorus in the AOL water during the lake state was 42.48% higher than that in the river state, which was beneficial for the weakly bounded phosphorus (NH4Cl-P) in the sediment surface to be in an adsorption-releasing equilibrium state. At the beginning of the spring algal bloom, with the increase in water temperature and APA in the sediments, the content of potential mobile phosphorus (PMP) in the sediments increased; however, the stable-form phosphorus content decreased, showing a tendency of transformation between these two forms of phosphorus, which may be one of the available phosphorus sources for algal blooms. The stable-form phosphorus content in the sediments of the Gaoyang Lake accounted for approximately 81.79% of the total phosphorus content, its coefficient of variation was relatively small (2.90%-4.21%), and there was a significant trend of accumulation over time (P<0.05). The study revealed the transformation of different phosphorus forms in sediments and their relationship with the state shift of the waterbodies, and provided a reference to understand the internal phosphorus cycle in other tributaries of the TGR area or other reservoir tributaries under similar situations.

Enviro-economic investigation of various flare gas recovery and utilization technologies in upstream and downstream of oil and gas industries

The flaring network is an inseparable part of the oil, gas, and petrochemical industries to provide safe and reliable operating conditions. Since flaring results in significant greenhouse gas emissions and economic loss, over the last decade, different processes have been developed to recover and utilize flare gas in upstream and downstream of oil and gas industries. According to the wide range of flare and associated gas specifications, all flare gas recovery and utilization technologies are not always feasible and economically justified. Since performing a detailed analysis on all available recovery processes is time-consuming, a guideline for an initial screening and crossing out unattractive economic options for a specific flare gas would be beneficial. In the current research, for seven flare gas recovery and utilization technologies (compression and reinjection to well, natural gas liquids, gas to liquids, methanol and dimethyl ether production, liquefied natural gas, and power generation using reciprocating internal combustion engine cycle) and sixteen flare and associated gas samples economic analysis has been carried out. The results indicate that power generation using the reciprocating internal combustion engines is economically justifiable for an extensive range of flare gas specifications. The calculation of CO2 emissions shows that by using flare gas recovery and utilization technologies, the CO2 emission can be reduced by 50–90% compared to the flare stack. According to the results obtained in this study, some guidelines are provided for an initial screening on the flare gas recovery and utilization technologies.

A high efficiency zero-emission argon split cycle engine

The argon Otto cycle engine concept is a new approach to achieve both high efficiency and zero emissions. The high specific heat ratio (γ) of argon delivers an efficiency uplift relative to conventional air breathing engines. However, the high γ also results in high end of compression temperature and high risk of pre-ignition (knock). This limits the compression ratio (CR) and hence thermal efficiency (η) of an argon engine. The split cycle is a novel internal combustion engine thermodynamic cycle which yields high thermal efficiency under low CR conditions. In this paper, we propose a new engine concept combining the merits of both argon engine and split cycle engine. A theoretical analysis was conducted to investigate the fundamental operating mechanisms of the argon split cycle engine (ASCE). Experiments were undertaken to measure combustion parameters such as heat release with an argon-oxygen-hydrogen mixtures. A one-dimensional engine model was constructed and validated using the test results. Optimisation of the ASCE using the 1D validated simulation showed that a maximum 75% of the exhaust energy can be recovered in the ASCE. Compared to an engine with a conventional Otto cycle, the ideal thermal efficiency of ASCE with a CR = 6 is equal to an Otto cycle argon engine with a CR = 27. Consequently, an indicated thermal efficiency of 66% can be expected in a practical ASCE with low compression ratio (CR = 6).

Robust Instant Angle Speed Measurement for Internal Combustion Engines-A Novel Sensing Suite and Methodology.

This paper presents the development and implementation of a novel robust sensing and measurement system that achieves fine granularity and permits new insights into operation of rotational machinery. Instant angle speed measurements offer a wealth of useful information for complex machines in which the motion is the result of multidimensional, internal, and external interactions. The implementation of the proposed system was conducted on an internal combustion engine. The internal combustion engine crankshaft’s angular velocity is the result of the integration of all variables of motor and resisting forces. The crankshaft angular velocity variation also reflects the interaction between the internal thermodynamic cycle of the engine and the plant it powers. To minimise the number of variables, we used for our experiments an aero piston engine for small air-vehicles—a well-made and reliable powerplant—connected to a propeller. This paper presents the need for a better sensing and measurement system. Then, we show the development of the system, the measurement protocol and process, recording and analysis of the data, and results of some experiments. We then demonstrate the possibilities this sensing suite can achieve—a deeper insight into the operation of the machine—by performing high-quality analyses of engine cycles, well beyond capabilities in the state of the art. This system can be generalised for other rotational machines and equipment.

Seasonal phosphorus and nitrogen cycling in four Japanese cool-temperate forest species

PurposeIn plant-soil systems, phosphorus partitioning during the annual cycle related to nitrogen partitioning remains largely unknown. The present study aims at assessing the soil-plant P allocation patterns of four tree species along four phenological stages and its relationship with tissues and soil N concentrations.MethodsCryptomeria japonica, Larix kaempferi, Fagus crenata and Robinia pseudoacacia trees were selected to sample coarse roots, sapwood, foliage, litter and soil during four phenological stages where total and Olsen extractable P and nitrogen content were measured respectively.ResultsIntra- and inter plant tissue nitrogen correlated well with phosphorus during the four phenological stages, especially root nitrogen. Fagus and Robinia were phosphorus limited, Larix was nitrogen limited and Cryptomeria co-limited. All species reabsorbed phosphorus and nitrogen from foliage prior to leaf abscission and stored nitrogen in roots and sapwood. Phosphorus storage was solely found in sapwood of Robinia. Soil dissolved ammonium correlated positively with nitrogen reabsorption efficiency during the green leaf stage, while single soil nutrient variables did not correlate with phosphorus reabsorption efficiency.ConclusionsPlant tissues nitrogen partitioning correlated well with their respective phosphorus partitioning and the increase of soil NH4+ correlated positively with nitrogen reabsorption efficiency, regardless of tree species during the green leaf stage. The results of this study show the intricate relationship that exists between nitrogen and phosphorus in the soil-plant continuum as well as the tree species specific internal cycling of these nutrients.

AAIM Recommendations to Improve Learner Transitions

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Phosphorus Dynamics in Clementine Mandarin

ABSTRACT The study sought to investigate the internal cycling of phosphorus (P) in Clementine mandarin (Citrus reticulata Blanco “Clementine”). The biomass formation, P concentration, P uptake and accumulation of different organs (bud, flower, fruit, leaf and branches) identified as active organs and found on 1-year-old shoots on fruit trees of bearing age were periodically examined for 2 years. The biomass value was similar between both production seasons. At the beginning of shoot activity, the biomass of annual shoots had a very low rate in the total biomass (0.4%). The biomass increased from 9.7 kg/tree at the beginning of the production season to 62.8 kg/tree at harvest. The P concentrations were in the ranges of 0.11–0.22% in the branches of <1-year-old shoots throughout the 2 years, 0.07–0.15% in the branches of 1-year-old shoots, 0.17–0.31% in the leaves of <1-year-old shoots and 0.13–0.26% in the fruits of <1-year-old and 1-year-old shoots. The total P accumulation at harvest was 82 and 107 g/tree in the first and second years for <1-year-old shoots, respectively, while it was 44 and 48 g/tree for 1-year-old shoots, in the first and second years respectively. The mean daily P uptake amount was determined as 0.4 g/tree for both production years, and the highest daily P accumulation amount was between the fifteenth and twenty-eighth days for both production seasons.