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Roopa Jammula e Syeda Nishat Fathima. "Balancing act: Understanding nutrient interactions". World Journal of Biology Pharmacy and Health Sciences 18, n. 3 (30 giugno 2024): 243–47. http://dx.doi.org/10.30574/wjbphs.2024.18.3.0346.
Testo completoAbstract (sommario):
Nutrient interactions refer to the dynamic relationship between various nutrients, including minerals, vitamins, amino acids, and fatty acids, for proper functioning. An excess or deficiency of one nutrient can affect the requirements for many others, and increasing or decreasing a deficient nutrient may require an increase in other nutrients. Many nutrients require other nutrients to convert into other forms, and chemical combinations or reactions between nutrients can change their biological availability. Direct metabolic requirements of one nutrient can change the biological activity of another. Structurally similar nutrients can compete for absorption and utilization, and one nutrient can replace another with a different action. This review deals with different types of interaction observed in between dietary carbohydrates, dietary proteins and dietary fats.
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Mattson, Neil S., e Marc W. van Iersel. "Application of the “4R” Nutrient Stewardship Concept to Horticultural Crops: Applying Nutrients at the “Right Time”". HortTechnology 21, n. 6 (dicembre 2011): 667–73. http://dx.doi.org/10.21273/horttech.21.6.667.
Testo completoAbstract (sommario):
The 4R nutrient stewardship framework presents four concepts to consider when applying fertilizers in a responsible matter; the “right source” of nutrients should be applied at the “right rate” during the “right time” and supplied to the “right place” to ensure their uptake. In this article, we provide ideas to consider when attempting to provide nutrients at the right time. When nutrients are applied at a time when they are not required by the plant, the result can be economic and environmental losses. Oversupply relative to plant demand can result in losses of applied nutrients because of leaching or volatilization. Undersupply relative to demand, especially in the case of phloem-immobile nutrients, may limit plant growth and yield. Several factors interact to affect plant nutrient demand such as growth stage, life history (annual vs. perennial), environmental conditions, and plant health. Techniques such as soil and tissue testing, isotopic labeling, and spectral reflectance have been used with varying degrees of success and expense to measure plant nutrient demand and guide fertilizer decisions. Besides knowledge of plant nutrient demand, efficient nutrient supply also depends on systems that allow precise spatial and temporal delivery of nutrients. Future improvements to the timing of nutrient delivery will depend on improvement in knowledge of plant nutrient demands. For example, targeted gene expression chips show promise for use in rapidly assessing plant status for a broad suite of nutrients. Future developments that allow more precise nutrient delivery or more robust agroecosystems that scavenge available nutrients before they are lost to the environment will also help producers use nutrients more efficiently.
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Meirinawati, Hanny, e A'an Johan Wahyudi. "Deepening Knowledge of Nutrient Dynamics in Coastal Waters". ASEAN Journal on Science and Technology for Development 39, n. 1 (28 aprile 2022): 23–33. http://dx.doi.org/10.29037/ajstd.747.
Testo completoAbstract (sommario):
Nutrients are important compounds in waterbodies that regulate primary productivity and phytoplankton growth, the basis of food webs. Increased nutrient concentration has become a serious concern because it causes eutrophication and threatens the sustainability of ecosystems. Eutrophication is the process of nutrient enrichment in water bodies that affects their productivity and decreases water quality. Although information about nutrient distribution, limiting nutrients, and nutrient budgets is important for coastal water management, studies of wide-scale nutrient dynamics in Indonesian waters remain limited. To provide comprehensive data on nutrients, this review summarized the concentrations and compositions of nutrients in coastal waters, compared the limiting nutrients in various coastal waters based on the Redfield ratio, and described the factors affecting nutrient budgets using the database in ScienceDirect and Google Scholar. Curation was performed to summarize the nutrient dynamics in coastal waters. Results showed that nutrient concentration differed in each region due to many factors. Anthropogenic inputs greatly affected nutrients in tropical areas, such as Jakarta Bay (Indonesia). Understanding the quality and characteristics of water can help in managing waterbodies. This study provided knowledge related to nutrient dynamics in Indonesian waters and global biogeochemistry.
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Bugbee, Bruce. "284 Towards Efficient Nutrient Management in Recirculating Hydroponic Culture". HortScience 34, n. 3 (giugno 1999): 491C—491. http://dx.doi.org/10.21273/hortsci.34.3.491c.
Testo completoAbstract (sommario):
There is an increasing need to recirculate and reuse nutrient solutions to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Some authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is unnecessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance. During the past 18 years, we have managed nutrients in closed hydroponic systems according to the principle of “mass balance,” which means that the mass of nutrients is either in solution or in the plants. We add nutrients to the solution depending on what we want the plant to take up. Plants quickly remove their daily ration of some nutrients while other nutrients accumulate in the solution. This means that the concentrations of nitrogen, phosphorous, and potassium can be at low levels in the solution (<0.1 mM) because these nutrients are in the plant where we want them. Maintaining a high concentrations of some nutrients in the solution (especially P, K, and Mn) can result in excessive uptake that can lead to nutrient imbalances.
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Bagale, Suman. "Nutrient Management for Soybean Crops". International Journal of Agronomy 2021 (6 settembre 2021): 1–10. http://dx.doi.org/10.1155/2021/3304634.
Testo completoAbstract (sommario):
Soybean is one of the most important pulse crops in the world which supplies most of the protein and oil requirements. The efficient production of soybean crops is a constraint, with several biotic factors, abiotic factors, and crop management practices. Nutrient management is one of the important aspects for achieving higher production of crops. Effective nutrient management helps to assure the required nutrients needed for the plant without causing a significant decrease in the yield of crops. In addition to this, managing the nutrient efficiently helps the crop to cope with several types of biotic and abiotic stress. For soybean crop, altogether fifteen nutrients are needed, which comprises six macronutrients, namely, nitrogen, phosphorous, potassium, calcium, magnesium, and sulfur, which are required relatively in large amounts, and nine micronutrients which include iron, boron, zinc, cobalt, copper, manganese, molybdenum, nickel, and chlorine. These nutrients can be supplied to the plants through soil incorporation or foliar spray of commercially available fertilizers. Nutrient requirements for soybean crops vary in concentration, and deviations can cause nutrient deficiency or toxicity in soybean crops. Nutrient availability to soybean crops depends on the available nutrients in the soil solution, the form of available soil nutrients, mode of uptake of nutrients, its interaction with other soil nutrients, soil chemistry, and method of fertilizer application. This review article explores essential nutrients for sustainable soybean production in relation to the role and functions of nutrients, required concentration, and visual syndrome shown during deficiency, including findings from several researches. The review article is aimed to guide soybean farmers for effective nutrient management and academicians in reviewing the literature in soybean nutrient management.
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Nabilla, Sarah, Retno Hartati e Ria Azizah Tri Nuraini. "Hubungan Nutrien Pada Sedimen dan Penutupan Lamun Di Perairan Jepara". Jurnal Kelautan Tropis 22, n. 1 (13 aprile 2019): 42. http://dx.doi.org/10.14710/jkt.v22i1.4252.
Testo completoAbstract (sommario):
The availability of nutrients in seagrass beds can act as growth limiting factors. Absorption of nutrients in the water column is carried out by the leaves while the absorption of nutrients from the sediment is carried out by the roots but does not rule out the transport of nutrients by the roots will also arrive at the leaves of the seagrass. If the nutrient requirement is not met properly, then the growth will be disrupted. Like the difference in distribution and density of seagrass itself. Nutrient concentrations in waters vary. Nitrate and phosphate levels in the waters are strongly influenced by sources of organic material from outside/land (allochthonous) or from the water itself (autocthonous). This research was conducted with the aim of nothing: to determine the relationship between nutrient content (nitrate and phosphate) in sediment to seagrass cover in Teluk Awur and Pantai Blebak, JeparaData collection of seagrass and sediment was carried out on March 2018 in the waters of Teluk Awur and Blebak Beach, Kabupaten Jepara. Type identification, density, and coverage are carried out at the research location. Nitrate and phosphate analysis in sediments is carried out in Laboratorium Pengujian dan Peralatan. Based on the results of research that has been carried out, it can be concluded that there is a very strong positive relationship between nutrients and seagrass closure in the two research locations, each of which is 0.955 (91.1%) in Teluk Awur waters and 0.962 (92.6%) in Blebak Beach.Ketersediaan nutrien di perairan padang lamun dapat berperan sebagai faktor pembatas pertumbuhan. Penyerapan nutrien pada lamun pada kolom air dilakukan oleh daun sedangkan penyerapan nutrien dari sedimen dilakukan oleh akar namun tidak menutup kemungkinan pengangkutan nutrien oleh akar juga akan sampai pada bagian daun. Jika kebutuhan nutrien tidak terpenuhi dengan baik, maka pertumbuhannya mengalami gangguan. Seperti perbedaan sebaran dan kepadatan lamun itu sendiri. Konsentrasi nutrien di perairan bervariasi. Kadar nitrat dan fosfat di perairan sangat dipengaruhi oleh sumber bahan organik yang berasal dari luar/ daratan (allochthonous) maupun dari dalam perairan itu sendiri (autocthonous). Penelitian ini dilakukan dengan tujuan: untuk mengetahui hubungan antara kandungan nutrien (nitrat dan fosfat) pada sedimen terhadap tutupan lamun di Teluk Awur dan Pantai Blebak, Jepara. Identifikasi jenis, kepadatan dan penutupan dilakukan pada lokasi penelitian. Analisa nitrat dan fosfat dalam sedimen dilakukan di Laboratorium Pengujian dan Peralatan. Berdasarkan hasil penelitian yang telah dilakukan dapat di ambil kesimpulan bahwa terdapat hubungan sangat kuat positif antara nutrien dengan penutupan lamun pada dua lokasi penelitian, nilainya masing-masing sebesar 0,955 (91,1%) di Perairan Teluk Awur dan 0,962 (92,6%) di Pantai Blebak.
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De Souza, Juliana Sobreira, Deborah Guerra Barroso, Mirian Peixoto Soares da Silva e Daniele De Alvarenga Ferreira. "PRODUTIVIDADE DE MINICEPAS DE CEDRO-AUSTRALIANO EM FUNÇÃO DO TEOR INICIAL DE NUTRIENTES". FLORESTA 45, n. 3 (24 aprile 2015): 617. http://dx.doi.org/10.5380/rf.v45i3.36529.
Testo completoAbstract (sommario):
O objetivo do presente estudo foi avaliar a produtividade de minicepas de cedro-australiano em função do teor inicial de nutrientes em dois sistemas de minijardim multiclonal, conduzidos em canaletão e tubetes. Foi determinada a produtividade de miniestacas em 186 minicepas em cada sistema de manejo e os teores de nutrientes nas brotações emitidas por 20 minicepas selecionadas ao acaso em cada sistema. Foram realizadas cinco coletas de brotações em intervalos médios de 32 dias no sistema canaletão, enquanto no sistema tubete foram realizadas três coletas de brotações em intervalos médios de 31 dias. O número de miniestacas produzidas por minicepa foi correlacionado com o teor inicial de nutrientes da parte apical das mudas. A produtividade de minicepas de cedro-australiano manejadas em sistema canaletão e em tubetes está relacionada à nutrição mineral. Assim, níveis elevados de nutrientes nas minicepas favorecem o ganho em produtividade. Dessa forma, a reposição dos nutrientes conforme a exportação descrita favorecerá o aumento da produtividade das minicepas nos dois sistemas de produção.AbstractProductivity of cedar Australian ministumps in function of the initial nutrient. The aim of this research was to evaluate the productivity of Australian cedar ministumps in function of the initial content of nutrients in two systems of multiclonal minigarden; the experiment was conducted in tray and tubes. We determined the yield of minicuttings in 186 ministumps in each management system and the nutrient contents in shoots issued for 20 ministumps randomly selected in each system. We made a total of five collections of shoots in intervals of 32 days in the tray system, while in the cartridges system we made three collections of shoots in intervals of 31 days. The number of minicuttings produced by mini-stump was correlated with the initial content of nutrients in the apical part of seedlings. The productivity of australian cedar ministumps managed under tray and tubes is related to mineral nutrition. Thus, high levels of nutrients work in favor of ministumps gain in productivity. As result, the recovery of export nutrients, as described, work in favor of increased productivity of ministumps in both systems.Keywords: Vegetative propagation; Toona ciliata; multiclonal minigarden; mineral nutriton.
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Nyambaka, Hudson. "Impact of Processing on Nutrients and anti-Nutrients in Tubers and Leaves of Cassava (Manihot Esculenta Crantz)". Nutrition and Food Processing 7, n. 1 (30 gennaio 2024): 01–08. http://dx.doi.org/10.31579/2637-8914/185.
Testo completoAbstract (sommario):
Purpose The study investigated the effect of boiling and deep-frying on the levels of selected nutrients and anti-nutrients in tubers and leaves of new Migyera and MM96/2480 varieties planted in Busia County. Although cassava contains high levels of nutrients (elements and vitamins) that meet nutrient requirements when consumed as the main diet, it requires thorough cooking to reduce high levels of phytochemicals, anti-nutrients affecting nutrient bio-accessibility, and carcinogenic compounds; procedures which also affect the nutrient levels. Methods Tubers and leaves from the tips of the plant were harvested after 8 months. A portion of the tubers was boiled in water (100 ºC, 20 minutes), while another deep-fried in vegetable cooking oil until it turned brown (5 minutes). Leaves were pounded until uniformly macerated and boiled in water (100 ºC, 45 minutes). Levels of nutrients and antinutrients were determined by standard methods. Results The levels of nutrients and anti-nutrients were significantly higher in leaves than in tubers, and also differed significantly in different cassava varieties. Boiling of tubers significantly reduced the nutrients and anti-nutrients levels more compared to frying (P<0.001), ranging from 13.7 to 97.7%. Deep frying of Migyera variety had higher nutrient reduction than in MM96/2480 variety. Essential elements and antinutrients molar ratios indicated that the elements were not bio-accessible. Conclusion Boiling and deep-frying of cassava tubers and leaves results in significant reduction of nutrient and anti-nutrient levels, implying that cassava cannot be used as the main diet; explaining the high level of child malnutrition in such communities.
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Oriolowo, O. B., O. J. John, D. S. Abubakar, T. M. Jonah e D. Ismaila. "Anti-nutritional Composition of Honey Samples from Four Northern States of Nigeria". Nigerian Journal of Basic and Applied Sciences 27, n. 2 (27 maggio 2020): 32–38. http://dx.doi.org/10.4314/njbas.v27i2.5.
Testo completoAbstract (sommario):
Honey is sought globally for nutritional and therapeutic purposes because of the several chemical constituents that are abound in it. Some of these chemicals such as the anti-nutrients are defensive metabolic byproducts of plants from which bees obtained the nectars for honey production. This study was undertaken to determine the cyanide, oxalate, phytate, tannin and saponin compositions of honey samples from four North Central States of Nigeria. Anti-nutrients were analyzed following the Standards of Association of Official Analytical Chemists protocol for anti-nutrient compositions. Data obtained were compared using One-Way Analysis of Variance (ANOVA) and the means were separated using Fischer’s Least Significance Difference (LSD). The results showed that cyanide, phytate and tannin were present in all the four honey samples while oxalate and saponin were only present in two of the honey samples, though at varying concentrations each of them. All anti-nutrient except cyanide are within tolerable limit for human consumption. There were significant differences (p<0.05) in each of the anti-nutrient’s concentrations across the honey samples. The study showed that location and geographical region significantly influence honey’s anti-nutrient compositions as well as their concentrations.
Keywords: Honey, Anti-nutrients, Tannin, Saponin, Cyanide, Oxalate, Phytate.
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Anderson, Wendy B., e William G. Eickmeier. "Nutrient resorption in Claytonia virginica L.: implications for deciduous forest nutrient cycling". Canadian Journal of Botany 78, n. 6 (1 giugno 2000): 832–39. http://dx.doi.org/10.1139/b00-056.
Testo completoAbstract (sommario):
According to the vernal dam hypothesis, spring ephemeral herbs temporarily sequester large nutrient pools in deciduous forests prior to canopy closure and return the nutrients to the soil following senescence of aboveground tissues. However, many species resorb nutrients from their leaves back to belowground tissues during senescence, and the degree of resorption is often associated with soil nutrient availability. Species that store large proportions of their absorbed nutrients between years are not participating in the temporary sequestering and rapid recycling of nutrients implied by the vernal dam. We investigated the extent to which Claytonia virginica L. sequestered and returned nutrients to the soil in response to nitrogen (N) and phosphorus (P) availability. We tested the effect of nutrient availability on nutrient use efficiency, resorption efficiency, and resorption proficiency (% nutrient in senescent leaves) of Claytonia. Nutrient additions significantly decreased N but not P use efficiency of Claytonia, particularly as the growing season progressed. Nutrient additions also significantly reduced N resorption efficiency from 80 to 47% and decreased P resorption efficiency from 86 to 56%. N and P resorption proficiencies were also significantly lower in senesced leaves of fertilized plants: N concentrations were 2.33% when unfertilized and 4.13% when fertilized, while P concentrations were 0.43% when unfertilized versus 0.57% when fertilized. When unfertilized, Claytonia was more efficient at resorption compared with other spring herbs, but similar to other species when fertilized. However, Claytonia was much less proficient in resorbing nutrients than other reported plants, because senescent tissues maintained substantially higher concentrations of N and P, particularly when fertilized. In conclusion, Claytonia, an important spring ephemeral species, exhibits physiological responses that emphasize its role in the vernal dam by its temporary sequestration and substantial, rapid return of nutrients in deciduous forests. Adding nutrients to the site increases the total mass and the relative proportion of nutrients that Claytonia returns to the soil rather than sequestering between seasons, which ultimately increases nutrient recycling rates within the entire system.Key words: Claytonia virginica, nutrient response, resorption efficiency, nutrient cycling, spring ephemerals, vernal dam.
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Ridoutt, Bradley. "An Alternative Nutrient Rich Food Index (NRF-ai) Incorporating Prevalence of Inadequate and Excessive Nutrient Intake". Foods 10, n. 12 (20 dicembre 2021): 3156. http://dx.doi.org/10.3390/foods10123156.
Testo completoAbstract (sommario):
Most nutrient profiling models give equal weight to nutrients irrespective of their ubiquity in the food system. There is also a degree of arbitrariness about which nutrients are included. In this study, an alternative Nutrient Rich Food index was developed (NRF-ai, where ai denotes adequate intake) incorporating prevalence of inadequate and excessive nutrient intake among Australian adults. Weighting factors for individual nutrients were based on a distance-to-target method using data from the Australian Health Survey describing the proportion of the population with usual intake less than the Estimated Average Requirement defined by the Nutrient Reference Values for Australia and New Zealand. All nutrients for which data were available were included, avoiding judgements about which nutrients to include, although some nutrients received little weight. Separate models were developed for females and males and for selected age groups, reflecting differences in nutrient requirements and usual intake. Application of the new nutrient profiling models is demonstrated for selected dairy products and alternatives, protein-rich foods, and discretionary foods. This approach emphasises the need to identify foods that are rich in those specific nutrients for which intake is below recommended levels and can be used to address specific nutrient gaps in subgroups such as older adults. In addition, the new nutrient profiling model is used to explore other sustainability aspects, including affordability (NRF-ai per AUD) and ecoefficiency (NRF-ai/environmental impact score).
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Turner, John, e Marcia J. Lambert. "Analysis of nutrient use efficiency (NUE) in Eucalyptus pilularis forests". Australian Journal of Botany 62, n. 7 (2014): 558. http://dx.doi.org/10.1071/bt14162.
Testo completoAbstract (sommario):
Alternative indices to use for nutrient use efficiency (NUE) were analysed for nitrogen, phosphorus, potassium, calcium, magnesium and sulfur, using 17 Eucalyptus pilularis forest sites to test the hypothesis that NUE increases with decreasing nutrient availability. Reported indices represent different measures of nutrient use, including (1) efficiency of acquisition from soil, (2) quantities required for organic matter production, (3) organic matter production related to uptake, (4) ability to internally retranslocate nutrients and (5) physiological requirement of nutrients. Some indices are highly correlated but the highest correlations were according to age. Phosphorus, the main growth-limiting nutrient, on average, produced 6.5 and 10.9 t of organic matter per kilogram of phosphorus required and taken up from soil, respectively. Comparable estimates were made for other nutrients. NUEs of mobile nutrients increased with decreases in nutrient availability and this supported the hypotheses when age was taken into account. The NUEs of one nutrient are not independent of other nutrients. The inverse of foliage nutrient concentration is a valuable low-cost index of nutrient utilisation and correlates with net primary production/nutrient requirement, and is related to age. Resorption of nutrients, comparing new and abscised tissue, was of low value, but abscised-tissue nutrient correlations are related to a lower benchmark and are of value. The use of selected NUE indices for species comparison was discussed.
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Ardianti, Arini Ayu, Faris Nur Fauzi Athallah, Restu Wulansari e Kurniawan Sigit Wicaksono. "The relationship Between Soil Chemical Properties and Uptake of Tea Plant Nutrient in PTPN VI Jambi". Jurnal Tanah dan Sumberdaya Lahan 9, n. 1 (1 gennaio 2022): 181–91. http://dx.doi.org/10.21776/ub.jtsl.2022.009.1.20.
Testo completoAbstract (sommario):
Healthy soil could support plant growth by optimizing the availability of nutrients. The availability of nutrients influences the health of tea plants. Nutrient deficiencies would affect the plant physiology that exhibits the plant withering. This study aimed to define the relationship between soil nutrient availability with plant nutrient uptake. This research was conducted by managing secondary data soil chemical properties, and tea plant nutrients analyzed statistically with Pearson correlation. This study only found a significant correlation between soil pH with P and Mg uptake. Correlation results between soil nutrient and plant nutrient uptake obtained a significantly negative correlation on soil pH with P and Mg nutrients with a correlation value of pH-P (r=-0.52), pH-Mg (r=-0.52). There was no correlation between other soil nutrients and plant nutrient uptake. The results of this study can be used to determine the dose of fertilization and the management recommendation of tea plants.
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Kumar, Balwant, e G. K. Sharma. "Assessment of Soil Fertility through Response of Rice (Oryza sativa L.) to Nutrient Omission in Alfisols of Kondagaon District of Chhattisgarh in India". International Journal of Plant & Soil Science 35, n. 4 (6 marzo 2023): 58–67. http://dx.doi.org/10.9734/ijpss/2023/v35i42799.
Testo completoAbstract (sommario):
The investigation was carried out with the aim to identify the specific yield limiting nutrients through response of rice to nutrient omission in pot culture under completely randomized design with 3 replications and 11 treatments during kharif season 2017 and to demonstrate the optimum use of identified limiting nutrients in wheat crop at field level in Kondagaon district during rabi season 2017-18. The treatments were formulated by keeping one treatment with application of all nutrients in optimum level and others by sequentially omitting each nutrient. The soil had a clay loam texture, neutral reaction (pH 6.6), normal electrical conductivity, medium organic C, available P and K, low available N and S, high available Ca, Mg, Fe, Mn and Cu and marginal available Zn and B. Omission of N and P nutrients significantly reduced the growth, yield and nutrients uptake by rice in comparison to all nutrients. The maximum grain yield of 73.0 g pot-1 was recorded, in all nutrients pot and 50.1 % reduction in grain yield of rice, from the maximum yield, was recorded in N omitted pots, followed by 18.8 % reduction in P omitted pots and omission of other nutrients didn’t reduce the grain yield significantly indicating that only N and P were yield limiting nutrients. In field verification during rabi season, 19.0 % increase in wheat grain yield and 23.0 % increase in net return was recorded, due to optimum dose of identified yield limiting nutrients over farmer's practice dose. The results clearly indicate that the site specific nutrient management dose based on yield limiting nutrient identified through nutrient omission study was found economically profitable to the farmers.
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Yan, Jing, Nathaniel A. Bogie e Teamrat A. Ghezzehei. "Root uptake under mismatched distributions of water and nutrients in the root zone". Biogeosciences 17, n. 24 (17 dicembre 2020): 6377–92. http://dx.doi.org/10.5194/bg-17-6377-2020.
Testo completoAbstract (sommario):
Abstract. Most plants derive their water and nutrient needs from soils where the resources are often scarce, patchy, and ephemeral. It is not uncommon for plant roots to encounter mismatched patches of water-rich and nutrient-rich regions in natural environments. Such an uneven distribution of resources necessitates plant reliance on strategies for exploring and acquiring nutrients from relatively dry patches. We conducted a laboratory study that elucidates the biophysical mechanisms that enable this adaptation. The roots of tomato (Solanum lycopersicum) seedlings were laterally split and grown in two adjacent, hydraulically disconnected pots, which permitted precise control of water and nutrient applications to each compartment. We observed that the physical separation of water-rich and nutrient-rich compartments (one received 90 % water and 0 % nutrients and the other received 10 % water and 100 % nutrients) does not significantly stunt plant growth and productivity compared to two control treatments (control 1: 90 % water and 100 % nutrients versus 10 % water and 0 % nutrients; control 2: 50 % water and 50 % nutrients in each compartment). Specifically, we showed that soil dryness does not reduce nutrient uptake, vegetative growth, flowering, and fruiting compared to control treatments. We identified localized root proliferation in nutrient-rich dry soil patches as a critical strategy that enabled nutrient capture. We observed nocturnal rewetting of the nutrient-rich but dry soil zone (10 % water and 100 % nutrients) but not in the nutrient-free and dry zone of the control experiment (90 % water and 100 % nutrients). We interpreted the rewetting as the transfer of water from the wet to dry zones through roots, a process commonly known as hydraulic redistribution (HR). The occurrence of HR likely prevents the nutrient-rich soil from drying due to permanent wilting and the subsequent decline of root functions. Sustaining rhizosphere wetness is also likely to increase nutrient mobility and uptake. Lack of HR in the absence of nutrients suggests that HR is not entirely a passive, water-potential-gradient driven flow. The density and size of root hairs appeared to be higher (qualitative observation) in the nutrient-rich and dry compartments than in the nutrient-free and dry compartments. We also observed organic coating on sand grains in the rhizosphere of the nutrient-rich and dry compartments. The observations are consistent with prior observations that root hairs and rhizodeposition aid rhizosphere wetting. These findings were synthesized in a conceptual model that explains how plants of dry regions may be adapted to mismatched resources. This study also suggests that separating the bulk of applied nutrients from the frequently irrigated soil region can increase nutrient use efficiency and curtail water pollution from intensive agricultural systems.
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Nóra Bákonyi. "The effect of apoplastic pH on the nutrient uptake". Acta Agraria Debreceniensis, n. 50 (16 dicembre 2012): 65–71. http://dx.doi.org/10.34101/actaagrar/50/2568.
Testo completoAbstract (sommario):
The pH of soil and rhizosphare –around the roots- determine the mobility and solubility of nutrients. The exudates organic acids of plant able to modify the pH, as well as the microorganisms also take part in mobilization of nutrients. The nutrient solve mostly in mildly acidic and neutral pH. The either assumption of utilization of nutrients is the uptake by roots and of course uptake to the cells to take part in metabolism. The pH of apoplast fluid determines the solubility and uptake of nutrients to the cells.The aim of this study was to examine the effect of nutrient solution and apoplastic pH together with a bacteria based biofertiliser (Phylazonit MC®) on nutrient uptake and pH of apoplast fluid in case of nutrient solution grown plants in laboratory experiment. According to my results, the bicarbonate increased the pH of nutrient solution in due to influence the solubility and uptake of nutrients. The given bicarbonate to the nutrient solution and infiltrated into the apoplazma also modified the pH of the apoplast fluid of the test plants. The effect of bicarbonate and biofertilizer were different on the pH of the apoplast fluid and nutrient solution in nutrient solution experiment.
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Rose, Laura, Robert Buitenwerf, Michael Cramer, Edmund C. February e Steven I. Higgins. "Effects of nutrient supply on carbon and water economies of C4 grasses". Functional Plant Biology 45, n. 9 (2018): 935. http://dx.doi.org/10.1071/fp17359.
Testo completoAbstract (sommario):
C3 plants can increase nutrient uptake by increasing transpiration, which promotes the flow of water with dissolved nutrients towards the roots. However, it is not clear if this mechanism of nutrient acquisition, termed ‘mass flow’, also operates in C4 plants. This is an important question, as differences in mass flow capacity may affect competitive interactions between C3 and C4 species. To test if mass flow can be induced in C4 species, we conducted an experiment in a semiarid seasonal savanna in South Africa. We grew six C4 grasses in nutrient-poor sand and supplied no nutrients, nutrients to the roots or nutrients spatially separated from the roots. We measured the rates of photosynthesis and transpiration, water-use efficiency (WUE), nitrogen gain and biomass. For all species biomass, N gain, photosynthesis and transpiration were lowest in the treatment without any nutrient additions. Responses to different nutrient positioning varied among species from no effect on N gain to a 50% reduction when nutrients were spatially separated. The ability to access spatially separated nutrients showed a nonsignificant positive relationship with both the response of transpiration and the response of WUE to spatial nutrient separation. This indicates that nutrient acquisition is not regulated by decreasing WUE in C4 grasses. Overall, our study suggests that under elevated CO2, when evaporative demand is lower, C4 species may be at a competitive disadvantage to C3 species when it comes to nutrient acquisition.
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Liu, Ao, Aixi Han e Li Chai. "Assessing the Nutrient Adequacy in China’s Food Supply from 1965 to 2018". Nutrients 13, n. 8 (9 agosto 2021): 2734. http://dx.doi.org/10.3390/nu13082734.
Testo completoAbstract (sommario):
Nutritional intake has important impacts on human health. A sufficient supply of nutrients is required to ensure high-level nutrition in a population. Assessment of nutrient supply adequacy can help to develop evidence-based policies and thereby promote public health. This study estimates the supply adequacy of nutrients in China’s food system from 1965 to 2018 at the national level, aiming to reveal whether the supply of nutrients meets the demand. The results show that the nutrient supply in China’s food system has experienced a sharp increase in the past five decades, and the deficiency in nutrient supply has been greatly mitigated. Although most nutrients such as potassium are already sufficiently supplied in China’s current food system, some nutrients, especially calcium and zinc, still need a further enlarged supply to improve the nutrition condition of the Chinese population. Besides encouraging a healthy diet, supply-side regulation, e.g., fortification and enrichment, is also needed to improve nutrient availability. This study helps people better understand the development and current situation of nutrient adequacy in China’s food supply, thereby providing information and implications for policymakers.
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Johnson, Andrew S., Gianluca Polese, Max Johnson e William Winlow. "Appropriate Human Serum Albumin Fluid Therapy and the Alleviation of COVID-19 Vulnerabilities: An Explanation of the HSA Lymphatic Nutrient Pump". COVID 2, n. 10 (30 settembre 2022): 1379–95. http://dx.doi.org/10.3390/covid2100099.
Testo completoAbstract (sommario):
COVID-19 and long COVID-19 vulnerabilities may be caused indirectly by albumin binding deficiency (ABD), which can be corrected by the correct administration of human serum albumin (HSA). The liver is the primary site of nutrient regulation and fluid volume maintenance; control of both is by changes to albumin concentration. In healthy subjects, the HSA lymphatic nutrient pump (HSALNP) ensures continual pumping of nutrients from the liver and that nutrients are appropriately distributed to organs. Nutrients are delivered to cells according to the availability of binding to HSA. The HSALNP, therefore, maintains the correct nutrient and colloidal pressure balance in all tissues independently. In unhealthy tissues, following COVID-19 infection, the passage of HSA/nutrients through the interstitial spaces and lymph will be impeded. Fluid therapy into the periphery leads to the dilution of essential nutrients attached to the protein carriers such as albumin. The levels of albumin being charged by the liver with nutrients is critical in maintaining immune stability by maintaining nutrient support and colloidal pressure of the cellular structures. The site of HSA binding by the liver is of great importance, and direct infusion of albumin into the hepatic portal vein is the most appropriate method of maintaining colloid pressure and cellular nutrient levels.
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Gustiar, Fitra, Munandar Munandar, M. Amar, Arsi Arsi, Puspa A. Pitayati, Tri O. Amanah e Nadiya Assyfa. "Growth of Pakcoy (Brassica rapa L.) Hydroponic System Using Nutrients of Catfish Cultivation Waste". Jurnal Lahan Suboptimal : Journal of Suboptimal Lands 11, n. 1 (1 aprile 2022): 86–93. http://dx.doi.org/10.36706/jlso.11.1.2022.560.
Testo completoAbstract (sommario):
Organic hydroponic cultivation systems require substitute nutrients other than inorganic fertilizers as a source of plant nutrients. Catfish cultivation waste is one of the potentials that can be used as hydroponic nutrients. This study aimed to find out the concentration of Liquid Organic Fertilizer (LOF) from fish cultivation waste as a substitute for commercial inorganic nutrients on the growth of pakcoy (Brassica rapa L.). This research was carried out in 2 stages, namely the manufacture of LOF from catfish culture waste and experiments using LOF as hydroponic nutrients. The results of this study showed that the increase in LOF nutrient content in anaerobic fermentation was higher than in aerobic fermentation. The use of LOF as a hydroponic nutrient, based on the parameters of plant height, number of leaves, SPAD value, root weight, crown weight, and dry weight obtained a smaller value that was significantly different compared to the inorganic nutrient treatment of AB mix. LOF concentration of 20%, both fermented aerobically and anaerobically, gave better growth when compared to higher concentration treatments. The nutrient content in LOF is difficult to adjust to the needs of hydroponic pakcoy, so that it will have a toxic impact on macro nutrients on the other hand, it also provides a response to micro nutrient deficiency.
21
Havlin, John, e Ron Heiniger. "Soil Fertility Management for Better Crop Production". Agronomy 10, n. 9 (8 settembre 2020): 1349. http://dx.doi.org/10.3390/agronomy10091349.
Testo completoAbstract (sommario):
Increasing crop productivity per unit of land area to meet future food and fiber demand increases both soil nutrient removal and the importance of replenishing soil fertility through efficient nutrient management practices. Significant progress in enhancing nutrient-use efficiency in production agriculture requires improved estimates of plant-available nutrients in the root zone, enhanced crop response to applied nutrients, and reduced offsite nutrient transport. This special issue, Soil Fertility Management for Better Crop Production, presents 15 manuscripts that advance our knowledge of interrelated soil, plant, and management factors important to increasing the nutrient availability and crop recovery of applied nutrients.
22
Wogalter, Michael S., e Michael J. Kalsher. "Product Label List Format: Effects of Item Arrangement and Completeness on Comparison Time and Accuracy". Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, n. 5 (ottobre 1994): 389–93. http://dx.doi.org/10.1177/154193129403800508.
Testo completoAbstract (sommario):
This research examined the influence of two factors on the ease of gaining information from item lists: the order and completeness of the items displayed. Food nutrition labels served as the vehicle to test the manipulated lists on comparison time and accuracy performance measures. Four booklets, each containing 12 pairs of nutrient labels, were constructed in which the listed items were: (1) either arranged in a standard order or in a random order, and (2) either had a complete set of nutrients (including nutrients not present in the product) or a partial set of nutrients (excluding nutrients with zero or near-zero amounts in the product). Thirty-two participants were instructed to assume that their physician has told them to increase their intake of three specific nutrients and decrease their intake of three other nutrients. One label of each pair contained a higher level of one nutrient that should be increased or a lower level of one nutrient that should be decreased. Participants were to determine which of the two labels would be better given the prescribed diet. Time and accuracy measures were collected. Participants made significantly faster judgments for nutrients arranged in a standard order than for nutrients arranged in a random order. For all conditions, the error rate was low. An interaction indicated that labels with a complete set of nutrients in a standard order produced fewer errors than (a) labels in a standard order with some nutrients missing or (b) labels with a complete set of nutrients in a random order. Implications of making lists compatible with expectations are described.
23
May, Geoffrey M., e Marvin P. Pritts. "Phosphorus, Zinc, and Boron Influence Yield Components in `Earliglow' Strawberry". Journal of the American Society for Horticultural Science 118, n. 1 (gennaio 1993): 43–49. http://dx.doi.org/10.21273/jashs.118.1.43.
Testo completoAbstract (sommario):
The main effects and interactions of soil-applied P, B, and Zn on yield and its components were examined in the field at two pH levels with `Earliglow' strawberries (Fragaria × ananassa Duch.). Applied nutrients had significant effects on several yield components, but responses depended on the levels of other nutrients or the soil pH At a soil pH of 5.5, yield responded linearly to B and quadratically to P. At pH 6.5, P interacted with B and Zn. Fruit count per inflorescence was the yield component most strongly associated with yield followed by individual fruit weight. However, these two yield components responded differently to soil-applied nutrients. Foliar nutrient levels generally did not increase with the amount of applied nutrient, but often an applied nutrient had a strong effect on the level of another nutrient. Leaf nutrient levels were often correlated with fruit levels, but foliar and fruit levels at harvest were not related to reproductive performance. Our study identifies some of the problems inherent in using foliar nutrient levels to predict a yield response and demonstrates how plant responses to single nutrients depend on soil chemistry and the presence of other nutrients.
24
Rusyadi, Imron, Sahala Hutabarat e Churun Ain. "PENGARUH KANDUNGAN NUTRIEN TERHADAP KESUBURAN DI KOLAM BUDIDAYA IKAN NILA (Oreochromis sp.) DI BALAI BENIH IKAN MIJEN, SEMARANG". Management of Aquatic Resources Journal (MAQUARES) 6, n. 1 (9 marzo 2018): 61–66. http://dx.doi.org/10.14710/marj.v6i1.19811.
Testo completoAbstract (sommario):
ABSTRAK Ikan Nila (Oreochromis sp) merupakan jenis ikan yang memiliki toleransi tinggi terhadap perubahan lingkungan perairan, namun kualitas air dalam wadah budidaya harus tetap dikelola dengan baik agar pertumbuhannya optimal. Tujuan penelitian ini adalah mengetahui nilai nutrien yang dilihat dari kadar nitrat dan fosfat serta nilai kesuburan perairan yang dilihat dari klorofil-a dan fitoplankton, mengetahui kondisi perairan di kolam budidaya ikan Nila yang ditinjau dari kadar nutrien dan tingkat kesuburannya, serta mengetahui keterkaitan antara kandungan klorofil-a dengan nutrien dan juga fitoplankton dengan nutrien di perairan kolam budidaya ikan Nila (Oreochromis sp) BBI Mijen Semarang. Penelitian ini dilaksanakan pada bulan Juni 2016 di Balai Benih Ikan (BBI) Mijen, Semarang dan di Laboratorium Balai Lingkungan Hidup, serta Laboratorium Pengelolaan Sumberdaya Ikan dan Lingkungan FPIK Undip, Tembalang, Semarang. Metode yang digunakan dalam penelitian ini adalah metode deskriptif analisis, metode pengambilan sampel menggunakan purposive sampling. Hasil penelitian yang diperoleh nilai nutrien yang didapatkan yaitu nitrat sebesar 0,900-1,463 mg/l dan fosfat sebesar 0,092-0,100 mg/l. Nilai kesuburan perairan yang dilihat dari klorofil-a yaitu 2,44-3,41 mg/m3 dan kelimpahan fitoplankton sebesar 480-800 ind/l. Keterkaitan antara kandungan klorofil-a dengan nutrien, serta fitoplankton dengan nutrien secara keseluruhan menunjukkan bahwa kesuburan perairan lebih banyak dipengaruhi oleh nitrat daripada fosfat dan kondisi kesuburan di kolam budidaya ikan Nila (Oreochromis sp) BBI Mijen ditinjau dari kadar nutrien dan tingkat kesuburannya secara keseluruhan menunjukkan bahwa perairan pada kondisi tingkat kesuburan yang sedang. Kata kunci: kesuburan perairan; nutrien; fitoplankton; ikan Nila ABSTRACT Nila fish(Oreochromis sp) is a species of fish that have a high tolerance to changes in the aquatic environment, so it can save amount of feeds that used. however the quality of the water in the cultivation container should be well managed in order to gain optimal growth. The purpose of this study was to determine the nutrient value as seen from nitrate and phosphate as well as the value of the fertility waters seen from chlorophyll-a and phytoplankton, determine the condition water in terms of levels nutrients and fertility in the pond farm of parrot fish, and to know the relationship between chlorophyll-a with nutrients and also phytoplankton with nutrients in the waters of aquaculture ponds Nila fish (Oreochromis sp) at BBI Mijen Semarang. This research was conducted in June 2016 at Balai Benih Ikan (BBI) Mijen, Semarang and Central Laboratory of Environment, as well as the Laboratory of Fish Resources Management and Environment FPIK Undip, Tembalang, Semarang. The method used in this research is descriptive analysis , methods of sampling using purposive sampling. The results of research, obtained amount nutrient value of nitrate about 0.900 to 1.463 mg / l and phosphate around 0.092 to 0.100 mg / l. Value of fertility waters as seen from chlorophyll-a is 2.44 to 3.41 mg / m3 and abundance of phytoplankton value are 480-800 ind / l. The linkage between the content of chlorophyll-a with nutrients, and phytoplankton with nutrients as a whole show that the fertility waters more influenced by nitrates than phosphates and fertility conditions in aquaculture of Nila fish (Oreochromis sp) in terms level of nutrients and fertility rates show that the waters was on good fertility condition Keywords: fertility waters; nutrient; phytoplankto; Nila fish
25
Doaei, Saeid, Alireza Mosavi Jarrahi, Maryam Gholamalizadeh e Milad Nazarzadeh. "Substitution Analysis in Nutrition Sciences: A Tutorial". Asian Pacific Journal of Cancer Biology 1, n. 3 (25 settembre 2016): 55–57. http://dx.doi.org/10.31557/apjcb.2016.1.3.55-57.
Testo completoAbstract (sommario):
Evaluating the effects of nutrients in our diet needs to enter more than one nutrient item (or food groups) in a single statistical unit. Accordingly, not only we consider the effects of a nutrient in health-related subjects, but also we find out the consequences of replacing and deleting nutrients. In nutritional epidemiology, substitutional analysis is used to evaluate the effects of various nutrients on a specific outcome. In the substitutional analysis, when some nutrients or foods are included in a single statistical model, investigation of the effects of several nutrients on the specific outcome is more achievable. The objective of this paper was to provide a detailed examination of the key aspects of substitutional analysis in nutritional sciences.
26
Zandonà, Eugenia, Priscila Oliveira-Cunha e Beatriz Moreira-Ferreira. "PAPEL DOS PEIXES NA RECICLAGEM DE NUTRIENTES EM RIACHOS TROPICAIS". Oecologia Australis 25, n. 02 (16 giugno 2021): 449–63. http://dx.doi.org/10.4257/oeco.2021.2502.14.
Testo completoAbstract (sommario):
Fish can contribute directly and indirectly to nutrient recycling in aquatic environments, affecting community structure and ecosystem processes. Through the excretion of metabolic waste, fish make inorganic nutrients available in the environment that can be used by algae and bacteria. Nitrogen and phosphorus are often limiting nutrients in streams, so fish can be a relevant source of these nutrients. Many factors can influence excretion rates, including diet, body nutrient demand (for reproduction and growth), ontogeny, body size, temperature and other abiotic factors. Currently, two theories propose to explain which factors control excretion rates: 1) The Theory of Ecological Stoichiometry is based on mass balance models and uses the amount of nutrients in the diet and the fish nutrient demand as predictors of excretion rates; and 2) the Metabolic Theory of Ecology that uses body size and temperature as factors that regulate an organism metabolic rates and, thus, its excretion rates. The relative importance of fish as nutrient recyclers in streams varies depending on species intrinsic characteristics and environmental factors. This includes the magnitude of excretion rates from the entire fish community, the nutrient concentration and nutrient input into the stream, the stream nutrient demand and the period of activity and behavior of the fish. For example, species that are abundant in oligotrophic streams have the potential to represent an important source of nutrients. But other peculiarities, such as diet, specific nutrient demands, or migratory behaviors, can make them important sources or sinks of nutrients in a stream. This article reviews studies that address the role of fish as nutrient recyclers and explains the most common techniques used in this type of studies.
27
Scagel, Carolyn F., Guihong Bi, Leslie H. Fuchigami e Richard P. Regan. "Nutrient Uptake and Loss by Container-grown Deciduous and Evergreen Rhododendron Nursery Plants". HortScience 46, n. 2 (febbraio 2011): 296–305. http://dx.doi.org/10.21273/hortsci.46.2.296.
Testo completoAbstract (sommario):
The influence of nitrogen (N) fertilizer application on plant allocation, uptake, and demand for other essential nutrients was evaluated from May 2005 to Feb. 2006 in evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown in containers filled with soilless substrate. Net nutrient uptake and losses were calculated using piecewise regression and uptake efficiency, root absorption capacity, aboveground demand, nutrient use efficiency, and uptake ratios between N and other nutrients (N ratios) were calculated using net uptake between harvest dates. Nitrogen application increased uptake rate of all nutrients, enhanced late-season uptake of many nutrients, and increased the rate of nutrient loss during the winter. Nutrient uptake often occurred as late as November in plants grown with N but was usually undetectable after September in plants grown without additional N fertilizer. Nutrient losses during the winter were not always associated with biomass loss and were related to differences in preferential nutrient allocation to different structures and the plant's ability to export nutrients before biomass loss. Plants with a greater potential for rapid growth were more capable of later-season nutrient uptake than plants with slower growth rates. Nitrogen availability altered N ratios indicating that when adding N to container-grown Rhododendron, fertilizers with higher ratios of N/phosphorus (PJM, AZ), N/calcium (PJM, ER), N/boron (PJM AZ), N/copper (PJM, ER), and N/iron (PJM, ER) and lower ratios of N/potassium (PJM, ER, AZ), N/sodium (PJM, ER, AZ), N/calcium (AZ), N/boron (ER), N/manganese (AZ), and N/zinc (ER) may be needed to optimize growth and minimize nutrient inputs. Increasing N availability altered uptake efficiency, root absorption capacity, aboveground demand, and nutrient use efficiency for several nutrients, indicating that changes in N management practices need to consider how altering N application rates may influence the plant's ability to take up and use other nutrients. This information can be used to develop fertilizer formulations to minimize excess application of nutrients and to evaluate the potential effects of altering N management practices on use of production resources. Our results indicate that nutrient management strategies for perennial crops such as Rhododendron need to take into consideration not only the nutrient demand for current growth, but also how to optimize nutrient availability for uptake that contributes to future growth potential and end-product quality.
28
Aye, Hinotoli N., e Shalini Masih. "Role of Nutrients in Plants, Its Deficiency and Management". International Journal of Plant & Soil Science 35, n. 10 (27 aprile 2023): 129–36. http://dx.doi.org/10.9734/ijpss/2023/v35i102932.
Testo completoAbstract (sommario):
Plants like all living beings need energy source. The energy needed by the plants are uptaken in the form of 17 essential elements. Among which Carbon, hydrogen, and oxygen are derived from surrounding. The remaining 14 essential necessary elements are supplied either from rhizosphere and soil organic matter or by important organic or inorganic fertilizers or value added soil amendments. Plants start showing nutrient deficiency when they do not get the necessary nutrients. More nutrient use can also show poor growth because of toxic chemicals in soil. So, required amount of use and the placement of nutrients is necessary. Soil and plant tissue tests have been developed to assess their’ nutrient content. By analysis, plant scientists determined the nutrient need of plant in a given soil. In addition to the levels of available nutrients, soil pH shows its role in nutrient availability and elemental toxicity in soil. In the majority, disease effect in crop plants has been reduced by fertilizer application. This is due to the host plant tolerance or resistance mechanisms involve these nutrients. When the plants were deficient, the application of nutrients significantly reduced disease.
29
Li, Huandi, Jiang Li, Xiyun Jiao, Hongzhe Jiang, Yong Liu, Xinglang Wang e Chao Ma. "The Fate and Challenges of the Main Nutrients in Returned Straw: A Basic Review". Agronomy 14, n. 4 (28 marzo 2024): 698. http://dx.doi.org/10.3390/agronomy14040698.
Testo completoAbstract (sommario):
Due to containing an abundance of essential nutrients, straw has significant potential to mitigate carbon (C), nitrogen (N), phosphorus (P), and potassium (K) deficits in soil. However, a lack of comprehensive and systematic reviews on C, N, P, and K release and conversion from straw and on the impact of available nutrients in soils supplemented using straw-returning (SR) practices is noticeable in the literature. Therefore, we investigated straw decomposition, its nutrient release characteristics, and the subsequent fate of nutrients in soils. At early stages, straw decomposes rapidly and then gradually slows down at later stages. Nutrient release rates are generally in the K > P > C > N order. Nutrient fate encompasses fractions mineralized to inorganic nutrients, portions which supplement soil organic matter (SOM) pools, and other portions which are lost via leaching and gas volatilization. In future research, efforts should be made to quantitatively track straw nutrient release and fate and also examine the potential impact of coordinated supply-and-demand interactions between straw nutrients and plants. This review will provide a more systematic understanding of SR’s effectiveness in agriculture.
30
Adkison, Milo D. "Models of the effects of marine-derived nutrients on salmon (Oncorhynchus spp.) population dynamics". Canadian Journal of Fisheries and Aquatic Sciences 67, n. 1 (gennaio 2010): 5–15. http://dx.doi.org/10.1139/f09-161.
Testo completoAbstract (sommario):
Pacific salmon ( Oncorhynchus spp.) populations transfer large quantities of nutrients from their marine to their freshwater habitats. These nutrients have been shown to affect salmon populations in fresh water, including increasing basal food resources and elevating juvenile salmon growth rates and condition. The broader effects on recruitment and commercial harvests, however, are not clear. I developed and explored mathematical models of the effects of these nutrients on stock–recruitment relationships and used these models to investigate management implications. Populations strongly dependent on nutrients had lower sustained yields than those not dependent on nutrients. When nutrients strongly affected the stock–recruitment relationship, relatively low harvest rates and high escapement levels were necessary to maintain the population’s productivity. However, in some scenarios, the highest yields were obtained from small, nutrient-depleted populations. In other scenarios, the nutrient dependence had few management implications.
31
Zhang, Peng, Zhiyi Cui, Xiaojin Liu e Daping Xu. "Above-Ground Biomass and Nutrient Accumulation in Ten Eucalyptus Clones in Leizhou Peninsula, Southern China". Forests 13, n. 4 (29 marzo 2022): 530. http://dx.doi.org/10.3390/f13040530.
Testo completoAbstract (sommario):
Selecting suitable clones and regulating nutrients for Eucalyptus plantation are a key management practice for improving productivity and nutrient use. Therefore, this study evaluated growth performance, above-ground biomass, nutrient content (nitrogen, phosphorus, potassium, calcium, and magnesium) and nutrient use efficiency (NUE) of ten Eucalyptus Clones for three sites in Leizhou Peninsula. The present study showed a significant genetic variation among clones in growth parameters. Organs have different characteristics in biomass and nutrient content. Stemwood had the highest biomass but lowest total nutrient concentration. While, the stembark exhibited high contents of nutrients and biomass. On average, the NUE of clones was in the following order: phosphorus > magnesium > nitrogen > potassium > calcium. Taken together, among ten clones tested, clones LH1-9211, TH9224, DH32-13, M1 and DH32-22 showed consistently growth and production performance, as well, their NUE were superior in ten clones. Maximum amount of biomass was allocated to economically harvestable component (stemwood) and nutrients in non-harvestable components (stembark and foliage). While nutrients are removed from the planting area as part of the harvest, we can calculate nutrients loss by NUE and biomass. These findings provided useful insights for selection of Eucalyptus Clones and regulating nutrient export during the harvest of Eucalyptus Clones from a planted forest system.
32
Mitra, Aditee, e Kevin J. Flynn. "Promotion of harmful algal blooms by zooplankton predatory activity". Biology Letters 2, n. 2 (marzo 2006): 194–97. http://dx.doi.org/10.1098/rsbl.2006.0447.
Testo completoAbstract (sommario):
The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios.
33
Walsh, Sheila M. "Ecosystem-Scale Effects of Nutrients and Fishing on Coral Reefs". Journal of Marine Biology 2011 (2011): 1–13. http://dx.doi.org/10.1155/2011/187248.
Testo completoAbstract (sommario):
Nutrient pollution and fishing are the primary local causes of coral reef decline but their ecosystem-scale effects are poorly understood. Results from small-scale manipulative experiments of herbivores and nutrients suggest prioritizing management of fishing over nutrient pollution because herbivores can control macroalgae and turf in the presence of nutrients. However, ecological theory suggests that the opposite occurs at large scales. Moreover, it is unclear whether fishing decreases herbivores because fishing of predators may result in an increase in herbivores. To investigate this paradox, data on the fish and benthic communities, fishing, and nutrients were collected on Kiritimati, Kiribati. Oceanographic conditions and a population resettlement program created a natural experiment to compare sites with different levels of fishing and nutrients. Contrary to theory, herbivores controlled macroalgae in the presence of nutrients at large spatial scales, and herbivores had greater effects on macroalgae when nutrients were higher. In addition, fishing did not increase herbivores. These results suggest that protecting herbivores may have greater relative benefits than reducing nutrient pollution, especially on polluted reefs. Reallocating fishing effort from herbivores to invertivores or planktivores may be one way to protect herbivores and indirectly maintain coral dominance on reefs impacted by fishing and nutrient pollution.
34
Pandey, Meena, Jiban Shrestha, Subash Subedi e Kabita Kumari Shah. "ROLE OF NUTRIENTS IN WHEAT: A REVIEW". Tropical Agrobiodiversity 1, n. 1 (18 giugno 2020): 18–23. http://dx.doi.org/10.26480/trab.01.2020.18.23.
Testo completoAbstract (sommario):
Wheat (Triticum aestivum L.) is an important cereal crop that provides ample nutritious calories for humans and animals. The nutrient plays a vital role in the production of wheat. In this review, previous works were evaluated to investigate the role of nutrients, nutrient deficiency and toxicity in wheat. Both macro and micronutrients are necessary for wheat plants. Every nutrient has its own character and is involved in different metabolic processes of plant life. Nutrient deficiency and toxicity conditions inhibit normal plant growth and exhibit characteristic symptoms. For optimal growth, development, and production, plants need all the necessary nutrients in balance. A balanced application of the primary nutrients (N, P, K), secondary nutrient (S) and some other micronutrients (Zn, B) are needed to enhance wheat production. The soil tests and the demand for crop nutrients should be assessed to identify the quantity of fertilizer recommended for the crop. This study would be a valuable means to wheat growers and researchers for sustainable and higher wheat production.
35
Illukpitiy, Prabodh, e Jason P. DeKoff. "An Economic Assessment of Nutrient Removal from Switchgrass Production". Research in Applied Economics 11, n. 2 (30 giugno 2019): 26. http://dx.doi.org/10.5296/rae.v11i2.14998.
Testo completoAbstract (sommario):
The on-site loss of nutrients due to biomass removal creates additional costs for ethanol production however this aspect has not been properly incorporated in economic analyses of biomass production and processing. This study investigates costs of on-site nutrient losses in switchgrass fields in Tennessee. The replacement cost methodology was applied to measure on-site cost of nutrient losses due to biomass removal and was based on the costs of replacing nutrients removed from the production site. The estimated costs for total on-site nutrient loss due to biomass removal show a substantial loss of nutrients in switchgrass fields. The loss of major nutrients from biomass removal represents the major part of on-site economic costs. A declining trend of nutrient costs per Mg of harvested biomass was observed with increasing in harvesting time. The internalization of on-site costs of nutrient losses is possible by adopting an appropriate harvest schedule for switchgrass.
36
Tiani, Kendra A., Patrick J. Stover e Martha S. Field. "The Role of Brain Barriers in Maintaining Brain Vitamin Levels". Annual Review of Nutrition 39, n. 1 (21 agosto 2019): 147–73. http://dx.doi.org/10.1146/annurev-nutr-082018-124235.
Testo completoAbstract (sommario):
It is increasingly recognized that tissue-specific nutrient deficiencies can exist in the absence of whole-body deficiency and that these deficiencies may result from disease or disease-related physiological processes. Brain and central nervous system tissues require adequate nutrient levels to function. Many nutrients are concentrated in the cerebrospinal fluid relative to the serum in healthy individuals, and other nutrients resist depletion in the presence of whole-body nutrient depletion. The endothelial, epithelial, and arachnoid brain barriers work in concert to selectively transport, concentrate, and maintain levels of the specific nutrients required by the brain while also blocking the passage of blood-borne toxins and pathogens to brain and central nervous system tissues. These barriers preserve nutrient levels within the brain and actively concentrate nutrients within the cerebrospinal fluid and brain. The roles of physical and energetic barriers, including the blood–brain and blood–nerve barriers, in maintaining brain nutrient levels in health and disease are discussed.
37
Elsdon, Travis S., e Karin E. Limburg. "Nutrients and their duration of enrichment influence periphyton cover and biomass in rural and urban streams". Marine and Freshwater Research 59, n. 6 (2008): 467. http://dx.doi.org/10.1071/mf07085.
Testo completoAbstract (sommario):
Although it is well known that land use affects nutrient dynamics and algal growth in streams, the responses to different durations of nutrient supply are poorly understood. The associations of benthic (periphyton-dominated) biomass with concentrations of dissolved nitrogen and phosphorus in rural and urban streams in New York were quantified. Biomass was significantly greater (2-fold) in the urban compared with the rural stream, which was associated with differences in dissolved nutrients. Experimental field enrichment of nutrient concentrations and duration of exposure altered benthic periphyton. Increasing nutrients by 60–99% of ambient concentrations increased periphyton percentage cover and biomass. Periphyton abundance also increased with increasing duration of exposure to nutrients (2, 4 and 8 weeks); however, short-term pulses of nutrients (2 weeks) had no significant effect in the rural stream. These results indicate that effective management of nutrient delivery, by reducing time periods of high nutrient load, will minimise impacts to benthic environments.
38
Salvador, Simone Martini, Aline Aparecida Ludvichak, Dione Richer Momolli, Kristiana Fiorentin dos Santos, Catarine Barcellos Consensa, Mauro Valdir Schumacher e James Stahl. "Removal of nutrients due to biomass harvest of Eucalyptus urograndis in different soils: macronutrients". Ambiente e Agua - An Interdisciplinary Journal of Applied Science 16, n. 3 (17 maggio 2021): 1. http://dx.doi.org/10.4136/ambi-agua.2671.
Testo completoAbstract (sommario):
Intensive management of forest stands can increase biomass production, as well as increase the removal of nutrients from the site. This study therefore sought to simulate different harvest intensities and to calculate the nutrient-use efficiency of Eucalyptus urograndis in different types of soil. The study was carried out in a plantation of seven-year-old hybrid E. urograndis in the city of Telêmaco Borba, Paraná, Brazil. The study site included two sub areas with sandy soil and clayey soil (Cambisols Inceptisol and Ferralsols Oxisols, respectively). Using biomass and nutrients stock data, nutrient removal was simulated under five different harvest scenarios. Nutrient-use efficiency was obtained from the relation between the amount of biomass and nutrients of each tree component. Harvesting the whole tree resulted in the removal of approximately 61% of the nutrients from the site in sandy soil, while in clayey soil 57% of the nutrients were removed. With harvesting of only the commercial stemwood, only 22% of the nutrients were removed from the sandy soil, and 21% from the clayey soil. Stemwood was the component that had the highest nutrient-use efficiency values for all the analyzed nutrients. In conclusion, to achieve nutritional sustainability of E. urograndis stands, the best harvesting system involves the removal of only commercial stemwood. For the production of stemwood, sandy soils have a greater biological efficiency of calcium and magnesium when compared to clayey soil.
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Bockheim, J. G., e J. E. Leide. "Foliar nutrient dynamics and nutrient-use efficiency of oak and pine on a low-fertility soil in Wisconsin". Canadian Journal of Forest Research 21, n. 6 (1 giugno 1991): 925–34. http://dx.doi.org/10.1139/x91-128.
Testo completoAbstract (sommario):
Seasonal changes in 10 nutrients were investigated in the foliage and current twigs of jack pine (Pinusbanksiana Lamb.) and northern pin oak (Quercusellipsoidalis E.J. Hill) growing on a sandy, nutrient-poor soil in northwestern Wisconsin. Midsummer (July 26) concentrations of all nutrients except Zn were significantly greater in oak foliage than in current needles of pine. Whereas the absolute amounts of N, P, K, Mg, S, B, and Fe in oak foliage peaked in midsummer, generally in late July, the amounts of Ca, Zn, and Mn continued to increase until leaf abscission. The absolute amounts of all 10 nutrients in current needles of pine increased over the growing season. Absolute amounts of nutrients in 2- and 3-year-old needles generally decreased from midsummer to leaf abscission. The two species differ in mechanisms of nutrient-use efficiency. Northern pin oak has a greater requirement for all macronutrients except Mg than jack pine. Although the absolute amounts are greater, proportionally lower amounts of required nutrients are retained in perennial tissues of northern pin oak than in jack pine. A large portion of the nutrient requirement in oak is met by recycling of nutrients contributed by litterfall, throughfall, and fine-root turnover. Northern pin oak resorbed greater amounts of N and K prior to leaf abscission than jack pine. In contrast, jack pine conserves nutrients by investing low amounts of nutrients per unit of leaf or bolewood production and by returning a low proportion of nutrients in litterfall per unit aboveground tissue produced.
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Mukhina, Irina, Elena Rizhiya e Tatiana Bankina. "Biochar Effect on Nutrients Availability to Barley". Environmental Research, Engineering and Management 76, n. 2 (3 luglio 2020): 43–53. http://dx.doi.org/10.5755/j01.erem.76.2.21854.
Testo completoAbstract (sommario):
Biochar can serve as a soil ameliorant preventing nutrient leaching. Due to its porous structure and chemical composition, it can also adsorb elements on its surface. However, various biochars have different sorption ability, and the mechanistic understanding of nutrient storage in biochar is missing. It is not clear if nutrients adsorbed by biochar will be available for plants. Therefore, it is necessary to investigate biochar efficacy in pure substrates to characterise its specific influence on plants. In this study, the sorption capacity and ability of the wood-based biochar to provide barley plants with nutrients was investigated. The sorption capacity of biochar was investigated by saturating it with Gelrigel nutrient solution. Then nutrient-enriched biochar was tested for its effect on barley growth in comparison with non-enriched biochar. The results of the sorption experiment showed that the wood-based biochar could adsorb high amounts of nutrients such as ammonium (NH4+), potassium, calcium and phosphate (PO43-), but not nitrate (NO3-). Nutrient-enriched biochar showed an ability to support 46% higher dry biomass of barley than non-enriched biochar. These results suggest a potential of nutrient-enriched biochar for recovering essential nutrients for plants.
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Treter, Renan Jardel, Ivan Ricardo Carvalho, Danieli Jacoboski Hutra, Murilo Vieira Loro, Mariluci Cavinatto, Francine Lautenchleger e Inaê Carolina Sfalcin. "Symptoms and interrelationships of macro and micronutrients available for soybean". Agronomy Science and Biotechnology 8 (2 dicembre 2021): 1–15. http://dx.doi.org/10.33158/asb.r150.v8.2022.
Testo completoAbstract (sommario):
Nutrients have differences in their functions as metabolic and structural constituents in plant organs. The specific identification of the symptoms of excess or deficiency of nutrients is essential for the correct management to be carried out in order to avoid production losses. In this context, this research aimed to evaluate the symptoms of deficiency and excess of nutrients in soybean. The experiment was carried out on a bench, with 3-liter containers, in which uniformly germinated seedlings were selected for implantation. Initially, the seedlings were subjected to a complete nutrient solution to allow for a uniform and unrestricted initial development over a period of one week. Then, the plants were subjected to solutions with twice as much nutrient, absence of nutrients, complete solution and nutrient restriction, individual omissions resulted in morphological changes, which translated into visual symptoms characteristic of the nutritional deficiency of the respective nutrient. The solution with twice the nutrient concentration of the complete solution showed an increase in the absorption of N, Mg, K and Fe, for Cu it was twice the absorption and for Zn five times more. There was a decrease in the absorption of Ca and Mn and, with that, it is concluded that the availability of twice as many nutrients did not result in double their absorption.
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Ndakara, Ofudjaye Emmanuel, e Ifeanyi Morrison Atuma. "Characterising Rainwash Nutrient Fluxes and Soil Nutrients under Anacardium occidentale L. (Anacardiaceae) and Lowland Rainforest: implications for Ecosystem Management". Biodiversity Journal 15, n. 2 (2024): 143–55. http://dx.doi.org/10.31396/biodiv.jour.2024.15.2.143.155.
Testo completoAbstract (sommario):
This study aimed to ascertain the relationship between rainwash nutrient fluxes and soil nutrient properties under Anacardium occidentale L. (Anacardiaceae) and lowland rainforest for the purpose of sustainable ecosystem management. Both experimental and quasi experimental research designs were adopted. Samples from rainwash (for 12 months) and soil (from 0–15 cm and 15–30cm) were taken from 12 A. occidentale stands and 12 rainforests within 12 stratified quarters. Laboratory analyses of samples involved standard procedures, while data generated where statistically analysed. Results revealed that from A. occidentale and rainforest, fluxes of nutrients varied between throughfall (Tf) and stemflow (Sf), and between rainy season and dry season. The monthly nutrient fluxes by rainwash is such that Tf > Sf for both A. occidentale and native rainforest. The highest fluxes of nutrients by Tf occurred during dry months, with corresponding Sf fluxes were observed during rainy months. At 0.05 alpha levels, nutrient fluxes between Tf and Sf differed significantly; as well as between soil nutrient contents under A. occidentale and rainforest. Rainwash nutrients correlated positively and significantly with soil nutrients. Over time, A. occidentale add nutrients to soil through rainwash, therefore its cultivation is recommended for agro-forestry and sustainable ecosystem management.
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Marinov, I., S. C. Doney e I. D. Lima. "Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light". Biogeosciences 7, n. 12 (2 dicembre 2010): 3941–59. http://dx.doi.org/10.5194/bg-7-3941-2010.
Testo completoAbstract (sommario):
Abstract. The response of ocean phytoplankton community structure to climate change depends, among other factors, upon species competition for nutrients and light, as well as the increase in surface ocean temperature. We propose an analytical framework linking changes in nutrients, temperature and light with changes in phytoplankton growth rates, and we assess our theoretical considerations against model projections (1980–2100) from a global Earth System model. Our proposed "critical nutrient hypothesis" stipulates the existence of a critical nutrient threshold below (above) which a nutrient change will affect small phytoplankton biomass more (less) than diatom biomass, i.e. the phytoplankton with lower half-saturation coefficient K are influenced more strongly in low nutrient environments. This nutrient threshold broadly corresponds to 45° S and 45° N, poleward of which high vertical mixing and inefficient biology maintain higher surface nutrient concentrations and equatorward of which reduced vertical mixing and more efficient biology maintain lower surface nutrients. In the 45° S–45° N low nutrient region, decreases in limiting nutrients – associated with increased stratification under climate change – are predicted analytically to decrease more strongly the specific growth of small phytoplankton than the growth of diatoms. In high latitudes, the impact of nutrient decrease on phytoplankton biomass is more significant for diatoms than small phytoplankton, and contributes to diatom declines in the northern marginal sea ice and subpolar biomes. In the context of our model, climate driven increases in surface temperature and changes in light are predicted to have a stronger impact on small phytoplankton than on diatom biomass in all ocean domains. Our analytical predictions explain reasonably well the shifts in community structure under a modeled climate-warming scenario. Climate driven changes in nutrients, temperature and light have regionally varying and sometimes counterbalancing impacts on phytoplankton biomass and structure, with nutrients and temperature dominant in the 45° S–45° N band and light-temperature effects dominant in the marginal sea-ice and subpolar regions. As predicted, decreases in nutrients inside the 45° S–45° N "critical nutrient" band result in diatom biomass decreasing more than small phytoplankton biomass. Further stratification from global warming could result in geographical shifts in the "critical nutrient" threshold and additional changes in ecology.
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Draper, Harold H. "Nutrients as Nutrients and Nutrients as Prophylactic Drugs". Journal of Nutrition 118, n. 11 (1 novembre 1988): 1420–21. http://dx.doi.org/10.1093/jn/118.11.1420.
Testo completo
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Hariadi, Badi, Hermantoro Sastrohartono, Andreas Wahyu Krisdiarto, Sukarman Sukarman, Septa Primananda e Tri Haryo Sagoro. "The Prediction of Nitrogen, Phosphate, and Potassium Contents of Oil Palm Leaf Using Hand-Held Spectrometer". Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) 13, n. 1 (29 gennaio 2024): 71. http://dx.doi.org/10.23960/jtep-l.v13i1.71-81.
Testo completoAbstract (sommario):
A hand-held spectrometer can be used to evaluate oil palm (Elaeis guineensis Jacq.) leaf nutrient contents without being destructive. This study aims to develop regression equations and analyze the performance of the prediction models for Nitrogen, Phosphate, and Potassium leaf nutrient contents. The dependent variable in this study was the result of the analysis of nutrient contents in frond number 17 which was carried out in the laboratory, while the independent variable was the leaf reflectance value scanned with a hand-held spectrometer. The Normalized Difference approach is used to create a vegetation index from the combination of reflectance values at two wavelengths. Vegetation index with the highest correlation value to the nutrient content of leaves, is used to make a prediction model for leaf nutrients using the Simple Linear Regression. The regression equations formed to predict the contents of nutrients N, P, and K have high R2. The RMSE values of the predicted contents of N, P, and K nutrients, respectively were 0.21, 0.01, and 0.13; and correctness values of those nutrients respectively were 93.29%, 95.5%, and 88.81%. Keywords: Hand-held spectrometer, Oil palm, Prediction, Leaf nutrients contents.
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Louca, Panayiotis, Olatz Mompeo, Emily R. Leeming, Sarah E. Berry, Massimo Mangino, Tim D. Spector, Sandosh Padmanabhan e Cristina Menni. "Dietary Influence on Systolic and Diastolic Blood Pressure in the TwinsUK Cohort". Nutrients 12, n. 7 (17 luglio 2020): 2130. http://dx.doi.org/10.3390/nu12072130.
Testo completoAbstract (sommario):
Nutrition plays a key role in blood pressure (BP) regulation. Here, we examine associations between nutrient intakes and BP in a large predominantly female population-based cohort. We assessed the correlation between 45 nutrients (from food frequency questionnaires) and systolic BP/diastolic BP (SBP/DBP) in 3889 individuals from TwinsUK not on hypertensive treatments and replicated in an independent subset of monozygotic twins discordant for nutrient intake (17–242 pairs). Results from both analyses were meta-analysed. For significant nutrients, we calculated heritability using structural equation modelling. We identified and replicated 15 nutrients associated with SBP, 9 also being associated with DBP, adjusting for covariates and multiple testing. 14 of those had a heritable component (h2: 27.1–57.6%). Strong associations with SBP were observed for riboflavin (Beta(SE) = −1.49(0.38), P = 1.00 × 10−4) and tryptophan (−0.31(0.01), P = 5 × 10−4), while with DBP for alcohol (0.05(0.07), P = 1.00 × 10−4) and lactose (−0.05(0.0), P = 1.3 × 10−3). Two multivariable nutrient scores, combining independently SBP/DBP-associated nutrients, explained 22% of the variance in SBP and 13.6% of the variance in DBP. Moreover, bivariate heritability analysis suggested that nutrients and BP share some genetic influences. We confirm current understanding and extend the panel of dietary nutrients implicated in BP regulation underscoring the value of nutrient focused dietary research in preventing and managing hypertension.
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Kraus, Cleber, Marie-Paule Bonnet, Ina de Souza Nogueira, Maria Morais Pereira Souza Lobo, David da Motta Marques, Jérémie Garnier e Ludgero Cardoso Galli Vieira. "Unraveling Flooding Dynamics and Nutrients’ Controls upon Phytoplankton Functional Dynamics in Amazonian Floodplain Lakes". Water 11, n. 1 (16 gennaio 2019): 154. http://dx.doi.org/10.3390/w11010154.
Testo completoAbstract (sommario):
The processes in tropical floodplain lakes enable maintaining phytoplankton nutrient requirements over a hydrological year. The nutrients such as nitrogen, phosphorus and carbon compounds play an essential role in phytoplankton growth. However, the way that nutrients and phytoplankton interact and how this relationship varies seasonally in tropical freshwater ecosystems is not clear. In this study, we evaluate the relationship between phytoplankton–nutrients over the hydrological cycle in Amazonian floodplain lakes and verify if this relationship influences the biomass of cyanobacteria. We also check what factors linked to nutrients act in structuring phytoplankton community. Using the phytoplankton functional approach, we verified how their ability to respond to hydrological and environmental variations reflects the ecological conditions and investigated how these interactions work. The results show that the Amazonian floodplain lakes could maintain long-term nutrient enrichment status. The nutrients input conduces to cyanobacteria dominance, that allied to other factors, play an essential role in supporting the stability of the phytoplankton–nutrients relationship over the hydrological cycle.
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Thomson, V. P., e M. R. Leishman. "Survival of native plants of Hawkesbury Sandstone communities with additional nutrients: effect of plant age and habitat". Australian Journal of Botany 52, n. 2 (2004): 141. http://dx.doi.org/10.1071/bt03047.
Testo completoAbstract (sommario):
Australian soils are naturally low in nutrient concentrations, particularly nitrogen (N) and phosphorus (P). Native plants are well adapted to low-nutrient soils, and can be adversely affected when exposed to higher concentrations of nutrients. The Hawkesbury Sandstone soils in northern Sydney are naturally low in nutrients, but often receive additional nutrient input from urban stormwater run-off. Increases in soil nutrients in urban bushland are associated with the presence of exotic species, and the decline in the diversity of native species. This study tested the hypothesis that high concentrations of nutrients, in particular P, in the disturbed soils of urban bushland, reduce survival of native plants. We examined the survival of native species under five different nutrient concentrations that are typical of nutrient-enriched urban bushland soil, in two glasshouse experiments. The experiments examined both survival of seedlings and survival of 6-month-old plants. We used native species that are adapted to both nutrient-poor and nutrient-rich soils. In general, the survival of native plants decreased with increasing nutrient concentrations. At soil total-P concentrations >200 mg kg–1, most plants died. Seedlings were more sensitive to added nutrients than the 6-month-old plants. Species that were from higher-nutrient soil had consistently higher survival than species from low-nutrient soils, under the nutrient addition treatments. These results suggest that at high soil nutrient concentrations typical of stormwater-affected urban bushland, native plant species of low-nutrient soils will be unable to survive. If ecological restoration works are to be done in such areas, replanting with more mature plants from naturally high-nutrient habitats is likely to be the most successful. However, restoration of these areas may have limited success and they are likely to remain dominated by exotic plant species.
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Yamamoto, K., e T. Suetsugi. "Estimation of particulate nutrient load usingturbidity meter". Water Science and Technology 53, n. 2 (1 gennaio 2006): 311–20. http://dx.doi.org/10.2166/wst.2006.065.
Testo completoAbstract (sommario):
The “Nutrient Load Hysteresis Coefficient” was proposed to evaluate the hysteresis of the nutrient loads to flow rate quantitatively. This could classify the runoff patterns of nutrient load into 15 patterns. Linear relationships between the turbidity and the concentrations of particulate nutrients were observed. It was clarified that the linearity was caused by the influence of the particle size on turbidity output and accumulation of nutrients on smaller particles (diameter <23 μm). The L-Q-Turb method, which is a new method for the estimation of runoff loads of nutrients using a regression curve between the turbidity and the concentrations of particulate nutrients, was developed. This method could raise the precision of the estimation of nutrient loads even if they had strong hysteresis to flow rate. For example, as for the runoff load of total phosphorus load on flood events in a total of eight cases, the averaged error of estimation of total phosphorus load by the L-Q-Turb method was 11%, whereas the averaged estimation error by the regression curve between flow rate and nutrient load was 28%.
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Cui, Yaqi, e Qin Yue. "Regional Soil Nutrient Content Prediction Model Based on Big Data". Journal of Physics: Conference Series 2555, n. 1 (1 luglio 2023): 012005. http://dx.doi.org/10.1088/1742-6596/2555/1/012005.
Testo completoAbstract (sommario):
Abstract Soil nutrients play a decision-making role in environmental management, and the prediction of soil nutrients can be used to achieve precise fertilization and regulate production. In response to the problem of low accuracy of soil nutrient content prediction by traditional prediction models, this paper designs a prediction model of soil nutrient content based on big data statistics. Soil nutrient content data are collected using a spectral collector, and the data are smoothed, standardized, and orthogonalized to eliminate the data that affect the prediction accuracy. The processed spectrograms are analyzed to summarize the big data law of soil nutrients and clarify that different bands at the abrupt change of reflection curve correspond to different contents of soil nutrients. After repeating several times, the calibration of model accuracy is completed, and the design of the soil nutrient content prediction model based on big data statistics is realized. Through comparison experiments with the traditional model, it was verified that the designed model can improve the prediction accuracy by about 3 times and is more suitable for the prediction of soil nutrient content.