scholarly journals Hazenite: a new secondary phosphorus, potassium and magnesium fertiliser

2020 ◽  
Vol 66 (No. 1) ◽  
pp. 1-6 ◽  
Author(s):  
Conor Watson ◽  
Joachim Clemens ◽  
Florian Wichern
Keyword(s):  
Soil Amendment ◽  
Phosphorus Uptake ◽  
Good Alternative ◽  
P Uptake ◽  
Shoot Biomass ◽  
Forage Grasses ◽  
Triple Superphosphate ◽  
First Time ◽  
Muriate Of Potash ◽  
The Ideal

Secondary fertilisers are becoming an important alternative to conventional mined fertilisers. For the first time, the struvite "relative" hazenite (KNaMg<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>∙14 H<sub>2</sub>O) has been artificially synthesised. A pot trial assessed whether hazenite-fertilised ryegrass had comparable potassium (K), magnesium (Mg), or phosphorus (P) uptake and shoot yields with treatments receiving conventional K (muriate of potash), Mg (kieserite) or P (triple superphosphate, TSP) fertilisers. Ryegrass shoot biomass production and K/Mg uptake in replicates receiving hazenite were as good as or superior to those amended with conventional fertilisers. Phosphorus uptake of plants whose P source was TSP was significantly higher than that of the hazenite-amended replicates without significantly higher shoot biomass, indicating luxury P uptake. Hazenite’s constituent sodium (Na) makes it a potentially useful soil amendment for forage grasses or natrophilic crops such as sugar beet. Its component Mg would also be desirable in forage grasses to pre-empt ruminant hypomagnesemia or in crops with a relatively high Mg demand, for example, maize. Furthermore, hazenite represents a good alternative to KCl for chlorophobic crops such as potatoes. However, given its unusual ratio of Mg, P, and K, the ideal application of hazenite would probably be in combination with other fertilisers.

scholarly journals Mycorrhiza Reduces Phosphorus Uptake from Struvite in Rye (Secale cereale L.) Plants

2021 ◽  
Author(s):  
Sanja Annabell Schwalb ◽  
Michael Hemkemeyer ◽  
Conor Watson ◽  
Florian Wichern
Keyword(s):  
Secale Cereale ◽  
Arbuscular Mycorrhizae ◽  
Phosphorus Uptake ◽  
Inorganic Phosphorus ◽  
P Uptake ◽  
Control Treatment ◽  
Shoot Biomass ◽  
Extractable P ◽  
Secale Cereale L ◽  
Middle Compartment

AbstractTo reduce dependency on inorganic phosphorus (P) fertiliser, secondary P fertilisers such as struvite are becoming more important. However, the P uptake of these new fertilisers by plants is often not known and may be enhanced by plant associated microorganisms. We therefore investigated the effect of arbuscular mycorrhizae (AM) on P uptake in rye (Secale cereale L.), grown in the middle compartment of a box with chambers separated by a 30 µm mesh allowing fungal hyphae but not roots to penetrate. Plants with (AM) or without (control) mycorrhizae (Rhizophagus irregularis) were grown in a P limited sand medium for 72 days. After harvest, plants were analysed for mycorrhizal colonization, shoot and root development and nutrient (P, Ca, Mg) uptake. Further, pH was measured in each compartment. Shoot biomass of both treatments was not different, but root biomass was significantly lower in AM plants. Despite plants of the AM treatment being colonised by mycorrhizae, their P uptake was substantially lower compared to the control treatment, but root nutrient concentration was higher. Even though the pH in the mycorrhizal compartment of the AM treatment was significantly lower compared to the control, water- and CAL-extractable P were similar, indicating little P uptake from this compartment. Extractable P was reduced only in the root compartment of the control, which was associated with a lower pH compared to the AM treatment. In conclusion, mycorrhizae did not increase P uptake from struvite in rye plants. Non-mycorrhizal plants which invested more biomass into roots took up more P. Graphical abstract

The Republic

2019 ◽  
pp. 205-229
Author(s):  
Dominic Scott
Keyword(s):  
Political Theory ◽  
Left Behind ◽  
Ideal State ◽  
The Republic ◽  
Individual Justice ◽  
The Individual ◽  
Political Right ◽  
First Time ◽  
The Ideal

This chapter presents a reading of Plato’s Republic. The Republic is among Plato’s most complex works. From its title, the first-time reader will expect a dialogue about political theory, yet the work starts from the perspective of the individual, coming to focus on the question of how, if at all, justice contributes to an agent’s happiness. Only after this question has been fully set out does the work evolve into an investigation of politics—of the ideal state and of the institutions that sustain it, especially those having to do with education. But the interest in individual justice and happiness is never left behind. Rather, the work weaves in and out of the two perspectives, individual and political, right through to its conclusion. All this may leave one wondering about the unity of the work. The chapter shows that, despite the enormous range of topics discussed, the Republic fits together as a coherent whole.

Philosophy and Education

1998 ◽  
pp. 32-36
Author(s):  
Luciana Bellatalla
Keyword(s):  
Western Culture ◽  
Cultural Tradition ◽  
The World ◽  
Dialogic Approach ◽  
First Time ◽  
The Ideal

From its first appearance in western culture, philosophy has been considered able to build up reality, to educate people, and to disclose truth. Plato proposed philosophers as governors in life-long pursuit of philosophical learning. Socrates was the ideal paradigm of an educating philosopher: he tried to wake up human minds so that they could be aware of themselves and of the world, criticizing tradition and prejudices in a logically consistent perspective. A critical and dialogic approach—not by mere chance defined as "Socratic"—to problems has been considered until now the most profitable method of teaching. Socrates is a pioneer in discussing the question of a philosophical (paideia), as he defined his method "maieutic." He was not an authoritarian teacher, but a sparring partner in the process of self-education. Moreover, he considered himself as the most learned and, at the same time, the wisest in Greece, just because he was conscious of his ignorance. Therefore, he understood for the first time in our cultural tradition that knowledge is an endless process rather than a product, within marked bounds.

Nitrogen fertilization stimulates germination of dormant pin cherry seed

1979 ◽  
Vol 9 (4) ◽  
pp. 514-516 ◽  
Author(s):  
L. R. Auchmoody
Keyword(s):  
Ammonium Sulfate ◽  
Nitrogen Fertilization ◽  
Forest Floor ◽  
Calcium Nitrate ◽  
Nitrogen Fertilizers ◽  
Triple Superphosphate ◽  
Breaking Dormancy ◽  
Muriate Of Potash

Nitrogen fertilizers triggered germination of dormant Prunuspensylvanica L. seed naturally buried in the forest floor of 60-year-old Allegheny hardwood stands. Neither triple superphosphate nor muriate of potash applied with urea increased germination over that which occurred with urea alone. Rates as low as 56 kg/ha N from urea and calcium nitrate and 112 kg/ha N from ammonium sulfate stimulated germination. Nitrate was apparently responsible for breaking dormancy.

The Activities of the Tube Feet of Asterias Rubens L

1947 ◽  
Vol s3-88 (1) ◽  
pp. 1-14
Author(s):  
J. E. SMITH
Keyword(s):  
Forward Direction ◽  
The Other ◽  
Asterias Rubens ◽  
Ideal Form ◽  
First Time ◽  
Intrinsic Musculature ◽  
Tube Feet ◽  
Postural Muscles ◽  
The Ideal

1. An account is given of the muscular anatomy of the foot and ampulla of Asterias rubens. An intrinsic musculature of the sucker figured by Cuénot (1891) and Chadwick (1923) is shown not to be present; on the other hand, postural muscles responsible for orientating the podium, levator fibres which ‘cup’ the sucker, and radial fibres which flatten it are described and figured for the first time. 2. The role of the different muscle systems, the collagen connective tissue, and the fluid of the hydrocoel in protracting and retracting the foot, and in effecting the attachment and detachment of the sucker, is discussed. 3. Evidence is presented, to show that postural pointing of the foot is brought about by the contraction of a ring of muscles encircling the base of the podium. The orienting muscles are functionally, but not anatomically, distinct from the longitudinal fibres of the retractor sheath. 4. The ambulatory step is shown to comprise a series of linked phases of static posture and of movement. Each phase is characterized by the contraction of one member of each of the two opposing pairs of muscles engaged in the development of the step. The two pairs of muscles are (1) the anterior and posterior orienting fibres, and (2) the protractors and retractors of the foot. In its ideal form the step comprises four phases of static posture alternating with four movements. Each movement is ushered in by a reversal of the contraction-relaxation relationships of one of the two pairs of opposing muscle systems. Four such changes are possible and they occur in a sequence that ensures the orderly succession of the four movements of protraction, swing back, retraction, and swing forward, of which movements the idealized stepping cycle is composed. 5. The actual locomotory step departs from the ideal form in two respects: (1) it is liable to become disrupted by a delay in the initiation of the protraction or of the backswing movement, and (2) withdrawal of the podium occurs simultaneously with its re-orientation in the forward direction. It is pointed out that these variations are explicable on the assumption that, in the two series of opposing muscle pairs, the retractor fibres are more readily excited to contract than are their antagonists, and the anterior postural muscles than the posterior postural fibres.

Franciscan Books and their Readers

2022 ◽  
Author(s):  
René Hernández
Keyword(s):  
Space Form ◽  
Northern Italy ◽  
Ideal Space ◽  
Skilled Readers ◽  
Personal Library ◽  
Key Aspects ◽  
Cultural Agency ◽  
First Time ◽  
The Ideal

The book explores the manuscripts written, read, and studied by Franciscan friars from the thirteenth to the fifteenth centuries in Northern Italy, and specifically Padua, assessing four key aspects: ideal, space, form and readership. The ideal is studied through the regulations that determined what manuscripts should aim for. Space refers to the development and role of Franciscan libraries. The form is revealed by the assessment of the physical configuration of a set of representative manuscripts read, written, and manufactured by the friars. Finally, the study of the readership shows how Franciscans were skilled readers who employed certain forms of the manuscript as a portable, personal library, and as a tool for learning and pastoral care. By comparing the book collections of Padua’s reformed and unreformed medieval Franciscan libraries for the first time, this study reveals new features of the ground-breaking cultural agency of medieval friars.

The impact of biomass harvesting on phosphorus uptake by wetland plants

2001 ◽  
Vol 44 (11-12) ◽  
pp. 61-67 ◽  
Author(s):  
S-Y. Kim ◽  
P.M. Geary
Keyword(s):  
Plant Biomass ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Plant Parts ◽  
Biomass Harvesting ◽  
Below Ground ◽  
The Impact ◽  
Total P ◽  
Better Than ◽  
P Removal

Two species of macrophytes, Baumea articulata and Schoenoplectus mucronatus, were examined for their capacity to remove phosphorus under nutrient-rich conditions. Forty large bucket systems with the two different species growing in two types of substrate received artificial wastewaters for nine months, simulating a constructed wetland (CW) under high loading conditions. Half of the plants growing in the topsoil and gravel substrates were periodically harvested whereas the other half remained intact. Plant tissue and substrate samples were regularly analysed to determine their phosphorus concentrations. With respect to phosphorus uptake and removal, the Schoenoplectus in the topsoil medium performed better than the Baumea. Biomass harvesting enhanced P uptake in the Schoenoplectus, however the effect was not significant enough to make an improvement on the overall P removal, due to the slow recovery of plants and regrowth of biomass after harvesting. From P partitioning, it was found that the topsoil medium was the major P pool, storing most of total P present in the system. Plant parts contributed only minor storage with approximately half of that P stored below ground in the plant roots. The overall net effect of harvesting plant biomass was to only remove less than 5% of total phosphorus present in the system.

scholarly journals Gafsa rock phosphate and triple superphosphate for dry matter production and P uptake by corn

2005 ◽  
Vol 62 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Rossini Mattos Corrêa ◽  
Clístenes Williams Araújo do Nascimento ◽  
Silvana Keely de Sá Souza ◽  
Fernando José Freire ◽  
Gleibson Barbosa da Silva
Keyword(s):  
Dry Matter ◽  
Rock Phosphate ◽  
P Uptake ◽  
Production Costs ◽  
Dry Matter Production ◽  
Triple Superphosphate ◽  
Broadcast Application ◽  
Matter Production ◽  
Plant P Uptake ◽  
Corn Plants

Crops in general make poor use of phosphorous fertilizer and, as a result, recommended rates and production costs are very high. Phosphorus can be made more readily available to plants by proper management of phosphate fertilization, selecting both, type of fertilizer and application method. This study was carried out to evaluate the efficiency of the natural Gafsa rock phosphate and the triple superphosphate on dry matter production and P uptake by corn plants cultivated in a greenhouse. Fertilizers were applied localized and broadcast/incorporated on to two soils with contrasting phosphorus capacity factors (PCF). Rock phosphate broadcast application was as efficient as triple superphosphate in increasing corn plant dry matter in the Tropudult, with lower PCF. This effect was not observed on the Haplustox, owing to the lower P solubility due to the higher Ca concentration in this soil. Triple superphosphate rates increased plant P uptake in both soils and for both application forms. Rock phosphate resulted in higher P-content in plants, but only for broadcast application on the Ultisol.

scholarly journals Water and phosphorus uptake by upland rice root systems unraveled under multiple scenarios: linking a 3D soil-root model and data

2020 ◽  
Author(s):  
Trung Hieu Mai ◽  
Pieterjan De Bauw ◽  
Andrea Schnepf ◽  
Roel Merckx ◽  
Erik Smolders ◽  
...  
Keyword(s):  
Upland Rice ◽  
Phosphorus Uptake ◽  
Root Systems ◽  
Multiscale Model ◽  
P Uptake ◽  
Water Dynamics ◽  
Small Scale ◽  
P Availability ◽  
P Deficiency ◽  
Plant P Uptake

AbstractBackground and aimsUpland rice is often grown where water and phosphorus (P) are limited and these two factors interact on P bioavailability. To better understand this interaction, mechanistic models representing small-scale nutrient gradients and water dynamics in the rhizosphere of full-grown root systems are needed.MethodsRice was grown in large columns using a P-deficient soil at three different P supplies in the topsoil (deficient, suboptimal, non-limiting) in combination with two water regimes (field capacity versus drying periods). Root architectural parameters and P uptake were determined. Using a multiscale model of water and nutrient uptake, in-silico experiments were conducted by mimicking similar P and water treatments. First, 3D root systems were reconstructed by calibrating an architecure model with observed phenological root data, such as nodal root number, lateral types, interbranch distance, root diameters, and root biomass allocation along depth. Secondly, the multiscale model was informed with these 3D root architectures and the actual transpiration rates. Finally, water and P uptake were simulated.Key resultsThe plant P uptake increased over threefold by increasing P and water supply, and drying periods reduced P uptake at high but not at low P supply. Root architecture was significantly affected by the treatments. Without calibration, simulation results adequately predicted P uptake, including the different effects of drying periods on P uptake at different P levels. However, P uptake was underestimated under P deficiency, a process likely related to an underestimated affinity of P uptake transporters in the roots. Both types of laterals (i.e. S- and L-type) are shown to be highly important for both water and P uptake, and the relative contribution of each type depend on both soil P availability and water dynamics. Key drivers in P uptake are growing root tips and the distribution of laterals.ConclusionsThis model-data integration demonstrates how multiple co-occurring single root phene responses to environmental stressors contribute to the development of a more efficient root system. Further model improvements such as the use of Michaelis constants from buffered systems and the inclusion of mycorrhizal infections and exudates are proposed.

scholarly journals Simultaneous phosphorus uptake and denitrification by EBPR-r biofilm under aerobic conditions: effect of dissolved oxygen

2015 ◽  
Vol 72 (7) ◽  
pp. 1147-1154 ◽  
Author(s):  
Pan Yu Wong ◽  
Maneesha P. Ginige ◽  
Anna H. Kaksonen ◽  
Ralf Cord-Ruwisch ◽  
David C. Sutton ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Aerobic Denitrification ◽  
Biological Phosphorus Removal ◽  
Denitrification Activity ◽  
Biofilm Process ◽  
Oxygen Intrusion ◽  
Biofilm Structure ◽  
Biological Phosphorus

A biofilm process, termed enhanced biological phosphorus removal and recovery (EBPR-r), was recently developed as a post-denitrification approach to facilitate phosphorus (P) recovery from wastewater. Although simultaneous P uptake and denitrification was achieved despite substantial intrusion of dissolved oxygen (DO &gt;6 mg/L), to what extent DO affects the process was unclear. Hence, in this study a series of batch experiments was conducted to assess the activity of the biofilm under various DO concentrations. The biofilm was first allowed to store acetate (as internal storage) under anaerobic conditions, and was then subjected to various conditions for P uptake (DO: 0–8 mg/L; nitrate: 10 mg-N/L; phosphate: 8 mg-P/L). The results suggest that even at a saturating DO concentration (8 mg/L), the biofilm could take up P and denitrify efficiently (0.70 mmol e−/g total solids*h). However, such aerobic denitrification activity was reduced when the biofilm structure was physically disturbed, suggesting that this phenomenon was a consequence of the presence of oxygen gradient across the biofilm. We conclude that when a biofilm system is used, EBPR-r can be effectively operated as a post-denitrification process, even when oxygen intrusion occurs.

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