scholarly journals Posidonia-based Compost as a Peat Substitute for Lettuce Transplant Production

HortScience ◽  
2012 ◽  
Vol 47 (10) ◽  
pp. 1438-1444 ◽  
Author(s):  
Carlo Mininni ◽  
Pietro Santamaria ◽  
Hamada M. Abdelrahman ◽  
Claudio Cocozza ◽  
Teodoro Miano ◽  
...  

Posidonia [Posidonia oceanica (L.) Delile] is a marine phanerogam endemic of the Mediterranean Sea that grows all along the coast forming extensive underwater meadows. Senescent posidonia leaves, together with fibers (residues of rhizomes and decomposed leaves), periodically accumulate along Mediterranean beaches, covering vast areas of coast. Removal and disposal of these large volumes of plant biomasses represent a high cost for local administrations. Therefore, in this experiment, beached residues of posidonia were composted with olive pruning and green wastes with the objective to assess the efficacy of posidonia-based compost (63% on a volume basis) as a peat replacement. The compost was then mixed with a peat-based commercial substrate at rates of 0% (C0, pure peat-based commercial substrate tested as control), 25% (C25), 50% (C50), 75% (C75), and 100% (C100, pure posidonia-based compost) v/v. Mixtures were used as growing media to produce lettuce seedlings for transplant. Two lettuce cultivars (8511RZ and Satine) were tested. Main physical and chemical properties of the five growing media, shoot and root fresh and dry weight, leaf area, root morphology, and elemental leaf tissue composition were studied. Growing media containing posidonia-based compost, C25 and C50 in particular, showed good physical properties. Increasing compost proportions in the mixtures resulted in enhanced: 1) availability of macro- and micronutrients in the growing media; and 2) overall growth parameters of lettuce seedlings, in particular for the cultivar Satine. In conclusion, posidonia-based compost shows a considerable potential as a peat substitute in horticultural substrates; posidonia residues are a low-cost renewable material. In growing media for lettuce seedlings production, posidonia-based compost could be used as a complement to peat at a rate of 25% or 50% to obtain optimal physical properties and to limit the negative effects of high B content, which are typical of posidonia residues.

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Sergio Arias Quintero ◽  
Joshua Schmitt ◽  
Richard Blair ◽  
Jayanta Kapat

Historically, gas turbine fuels have been procured based on availability and low cost criteria. However,in the past few decades, with the growing concern over the negative environmental impacts produced by emissions, alternative fuels have been developed and tested under the objective of reducing such negative effects. The physical properties and broad chemical composition of fuels, including trace elements, may result in engine performance issues found only after extensive operation. This, in turn, results in higher maintenance and operation costs. This paper studies the feasibility of several renewable fuels for microturbine application, identifying key relationships between the physical and chemical properties, thermal stability, materials compatibility, and turbine performance.


AGRICA ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 38-43
Author(s):  
Ketut Turaini Indra Winten

The low of growth and yield of lettuce is quite often caused by the low of soil fertility, especially nitrogen and C-organic content. Poor soil physical properties also contribute to the cause of low yield of lettuce. Improved soil physical and chemical properties by adding casting fertilizers and nitrogen are expected to be able to increase the yields of lettuce. The field experiment was conducted in Candikuning village, district of Baturiti, Tabanan regency, from October 2005 to January 2006. The objective of the experiment was to study the effect of casting fertilizer and nitrogen rates on the growth and yields of lettuce. A randomized complete block design was used in this experiment and two treatment factors were imposed. Those two treatment factors were rates of casting fertilizers (i.e. 0, 10, 20 and 30 t ha"1 ) and rates of N (i.e. 0, 92, 138 and 184 kg N ha"1), which were arranged factorially and repeated three times. Results of the experiment indicated that interaction between casting fertilizer and nitrogen rates did not significantly affect the yields of lettuce. The rates of N only significantly affected several growth variables and the oven-dry weight of heads plant-1. Increased rates of N from 0 to 92 kg N ha-1 significantly resulted in the oven-dry weight of heads of 2.798 g plant-1 which was 13.9% higher than that of 0 kg N ha-1. Rates of casting fertilizer significantly affected head diameter and the oven-dry weight of heads plant"1 and ha-1. Increased rates of casting fertilizer from 0 to 10 t ha-1 gave the oven-dry weight of heads as much as 0.232 t ha"1 or 9.43% higher than the weight given by the rate of 0 t ha-1. The effects of rates of casting fertilizer and N were only significant on several soil physical properties. The relationship between rates of casting fertilizer and yields of lettuce was quadratic (Y = 0.21135 + 0.0032 X - 0.001 X2 ; R2 = 0.981). The optimum rate of casting fertilizer was 16.0 t ha-1 with the maximum oven-dry weight of heads of 0.237 t ha-1, meanwhile, the optimum rate of N had not obtained in this experiment.


1992 ◽  
Vol 22 (7) ◽  
pp. 945-949 ◽  
Author(s):  
R. S. Folk ◽  
V. R. Timmer ◽  
J. B. Scarratt

Jack pine (Pinusbanksiana Lamb.) seedlings were grown in paperpots filled with 26 different horticultural peat moss substrates to evaluate conventional laboratory indices for characterizing container growing media. Seedling growth performance varied on the different substrates; dry weight differed 52% and height at harvest differed 37% between the best and poorest yielding peat. Precultural physical and chemical properties of the growing media varied widely, but correlated weakly with growth and nutrient composition of the seedlings, suggesting that conventional laboratory indices were not sensitive enough to predict peat suitability for jack pine culture. Height growth was significantly related to nutrient composition of the seedlings; however, correlations were low when tested against initial measures of peat nutrient status. Foliar vector diagnoses of both high- and low-yield plants identified N and P as the primary and secondary nutritional constraints upon growth, respectively. Since plants received a common fertilizer regime, seedling development may be more closely associated with specific fertilizer–substrate interactions rather than conventional precultural test measures. Further research is needed to develop quality indices more sensitive to potential nutrient supply and fertilizer reactions in container rooting media.


Author(s):  
S. Arias Quintero ◽  
J. Schmitt ◽  
R. Blair ◽  
J. Kapat

Historically, gas turbine fuels have been procured based on availability and low cost criteria. But in the last few decades, with the growing concern over the negative environmental impacts produced by emissions, alternative fuels have been developed and tested with the objective to reduce such negative effects. Physical properties and the broad chemical composition, including trace elements, may result in engine performance issues found only after extensive operation. This, in turn, results in higher maintenance and operation costs. This paper studies the feasibility for microturbine application of several renewable fuels, identifying key relationships between physical and chemical properties, thermal stability, materials compatibility, and turbine performance.


2020 ◽  
Vol 71 (1) ◽  
pp. 192-200
Author(s):  
Anca-Luiza Stanila ◽  
Catalin Cristian Simota ◽  
Mihail Dumitru

Highlighting the sandy soil of Oltenia Plain calls for a better knowledge of their variability their correlation with major natural factors from each physical geography. Pedogenetic processes specific sandy soils are strongly influenced by nature parent material. This leads, on the one hand, climate aridity of the soil due to strong heating and accumulation of small water reserves, consequences emphasizing the moisture deficit in the development of the vegetation and favoring weak deflation, and on the other hand, an increase in mineralization organic matter. Relief under wind characteristic sandy land, soil formation and distribution has some particularly of flat land with the land formed on the loess. The dune ridges are less evolved soils, profile underdeveloped and poorly supplied with nutrients compared to those on the slopes of the dunes and the interdune, whose physical and chemical properties are more favorable to plant growth.Both Romanati Plain and the Blahnita (Mehedinti) Plain and Bailesti Plain, sand wind shaped covering a finer material, loamy sand and even loess (containing up to 26% clay), also rippled with negative effects in terms of overall drainage. Depending on the pedogenetic physical and geographical factors that have contributed to soil cover, in the researched were identified following classes of soils: protisols, cernisols, cambisols, luvisols, hidrisols and antrosols.Obtaining appropriate agricultural production requires some land improvement works (especially fitting for irrigation) and agropedoameliorative works. Particular attention should be paid to preventing and combating wind erosion.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1476
Author(s):  
Ana Cristina Ferrão ◽  
Raquel P. F. Guiné ◽  
Elsa Ramalhosa ◽  
Arminda Lopes ◽  
Cláudia Rodrigues ◽  
...  

Hazelnuts are one of the most appreciated nuts worldwide due to their unique organoleptic and nutritional characteristics. The present work intended to analyse several physical and chemical properties of different hazelnut varieties grown in Portugal, namely Tonda de Giffoni, Grada de Viseu, Segorbe, Longa de Espanha, Butler, Gunslebert, and Negreta. In general, the results revealed statistically significant differences between the varieties under study. The Gunslebert had more elongated hazelnuts and with heavier shelled fruits, while the kernels of the Grada de Viseu revealed to be heavier. Grada de Viseu was harder in the shell, Gunslebert had a harder core, and Segorbe was more resistant to fracture. Fat was the more representative component for all varieties and in some cases the values of moisture and water activity were over the recommended amount (≥0.62). Tonda de Giffoni was the variety with the highest induction time, indicating the highest oxidation stability. Moreover, discriminant analysis revealed that the variables more important to distinguish the varieties were protein (λ = 0.007) and water activity (λ = 0.010). The results of this study help to better understand the differences between some hazelnut varieties that are cultivated in Portugal, which gives important hints for all players in the hazelnut sector.


2021 ◽  
pp. 1-10
Author(s):  
Anshu Siwach ◽  
Siddhartha Kaushal ◽  
Ratul Baishya

Abstract Mosses are one of the most important and dominant plant communities, especially in the temperate biome, and play a significant role in ecosystem function and dynamics. They influence the water, energy and element cycle due to their unique ecology and physiology. The present study was undertaken in three different temperate forest sites in the Garhwal Himalayas, viz., Triyuginarayan (Kedarnath Wildlife Sanctuary (KWLS)), Chakrata, and Kanasar forest range. The study was focused on understanding the influence of mosses on soil physical properties and nutrient availability. Different physico-chemical properties were analysed under two different substrata, that is, with and without moss cover in two different seasons, viz., monsoon and winter. We observed mosses to influence and alter the physical properties and nutrient status of soil in both seasons. All soil physical and chemical properties, except magnesium, showed significant difference within the substrates, among all the sites and across the two seasons. Besides the soil characteristics underneath the moss vegetation, the study also highlights the diversity of mosses found in the area. Mosses appear to create high nutrient microsites via a high rate of organic matter accumulation and retain nutrients for longer periods thus, maintaining ecosystem stability.


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2998
Author(s):  
Mohammed Nadeem Bijle ◽  
Manikandan Ekambaram ◽  
Edward Lo ◽  
Cynthia Yiu

The in vitro study objectives were to investigate the effect of arginine (Arg) incorporation in a 5% sodium fluoride (NaF) varnish on its physical and chemical properties including F/Arg release. Six experimental formulations were prepared with L-arginine (L-Arg) and L-arginine monohydrochloride at 2%, 4%, and 8% w/v in a 5% NaF varnish, which served as a control. The varnishes were subjected to assessments for adhesion, viscosity, and NaF extraction. Molecular dynamics were simulated to identify post-dynamics total energy for NaF=Arg/Arg>NaF/Arg<NaF concentrations. The Arg/F varnish release profiles were determined in polyacrylic lactate buffer (pH-4.5; 7 days) and artificial saliva (pH-7; 1 h, 24 h, and 12 weeks). Incorporation of L-Arg in NaF varnish significantly influences physical properties ameliorating retention (p < 0.001). L-Arg in NaF varnish institutes the Arg-F complex. Molecular dynamics suggests that NaF>Arg concentration denotes the stabilized environment compared to NaF<Arg (p < 0.001). The 2% Arg-NaF exhibits periodic perennial Arg/F release and shows significantly higher integrated mean F release than NaF (p < 0.001). Incorporating 2% L-arginine in 5% NaF varnish improves its physical properties and renders a stable matrix with enduring higher F/Arg release than control.


2011 ◽  
Vol 3 (5) ◽  
pp. 37-42
Author(s):  
Renata Mikalauskienė ◽  
Donatas Butkus ◽  
Ingrida Pliopaitė Bataitienė

The present article describes changes in specific activities and fluctuations in the ratio of natural 40K and artificial 137Cs radionuclides in soil samples taken from different places of Lithuanian territory. The samples of soil have been selected from the districts polluted after the accident in Chernobyl nuclear plant performing nuclear testing operations. The study has established the main physical and chemical properties of soil samples and their impact on the concentration of 40K activities. 137Cs/40K specific activities in soil have been observed under the dry weight of the sample that varied from 0.0034 to 0.0240. The results of the study could be used for establishing and estimating 137Csand 40K transfer in the system “soil-plant”. Santrauka Straipsnyje nagrinėjama gamtinės (40K) ir dirbtinės (137Cs) kilmės radionuklidų savitųjų aktyvumų ir jų santykio kaita skirtinguose Lietuvos teritorijos dirvožemiuose. Dirvožemio mėginiai parinkti iš vietovių, kurios buvo labiau užterštos po Černobylio atominės elektrinės avarijos ir buvusių branduolinių bandymų. Tyrimo metu nustatytos pagrindinės fizinės cheminės dirvožemio savybės ir jų poveikis 40K aktyvumų koncentracijai. 137Csir 40K savitieji aktyvumai dirvožemyje tirti esant sausam mėginio svoriui. 137Cs savitieji aktyvumai sausame dirvožemyje svyravo nuo 1,1±1,0 iki 14,3±0,9 Bq/kg, o 40K savitieji aktyvumai – nuo 326±29 iki 740±15 Bq/kg. 137Csir 40K savitųjų aktyvumų santykis skirtingų vietovių dirvožemiuose kito nuo 0,0034 iki 0,0240 Bq/kg. Tyrimo rezultatai gali būti panaudoti, nustatant ir įvertinant 137Csir 40K pernašą sistemoje dirvožemis–augalai.


2021 ◽  
Vol 410 ◽  
pp. 469-474
Author(s):  
Ivan S. Safronov ◽  
Alexander I. Ushakov

One of the most important purposes of materials science is the ability to govern the physical properties of materials characterized by different structures. The strength properties of nanostructured metal alloys do not always meet the exploitation requirements. The set of properties of such materials is stable within narrow limits: temperature, mechanical, and corrosion conditions. Traditional processing modes are ineffective for such materials. Attempts to use them often lead to the loss of unique physical and chemical properties. The most effective methods of processing such materials are associated with the use of laser radiation. The laser pulse has a number of features, including a complex effect on the surface layers of the material. Spot and short irradiation with high-energy rays can preserve the unique physical properties of samples as a whole and improve strength indicators without destroying the structure of the material as a whole.


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