Effect Of Different Rates Research Articles

Fast Heating Induced Thermoacoustic Waves in Supercritical Fluids: Experimental and Numerical Studies

Thermoacoustic waves in near-critical supercritical carbon dioxide are investigated experimentally on acoustic time scales using a fast electrical heating system along with high speed pressure measurements. Supercritical carbon dioxide (near the critical or the pseudocritical states) in an enclosure is subjected to fast boundary heating with a thin nickel foil and an R-C circuit. The combination of very high thermal compressibilities and vanishingly small thermal diffusivities of the near-critical fluid affect the thermal energy propagation, leading to the formation of acoustic waves as carriers of thermal energy (the so called piston effect). The experimental results show that under the same temperature perturbation at the boundary, the strength of the acoustic field is enhanced as the initial state of the supercritical fluid approaches criticality. The heating rate, at which the boundary temperature is raised, is a key factor in the generation of these acoustic waves. The effect of different rates of boundary heating on the acoustic wave formation mechanism near the critical point is studied. The thermoacoustic wave generation and propagation in near-critical supercritical fluid is also investigated numerically and compared with the experimental measurements. The numerical predictions show a good agreement with the experimental data.

Physiological Response of Forage Sorghum to Polymer under Water Deficit Conditions

Sorghum [Sorghum bicolor (L.) Moench] is among the most important warm‐season forages that is grown in mainly arid and semiarid regions of southeastern Iran. Irrigation water is an energy‐intensive input and it is also becoming scarce and costly in this country. Soil application of polymeric materials such as Superab A200 (SAP) can increase soil water storage capacity and increase water use efficiency (WUE). The objective of this study was to investigate the effect of different rates of SAP and irrigation regimes on dry matter yield, WUE, and some physiological and yield‐related traits of Speedfeed sorghum. The experiment was conducted in Zahedan, Iran, during the 2009 and 2010 seasons under limited irrigation regimes (irrigation after 40, 60, 80, and 100% crop evapotranspiration = ETc) and four rates of SAP application (0, 75, 150, and 225 kg ha–1). Results indicated significant effects of irrigation regimes, SAP levels, and their interaction. The analysis for dry matter, WUE, and benefit/cost ratio showed that applying SAP at 100% ETc had no effect on these traits, but in the treatments with water deficit, it improved all the studied traits of sorghum. With regard to economic analysis, applying 75 kg ha–1 SAP for a decrease in the sorghum’s water requirement of as much as 20% is economically justified at moderate water deficits.

Doses e épocas de aplicação de regulador de crescimento em híbridos de milho

A fim de avaliar o efeito do regulador de crescimento trinexapac-ethyl em diferentes doses e épocas de aplicação em dois híbridos de milho, instalaram-se dois experimentos em Ponta Grossa, PR, Brasil, no ano agrícola de 2010/11. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 4 x 4 (doses x épocas de aplicação), com quatro repetições. Os tratamentos constaram da aplicação do trinexapac-ethyl (Moddus®) nas doses de 0,0, 187,5, 375,0 e 562,5 g ha-1 nos estádios V2, V4, V6 e V8 do milho, nos híbridos Status TL e Maximus TLTG. Avaliaram-se características agronômicas, componentes de produção e produtividade. A época de aplicação do trinexapac-ethyl não afetou características agronômicas e a produtividade dos dois híbridos de milho. Em relação à dose do regulador, somente o Maximus TLTG mostrou aumento da largura e diminuição do comprimento das folhas com o incremento da dose do produto, sem efeitos substanciais nos componentes da produção e na produtividade. Os resultados mostraram pouca resposta dos híbridos avaliados à dose e época de aplicação do trinexapac-ethyl; ao contrário do trigo, o uso na cultura deve ser mais bem avaliado, especialmente em relação à dose do produto e à reação de híbridos.

The effecT of ferTIlIzaTIon wITh dIfferenT ra Tes of poTassIuM and calcIuM carbonaTe on yIeld, vITaMIn c conTenT, and salT concenTra TIon In The MedIuM of sTalk celery

The effect of different rates of potassium: 0.4; 0.8; 1.2; 1.6 g K ∙ dm -3 , and calcium carbonate: 5 g and 15 g CaCO 3 ∙ dm -3 , on stalk celery yield and vitamin C content as well as on salt concentration in the medium was analysed in a greenhouse experiment. Stalk celery weight and vitamin C content were found to be reduced after the application of the potassium rate higher than 1.2 g K ∙ dm -3 . The study found that the salt concentration in the medium increased with an increase in the rate of potassium and that there was no effect of the increased rate of calcium carbonate on total salt concentration in the medium of stalk celery. The different rates of calcium carbonate affected the uptake of nitrogen, phosphorus, and magnesium by stalk celery.

The Development of Collective Structure and Its Response to Environmental Change

How do collective processes in decentralized, self-organizing systems respond to environmental change? What are the contrasting roles of collective structures and innovative components (variation, diversity, entropy), and how do these roles change with different rates of environmental change? To answer these questions, a simple self-organizing system is examined – a simulation of foraging for food by ants in the presence of environmental change. This model system has been argued to be similar in dynamics to decentralized components of many collective systems - ecologies, economies, knowledge systems, societies, political systems, etc. The simulations are first shown to illustrate a developmental view of evolving systems, captured by the developmental stages of Formative, Co-Operational and Condensed. The effects of different rates of environmental change are then presented. For small rates of change, the system productivity is largely unchanged. As the rate increases, innovative information becomes more important to sustaining the productivity. As the rate further increases, episodic failure is observed as stabilizing collective structures fail, and the system regresses to earlier developmental stages. The collective structures are shown to inhibit the performance of the system as a whole in rapidly changing environments. A quantitative measure is developed that captures the efficacy of the collective structure. A variation of the system with a mechanism for sustaining collective structures is found to be more sensitive to environmental change, duplicating the decline in productivity observed in aging systems.

Produtividade e composição química do capim-Tifton 85 submetido a diferentes taxas de aplicação do percolado de resíduo sólido urbano

Este trabalho foi realizado com o objetivo de avaliar o efeito da aplicação de diferentes taxas de percolado de resíduo sólido urbano (RSU) na produtividade e na composição química da parte aérea do capim-Tifton 85 (Cynodon spp). O percolado foi aplicado nas taxas de 0 testemunha); 250; 500; 750 e 1.000 kg ha-1 d-1 de DBO5, durante 8 meses. No tratamento-testemunha, não receptor do percolado, aplicou-se água da rede de abastecimento público, sendo a lâmina de aplicação definida com base na Evapotranspiração de Referência (ETo). O experimento foi analisado no esquema de parcelas subdivididas, tendo nas parcelas cinco concentrações de DBO5, e nas subparcelas, os cortes, no delineamento em blocos casualizados, com quatro repetições. Os dados foram submetidos à análise de regressão e variância. Observou-se aumento na produtividade de matéria seca, nos teores de proteína bruta e nas concentrações de N, K, Na, Ca, Mg, Mn, Cd, Pb e Fe,na parte aérea do capim,com o aumento nas taxas de aplicação do percolado. As concentrações de N, P e Mn tenderam a decrescer com o número de cortes do capim; as de Cd, Pb e Fe tenderam à estabilização após o 2º ou 3º cortes; e as de Na tenderam a aumentar após o 3º corte. As concentrações de K, Ca e Mg ficaram instáveis.

Effect of different rates of composted organic amendment on urban soil properties, growth and nutrient status of three Mediterranean native hedge species

Increasing green space, especially in densely built-up areas is considered to be a valuable climate change adaptation response in order to reduce the threat of high temperatures to human health and comfort and to controlled global greenhouse gas emissions. Practical responses to climate change, under urban conditions, in order to avoid or reduce trees and shrubs vulnerability, can be considered drought resistant planting approaches, as the addition of organic amendeds to soil. The improvement of physical–chemical soil quality is a key step for carrying out xeriscaping programs of urban green spaces in Mediterranean semiarid areas. Organic amendments, particularly compost, have been receiving a renewed attention not only in horticulture but also in the context of restoring disturbed urban soils to address environmental issues as well as to improve trees and shrubs growth. The influence of increasing rates (0, 15, 30, and 45%) of composted sewage sludge (SSC) placed in the plantation hole on both urban soil properties and growth for three native Mediterranean woody hedge species was monitored over a 2-year period after planting. The experiment was supported by a xerogardening project in an urban context under semi-arid conditions. The results indicate that the urban soil physical characteristics were positively influenced by the addition of SSC: the 45% rate showed an increase in both moisture and infiltration values, thereby increasing the volume of plant-available water in the soil. The chemical properties of the amended soils were also directly affected by the SSC rate, but the effect of the compost on organic matter, nitrogen and potassium contents decreased over time. Our results prove that the hedge growth response to the compost treatments is also highly dependent on the rate of compost used. At the end of the trial, in Rhamnus and Myrthus plants 30% compost level guarantees the best performance; in fact, the further addition of 15% of compost led to a significant decrease in hedge and diameter values, in particular in Myrtle. This could be explained by the high pH at 45% compost, which would seem not to suit the physiology of the two species. On the other hand, in Phillyrea plants, the rate of 45% compost gives high performance equal to that of 30%; it would therefore seem that the high pH at 45% compost does not influence the nutritive elements’ absorption and, as a consequence, the growth. The use of composted sludge as an amendment for sclerophyllous could be feasible and, what is more, helpful to mitigate the environmental impact of organic waste disposal. Moreover more natural vegetation can be introduced into urban parks and green spaces in semi-arid environments to encourage sustainable landscaping and xerogardening.

Effect of mineral fertilizers rate on yield and quality of the oriental tobacco variety NS-72

Field experiments were carried out during 2005-2006 in Scientific Tobacco Institute, Prilep, Macedonia to investigate the effects of different rates of mineral fertilizers on the yield and quality of oriental tobacco variety Prilep NS-72. The experiment was set up as a randomized complete block design in 7 variations in 3 replications. The purpose of this research was to determine which fertilizer has the best effect on yield and quality of the investigated variety. According to the results the best effect on yield was found with application of fertilizer Nutrifert 6 (50 kg/ha), with an increase of 39.03%. The quality of tobacco is expressed in % of quality classes (I, II, III, IV). Application of 30 kg/ha NPK (8:22:20) gave an increase of 7.18% in NS-72 compared to the control. In all other variants a mild deterioration of quality was observed.

Effects of potassium, sodium and chloride fertiliser rates on fodder beet yield and quality in Canterbury

There is renewed interest in fodder beet (Beta vulgaris L.) production in the South Island of New Zealand. However, recommended agronomic practices for maximising productivity and quality are limited. Two experiments investigating the effects of different rates (kg/ha) of potassium (K; 150 or 300), sodium (Na; 100 or 200) and chloride (Cl; 240) fertiliser application on fodder beet dry matter (DM) production, nutrient concentration and uptake were carried out at Southbridge (2011) and Bankside (2012), Canterbury, New Zealand. Final DM yield was unaffected by the treatments: averaging 32 t DM/ha at Southbridge and 21 t DM/ha at Bankside. However, there was a significant interaction between K and both Cl and Na, on DM yield at Southbridge. Specifically, yield increased to 38 t DM/ha with Na and decreased to 30 t DM/ha with Cl, in the presence of K. Application of K, Na, and Cl fertiliser increased the respective tissue mineral concentration and respective total uptake for both the bulb and shoot components. Potassium tended to depress crude protein, neutral detergent fibre and ash content of the bulbs and increase the metabolisable energy and soluble sugar. The combination of low fibre and high soluble sugar concentrations puts animals at risk of rumen acidosis. These results suggest that fodder beet crops subjected to high rate of soil and/ or fertiliser K should be supplemented with feed high in crude protein and fibre. Key words: Beta vulgaris L., agronomic practices, mineral concentration, mineral uptake, quality attributes.

Wheat yield and physico-chemical properties of a sodic soil from semi-arid area of Iran as affected by applied gypsum

Irrigation by highly sodic water has been practiced only in recent years in Iran but has led to impaired productivity of thousands of hectares of agricultural lands. So, the present study was set out to evaluate the effectiveness of different rates and sizes of gypsum as an amendment which improves the physical and chemical properties of soil and crop productivity. A field experiment was conducted in a sodic soil at a farmer's field in Ramjerd, Fars. The treatments consisted of two gypsum granule sizes (1–10mm and <1mm), and two application methods (adding gypsum to the irrigation water and mixing it with soil) were employed at three soil-applied gypsum levels, i.e., 50%, 75% and 100% of gypsum requirement (GR). The findings of the study showed that the application of gypsum increased soil salinity and hydraulic conductivity but decreased sodium adsorption ratio (SAR) and pH. The increase of wheat yield in coarse gypsum was greater than that observed in fine gypsum but, concerning most soil and plant parameters, the difference between fine and coarse gypsum was not significant at all in terms of rates of GR. Drought condition was found to diminish the effect of gypsum on soil and plants as a 10% reduction in wheat yield was observed in a drought year as compared with a normal year. Plant density, fertile spikelets, and 1000-grain weight were improved as the soil-applied gypsum increased. Regarding chemical composition of leaf, plants grown on un-amended plots had higher Na and lower potassium (K) and calcium (Ca) concentrations in leaf tissue. The application of gypsum caused a significant increase in nitrogen (N), phosphorus (P), Ca, K, iron (Fe), and zinc (Zn) concentrations in wheat tissue but copper (Cu) and manganese (Mn) concentrations remained unchanged. It also increased Ca:Na and K:Na ratios in leaf tissue and had positive effects on crop yield. It was finally recommended that farmers reclaim sodic soil by applying coarse gypsum at the rate of 100% GR since it is a more cost-effective way of reclamation of sodic soil.

An integrated model system for coastal flood prediction with a case history for Walcott, UK, on 9 November 2007

AbstractAn integrated model system is based on downscaling from climate models, to wave climate and continental shelf models for tides and surge, to coastal models for waves and water levels, to beach levels and overtopping of sea defences and inundation. Present operational practice in the UK is described. The model system is applied to the prediction of flooding at Walcott on 9 November 2007. Inundation levels are predicted in reasonable agreement with those at certain residential properties in Walcott as reported by the occupants. The effect of time‐varying and time‐averaged overtopping discharge is considered. Sensitivity of overtopping and inundation to uncertainties in nearshore wave height and water level is analysed, with the greatest sensitivity being to water level. Extreme joint probability analysis is undertaken, showing the event to be close to a 1 in 100‐year event. Finally, the effects of different rates of sea level rise and a climate change scenario are investigated for 2100; the simulations indicate that the return period of the equivalent 2007 event could reduce to less than 2 years with a 0.5m sea level rise.

Produção e qualidade da melancia submetida a adubação nitrogenada

Propôs-se, neste trabalho, avaliar o efeito da aplicação de diferentes doses de nitrogênio sobre a produção e qualidade de melancia 'Crimson Sweet'. Conduziu-se esta pesquisa na área experimental da Universidade Federal de Roraima, Boa Vista, RR, no período de janeiro a abril de 2010. O delineamento experimental utilizado foi o de blocos inteiramente casualizados, com 4 repetições. Os tratamentos consistiram de 5 níveis de nitrogênio (50, 100, 150, 200 e 250 kg ha-1 de N) aplicados na forma de ureia, de modo convencional. A produção comercial máxima obtida foi de 40.428 kg ha-1 com 144,76 kg ha-1 de N. Referente à qualidade dos frutos, o pH não foi influenciado pelos tratamentos, apresentando média de 5,34. A relação comprimento/diâmetro e a espessura da casca também não sofreram influência dos tratamentos enquanto a firmeza do fruto, o conteúdo de sólidos solúveis (SS), a acidez titulável (AT), o conteúdo de açúcares (redutores, não redutores e totais), o teor de ácido ascórbico e a relação SS/AT, foram influenciados pelos níveis de N.

The effect of different rates and forms of sulfur on seed yield and micronutrient uptake by chickpea

Field experiments were conducted at two different locations (Barani Agricultural Research Institute Chakwal and farm field Talagang, district Chakwal) for two crop-growing seasons in northern rainfed Punjab, Pakistan to assess the yield and micronutrient uptake of chickpea (Cicer arietinum). The treatments were four combinations of two levels of sulfur (15 and 30 kg/ha) from two sources (gypsum and ammonium sulfate) and a no-sulfur control. Application of sulfur resulted in a significant increase in seed yield up to 17% over control. Ammonium sulfate was a more efficient source of sulfur as compared to gypsum at both the locations. Sulfur application resulted in a significant increase in micronutrient uptake by plant; however effect of sulfur application on soil pH at the end of experiment was not significant. Availability of soil zinc and copper increased with sulfur application at the end of two year experiment. Tissue copper and iron and soil available copper and iron correlated negatively with soil pH. Sulfur should be applied to chickpea grown under rainfed conditions in order to increase seed yield, to improve nutritional composition of product and to enhance efficiency of other fertilizers.

Effects of different rates of Gaeumannomyces graminis var. tritici inoculum for detecting take-all suppression in soils

The introduction of Gaeumannomyces graminis var. tritici (Ggt) inoculum into soils to screen for take-all suppression has been widely used in field and laboratory studies. However, the amounts of Ggt inoculum reported have varied greatly. The effects of adding Ggt in sand/maizemeal to three soils of different cropping history at the rates of 0, 0.2, 0.5, 1 and 4 % (w/w) were investigated in a pot assay using wheat plants. The three soils had previously been cropped with ryegrass for 5 years, wheat for 8 years, and wheat for 2 years. The soils represented a putative non-suppressive, non-wheat soil; a suppressive wheat soil; and a non-suppressive wheat soil, each containing natural background concentrations of Ggt DNA of 0, 200 and 1126 pg g−1 soil, respectively. Root assessments of wheat plants after 4 weeks growth showed that 4 % of Ggt reduced root growth slightly, decreased water uptake of the wheat plants and effectively differentiated the suppressive activity of the soils (P < 0.01, take-all incidences of 83, 69 and 81 %, respectively), and was therefore suitable for investigating take-all suppression in soils.

More rapid climate change promotes evolutionary rescue through selection for increased dispersal distance

Species can either adapt to new conditions induced by climate change or shift their range in an attempt to track optimal environmental conditions. During current range shifts, species are simultaneously confronted with a second major anthropogenic disturbance, landscape fragmentation. Using individual-based models with a shifting climate window, we examine the effect of different rates of climate change on the evolution of dispersal distances through changes in the genetically determined dispersal kernel. Our results demonstrate that the rate of climate change is positively correlated to the evolved dispersal distances although too fast climate change causes the population to crash. When faced with realistic rates of climate change, greater dispersal distances evolve than those required for the population to keep track of the climate, thereby maximizing population size. Importantly, the greater dispersal distances that evolve when climate change is more rapid, induce evolutionary rescue by facilitating the population in crossing large gaps in the landscape. This could ensure population persistence in case of range shifting in fragmented landscapes. Furthermore, we highlight problems in using invasion speed as a proxy for potential range shifting abilities under climate change.

Effect of nitrogen rate and stubble catch crops on concentration of macroelements in spring wheat grain

The aim of this study was to determine the effect of different rates of nitrogen fertilizer and stubble catch crops on the content of nitrogen, phosphorus, potassium and magnesium in the grain of spring wheat. Field experiment was carried out in 2005-2008 at Moche³ek near Bydgoszcz (53° 13' N, 17° 51' E) on the Alfisols soil classified as a very good rye complex and IIIb quality class. Nitrogen fertilization was applied at the rates of (kg N ha–1 year–1): 0; 40 (before sowing), 80 (40 kg before sowing and 40 kg in BBCH 31-32 stage), 120 (60 kg before sowing and 60 kg in the BBCH 31 – 32 stage) and 160 (60 kg before sowing and 60 kg in BBCH 31-32 stage and 40 kg in BBCH 45-47 stage). Stubble catch crops (field pea and oilseed radish) were sown in the period from 3 to 11 of August in 2005 to 2007. After 70-77 days of plant growing, the whole biomass was plowed in as green manure. Spring wheat cv. Tybalt was sown following the catch crop,between March 30 to April 11 in 2006 to 2008. Nitrogen fertilization affected the concentrations of N, P and Mg in grain of spring wheat. Every 40 kg increment of nitrogen fertilization per ha resulted in a significant increase in the N content in wheat grain. The concentration of Mg in spring wheat grain was significantly higher when nitrogen fertilization was dosed at 120 or 160 kg per ha than at lower doses. The phosphorus content in grain of wheat grown after field pea catch crop was not related to nitrogen fertilization rates, while after the radish and in the control (without catch crop), it was significantly higher at 120 and 160 kg N per ha than at 40 kg N per ha. No effect of nitrogen fertilization on the K

Effect of Different Rates of Nitrogen and Phosphorus on Yield and Yield Components of Potato (Solanum tuberosum L.) at Masha District, Southwestern Ethiopia

Effect of Different Rates of Nitrogen and Phosphorus on Yield and Yield Components of Potato (Solanum tuberosum L.) at Masha District, Southwestern Ethiopia

Effect of Potassium Fertilizers on Cotton Yield and Nitrogen Uptake Efficiency in an Aridisol

A field experiment was carried out to study the effect of different rates of potassium (K) fertilizer [0, 50, 100, and 150 potassium oxide (K2O) ha–1] in the presence of increased supply of nitrogen (N) (120, 180, and 240 kg N ha–1) on cotton (Gossypium hirsutum L.) yield and the N and K use efficiencies using the 15N isotopic dilution technique. Potassium fertilizer increased cotton yield, which was significant and more pronounced with the application of N in the high level (N3). The greatest cotton yield (6442 kg ha–1) was obtained in N2K3 treatment with an increase of 14% over the control. In addition, K fertilizer significantly increased N uptake efficiency in the N2 and N3 treatments. The greatest N uptake efficiency (98%) was in N2K3 treatment. The greatest K uptake efficiency (42%) was occurred in N3K1 treatment. In conclusion, the use of K fertilizer could be useful when growing cotton in soils of moderate to high N content to improve N uptake efficiency and consequently increase cotton yield.

Effect of different rates and forms of sulphur on content of available phosphorus in soil

A three-year field experiment was conducted in Byszwa³d near Lubawa in 2000-2002. The aim of this study has been to determine the influence of increasing rates of sulphur on the dynamics of available phosphorus in soil at two horizons: 0-40 and 40-80 cm. The trial was set up on acid brown soil of the granulometric composition of heavy loamy sand. The initial soil had the following properties: pH (KCl) = 5.30, mineral nitrogen 24.0, sulphate sulphur 4.10, available phosphorus 34.5 and potassium 110.0 mg kg -1 of soil. Three levels of sulphur fertilization were applied: 40, 80 and 120 kg⋅ha -1 in the sulphate form (S-SO4) and as elementary sulphur (S-S 0 ). During the whole duration of the field trials, the results demonstrating the effect of fertilization with different forms and rates of sulphur on the content and transfer of available phosphorus in soil were inconsistent. Only the dose of 120 kg⋅ha -1 S-SO 4 caused a significant increase in the concentration of available sulphur in soil in the 0-40 and 40-80 cm layers. All the rates of elementary sulphur as well as 40 and 80 kg⋅ha -1 sulphate sulphur caused little less but an increasing tendency in the content of phosphorus in soil. The effect of elementary sulphur became apparent as late as the third year of the trials. The effect of the doses of 40 and 80 kg⋅ha-1 of sulphur on properties of soil depended on the form of sulphur, duration of the experi

Nitrogen Response Behaviour of Developed Promising Lines of T.Aman Rice

Nitrogen is the most limiting nutrient for rice. Modern high yielding rice varieties may have differences in accumulating and using N from soil and applied fertilizer. A field experiment with 8 rice genotypes was conducted during 2008 wet season (T.Aman season) to study the effect of different rates of N fertilization on the yield performance and nitrogen nutrition under irrigated condition. Among the tested varieties/lines, BR7155-20-1-3 produced the significantly highest grain yield of 5.04 t/ha at N30 level followed by Swarna (4.66 t/ha) at the same level of N with similar growth duration (140 days). Agronomic efficiency of added N ranged from 0.7 to 23.3 for the promising line BR7155-20-1-3 and 3.3 to 27.0 for variety Swarna. Grain yield at No was the highest in BR7155-20-1-3 followed by the variety Swarna and the lowest in BR7870-5 *(Nils)- I 0-HR8. Percent nitrogen recovery ranged from 50 to 63 for variety Swarna and 13 to 30 for promising line BR7155-20-1-3. The promising line BR7155– 20-1-3 and the variety Swarna may be economically advantageous over the other varieties/ lines. DOI: http://dx.doi.org/10.3329/bjar.v37i2.11222 Bangladesh J. Agril. Res. 37(2): 207-213, June 2012