Fertilizer nitrogen balance on spring irrigated malting barley

The effect of mixed and band placement in soil on the dissolution of reactive North Carolina phosphate rock (PR) and the consequent increase in available P was investigated in a laboratory incubation study. The dissolution of PR in the soil was estimated from the increase in soil exchangeable Ca. The increase in available P was measured with the Olsen bicarbonate extractant. At the same level of application greater PR dissolution occurred for mixed than for band application. For both methods of PR application the amount of dissolution increased with the level of application and incubation period. The increase in the amount of PR that dissolved with increasing incubation period was greater for band than for mixed application due to the influence of unfertilized soil adjacent to the band. However, a higher proportion of dissolved P was soluble in bicarbonate solution for band than mixed PR.     

Guano as a nitrogen source for fertigation in organic farming

Guano is a natural organic fertilizer used in organic farming management when supplementary nitrogen is needed. In modern irrigated agriculture N top dressing is often applied through the irrigation water. The objective of this research was to evaluate the potential of guano as a source of available N when applied through water, compared with application to soil. The release of mineral and total soluble N from guano to water was monitored, as a function of time, under laboratory conditions, and compared with mineralization of guano in soils. The effect of guano:water ratio, aeration of the mixtures, addition of rock-phosphate or clay minerals, and temperature on the composition of the solutions was determined. Guano released more than 90% of its N content into solution during 10 d at a guano:water ratio of 1:10 at 27°C. The release of soluble N, of which 85% was NH₄-N, was linked with an increase of pH from 7.0 to 8.5 or more. None of the treatments increased the rate or the total N release beyond that. Suboptimal temperatures, 13.6 ± 4.7°C or 50°C, greatly reduced the rate of guano-N release to solution. The mineralization of guano in soil was more rapid than in water, but the total N release was the same, leading to the conclusion that the application of guano through the irrigation water may be as efficient as directly to soil, provided sufficient time for fermentation is allowed.Contribution from the ARO, The Volcani Center, Bet Dagan 50250, Israel, no. 3290-E, 1991 series.     

Methylene urea as a slow-release nitrogen source for processing tomatoes

The potential for improved fertilizer N use efficiency was tested using a slow release N fertilizer, methylene urea (MU), on processing tomato (Lycopersicon esculentum Mill.) in a 2-year field study in the Sacramento Valley, California. Fertilizer N use efficiency of urea and a (50:50, w:w) mixture of urea and MU (uMU) was determined in direct-seeded and transplanted tomato plots with winter cover crop (CC) or winter fallow (F) using ¹⁵N labeled fertilizers. Residual MU-N was estimated from tomato N uptake in the ¹⁵N microplots, and from residual ¹⁵N uptake of wheat grown after two tomato crops. No significant differences were found in the quantity and quality of tomato yields among fertilizer and management treatments during the first year. Total yields in transplanted FuMU plots were significantly lower in the second test year, suggesting slow mineralization of MU-N in the F treatment. On average, about 40% of added fertilizer N was taken up in both fertilizer treatments, and the recovery of ¹⁵N in plant biomass and soil was 75–96 and 50–74% in seeded and transplanted blocks, respectively. In the laboratory, mineralization of MU started faster in soils with past MU use, but the enhanced mineralization did not affect the plant N uptake in the field. MU is potentially an environmentally attractive fertilizer, but without an immediate increase in yield and N use efficiency compared to conventional fertilizers, its use on row crops may not be economically feasible unless the positive environmental factors like decreased leaching of N are considered.     

Root exudates of a legume tree as a nitrogen source for a tropical fodder grass

Exudation of nitrogenous compounds from the roots of dinitrogen-fixing plants is a potential source of nitrogen for adjacent plants in intercropping systems. We studied (1) the extent of N exudation from the roots of a tropical legume tree Gliricidia sepium (Jacq.) Kunth ex Walp., and (2) the ability of a C4 fodder grass Dichantium aristatum (Poir) C.E. Hubbard and its mycorrhizal symbionts to absorb N from tree exudates in a glasshouse experiment. Root exudates of ¹⁵N-labelled trees were collected in hydroponic culture and applied with irrigation water on grass grown in separate pots. During the 10-week experiment, the trees exuded 34.1 ± 5.0 mg of N, which represented 1.7 ± 0.2% of their total N by the end of the experiment. The total amount exuded would have been enough to supply 16% of grass N content by the end of the experiment. The grass, however, absorbed only 3.8–7.5% of ¹⁵N in exudates and gained 0.8–1.1% of its N from exudates. The low absorption of exudate N by grass was explained by probable soil microbial immobilisation and by the dilution of exuded N in the substantially larger pool of soil mineral N. A close contact between the root systems of N donor and recipient plants directly or via their mycorrhizal symbionts seems to be a precondition of the apparently direct N transfer earlier observed in field studies of the same soil-plant system.     

Recovery of nitrogen by spring barley from ammonium nitrate,urea and sulphur-coated urea as affected by time and method of application

The objective of this study was to increase the efficiency of fall-applied N either by placement in bands or by using a slow-release fertilizer. Four field experiments were conducted in north-central Alberta to determine the influence of N source, time of application and method of placement on the recovery of fall-applied N as soil mineral N in May, and on yield and recovery of N in grain of spring-sown barley. The recovery in soil of mineral N by May from the fall-applied fertilizers varied among treatments. More specifically, the recovery was lowest with topdressed application, highest with banding, and tended to be less with incorporation application as compared to banding. Recovery of mineral N was least for sulphur-coated urea (SCU) compared with A.N. and urea, regardless of method of application. The loss of fall-applied N was substantial, but leaching did not go beyond 60 cm deep.Yield and recovery of N in barley grain were much greater with spring application than with fall application at the 4 sites for ammonium nitrate (A.N.) and at 3 sites for urea. The SCU treatments were inferior. The A.N. and urea had greatest yield and N recovery with banding, followed by incorporation and then with topdressing for both fall- and spring-applied N. Method of application had little effect on yield and N uptake with SCU. In all, the greatest yield or crop N uptake was obtained with spring banding of A.N. or urea, while SCU did not function well as a fall- or spring-applied N fertilizer.(Contribution No. 680)     

Nitrogen in coal as a source of nitrogen oxide emission from furnaces

In this paper are presented some experimental results on the conversion of fuel-nitrogen to nitric oxide in both diffusion and premixed flames, and the results are used to speculate on mechanisms of nitric oxide formation. Models of pulverized-coal combustion are reviewed and used to examine the conditions under which fuel-nitrogen contributes significantly to nitric oxide emission. Mechanisms are suggested to explain why fuel-nitrogen contributes most of the emission from fluidized-bed combustors but only a small fraction of the emission from pulverized-coal flames.     

Use ofLeucaena leucocephala (Lam. de Wit) leaves as a nitrogen source for crop production

Field and pot trials were conducted to determine optimum management practices for usingLeucaena leucocephala (Lam. de Wit) leaves as a N source for crop production. Field trials with maize showed no benefit from split application of leucaena leaves or from application of fresh as opposed to dried material. Field trials also failed to show any difference between incorporation as opposed to surface application of leucaena leaves. This may be attributed to the low nitrogen response observed. Pot trials however, showed that soil incorporation of leucaena leaves was more effective than surface application in increasing plant dry weight.Leucaena leaves were not as effective as inorganic N in increasing maize grain yield (field trials) or dry matter production (pot trial). Unlike inorganic N, leucaena leaves had a significant residual effect on the succeeding maize crop. In decomposition studies, buried leucaena leaves decomposed more quickly than surface-applied leaves, and fresh leaves decomposed more rapidly than dried leaves.     

以氨为氮源的C-N偶联反应研究进展

C-N偶联反应是合成芳香胺的重要手段,咪唑、脂肪胺和氨常用作该反应的氮源。氨是最简单的氮化合物,应用在该反应中不仅廉价而且更加绿色环保。然而,由于氨结构以及偶联后产物结构使其存在一定的挑战性。各种催化体系的出现实现了以氨为氮源的C-N偶联反应。综述钯和镍在均相、多相体系中催化氨为氮源的C-N偶联合成苯胺类化合物的反应。这类金属催化剂催化活性较高,但存在进一步偶联生成二级胺的问题,且催化剂成本偏高。铜作为廉价金属在C-N偶联反应中的应用一直受到关注,重点介绍各种常见的铜盐、铜纳米材料和负载型铜催化剂等在氨为氮源的C-N偶联反应中的应用。     

煤基聚苯胺制掺N碳微纳米管的实验研究

我国煤炭资源丰富,以煤为原料制备碳纳米管,可以实现煤炭资源的高效利用,减少环境污染,为煤炭行业的发展提供新途径。以煤基聚苯胺为碳氮源,分别以乙酸镍或柠檬酸铁为碳源热解催化剂,以二茂镍、乙酸镍或二茂铁为碳管生长催化剂,采用催化热解-化学气相沉积耦合法成功制备出了三种高石墨化程度的掺N碳微纳米管。并对其进行了SEM、TEM、XRD、Raman、XPS等结构测试和甲醇氧化电催化剂载体应用测试,结果发现：三种掺N碳微纳米管的微观形态多样,有直立管、弯曲管、竹节状管等。二茂镍和二茂铁适合生长长而直的碳管,乙酸镍适合生长短而弯的碳管。二茂镍和乙酸镍所长碳管收率相当,约为5.8%（质量）;二茂铁所长碳管收率较高,为21.2%（质量）。N元素主要以石墨型N掺入三种碳微纳米管中,乙酸镍所长碳管的掺N量最高,为1.17%（质量）,且表现出良好的电催化剂载体性能。     

High-pressure high-temperature synthesis of GaN with melamine as the nitrogen source

Micron-sized grains of gallium nitride (GaN) crystallizing in the Wurtzite phase were synthesized through a chemical reaction between gallium (Ga) metal and melamine (C₃N₆H₆). The reaction occurred at the temperature range from 1073 to 1473 K and the pressure range from 3.5 to 5.5 GPa. X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations showed that the final black products mainly contained the clusters of tiny GaN crystals. Prism-like well-shaped single crystals were found in the TEM micrographs. A vapor–liquid–solid growth process was proposed to explain the growth mechanism of GaN in which the pyrolysis of melamine was responsible for the provision of reactive nitrogen.     

Crambe meal as a protein source for feeds

Crambe abyssinica may be grown for its seed oil containing 55-60% erucic acid, which fills a long-term, technologically important US industrial market. The residual meal could serve in animal feeds, but, like other Cruciferae, crambe seed contains glucosinolates that limit the feed value of the defatted meal. Protein content, amino acid composition, protein efficiency tests and numerous animal feeding experiments show that crambe meal contains protein of good nutritional quality. Means of reducing, nullifying or removing the glucosinolates and their hydrolysis (aglucon) products have been the object of many studies, and crambe meals containing native levels of glucosinolates and/or aglucon products have been shown to be lethal to mice, rats and chicks when fed at significant dietary levels. Animal performance is inversely related to sublethal concen-trations of these compounds in modified meals. However, water-extracted crambe meals have excellent nutritional quality when such extraction removes the glucosinolates and/or aglucon products. Feeding experiments suggest that these meals, although more costly to prepare, could be used in feeds for nonruminant animals. On the other hand, moist heat-toasting of crambe meals in conventional oilseed extraction facilities provides meals of value for supplemental protein in beef rations. For this use, specifications and FDA ap-proval are in place for commercial exploitation of crambe meal. These studies and the status of crambe as a protein source in feeds are reviewed.     

Chiastolite ores as a source for refractory production

Ore samples of the Bezymyanskoe deposit in the Kemerovo Region containing about 20% chiastolite (A1₂O₃ · SiO₂) are studied. It is shown that the ore can be enriched for the production of concentrate for highalumina refractories.     

改性碳铵为氮源的复混肥施用技术研究

碳铵加入稳定剂,改善物性,增强稳定性,提高了肥效.玉米、水稻专用肥与对照(空白)比,玉米增产18.5%,水稻增产30.6%.玉米、水稻专用肥与等价格磷酸二铵比,玉米专用肥增产7.8%,水稻专用肥增产10.3%.玉米、水稻专用肥最佳用量600～660/hm2.     

Evaluation of a novel Bacillus strain from a north‐western Spain hot spring as a source of extracellular thermostable lipase

BACKGROUND: Thermophilic microorganisms are receiving significant attention as a source of useful thermostable enzymes. However, the number of known strains is still limited, and very often their most interesting biocatalysts are intracellular or membrane‐bound and produced at low levels. Thus, the isolation and study of novel extracellular enzyme‐producing thermophilic microorganisms is very interesting. Moreover, the assessment of bioreactor performance is crucial, given the scarce information on the large‐scale culture of these strains. RESULTS: The production of a thermostable extracellular lipase in submerged cultures of a thermophilic microorganism, recently isolated in north‐west Spain, was investigated. The strain was identified by 16S rDNA sequencing as belonging to genus Bacillus. The influence of operating variables (i.e. pH, temperature, aeration) on lipase biosynthesis was analysed. Enzyme production at bioreactor scale was investigated, special attention being paid to the effect of aeration and agitation rates. CONCLUSION: The best conditions for the studied process were determined in shake flasks as pH 7.0, 55 °C and high aeration levels. Also, the non‐association between lipase production and cell growth was ascertained. The culture of this novel strain was successfully carried out in laboratory‐scale bioreactors, thus proving its potential for further applications. Copyright © 2009 Society of Chemical Industry     

Ammonia as a source of hydrogen for hardening oils

Summary and Conclusions Equipment for dissociating or “cracking” ammonia has been developed to deliver catalytically pure hydrogen under pressure. The cracker is practically automatic in operation, occupies but small space, and can be built to meet a wide range of capacity operating at high economy. While it is not claimed that cracked ammonia is the preferred source of hydrogen for large outputs, it should be considered for any requirement of less than 1,000 cu. ft. per hour, and in some cases for requirements of 1,000 cu. ft. and more. Cracked ammonia has been demonstrated to be suitable for hardening oils, and affords a source of cheap hydrogen with a minimum investment for those who desire to operate on small scale or who desire to decentralize large operations.     

Coal as a carbon source for carbon nanotube synthesis

This article reviews the recent advances on the various processes used in the synthesis of carbon nanotubes (CNTs) from different types of coal (anthracite, bituminous, etc.) and on the role played by coal as carbon source in the production of CNTs. The molecular solid coal is inexpensive and widely available in comparison to the most widely used solid carbon precursor, graphite (a lattice solid) and high purity hydrocarbon gas sources. An account is given on the different processes involved in the synthesis of various CNTs (single and multi-walled, bamboo-shaped, branched, etc.) from different types of coal (anthracite, bituminous, etc.). Both arc-discharge and thermal plasma jet produce high quality CNTs but fundamental disadvantages limit their use as large-scale synthesis routes. Chemical vapour deposition appears to be promising but further experimental work is necessary in order to develop an understanding of the complex factors governing the formation of different carbon nanomaterials from coal. Successful utilization of CNTs in various applications is strongly dependent on the development of simple, efficient and inexpensive technology for mass production and coal as a carbon source has the potential to meet the needs.     

Prospects for sphagnum peat as a source of fullerenes

The modification of slightly decomposed sphagnum peat for the synthesis of fullerenes is considered. Topographic images of the carbon nanotubes first synthesized on that basis are presented.     

Study on the possibility of waste mushroom medium as a biomass resource for biorefinery

In order to investigate the possibility of waste mushroom medium as a biomass resource for biorefinery, characteristics of hydrolysate and pretreated biomass obtained from oxalic acid pretreatment were examined. The hydrolysate contained high glucose and low concentrations of inhibitors. The glucose concentration in the hydrolysate particularly increased when temperature gradient was used during pretreatment, compared with that of isocratic condition. The highest increase rate of glucose was 63.16% when pretreatment was performed at 140 °C for 25 min with 0.032 oxalic acid (g/g), and increased temperature to 170 °C. At the same time, ethanol production of Scheffersomyces stipitis using hydrolysate was 15.72 g/L after 48 h, which correspond to an ethanol volumetric productivity of 0.33 g L^?1 h^?1. Most of the lignin and some of the cellulose remained in the pretreated biomass. The total lignin content of the pretreated biomass, represent between 31.81 and 45.05%, compared to 28.8% of the raw material. The calorific value of the pretreated biomass ranged from 4940 to 5111 kcal/kg which represent increase of 3–6% compared to the raw material, due to higher contents of lignin in the pretreated biomass.