Nitrogen (N) loss in the form of volatilized ammonia (NH₃) is a considerable problem when ammonium (NH₄⁺) forming fertilizers are applied to calcareous or alkaline soils. Large areas of agricultural land, contain alkalinity and salinity problems, are potentially suitable for crop production with little alteration. This study was conducted to determine and compare the effectiveness of urea phosphate (UP) in reducing soil alkalinity and NH₃ loss. The volatilization of NH₃ from UP and urea (U) was studied on 3 selected soils (Hayhook SL, Laveen L and Latene L) using an aeration system. Urea phosphate and U were each applied at rates of 0, 50, 100 and 200 ppm-N either to the surface dry or in solution or mixed with the soil. The volatilized NH₃ was trapped in sulfuric acid, sampled periodically and analyzed for N using the semi microkjeldahl distillation apparatus. The effect of UP, Sulfur-Foam (SF), Phosphuric Solution (PHP) and a mixture of SF and UP (Mix) on leaching soil sodium (Na) and salinity was also studies on two soils (Pima L and Crot CL) in columns. Each of these amendments was applied at a rate of one and two equivalent amounts of the exchangeable Naₑₓ. The highest N loss in the form of NH₃ occurred when U was applied to Hayhook soil. However, UP applied to Hayhook soil (neutral to acidic, coarse textured and low CaCO₃ content) resulted in the lowest NH₃-N loss. Less NH₃-N loss was found from U application to Laveen and Latene soils (fine textured with higher CaCO₃ content) than with Hayhook soil. The general trend was higher N loss, in the form of volatilized NH₃, with surface application dry or in solution than when mixed with the soil. This trend showed an increase in the amount of volatilized NH₃ with increasing rate of N application. Urea phosphate was as effective as PHP or Mix (acid containing fertilizers) treatments in reducing soil salinity and alkalinity in Pima and Crot soils. No difference was found between rates of application (1 and 2 equivalent amount of Naₑₓ) except for soil pH. A similar trend in the decrease in soil salinity was found to that of the pH which was in the order PHP, UP, Mix, SF and control treatments. No significant difference was found between SF and control treatments in all parameters. No significant difference was found between treatments for exchangeable Ca. This was affected by the Ca compounds present in the soil. Generally, UP is a potential fertilizer for supplying N and phosphorus (P) as plant nutrients, reducing NH₃ volatilization, and can be used as a soil amendment to control soil salinity and alkalinity.

Two laboratory experiments were conducted to study the effects of salt and nitrogen-sulfur compounds on the transformations of nitrogen in three Arizona soils. In the first experiment the effect of NaCl in concentrations of 0 to 1 m (molal) at moisture levels of 1/3 and 15 bars was studied in the Gila and Laveen loam soils. At 1/3 moisture nitrification of urea-¹⁵N and native soil nitrogen was appreciably reduced only at 1 m salt level. At 15 bars moisture, nitrification was almost completely inhibited by the 1 m salt concentration. Mineralization of soil nitrogen was reduced more by decreasing moisture than by increasing salt concentrations. Ammonia volatilization was increased by both salt and moisture stress and was associated with inhibition of nitrification. Slight effects of salt were observed on ¹⁵N immobilization and ¹⁵N recovery (including volatilization). In the second experiment nitrogen-sulphur combinations (¹⁵N labelled) of KNO₃, KNO₃ + S, urea, urea + S, APS (ammonia polysulfide) and Thiosul (ammonium thiosulfate) were studied at field capacity (FC) and 1.5 FC moistures. In the calcareous Gila soil nitrification was suppressed by the presence of sulfur at 1.5 FC moisture. Volatilization losses were appreciable only from APS. Immobilization of ¹⁵N was greatest from treatments with the higher sulfur rate (elemental S). Denitrification was slightly increased by sulfur at FC, however, at 1.5 FC dramatic losses occurred by denitrification (autotrophic in the presence of sulfur, especially with elemental S. The nitrifying ability of the slightly acid and coarse textured Sonoita soil was low. Nitrification was suppressed more by the presence of sulfur at both moistures. Ammonia volatilization was appreciable from APS followed by urea. ¹⁵N immobilization was high from urea followed by APS. Appreciable losses by denitrification occurred only with APS. The Sonoita soil showed a lower sulfur oxidizing power than the Gila with the only appreciable rate of oxidation from Thiosul followed by APS.

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Revised; Originally Published: 2006 / 4 pp.

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The grain amaranths, Amaranthus cruentus and Amaranthus hypochondriacus have been promoted as grain-bearing plants of possible high productivity in saline or hot arid habitats. To investigate these claims, seeds of both species were germinated at 10, 15, 20, 25, 30, 35 and 40°centigrade. Germination percentage for both species was above 90% after four days at 20, 25, 30, and 35°C. Germination was negligible at 10 and 15°C and very low at 40°C. Seeds were germinated in isotonic solutions of PEG and NaCl at 0.0, -0.2, -0.4, -0.5, -0.6, -0.8, and -1.0 MPa osmotic potential at 30°C. Germination percentage was high in the range 0.0 to -0.4 MPa and dropped rapidly to zero in the -0.6 to -1.0 MPa range. Differences due to chemical effects were significant. Species differences were not. Radicles and hypocotyls were measured after six days in the above media. PEG was more inhibitory of seedling growth than was NaCl and generally inhibited A. cruentus more than A. hypochondriacus. This was also true of NaCl. All growth functions were slightly inhibited at 0.0 to -0.4 MPa and very inhibited above -0.6 MPa. PEG radically increased root/shoot ratio in both species.

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The theoretical model of Beratan and Onuchic predicts a large attenuation of ET rates through hydrogen bonds; however, the effect of individual hydrogen bond on electron transfer reaction has not been systematically studied. The organic complexes in this study are a series of crown ether/ammonium salt, which incorporate a redox partner on each component of the complex. The dimethoxynaphthalene redox donor was attached to the crown ether and a series of ammonium salts was synthesized which bear substituted quinone and naphthoquinone acceptor. The complexes characterization and preliminary electron transfer rate measurement were completed with UV/Vis and steady-state emission spectroscopy.

This thesis concerns the development of metal-free reactions to obtain carbon-heteroatom and carbon-carbon bonds. This is achieved by transferring carbon ligands from hypervalent iodine reagents to suitable nucleophiles. The bulk of the work presented herein concerns arylation of oxygen and nitrogen nucleophiles, using the well-known diaryliodonium salts as aryl sources. In the first project, O-arylation of the oxime ethyl acetohydroxamate was studied. It was found that electron-poor as well as electron-rich aryl moieties could be transferred successfully to this nucleophile. Furthermore, the protocol could be extended to a sequential one-pot synthesis of benzo[b]furans. This method allowed for a fast synthesis of the natural product stemofuran A and formal syntheses of other natural products. In a successive project, O-arylation of hydroxide and aliphatic alkoxides was investigated. It is known that electron-poor aryl moieties can be transferred to these nucleophiles in moderate to high yields. However, combined with more electron-rich diaryliodonium salts, a large amount of side products were formed. These were suppressed upon addition of aryne traps, suggesting that aryne pathways are competing with the desired ligand coupling. It was also observed that secondary alcohols were oxidized to the corresponding ketones. The mechanism for this oxidation was investigated and aryne pathways could be excluded. Instead we suggest that the carbinol hydrogen gets deprotonated via an internal mechanism, after the alkoxide has coordinated to the iodonium salt. Highly sterically congested alkyl aryl ethers could be obtained in high yields by combining tertiary alcohols with ortho-blocked diaryliodonium salts.  Next, N-arylation of secondary acyclic amides was studied using acetanilide as the model substrate. This procedure was suitable for transfer of electron-poor as well as ortho-substituted aryl moieties, but attempts to transfer very electron-rich aryl groups were unsuccessful. On the other hand, the amides displayed a complementary reactivity, allowing phenylation of electron-rich amides.  In the final project, a one-pot synthesis of the cyclic iodonium reagent vinylbenziodoxolone is presented. These compounds have not been explored as reagents earlier. Initial screenings showed that the vinyl moiety could be transferred to nitrocyclohexane with opposite regioselectivity compared to the acyclic analogue of the reagent. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p>

Charge transfer salts of Tetracyanoquinodimethane (TCNQ) were synthesised and their electrical and magnetic properties were investigated. These salts show unusual electrical and magnetic behaviour in contrast to conventional organic compounds. These salts have crystal structures which in general consist of TCNQ radical ions stacked in chains, isolated from each other by the diamagnetic cations. They are thus regarded as "one-dimensional" electrical and magnetic systems. The ESR spectra of these salts are attributed to triplet excitons showing that the spin-spin and electronelectron correlation effects are important. In the ESR spectra (Chapter III) of some TCNQ salts dipolar splitting is observed confirming the spin-spin interaction. These triplet excitons are regarded as bound electron-hole pairs. The experimentally determined dipolar splitting tensors are presented in Chapter III and the intensity data in Chapter IV. A large number of fine structure lines are observed in the ESR spectra of Pyridinium-TCNQ and 4-Aminopyridinium-TCNQ apart from regular triplet exciton lines (Chapter III). These lines are attributed to the trapping of excitons on an extended formula finit (TCNQ2 )n. In Chapter IV the temperature dependent magnetic susceptibilities are discussed in terms of Heisenberg antiferromagnetism and Pauli paramagnetism. In Chapter V temperature dependent behaviour of electrical conductivity is discussed in terms of an exciton band model, the lattice structure of the salts and one-dimensional lattice consisting of defects giving rise to high and low conducting segments. Low temperature electrical and magnetic phases are discussed (Chapters IV and VII) in terms of a band and hopping mechanisms.In Chapter VI self consistent field calculations are made with reference to the tight binding one electron band theory using simplified Roothaan equations considering CNDO approximations. Theoretical results are related to experimental band gaps, spinspin interactions and charge alteration.