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In two greenhouse experiments, the response of maize plants (Zea mays L.) to macro and micronutrient fertilizers was studied. The first experiment was conducted in Cairo, Egypt in which maize plants were grown on saline soils with ECₑ values of 1.42, 6.12 and 12.1 dSm⁻¹ and fertilized with N, P, K alone and in combination. It was found that maize plants produced the highest dry matter when NP fertilizers were added in the Ca-form compared to the other fertilizer treatments, and this positive response decreased with increasing salinity level. Also, it was found that application of P and K fertilizers either alone or together as PK augmented the adverse effect of salinity on dry matter and nutrients uptake. In addition, the concentration and uptake of Na⁺ ions in the shoot tissues decreased with increasing salinity level up to ECₑ 12 dSm⁻¹. This could be due to Na+ exclusion or accumulation in root tissues. However, application of N and P fertilizers tended to decrease plant content of micronutrients, particularly Fe as well as Zn at high salt levels. The second experiment was conducted in a University of Arizona campus greenhouse. A Pima soil from the Marana area was artificially salinized with NaCl, Na₂SO₄, CaCl₂, and Mg₂SO₄ salts almost to the salinity levels mentioned above. Maize plants were grown and fertilized with NP fertilizer as a basic dressing. Chelated forms of Zn, Fe, and Mn were added with two different methods; soil and foliar spray application. Two pH values of spray nutrient solutions were used; pH 6 and pH 8. Data obtained showed increased dry matter and nutrient uptake in response to spraying maize plants with Zn + Fe or Zn+ Fe + Mn at pH value of 8 at the medium salt level relative to the other treatments. However, maize plants also showed high dry matter and nutrient uptake in response to Zn + Fe + Mn soil application at the high salt level, although Zn-pH 8 gave unexpectedly high dry matter production. It seems probable that this high dry matter obtained could be due to the effect of high pH spray treatment on increasing the activity of some enzymes, e.g. PEP-carboxylase and/or ribulose 1,5 diphosphate carboxylase, as well as the increase in rate of translocating the photosynthates and this effect was augmented by the nutrient(s) applied. Also, it was found that Na uptake decreased while total chlorophyll and chlorophyll a content increased with increasing salinity level. The increase in the chlorophyll content could be due to either Na exclusion by the plants and/or the decrease plant growth due high salts.

Salt-affected soils have undermined the effectiveness of agricultural development of considerable areas of the world, especially in the arid and semi-arid regions. This research is set out for the direct measurement of salt-affected soil. Two experiments were conducted to study the influence of different salt types and concentrations on spectral reflectance of soil. In the first experiment, five different salts (Na₂SO₄, NaHCO₃, CaCO₃, CaCl₂ and NaCl) were mixed individually with Gila soil at 0.51, 1.51 and 3.0% by weight. The second experiment was conducted to examine the spectral response of sodium sulfate and sodium bicarbonate (individually and in combination) in Gila soil at 3.0 and 6.0% by weight. Reflectance measurements were made over all soil treatments under different moisture conditions. Upon drying (24-hour after wetting), different salt types and concentrations showed different spectral response. The chemical analysis of soil samples have indicated some important relationships which influenced, directly and indirectly, the spectral reflectance of soil surfaces.

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This paper is an attempt to appraise the usefulness of the dropping gallium electrode (DGE) in fused LiNO3-KNO3, to compare it with the dropping mercury electrode (DME), and to study the DGE in fused LiCl-KCl.

Master of Science in Engineering - Engineering / Wastewater is generated in the production of water-based paints when vessels and filling lines are washed in between batches. This results in a dilute paint wastewater stream. This dissertation concerns the study of the treatment of wastewater, using flocculation and coagulation processes. Standard jar test were used in screening the flocculants. The inorganic flocculants used were ferric chloride (FeCl3) and aluminium sulphate (Al2(SO4)3) A thermodynamic model is developed for understanding the coagulation and flocculation process for inorganic flocculants. Properties such as the effect of bulk concentration, pH and feed concentration of flocculant on wastewater were investigated. The impact of kinetics and other properties such as the influence of redox potential on flocculation experiments are also evaluated in order to have an understanding of the properties that influence the flocculation of wastewater. It was found that thermodynamics could be used to predict gross flocculation behaviour. However mixing and the rate of the nucleation and growth of flocs are also important and need to be controlled for efficient and reproducible flocculation.