Protein upgrading of orange peel waste was carried out by Solid Substrate Fermentation using an Aspergillus sp. inoculum in a waste peel mixture containing peel waste, potassium dihydrogen orthophosphate (KH2 PO4), ammonium sulphate [(NH4)2SO4] and molasses. Fermentation lasted 72 hours at 30C. after which crude protein level in the substrate increased from 5% to 13%. Factors found to be important in determing the efficiency of the fermentation process included fermentable sugar content of the medium, nitrogen and mineral levels, initial temperature, PH, moisture, agitation of the medium, and size of particles constituting the substrate. Protein quality of the fermented peel was evaluated by PEP assay and a PER value of 0.78 was recorded. It is suggested that a low level of total amino acids is the major contributory factor to this low PEP value. Total amino acid level measured 5.75g per 100g fermented peel waste. / Master of Science (Hons)

This investigation explored the use of microcosms as a tool for studying the dynamics of tropical aquaculture ponds. The potential use of rabbit excreta as a pond fertilizer in integrated farming systems was also investigated. Twelve insulated fiber glass tanks were utilized as microcosms to simulate earthen ponds. Seven hand-sexed Nile Tilapia O. niloticus) were stocked per tank, and microcosm performance was observed for a 90- day experimental period. Three rabbit excreta loading rates corresponding to 50 and 75 kg/10,000 m³ /day, and a continuously adjusted manure loading rate were assessed. The fertilizer treatments were compared to a control treatment where fish were fed on a prepared food. Water quality variables and fish performance were regularly monitored. Nitrogen and phosphorous content of rabbit excreta were measured. The dynamics of the microcosms were similar to warm water earthen ponds with respect to physical and chemical characteristics. Statistical differences were detected between control and fertilized treatments in relation to dissolved oxygen levels, net primary productivity, total alkalinity, total ammonia and orthophosphate levels. Primary productivity was influenced more by light intensity and penetration than by nutrient limitation. Rabbit excreta overloading was observed in the 75 kg treatment. Fish growth was greatest in the control treatment, but it was not statistically different from the continuously adjusted fertilizer treatment (Pondclass) (0.0065 and 0.0056, respectively). Low daily fish gains were observed in the 50 and 75 kg treatments. Low dissolved oxygen and high total ammonia were concentrations resulted in low weight gains and condition indices of fish in the 50 and 75 kg treatments. Extrapolated fish yields corresponded to 6,205, 4,563, 3,686, 4,869 kg/ha/year for control, 50 kg, 75 kg and Pondclass treatments, respectively. The observed yields are comparable with field experiences in real ponds. The continuously adjusted treatment showed the lowest manure conversion ratio (3.85) in the fertilized treatments. The nitrogen content of rabbit excreta varied according to rabbit size, presence or absence of urine plus water waste, and food droppings. Urine plus water waste provided 28 % of the total nitrogen content in rabbit excreta, whereas food droppings provided 12 %. Rabbit urine may play an important role in aquacultural systems because it contains a large fraction of nitrogen in inorganic forms which are readily utilized for algal growth. Other rabbit excreta characteristics such as buoyancy may be advantageous in aquacultural systems. Rabbit excreta is a potentially rich source of fertilizer for use in fish ponds. / Graduation date: 1992

The sugar refinery process used by Lantic Sugar Ltd generates three by-products having characteristics that give them potential as soil amendments or fertilizers, particularly as a phosphorous and calcium source. Laboratory and a field trials were conducted in order to examine the changes in agronomic properties of soil produced by the application of these residues. / During the laboratory experiment, the by-products examined were spend bone char (SBC), filter-press mud (FPM), clarification scum (SCU) and a compost (COM) produced using FPM and SCU, where as in a field experiment, COM, SBC and a mixture (MIX) made of FPM and SCU, were compared to a commercial fertilizer (TSP) and non-treated soils. / The orthic humic gleysol of clay texture and low pH soil conditions in which the field experiment was conducted resulted in high P fixation of all the applied residues. Contrasts analysis showed that TSP behaved as the soils unamended P for all nutrient concentrations in tissues over two cropping seasons (1993 and 1994), on two crops, namely wheat (Triticum aestivum, L.) and corn (Zea mays, L.). Treatments (residues at different rates of application) did not significantly increase the Ca levels in COM plots nor did they increase the wet aggregate stability of soil under either crop. (Abstract shortened by UMI.)

Composting of biodegradable waste is an effective means of reducing landfill garbage and improving the state of our environment. The widespread adoption of this behaviour by community members is subject to various social psychological processes. Table top signs outlining a pro-composting injunctive norm, and models demonstrating the behaviour (descriptive norm) were employed in two shopping centre food courts and a fast food restaurant to attempt to increase the use of public compost bins. When diners viewed models composting ahead of them, they were more likely to compost as well. However, the signs had no effect on composting rates, either alone or in combination with the models. Results support the idea that behaving in a pro-environmental manner around others can have an influence on them to behave pro-environmentally as well.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Thesis (M.Sc.) -- Hawkesbury Agricultural College, 1985. / "A thesis submitted to Hawkesbury Agricultural College in partial fulfilment of the requirements for the degree of Master of Applied Science."

Thesis (Ph.D.)--University of Western Australia, 2005.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.