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Q T Wu

Publications and source records attributed to Q T Wu.

5 recordsLinked to original sources
PubMed2001

Co-composting of soybean residues and leaves in Hong Kong.

The goal of this project was to evaluate the feasibility of co-composting of soybean residues and leaves and the effects of turning frequency on compost quality. Soybean residues were mixed with leaves and sawdust in 1:1:3 (w/w wet weight) for achieving a C/N ratio of about 30. Three heaps of about 4 m3 of compost mixtures were prepared receiving a turning frequency of daily (pile A), 3-day (pile B) and weekly (pile C) turning. Different turning frequencies did not significantly affect the changes in pH and volatile solids throughout the composting period. High turning frequency caused a lower electrical conductivity and NH4-N contents as well as a shorter duration of thermophilic phase, because of a high heat loss by evaporation and volatilization of ammonia in the pile. The highest C decomposition of 4% occurred in the pile with a 3-day turning period, which coincided with the higher-nitrogen content in this treatment. All treatments with different turning frequencies reached maturation at 63 days as indicated by the soluble organic carbon, soluble NH4-N, C/N ratio and cress seed germination index. However, increasing the aeration during composting period was beneficial in accelerating the maturation process. Taking into consideration less labour and lower operation costs as compared to daily turning, it can be suggested that a 3-day turning frequency would be more appropriate for reaching acceptable quality of compost and ease in operation.

Biodegradation, Environmental↗
PubMed2001

Co-composting of pig manure with leaves.

The increase in the market price of sawdust makes it a less attractive bulking agent for pig manure composting. Hence, it was the aim of this project to evaluate the feasibility of co-composting pig manure with leaves with special emphasis on its effects on compost maturity and quality. Two piles were prepared with one pile (Pile A) just constituted of pig manureand sawdust at a mixing ratio of 3:2 (w/w, fresh weight), while the other one (Pile B) with pig manure, sawdust and leaves at 3:1:1 ratio (w/w, fresh weight) to achieve a C/N ratio of 30. Each 8 m3 heap was turned and mixed every 3 days to provide sufficient aeration and the moisture content was kept at 60-70% (w/w) throughout the composting period. After 49 days of composting, dissolved organic carbon (DOC), soluble NH4-N(solid), C/N(aqueous) and C/N(aqueous) of pile A decreased to <5%, 400 mgkg(-1), 20 and 6, respectively, indicating a high degree of maturity, while pile B with leaves required only 35days. Seed germination index (GI) of pile A increased to 66.5% at day 49, while pile B to 52.4% at day 35, which was higher than the phytotoxin-free level of 50% recommended for agricultural use. This demonstrated that the addition of leaves enhanced the humification process and shortened the time required for maturation and stabilization of pig manure composting. Therefore, it is recommended to co-compost pig manure with leaves to provide a means to reutilize this waste and in the same time to reduce the dependence on sawdust as a buLking agent.

Animals↗
PubMed2001

Nitrogen transformations during pig manure composting.

Composting is now suggested as one of the environmentally and friendly alternative method for disposal of solid organic wastes, as it leads to minimization, stabilization, and utilization of organic waste. Transformations of nitrogen were investigated in co-composting of pig manure with different amendments, such as sawdust and leaves. Samples were analyzed for pH, total-N, soluble NH4-N, soluble NO3-N and soluble organic-N. The total-N increased after 63 days of composting, as well as the soluble NO3-N and soluble organic-N. Soluble NH4-N increased significantly and showed peak values at day 7, thereafter decreased sharply and gradually to lower levels. Seed germination index (GI) showed that co-composting of pig manure with sawdust reached maturity after 49 days of composting, while co-composting of pig manure with sawdust and leaves required shorter time for 35 days. Soluble NH4-N was significantly negatively (P < 0.05), while soluble NO3-N and soluble organic-N were significantly positively (P < 0.05), correlated with seed germination index (GI). Addition of leaves in co-composting of pig manure with sawdust had no significant impacts on nitrogen transformations, but it was beneficial for maturity of pig manure compost.

Animals↗
PubMed1983

Studies of haemopoietic stem cells and microenvironment in chronic irradiated mice.

Mice were irradiated at a dose rate of 70 rad per day for 25 days. Changes in properties and functions of haemopoietic stem cells and microenvironment were observed through a period of 12 months after termination of continuous irradiation. It was shown that the radiation damage of haemopoietic stem cells played an important role in the radiation-induced damage of haemopoiesis. This was further supported by the fact that transplantation of syngeneic bone marrow cells immediately after termination of continuous irradiation at 70 rad per day for 25 days would greatly improve the haemopoietic function of the irradiated mice, including the total recovery of CFU-S and numbers in the bone marrow and cell counts in the peripheral blood.

Animals↗