Mahmoud Kalbassi, Akbar Gandomkar,
Volume 1, Issue 2 (fall 1997)
Abstract
The moisture content of urban solid wastes in Iran is very high. A large volume of leachate is, therefore, produced in the process of converting these wastes into compost. The leachate contains relatively large amounts of organic matter, plant nutrients, soluble salts as well as small amounts of some heavy metals. The effects of urban solid waste leachate on growth and yield of corn and heavy metals and nutrients concentrations in plant as well as the effects of leachate residual on soil were studied in a field trial conducted in two sites (Zeinal and Lavark) in central Iran (Isfahan). The treatments included applications of 0, 400, and 800 metric tons of leachate/ha as the main plots and two leaching treatments (0 and 15 cm leaching) as the sub-plots in a split plot design. Application of the leachate decreased crust formation and greatly improved germination and growth of corn in both sites. Biological yield of corn increased from 2.4 to 4.1 and 5.3 tons/ha in Zeinal field and from 8.1 to 13.4 and 15.0 tons/ha in Lavark field for 400 and 800 tons/ha of leachate applications (as compared to the control field), respectively. Leaching increased corn yield only in Zeinal field. Uptakes of N, P, K, Fe, Mn, Zn and Cu by corn increased as a result of leachate application. Concentrations of Fe, Mn, Zn, Cu, and Cl in plant tissues also increased but no toxic symptoms were observed in plants. Concentrations of Pb, Cd, Cr, Co, and Ni in aerial tissues of corn did not increase as a result of leachate application. The residual effects of leachate application on soil were a decrease in pH and corresponding increases in organic matter content, in electrical conductivity and in available amounts of N, P, K, Fe, Mn, Zn, and Cu. It is concluded that garbage leachate has the potential to be used as an organic liquid fertilizer and soil amendment to improve soil productivity.
M. R. Kalbassi, S. A. Johari,
Volume 12, Issue 44 (summer 2008)
Abstract
In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratios and gonad development were determined by histological studies. Final results showed that progenies produced by mating sex-reversed (masculinized) males and normal females were totally female (100 %). Also, applying early heat shocks (26.5° C lasting 20 min, 20 min after egg fertilization) induced about 80 % triploidy in fishes. All-female triploid, all-female diploid and mixed-sex diploid fishes did not show any significant difference in incubation stages (eyed-stage egg rate, hatching, survival from hatching to active feeding), (P>0.05). Eyed-stage eggs rate, and hatching rate of eyed eggs in mixed-sex triploids were significantly lower than in other treatments (P<0.05). Testes development in diploid males was similar to that of triploid and was in early stages of spermatogenesis in 8 month old fish. Also, diploid ovaries were packed with oocytes at previtellogenic or perinucleolus stages. Although they showed distinct lamellar structure of an ovary, triploid ovaries contained no oocytes
