Showing 2 results for E. Asadi
F. Raiesi Gahrooee, E. Asadi, J. Mohammadi,
Volume 9, Issue 3 (fall 2005)
Abstract
Over-grazing may induce changes in the dynamics of plant residue carbon and soil organic carbon (SOC). The objective of this study was to evaluate the litter quality of three dominant pasture species, and the relationship between litter quality and C dynamics under different range managements in native rangelands of SabzKou. Aboveground litters from three dominant species including, Agropyron intermedium (AP), Hordeum bulbosum (HB) and Juncus stenophylla (JU) were collected in an area protected from grazing for 15 years. Concentrations of N, P and K in litter samples were determined. Litter decomposition was also studied by using a litter bag experiment. Bagged litters were incubated under field conditions at grazed and ungrazed sites for one year. Concentrations of N in litters were 1.37, 1.36 and 0.98, respectively, for AP, JU and HB. Assuming 50 % C in the litter, C/N ratios of litters were 37.2, 37.3 and 51.1, respectively, for AP, JU and HB. The litters of AP, JU and HB contained, respectively, 0.13,0.12 and 0.21 % of P, and 1.04, 1.01 and 1.72 % of K. Results indicate no significant (p>0.05) and consistent difference in litter decomposition rates between grazed and ungrazed areas. The three pasture species, however, showed significant (p<0.01) differences in litter decomposition rate. It is appearing that the trend in litter decomposition of these plant species correlates initially with litter C/N ratio, but other quality parameters of litter as well as soil environmental conditions would likely affect the litter decomposability in advanced stages of decomposition process.
Z. Arabi , M. Homaee , M. E. Asadi ,
Volume 14, Issue 54 (winter 2011)
Abstract
In this study, the effects of enhancing synthetic chelators (HEDTA, EGTA) and low molecular weight organic acids (LMWOA) such as citric acid were compared on cadmium (Cd) solution in soils that were artificially contaminated. Also Cd phytoextraction capability by radish (Raphanus Sativus L.) was studied. The experiment was laid out in a randomized complete factorial design where each treatment was replicated three times. Concentration treatments of cadmium using CdCl2 were 0(control), 5, 20, 60 and 100 mg Cd kg-1. After complete growth of plants, 6, 20 and 20 mMkg-1 soil HEDTA, EGTA and Citric Acid were added per pot, keeping a control without any chelator application. In order to determine cadmium concentration ten days after adding chelates, samples were taken from the plants and soil of pots. The results showed that in all treatments the concentration of soluble Cd in soil was higher than the control. Also the results showed that synthetic chelators as compared with LMWOA (Citric Acid) have increased the solution remarkably. Among the other chelates, HEDTA had significant effects on Cd solution. In the current study, Cd concentration in shoot and root of (Raphanus Sativus L.) was increased with enhancement of Cd concentration in soil. Cd concentrations in shoots of radish were higher than those in roots. This could refer to higher bioavailability and solubility of Cd. In the current study, in all the treatments with HEDTA Cd concentrations in shoot and root of (Raphanus Sativus L.) were increased as compared with other chelates..
