Hamid reza Mehrabi; Mohammad reza Chaichi; Reza Tavakolafshari; Hasan Madah Arefi; Ghavamodin Zahedi Amiri
Volume 17, Issue 3 , October 2010, , Pages 489-498
Abstract
Applying methods like seed coating which result in germination improvement, reduction of environmental stresses and increase of range species establishment is utmost important. This experiment was performed to evaluate the effect of different seed coating methods on Sanguisorba minor seed germination ...
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Applying methods like seed coating which result in germination improvement, reduction of environmental stresses and increase of range species establishment is utmost important. This experiment was performed to evaluate the effect of different seed coating methods on Sanguisorba minor seed germination under drought stress and different sowing depths. A factorial experiment in a completely randomized design with three replications was conducted in this research. Treatments included three soil moisture levels (9, 14 and 21 percent of soil dry weight), two sowing depths (surface and three times the diameter of seed), and four seed coatings (control or no seed coating, organic matter, hydro gel and clay seed coatings). Germination percentage was recorded during the experiment. The results of main treatments showed that regardless of the coating type, the effect of all three coating materials on seed germination percentage was significant (p<0.01). The triple interaction effects of soil moisture, sowing depths and coating materials indicated that in surface sowing and all soil moisture levels, there was a significant difference (p<0.01) in seed germination percentage between seed coating and control treatments. No germination was observed in control treatment with 9% soil moisture and surface sowing. Germination percentage for control treatment with 14% soil moisture was 20% recorded as the second rank among the lowest germination levels. In treatment of three times the diameter of seed as sowing depth with 21% soil moisture, there was no significant difference in germination percentage between control and seed coating treatments.
Noor ... Abdi; Hasan Madah arefi; Ghava din Zahedi amiri
Volume 15, Issue 2 , January 2008, , Pages 269-282
Abstract
Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter ...
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Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter in a process termed terrestrial C sequestration. Rangelands ecosystems have a large potential to sequester C because they occupy about half of the world's land area. In Iran, the Astragalus rangelands with about 17 million hectare area have 10% of the country land area and have the important role in carbon sequestration. In order to investigation the role and potential of Astragalus rangelands in carbon sequestration, a study was carried out at a key area of Astragalus verus-Bromus tomentellus vegetation type in Malmir rangeland site, Shazand township of Markazi province and the content of aboveground and underground biomass carbon, litter carbon and soil organic carbon was determined. The results showed that the total carbon sequestration per hectare was 32.95 ton and 87.43 % of total carbon sequestration was soil organic carbon. The results of biomass carbon distribution showed that the carbon content in aerial biomass was higher than underground biomass. Correlation and stepwise regression analysis revealed that the content of carbon sequestration was positively related to Astragalus height and volume, aerial and underground biomass, total biomass, litter amount and soil organic carbon (SOC) content. It was concluded that the Astragalus rangelands have a large potential to sequester carbon and the soil is most important sink for organic carbon storage in this rangelands
Ali ashraf Jafari; Alireza Seydemohammadi; Noor alah Abdi; Hasan Madah arefi
Volume 15, Issue 1 , January 2008, , Pages 114-128
Abstract
Desert wheatgrass, Agropyron desertorum (Fisch. ex Link) Schult, is one of important perennial grass species that naturally grows in Zagrous and Alborz mountains rangelands in the west and north of Iran. In order to identification of superior genotypes for both seed and dry matter (DM) yield, 31 genotypes ...
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Desert wheatgrass, Agropyron desertorum (Fisch. ex Link) Schult, is one of important perennial grass species that naturally grows in Zagrous and Alborz mountains rangelands in the west and north of Iran. In order to identification of superior genotypes for both seed and dry matter (DM) yield, 31 genotypes were sown in two separate experiments under optimum and drought stress condition using randomized complete block designs with three replications in Arak, Iran, during 2004-2006. Seeds and DM yield in optimum (Yp) and stress (Ys) condition for each genotypes were used to estimate the five drought resistance indices as: tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI). The data subsequently used in principal components analysis. Based on bi-plot of the first two principal component scores, genotypes were distributed into four groups. For seed yield 631P5, 747M, 747P11 and 213P11 with average values 430 to 503 kg/h and for DM yield, 3477PM, 3477PM, 3965P11 and 341P11 with average values 2060 to 2260 Kg/h were recognized as the best varieties for dry condition. The 742P5, 1369P6, 3477P4, 287P8 and 341M for seed yield and 3477M, 3965P15, 631P2, 4036M and 341P11 for DM yield were introduced as the best genotypes for cultivation in semi arid regions. In simultaneous selection for both seed and DM yield, 631P5 (Ghazvin), 747M (Ghazvin), 341M were introduced for arid regions and 3477P4, 341P11, 287P8 (Hamadan), 1369P6 (Hamadan) and 3477M for semi arid regions of central province of Iran.