اثر قارچ ميكوريزا، لجن فاضلاب و بيوچار حاصل از آن بر شاخص هاي ساختمان و كيفيت فيزيكي خاك تحت كشت گياه ذرت

چكيده انگليسي :

The Effect of Mycorrhizal Fungi Sewage Sludge and Its Biochar on Structural and Physical Quality Indices of Soil under Corn Saeede Ebrahimi saeedeh ebrahimi@ag iut ac ir 15 January 2014 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiM Afyuni afyuni@cc iut ac irM R Mosaddeghi mosaddeghi@cc iut ac irAbstractIn sustainable agriculture conservation of soil structure and prevention of its degradation is important Consideringthe fact that Iran is located in arid and semiarid areas and the arable agricultural lands are limited soil degradationand erosion should be controled The objective of this study was to determine the effects of organic fertilizer andmycorrhizal fungi on soil structure physical quality and hydraulic properties under corn plant A greenhouse studywas conducted in the form of factorial experiment with 3 factors and a complete randomized blocks design withsewage sludge and its biochar in three replications Biochar was prepared in a special furnace at 300 C withoutoxygen Sewage sludge and biochar were applied to the soil at 0 control 5 10 20 and 40 ton ha The treatmentsalso included the presence or absence of mycorrhizal fungi Three months after planting the shoots and roots of cornplants were harvested and disturbed and undisturbed soil samples were collected from each pot Application of 40ton ha of sewage sludge and biochar in non inoculated mycorrhizal fungi condition significantly increased shootand root biomass the geometric and mean weight diameters MWD and GMD of waterstable aggregates the shapeparameter of van Genuchten model n residual water content r and mesoporosity and microporosity in the soil The rate of mycorrhizal fungi colonization in biochar treatments was more than the sewage sludge treatments andbiochar had an effective role in increasing the available water AW and aggregate stability One reason for this isbiochar high porosity with its high surface area that helps to increase aggregate stability With increasing levels ofsewage sludge and biochar soil water characteristic curve SWCC shifted up and right Thus soil water retention atspecific matric suction increased Adding organic fertilizer leads to an increase in the slope of SWCC and the peakof pore size distribution curves PSD i e the S index Consequently in the absence of mycorrhiza treatment of 40ton ha organic fertilizer improves the soil physical quality S However this treatment due to its water repellencyeffect increased structural instability mechanically dispersible clay MDC and decreased macroporosity and AW Adding the sewage sludge and biochar up to 20 ton ha in the presence of mycorrhizal fungi improved plant yield structural stability and soil physical quality to a greater extent than in the absence of mycorrhiza While 40 ton hasewage sludge and biochar in the presence of mycorrhiza did not have a positive effect on soil physical properties Mycorrhizal fungi even in low organic material inputs significantly reduced MDC and thus improved soil structure Adding sewage sludge and biochar up to 20 ton ha in the presence of mycorrhiza increased microporosity mesoporosity and especially macroporosity in the soil This increase was associated with a large percentagemycorrhizal colonization and is related to the hyphea network development of mycorrhizal fungi in soil As a result the use of organic fertilizers especially biochar and mycorrhizal fungi lead to increased soil physical quality andcrop yield Best combination treatmentis application of 20 ton ha organic fertilizer especially biochar withmycorrhizal fungi In addition to being economical this application rate increases soil available water for plants roots and shoots yields and percentage of mycorrhizal colonization It also decreases theamount of MDC andimproves pore size distribution and soil physical quality The increased stability of soil structure can probably helpto reduce soil erosion especially in arid and semi arid

ابراهيمي، سعيده

اثر قارچ ميكوريزا، لجن فاضلاب و بيوچار حاصل از آن بر شاخص هاي ساختمان و كيفيت فيزيكي خاك تحت كشت گياه ذرت

پايداري ساختمان خاك , رس قابل پراكنش