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Doctoral thesis, 2013

Influence of soil amendments and soil properties on macro– and micronutrient availability to microorganisms and plants

Ramezanian Bajgiran, Atefeh


Utilising by-products from industrial and domestic activities and from bioenergy production is one of the new ways of recovering and re-using nutrient resources in agriculture. However, these by-products can potentially add toxic elements or alter soil properties in ways that harm the soil and related environments. This thesis investigated the efficacy and potential adverse effects of using organic (biogas digestate, pot ale) and inorganic (rockdust, wood ash) by-products as amendments on the supply of nutrients to crops (wheat, mixed perennial ryegrass and red clover) and the impact on community-level physiological and genetic profiles of soil microorganisms. The influence of the inherent soil macro –and micronutrient concentration relative to a range of environmental variables was also investigated to explain the variation in physiological profiles of the microbial communities and the genotypic variation in Rhizobium/Agrobacterium in a landscape-scale study of pasture and arable soils. The nutrient status of soils proved to be an important factor for the efficacy of amendment application. The by-products studied generally enhanced crop biomass and the content of some macronutrients and micronutrients in soils and plants when applied to nutrient-poor soils. The concentration of potentially toxic elements (Cd, Pb) was not increased in soils or plants due to amendment application. The botanical composition of mixed ryegrass-red clover stands was also affected by amendments, with biogas digestate, rockdust and wood ash producing more clover than grass. Soil microorganisms were largely unaffected by these amendments. However, the soil microbial community composition was altered by increasing the availability of nutrients through a fully-fertilised treatment. The landscape study showed that aqua regia-extractable manganese and rainfall, respectively, were the main factors explaining the variation in microbial physiological profiles and Rhizobium/Agrobacterium genotypes.


biogas digestate; CLPP; pot ale; red clover; rhizobia; rockdust; ryegrass; T-RFLP; wood ash

Published in

Acta Universitatis Agriculturae Sueciae
2013, number: 2013:30
ISBN: 978-91-576-7798-3, eISBN: 978-91-576-7799-0
Publisher: Dept. of Crop Production Ecology, Swedish University of Agricultural Sciences

Authors' information

Ramezanian Bajgiran, Atefeh
Swedish University of Agricultural Sciences, Department of Crop Production Ecology

UKÄ Subject classification

Soil Science
Agricultural Science

URI (permanent link to this page)