Investigating the Impact of Different Land Management Practices On Soil Quality.

Abstract

Soil quality can either be directly inferred from soil organic carbon or through the combined evaluation of the soil physical, chemical and biologic properties.  There exists a strong link between land cover changes, soil quality and global warming.  While the consequences of soil quality reduction are generally recognized, several questions remain without satisfactory answers.  For example, synthesizing soil organic carbon changes are limited by the degree of uncertainty in existing estimates which may exceed 50 %.  Therefore it is possible that a rapid reduction or enhancement in soil quality may be occurring in locations that are not identifiable in existing maps. This research attempts to develop tools for precise inventory of C and N footprints with a view to assessing the soil quality within 4 different treatments i.e. no till with manure, no till without manure, natural vegetation (e.g. forest), and conventional tillage.  Soil samples were collected at similar landscape positions and soil types at four depths i.e. 0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm, in 5 different field sites within the state of Ohio.  In situ soil penetration and infiltration tests were conducted.  To investigate the influence of management on residue oxidation and quantify C inputs, the weight of the surface residue cover at the soil sampling locations were measured in the field.  After that, the soil moisture content, bulk density, and carbon contents were processed and analyzed in the laboratory.  The hypotheses of this study are that SOC is highest under no till management practice, with the natural vegetation (forest) considered as control.  The overall aim of this study is to develop standard methodologies for quantifying soil carbon stocks at regional scale, and soil quality indices.