Naveed, Muhammad6; Møldrup, Per1; Vogel, Hans-Jörg7; Lamande, Mathieu André Maurice6; Wildenschild, Dorthe8; Tuller, Markus9; de Jonge, Lis Wollesen6
1 The Faculty of Engineering and Science, Aalborg University, VBN2 Department of Civil Engineering, The Faculty of Engineering and Science, Aalborg University, VBN3 Division of Water and Soil, The Faculty of Engineering and Science, Aalborg University, VBN4 Water and Environment Research Group, The Faculty of Engineering and Science, Aalborg University, VBN5 Urban Water and Environment Research Group, The Faculty of Engineering and Science, Aalborg University, VBN6 Institut for Agroøkologi - Jordfysik og Hydropedologi7 Department of Soil Physics, Helmholtz Center for Environmental Research-UFZ, Theodor-Lieser-Straße 4, 06120 Halle (Saale)8 US Environmental Protection Agency, Corvallis, OR 973339 Univ Arizona, Dept Soil Water & Environm Sci, Tucson, AZ USA
The study characterized soil structure development and evolution in six plots that were amended with varying amounts of animal manure (AM) and NPK fertilizer over a period of 106 years in a long-term fertilization experiment in Bad Lauchstädt, Germany. Two intact soil cores (10-cm diameter and 8-cm tall) and bulk soil samples were extracted from a depth between 5 and 15-cm from each plot. Soil properties including texture, organic carbon, soil–water characteristic, air permeability and diffusivity were measured and analyzed along with X-ray computed tomography (CT) data. Long-term applications of AM and NPK had a major impact on soil organic carbon content which increased from 0.015 kg kg− 1 (unfertilized plot) to 0.024 kg kg− 1 (well fertilized plot, 30 T ha− 1 2y− 1 AM with NPK). Total porosity linearly followed the organic carbon gradient, increasing from 0.36 to 0.43 m3 m− 3. The water holding capacity of the soil was considerably increased with the increase of AM and NPK applications. Gas diffusivity and air permeability measurements clearly indicated that the level of soil aeration improved with increasing AM and NPK fertilizer amount. The three-dimensional X-ray CT visualizations revealed higher macroporosity and biological (earthworm) activity in the well fertilized areas when compared to plots without or only a small amount of fertilizer applied. A combined evaluation of the soil water characteristic, gas transport and X-ray CT results suggested that pore size distributions widened, and pore connectivity was significantly improved with increasing fertilizer amount. Furthermore, the soils fertilized with both AM and NPK showed a more aggregated structure than soils amended with AM only.
Geoderma, 2014, Vol 217-218, Issue April, p. 181-189
Animal manure; NPK fertilizers; Soil–water characteristic; Gas diffusivity; Air permeability; X-ray computed tomography