R. García Moreno

Managing the Selenium Content in Soils in Semiarid Environments through the Recycling of Organic Matter

Around 30% of the world’s population suffers from either a lack of one or more essential micronutrients, or the overconsumption of these minerals, which causes toxicity. Selenium (Se) is a particularly important micronutrient component of the diet with a well-documented and wide-ranging role in maintaining health. However, this important micronutrient can be lacking because soil and crop management are focused on high yields to the detriment of the quality of crops required to ensure a healthy human diet. Currently around 15% of the global population has selenium deficiency. This paper focuses on Se availability in semiarid soils and how micronutrients can be effectively managed through the recycling of organic matter. Because many mineral reserves are being exploited unsustainably, we review the advantages of using organic by-products for the management of the biofortification of Se in crops. This type of practice is particularly useful in arid and semiarid environments because organic matter acts as a reservoir for Se, preventing bioaccumulation and leaching. There are also potential local economic benefits from using organic by-products, such as manures and sewage sludge.

Effect of Management Practices on Soil Microstructure and Surface Microrelief

Soil surface roughness (SSR) and porosity were evaluated from soils located in two farms belonging to the Plant Breeding Institute of the University of Sidney. The sites differ in their soil management practices; the first site (PBI) was strip-tilled during early fall (May 2010), and the second site (JBP) was under power harrowed tillage at the end of July 2010. Both sites were sampled in mid-August. At each location, SSR was measured for three 1 m2 subplots using shadow analysis. To evaluate porosity and aggregation, soil samples were scanned using X-ray computed tomography with 5 μm resolution. The results show a strong negative correlation between SSR and porosity, 20.13% SSR and 41.38% porosity at PBI versus 42.00% SSR and 18.35% porosity at JBP. However, soil images show that when soil surface roughness is higher due to conservation and soil management practices, the processes of macroaggregation and structural porosity are enhanced. Further research must be conducted on SSR and porosity in different types of soils, as they provide complementary information on the evaluation of soil erosion susceptibility.

Multiscaling Analysis of Soil Drop Roughness

R. Garcia Moreno1, M.C. Diaz Alvarez2, A. Saa Requejo2 and J.L. Valencia Delfa3 1Departamento de la Navegacion y de la Tierra, Facultad de Ciencias, Universidad de La Coruna, A Coruna, 2CEIGRAM (Centre for Studies and Research on Agricultural and Environmental Risk Management). School of Agricultural Engineering, Polytechnic University of Madrid, Madrid, 3Escuela Universitaria de Estadistica. Universidad Complutense de Madrid, Madrid Spain