SOIL Seminar

Abstract: The metalloid selenium (Se), a natural-occurring element, is ubiquitous in the environment with total concentrations in most soils ranging from 0.01 to 2.0 mg/kg, however, higher concentrations occur worldwide in seleniferous areas. Soil Se concentrations and bioavailability vary with environmental conditions, and the distribution of Se in soil is usually heterogeneous and site specific.  Areas with high or excessive concentrations of Se, include China, parts of California, South Dakota, Colorado and Wyoming. These "hot spot areas" are characteristic for igneous rock, shale, granite and limestone, while soils developed under temperate and humid/sub-humid are quite poor in Se.  In low Se regions, over 1 billion people have been estimated to be affected by Se deficiency, which compromises the immune system, thyroid activity, male fertility and mental function. Selenium is like a Dr. Jekyll and Mr. Hyde element. In this regard, selenium is an essential micronutrient for many life forms including humans, animals, bacteria, archaea and some algae, however, it can be toxic to humans, animals, wildlife and the biological ecosystem at high concentrations. Hence, strategies are needed to both manage high Se soils when, while other strategies are needed to ensure that Se intake is sufficient to preserve human health.  In this talk, Dr. Banuelos will present two different strategies to address both vital Se-related issues: 1) to manage excessive Se in the soil environment he developed a strategy called "selenium phytoremediation," where plants are used to extract and volatize Se from the soil environment and 2) to increase Se intake for humans living in areas with low Se in the soil environment, he developed  the concept called "selenium biofortification," where plants are specifically grown for their ability to accumulate higher concentrations of bioavailable Se. Both plant-based and natural strategies are used worldwide in soils with excessive soil Se and in Se deficient soils.

Bio: Dr. Bañuelos completed his Ph.D in Germany and has spent over 5 sabbaticals at the University of Zurich. He has conducted scientific research for over 30 years with the USDA-ARS as a Plant/Soil Research Scientist and Adjunct Professor for University of California and California State University, and teaches as guest Professor in Switzerland, China, Thailand and Chile. He has focused his activities on the phytoremediation of soils and waters laden with selenium, boron and salinity, as well as the biofortification of food crops with selenium. His integrated approach to field phytoremediation and biofortification involves more than just the selection of alternative crops, e.g., guayule, agretti, cactus, poplar trees, mustard, and pistachios, but also considers crop rotation, irrigation and drainage management, natural chemical transformation processes within the soil, grower acceptance, and the production of innovative biofortified and biobased products, e.g., biofuel, Se-enriched feeds and vegetables. He strives on creating a functional agriculture strategy for phytomanaging trace elements under saline conditions worldwide and increasing biofortification strategies by generating plants that biofortify themselves with selenium and other nutrients during their growth in selenium rich soils. His strong cooperation with Chinese scientists, professors and graduate students for the last 15 years has contributed to the development of selenium biofortification strategies throughout selenium rich and deficient regions of China, as well has led to his organization of seven international selenium conferences in China, Sweden Thailand and Brazil.  He is author/ co-author of over 300 refereed journal articles, senior editor on five books, and has five patents on alternative crops under saline conditions.