Prof. Dr. Walter Horst

Prof. Dr. Walter Horst
Retired Professors
Institute of Plant Nutrition


Emeritus Prof. Horst has significantly influenced the Plant Nutrition in Germany and promoted its international orientation. He worked on a wide range of research topics which may be characterized by the term “Increasing nutrient efficiency and resistance against toxic mineral elements”. As wide as the selection of topics were also the methodological approaches which ranged from field trials to techniques of molecular biology.

His main research area to which he remained true since his time as a graduate student, was the damage to plants by aluminium and manganese in acid soils. He has studied the importance of other minerals for manganese and aluminum tolerance, as well as the impact of plant characteristics and mechanisms to adapt to manganese and aluminum stress. Understanding these mechanisms is the basis for the screening of genotypes with high toxic mineral element tolerance or resistance. Some examples of major findings from his work in this area are: the impact of silicon on manganese tolerance, the importance of mucilage for aluminum resistance, extent of formation of callose in aluminum stress, or the release of organic anions under aluminum stress and the role of the root and leaf apoplast, respectively, for the damage of plants by aluminum or manganese.

Other important and extensive research areas by Mr. Horst have been studies aiming at understanding and influencing the phosphate efficiency and nitrogen efficiency of plants. They ranged from studies on the nutrient uptake to the development of models for nutrient utilization by plants. The practical implications of this work were both the objective to increase yields under Low Input Conditions and to minimize adverse environmental effects under High Input Conditions. In his research in recent years Mr. Horst also approached issues on the relationship between Plant Nutrition and drought stress and Plant Nutrition and plant health.


  • Professional backgroud

    Professor Horst was born in Datteln in Westphalia. After graduating from high school and in military service, he studied agricultural sciences at the Technical University of Berlin, where he received his doctorate in 1976 with Professor Marschner with a thesis on the influence of silicon on the manganese tolerance of bush beans. He then worked as a postdoc at the International Institute of Tropical Agriculture in Ibadan, Nigeria, for two years. As far as I can tell, the experience of the living conditions there, which are much more difficult than us, have shaped Mr. Horst's further scientific career and has been the driving force behind many of the research projects he has carried out.

    In 1978 he returned to Germany, to the Institute for Plant Nutrition in Hohenheim, where his teacher, Professor Marschner, had in the meantime accepted a call.

    There, in 1980, Mr. Horst habilitated with a thesis on "Genotypical differences in aluminium and manganese tolerance in cowpea and soya". This was followed by a call to the C3 professorship for plant nutrition in Hohenheim, which he held from 1981 to 1987. From 1987 to 2011, Mr. Horst  finally took over the chair of plant nutrition at the Leibniz University of Hanover in place of Mr. Wehrmann.

  • Memberships and Authorities

    Mr Horst has accompanied numerous national and international honorary offices, the listing of which would go beyond the scope. I would just like to mention the chairmanship of the German Society for Plant Nutrition from 1993 to 1997 and the Presidency of the International Plant Nutrition Council from 1997 to 2001. In this capacity, he hosted the renowned "International Plant Nutrition Colloquium" with the University of Hanover in 2001. Since 2003 he has been a member of the Scientific Advisory Board for Fertilization Issues of the BMELV, and since 2008 its chairman. Under his aegis, numerous opinions have been prepared on the efficient, environmentally and resource-saving use of fertilisers, most recently a joint opinion of the scientific advisory councils on agricultural policy and fertilisation issues of the BMELV and the Federal Government's Council of Experts on Environmental Issues on the amendment of the Fertilisation Ordinance.