title: Potassium in agriculture--status and perspectives.
abstract: In this review we summarize factors determining the plant availability of soil potassium (K), the role of K in crop yield formation and product quality, and the dependence of crop stress resistance on K nutrition. Average soil reserves of K are generally large, but most of it is not plant-available. Therefore, crops need to be supplied with soluble K fertilizers, the demand of which is expected to increase significantly, particularly in developing regions of the world. Recent investigations have shown that organic exudates of some bacteria and plant roots play a key role in releasing otherwise unavailable K from K-bearing minerals. Thus, breeding for genotypes that have improved mechanisms to gain access to this fixed K will contribute toward more sustainable agriculture, particularly in cropping systems that do not have access to fertilizer K. In K-deficient crops, the supply of sink organs with photosynthates is impaired, and sugars accumulate in source leaves. This not only affects yield formation, but also quality parameters, for example in wheat, potato and grape. As K has beneficial effects on human health, its concentration in the harvest product is a quality parameter in itself. Owing to its fundamental roles in turgor generation, primary metabolism, and long-distance transport, K plays a prominent role in crop resistance to drought, salinity, high light, or cold as well as resistance to pests and pathogens. Despite the abundance of vital roles of K in crop production, an improvement of K uptake and use efficiency has not been a major focus of conventional or transgenic breeding in the past. In addition, current soil analysis methods for K are insufficient for some common soils, posing the risk of imbalanced fertilization. A stronger prioritization of these areas of research is needed to counter declines in soil fertility and to improve food security.
authors.affiliation: Universität Leipzig, Institute of Biology, Botany, Johannisallee 23, 04103 Leipzig, Germany. Electronic address: Christian.zoerb@uni-leipzig.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Zörb
authors.affiliation: Institute of Applied Plant Nutrition, University of Goettingen, Carl-Sprengel-Weg 1, D-37075 Göttingen, Germany.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Senbayram
authors.affiliation: Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences (IAEW), Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, 06099 Halle (Saale), Germany; Interdisciplinary Centre of Crop Research (IZN), Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, 06099 Halle (Saale), Germany.
authors.forename: Edgar
authors.initials: E
authors.lastname: Peiter
mesh_terms: D018556:Crops, Agricultural / Q000254:growth & development / Q000502:physiology*; D053147:Plant Exudates / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013312:Stress, Physiological
chemical_list: D053147:Plant Exudates; D012987:Soil; D011188:Potassium
keywords: Deficiency; Global demand; Potassium; Quality; Soil availability