What evidence exists of crop plants response to exposure to static magnetic and electromagnetic fields? A systematic map protocol.

Background: Increasing demand for food and concerns over the environmental impact of agriculture has prompted the search for alternatives to many conventional farming practices. Reports on exposing seeds and plants at various developmental stages to static magnetic field (SMF) and non-ionizing electromagnetic fields (EMF) as a form of priming indicate some positive effects on seed germinability, growth rate, resistance to stress conditions, and improved yield. However, there exist some inconsistent reported treatment protocols and contradictory study outcomes that make it difficult to draw objective conclusions on the potential use of SMF and EMF as sustainable alternatives to improving crop growth and yield. It is equally essential to understand any adverse effects of exposing plants to SMF and EMF considering the abundance of their sources in the environment. In order to provide a more coherent overview of how plants respond to exposure to SMF and EMF not only in their observed effects of agronomic importance but also in the mechanisms of action of SMF and EMF in plant cells, we prepare a systematic map.

Methods: Literature will be identified by searching six bibliographic databases and three web-based search engines using terms obtained from the population, exposure, and outcome parameters of the research question. Primary research published in peer-reviewed journals and grey literature will be the source for the evidence map. Studies eligible for inclusion may involve: food crops and related research model plants exposed to SMF or non-ionizing EMF; treatment at all plant developmental stages excluding post-harvest improvement of food crops; and the presence of control groups. Eligible literature will be screened at the title, abstract, and full text levels. The validity of studies will not be critically appraised for the evidence map. A process of double extraction and coding of relevant information from eligible literature will be conducted. Within the evidence map, relevant data will be presented in the forms of text, graphs, tables, and figures. This will illustrate research trends, bring clarity to the evidence base concerning clusters of sufficient findings and areas of significant gaps, and inform stakeholders in decisions concerning research planning and policy formulation.