Pre-sowing seed exposure to static magnetic field can improve cabbage yield

Abstract

The static magnetic field (SMF) has been shown to influence living organisms, for example, plants, fungi, insects, mice, and rats. It came as no surprise that the effects caused by SMF depend on the intensity of the applied field and exposure duration; however, discovered non-linear dependence on these parameters was not expected. In addition, it was found that the changes caused by SMF depend on the field direction and orientation as well as on the type of organism that is being affected. Numerous studies show that magnetic fields of various types regulate plant functions as well as enhance growth and tolerance to environmental stress. The studies that used SMF for exposure reported increased germination, seedling growth, length and biomass of plants as well as draught and salinity tolerance of different plants. However, majority of the experiments is performed in the laboratory conditions and is not extended farther into the agricultural field. Our goal was to extend the experiment into the agricultural field and investigate if and how the conditions of pre-sowing exposure of cabbage seeds to SMF affect the yield of crops. Prior to sowing, three groups of cabbage seeds (Brassica oleracea var. capitata) were treated with highly homogeneous SMF of 50, 100, and 300 mT for one hour. Plant samples from the non-exposed control group and the three treated groups were taken from the agricultural field and analyzed twice: in the transplant stage two months after sowing and in the mature stage 3-5 months after sowing. In the transplant stage plants from the groups exposed to 50 and 100 mT had statistically significant larger weight and number of leaves when compared to the control group. In this phase of plant development, the magnetic field of 100 mT was found to be the most efficient since it produced plant weight increase of 30.7% and 21.5% more leaves compared to the control group, whereas the corresponding increases for the 50 mT exposure were 19.0% and 10.4%, respectively. All the treated groups had much wider root than the control. The increase was 148.4, 211.7, and 129.6% for the group exposed to 50, 100, and 300 mT, respectively. Most likely, this is due to the absence of the cabbage root maggot in the roots of all treated groups contrary to the control group where numerous pests were found in the root systems of all sample plants. In the mature stage the seed treatment with 300 and 100 mT SMF caused statistically significant increase of the plant weight and head weight. In the group exposed to 300 mT the increase of plant and head weight was 22.7 and 24.8%, respectively, whereas for the 100 mT exposure the corresponding increases were 16.9 and 18.3%, respectively. Consequently, the pre-sowing lh exposure of cabbage seeds to 300 mT was found to be the most effective of the three studied SMF treatments, since it can produce 24.8% larger cabbage yield compared to the nontreated control.