Magnetized water irrigating influences the growth and quality characteristics of Capsicum annuum L. under greenhouse cultivation in Shouguang city

Abstract Background: Magnetic techniques have been reported as a feasible technology to improve the plant growth environment and help to promote soil restoration. Hence, it we applied these techniques, aiming to explore the effect of the magnetic treatment of irrigation water on promoting soil microecological conditions and seedling growth and production. A field experiment was performed under the cultivation conditions of a solar greenhouse. The crop Capsicum annuum L. was cultured in season during 2017 and 2018. A magnetic device was used to treat water, and two irrigation treatments were carried out. The physicochemical properties in the soil and the characteristics of seedling growth and parameters of fruits in long hot green pepper were analyzed.Results: Magnetized water irrigation (MWI) had the potential to promote bacterial and enzyme activities through increases in alpha-diversity indexes, abundance and multiple species, whereas mineral nutrient contents were enhanced. MWI had positive effects on promoting the physical characteristics in soil, which reduced the pH and bulk density and increased the total porosity and moisture content. MWI promoted morphological characteristics in both leaves and fruits and increased the fresh weight per fruit. MWI improved mineral nutrient contents and fruit quality. Moreover, the results of a correlation analysis between mineral nutrients, alpha-diversity parameters and bacterial communities showed that the relative abundance value was more than 10%, revealing that the dominant bacterial group of Proteobacteria was the opposite of Firmicutes and Bacteroidetes, whereas the latter two groups were significantly negatively correlated with the total contents of nitrogen and phosphorus and the contents of nitrate and ammonium nitrogen and available phosphorus but positively correlated with pH.Conclusions: In conclusion, The above results showed that irrigation with magnetically treated water could have helpful influences on soil quality; additionally, the improved soil conditions could be beneficial for the formation of bacterial groups, crop growth and output.