authors: Daniel Ishlyamski, Deyan Lesigyarski, Bozhurka Georgieva, Diana Jordanova, Neli Jordanova

article abstractProximal sensing receives increasing attention in soil science and potting media research because of favorable simplicity, speed and nature-friendly approaches. The aim of the present study is to test the utility of the environmental magnetic methods for quality characterization of various potting substrates. A pilot collection of ten samples from commercially available growing media (potting soils, potting mixes and vermicomposts) was analyzed using mineral magnetic methods (magnetic susceptibility (X), percent frequency dependent magnetic susceptibility (Xfd%), remanent magnetizations – anhysteretic (ARM) and isothermal (IRM), thermomagnetic analysis of magnetic susceptibility). Elemental composition was determined using pXRF spectrometer. The results show that the magnetic signal of potting substrates is governed by the content of the mineral fraction, being the highest in potting soils and vermicomposts. Magnetic data suggest that most of the magnetic particles are coarse multidomain and stable single domain grains. Correlation analysis between magnetic parameters, elemental composition and pH show that the strongest correlation is observed between c and ARM with the K2O content and pH. It is proposed that this relation reflects both pedogenic and lithogenic contribution of iron oxides in compost media. In a germination experiment with tomato seeds, magnetic ratio ARM/IRM of potting substrates correlates with the mean seedlings length. Results obtained show that magnetic measurements can be used as a fast proxy for assessment of substrates’ nutrient content and pH.