**Immediate Changes in Organic Matter and Plant Available Nutrients of Haplic Luvisol Soils Following Di** ff**erent Experimental Burning Intensities in Damak Forest, Hungary**

### **Jack M. Bridges 1,\*, George P. Petropoulos 2 and Nicola Clerici 3**


3 Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Carrera26#nicola.clerici@urosario.edu.co

 63B-48, Bogotá 111221, Colombia; **\***Correspondence:bridgesj874@gmail.com;Tel.:+44-741-156-5456

Received: 3 May 2019; Accepted: 23 May 2019; Published: 24 May 2019

**Abstract:** One of the major pedological changes produced by wildfires is the drastic modification of forest soil systems properties. To our knowledge, large research gaps are currently present concerning the e ffect of such fires on forest Haplic Luvisols soils in Central Europe. In this study, the e ffects of experimental fires on soil organic matter and chemical properties at di fferent burning intensities in a Central European forest were examined. The study was conducted at Damak Forest, in Hungary, ecosystem dominated by deciduous broadleaf trees, including the rare Hungarian oak *Quercus frainetto* Ten. The experimental fires were carried out in nine di fferent plots on Haplic Luvisol soils transferred from Damak Forest to the burning site. Three types of fuel load were collected from the forest: litter layer, understorey and overstorey. Groups of three plots were burned at low (litter layer), medium intensity (litter and understorey) and high intensity (litter, understorey and overstorey). Pre-fire and post-fire soil samples were taken from each plot, analysed in the laboratory and statistically compared. Key plant nutrients of organic matter, carbon, potassium, calcium, magnesium and phosphorus were analysed from each sample. No significant di fferences in soil organic matter and carbon between pre- and post-fire samples were observed, but high intensity fires did increase soil pH significantly. Calcium, magnesium and phosphorus availability increased significantly at all fire intensity levels. Soil potassium levels significantly decreased (ca. 50%) for all intensity treatments, in contrast to most literature. Potassium is a key nutrient for ion transport in plants, and any loss of this nutrient from the soil could have significant e ffects on local agricultural production. Overall, our findings provide evidence that support the maintaining of the current Hungarian fire prevention policy.

**Keywords:** soil properties; experimental fires; nutrients; UV-spectroscopy analysis; thermal infrared thermometer
