The effects of mulch (Olea europea and Pinus halepensis) on burned soils: A preliminary study in Adriatic coast (Croatia)

The effects of mulch (Olea europea and Pinus halepensis) on burned soils: A preliminary study in Adriatic coast (Croatia)

Delac, Domina^1*; Pereira, Paulo^2*; Kisic, Ivica¹

¹University of Zagreb, Faculty of Agriculture, Department of General Agronomy, Svetosimunska cesta 25, 10000 Zagreb, Croatia. (*ddelac@agr.hr)

²Mykolas Romeris University, Environmental Management Laboratory, Ateitis street 20, LT-08303, Vilnius, Lithuania (*pereiraub@gmail.com)

 

In the recent decades the frequency and intensity of summer drought periods is increasing in Adriatic coast. These changes in climate increase the vulnerability to wildfires. Wildfires can change soil physical and chemical properties. However, these effects can be mitigated by mulching. The aim of this work is to study the effects of mulch (Olea europea and Pinus halepensis) on fire affected soils. The wildfire occurred on 28 July 2019 and affected an area of about 900 ha in Dalmatia, near Adriatic Coast (43°45'06.0"N 15°56'02.9"E with an elevation of 105 m a.s.l.).  The mean annual temperature is 15.8 °C, and the annual precipitation is 800 mm. It was affected agricultural land with dominant culture Olea europea and abandoned grassing where dominates Pinus halepensis. Soils are classified as calcocambisols. Twenty-five days after the fire, two plots (5 treatments per plot) were established and covered with Olea europea and Pinus halepensis mulch. A control plot was established as well. Soil were sampled (0 – 5 cm), twenty- days after fire (August, 2019), before mulch application, and then 3 months after fire (November, 2019). A total of 15 samples were collected per treatment (45 each sampling date). The soil properties analysed were soil pH, soil organic matter (SOM), mean weight diameter (MWD) to express aggregate stability, and soil water repellency (SWR) measured with water drop penetration time method (WDPT) in different fractions (2 – 1 mm; 1 – 0.5 mm, 0.5 – 0.25 mm, and <0.25 mm). Soil pH was not significantly different among sampling dates and treatments. SOM was significantly different among sampling dates for Olea europeae treatment and control. Olea europeae treatment had a significantly higher SOM then Pinus halepensis and control treatment. MWD was significantly higher within Olea europeae treatment. Within Pinus halepensis and control treatment no significant difference was observed. The soil was classified as slightly water repellent (5 – 60 seconds) in Olea europeae soil finer fraction (0.5 – 0.25 mm and <0.25) in both sampling dates. In Pinus halepensis treatments and control, soil was wettable (<5 seconds), and no significant difference was observed among sampling date. Future sampling and analysis will be conducted during one year to estimate the effect of Olea europeae and Pinus halepensis mulch on soil properties.

Keywords: Wildfire, Olea europeae, Pinus halepensis, mulch.

 

Acknowledgments

This work was supported by Croatian Science Foundation through the project "Influence of Summer Fire on Soil and Water Quality” (IP-01-2018-1645).