Sustainability of soils to fires as a factor of preservation the shape of steppe Protected Areas

Abstract

Protected areas located in the steppe zone of Russia represent unique territories. Fires are a constant strong factor affecting the plant and soil components of ecosystems. The resistance of soils to fire in the conditions of semi-arid climate and hilly topography determines the speed of recovery of vegetation and soils in the steppe landscape. The study was devoted to the restoration of water-physical, physico-chemical and chemical properties of soils after the fire in 2014 on the site of the site «Burtinskaya Steppe» of the Orenburg State Nature Reserve (Russia). The study sites were represented by two polygons with burned and unburned (control) areas. The destruction of vegetation by fire contributed to the reduction of moisture reserves in the layer of 0–30 cm by more than 30% in the first years after the fire. For burning soils, there was a greater warming and migration of easily soluble salts and gypsum to the upper part of the soil profile. The most intense accumulation of СаЅО4 and sodium salts was noted in the soils of polygon 1. The study of the fire influence on the content of soil organic matter and nutrients demonstrated their significant reduction in the first two years of research. The restoration of phosphorus and potassium content to the level of control sites was noted by the end of three years of monitoring. The content of soil organic matter and nitrogen significantly exceeded the values in control sites. The conducted research has allowed drawing a conclusion about the ability of soils of steppe landscapes to restoration of stocks of biogenic elements after the fire. At the same time, changing the granulometric composition and migration of soil salts up the profile can contribute to the restructuring of plant communities and change the basic properties of the soil cover. The particular danger of changing the soils of steppe landscapes arises in the context of recurring fires and changing climate. The observed post-pyrogenic dynamics of soil processes indicate the need for a deep and comprehensive study of the impact of fires on the soil as a key link in the functioning of steppe ecosystems.

Keywords

• chernozem
• consequences of fires
• organic carbon
• particle size distribution
• steppe ecosystems
• water-physical properties of soils