Data on N-fixing and Pioneer tree spp
Evaluating how different tree species affect the microbial and physicochemical properties of technosols from combustion wastes and reclaimed mine soil (RMS) is vital in species selection to enhance restored ecosystem services. Therefore, the aim of this research was to evaluate the effect of pioneer and N-fixing tree species on the mine soil microbial and physicochemical properties under different substrate types. Common birch (Betula pendula Roth) and scots pine (Pinus sylvestris L.), as the commonly introduced species on RMS in eastern and central Europe, were selected as pioneer species, whereas black alder (Alnus glutinosa (L) Gaernt.) and black locust (Robinia pseudoacacia L.) were selected as N-fixer species. Soil samples were collected from different technosols and RMS developed under three substrates (fly ashes, clay, and sand) and measured for the content of total nitrogen (Nt), organic carbon (Corg), exchangeable calcium (Ca2+), exchangeable potassium (K+), exchangeable magnesium (Mg2+), C to N ratio (C:N), basal respiration rate (RESP) and microbial biomass. The research indicated that tested tree species influenced water holding capacity (WHC), Nt, C:N and RESP value. The highest Nt accumulation in soil was observed under N-fixing, but it did not transfer into higher organic carbon content under N-fixers. The soil under pine had a greater C:N ratio than soil under birch, alder and locust. The RESP rate was highest under birch. In terms of substrate type, RMS developed on Miocene clays exhibited higher carbon and macronutrient contents followed by ashes, whereas sands exhibited the lowest values of both physicochemical and microbial properties. The study suggested that both tree species and substrates affect microbial activities and physicochemical properties of RMS, however, the substrate effect is stronger.
Steps to reproduce
A total of seventy-two (6 replications × 3 RMS substrates × 4 tree species) 10×10 m plots were established. Soil samples were collected in August and September 2019. Tree stands on plots ranged in age from 18 to 44 years (Table 1). At each plot, one composite sample was collected from five locations (from four corners and at the center) at the depth of 0-5 cm. The samples were sieved with 2 mm mesh prior to laboratory analysis. Samples for physicochemical analyses were air-dried, whereas for microbial analyses stored field-moist at 4°C. LECO TruMac CNS analyzer was used to analyze the content of organic carbon (Corg) and total nitrogen (Nt). Soil texture was measured with a Fritsch GmbH Laser Particle Sizer ANALYSETTE 22. Basic exchangeable cations (Ca2+, Mg2+ and K+) were measured with an ICP OES ICAP 6000 series spectrophotometer after extraction in 1 M NH4Ac. The pH of the samples was measured in H2O (pHH2O) and 1 M KCl solution (pHKCl) (soil/liquid ratio 1:5, w/v) with a digital pH meter (CPC-411, ELMETRON) at temperature 20˚C. Prior to microbial analyses, the samples were adjusted to 50% of maximum water holding capacity (WHC) and pre-incubated at 22°C for 6 days; WHC was determined gravimetrically according to Schlichting and Blume (1966). For microbial biomass (Cmic) and basal respiration rate (RESP) measurement, samples (50 g d.w.) unamended for RESP measurements and amended with 8 mg glucose for Cmic measurements were incubated at 22° C in gas-tight jars. The incubation time was 24 hours for the determination of RESP and 4 hours for Cmic. The jars contained beakers with 5 ml 0.2 M NaOH to trap the evolved CO2. After the jars were opened, 2 ml 0.9 M BaCl2 was added to the NaOH; the excess of hydroxide was titrated with 0.1 M HCl in the presence of phenolphthalein as an indicator. Cmic was calculated from the substrate-induced respiration rate according to the equation given by Anderson and Domsch (1978): Cmic [mg g-1] = 40.04 y + 0.37, where “y” is ml CO2 × h-1 × g-1.