Raimonds Kasparinskis

Influence of afforestation on soil genesis, morphology and properties in glacial till deposits

A study of soil morphological, physical and chemical properties was performed in woodland of different ages, in which spruce (Picea abies), aspen (Populus tremula) and birch (Betula pendula) growing stocks have colonized former agricultural land. The aim of the study was to clarify changes in soil genesis, morphology and properties due to the afforestation of abandoned agricultural land in glacial till deposits. The research showed that soil in these deposits (loamy sand, loam, clay) retains the morphological properties of agricultural land for up to 100 years. Secondary podzolization features in the soil profiles were observed within 100 years of the start of afforestation, whereas the diagnostic properties of Albic and Spodic horizons had not developed in the soil profile after 200 years. This study demonstrated that the morphological and physico-chemical properties of forest litter horizons, including the accumulation of organic substances, are dependent on forest age; however, changes in the properties of mineral soil horizons are mainly related to woodland age. Following the afforestation of agricultural lands, changes in soil pHKCl, organic matter content and extractable Al and Fe concentrations occur more rapidly than changes in soil diagnostic properties and profile formation.

Soil–vegetation interactions in abandoned farmland within the temperate region of Europe

Forests are becoming increasingly dominant in the landscape of north-eastern Europe as a result of a decline in agriculture, land abandonment and the related trend of afforestation. This is also the case in Latvia, where former agricultural land is either artificially afforested or taken over by the natural process of secondary succession. A large spatial and temporal variety of succession and compositional diversity of tree species colonizing fields is observed in the central part of Latvia. Understanding of the possible scenarios in the development of plant communities after land abandonment is important for deciding on viable management solutions, e.g. restoration of semi-natural grasslands or forest regeneration. The aim of the research was to determine the factors affecting the course of secondary succession at its initial stage and the composition of tree species that are colonizing abandoned fields. Ten abandoned fields were surveyed, recording species composition and vegetation structure, determining soil properties and analysing correlations between these factors. The research results help to explain the mechanisms of how soil properties affect the course of succession. On fertile soils a dense herbaceous layer developed, which in abandoned fields resulted in accumulation of a thick cover of litter. Such conditions hinder establishment of typical pioneer species, e.g. grey alder Alnus incana, aspen Populus tremula and birch Betula pendula, whereas Norway spruce Picea abies is able to compete with grass species and thus can more easily establish in abandoned fields, creating favourable conditions for invasion by other tree species.

Leaching of Contamination from Stabilization/Solidification Remediated Soils of Different Texture

Abstract Development of soil and groundwater remediation technologies is a matter of great importance to eliminate historically and currently contaminated sites. Stabilization/solidification (S/S) refers to binding of waste contaminants to a more chemically stable form and thus diminishing leaching of contamination. It can be performed using cement with or without additives in order to stabilize and solidify soil with the contamination in matrix. A series of experiments were done to determine leaching properties of spiked soils of different texture bound with cement. Results of experiments showed, that soil texture (content of sand, silt and clay particles) affects the leaching of heavy metals from stabilized soils.

Particular characteristics of soil microbial communities in forest stands infected with Heterobasidion parviporum and Armillaria spp.

We compared soil microbial communities of forests infected with Heterobasidion parviporum and Armillaria spp. with soils of healthy forests using conventional plating and molecular methods. Plate counts from the soils of the infected forests reflected a significant decrease of the number of cultivable filamentous fungi (CFF) and a slight decrease of the total number of cultivable microorganisms. The diversity of CFF was reduced in the stands infected with H. parviporum. In the stands infected with Armillaria spp. the diversity of CFF and relative abundance of cultivable Trichoderma spp. was even higher than in healthy forest stands. Quantitative PCR revealed increased concentrations of total fungal DNA and Trichoderma spp. DNA in the soil of H. parviporum infected stands. In Armillaria spp. infected stands the total concentration of fungal DNA was decreased, but relative amount of Trichoderma spp. DNA was increased. No significant differences in the species diversity of fungi in the soil were found by ARDRA.

The impact of wood-derived biochar on the survival of Trichoderma spp. and growth of Secale cereale L. in sandy soil

ABSTRACT The interrelations between biochar (BC) and soil microbiota remain unclear. Addressing this will be important for understanding how BC affects soil properties and plant growth. Here, we tested the influence of wood-derived BC with immobilised Trichoderma viride on rye Secale cereale L. in sandy soil. We found that the addition of BC leads to a significant (P < .05) increase in the concentrations of Ca2+ and Mg2+, as well as a decrease in the concentration of Al3+, irrespective of BC particle size and the presence of T. viride. Plant growth was stimulated in the presence of small (<2 mm) particle-sized BC. Fungal diversity, as well as an absolute and relative abundance of Trichoderma spp., was tested by cultivation-dependent methods and qPCR. Both of these approaches revealed a positive effect of BC on the survival of Trichoderma spp. under the tested conditions, especially in the presence of a small particle size fraction.