Lech Wojciech Szajdak

In the context of declining water quality, the threat of nonpoint source pollution (NSP) to aquatic habitats and species is a well-recognized phenomenon. The recognition of NSP continues to grow as legal regulatory practices as well as public and scientific awareness of this source of pollution increase. Agricultural runoff from farms and fields often contains various contaminants such as pesticides, fertilizers, pathogens, sediments, salts, trace metals, and substances that contribute to changes in biological oxygen demand. Farmers and growers releasing agricultural runoff are increasingly required to implement water-quality regulations and management practices to reduce NSP. Constructed or restored shelterbelts and natural peatlands can be two of the many best management practices farmers can use to address this problem. We compared the barrier efficiency of the agricultural landscape elements, i.e., a shelterbelt of various plant compositions and a peatland, to control the spread of NSP in groundwater between ecosystems. In agricultural areas with high water tables, biogeochemical barriers in the form of shelterbelts and peatlands can remove or retain many groundwater pollutants from agricultural runoff with careful planning and management.

In soil, the following forms of nitrogen (total, organic, amino acids in dry mass and humic acids) and in humus substances, dry mass, urease activity in groundwater and in soils under the shelterbelt were determined. The study was carried out during the entire vegetation season. The shelterbelt efficiently decreased the amount of total organic substances in groundwater as well as total nitrogen and free and bound amino acids in humic acids. In soil under the shelterbelt a lower pH, urease activity and the content of amino acids in humic acid as compared to that in adjoining cultivated soil were measured.

The content of bound amino acids was investigated in various transformed moorsh soils formed from low peat and utilised as a meadow. The total quantity of the bound amino acids in the analysed soils ranged from 5.30 to 18.66 g·kg^-1 of soil. Neutral amino acids predominated and sulphur amino acids occurred in the smallest quantities. In moorsh soils, up to 26 amino acids were determined. Aspartic acid, glycine, alanine, cysteine, 1-methylhistidine and arginine predominated in all soil samples. The concentrations of -alanine and lysine were the highest in strongly and very strongly secondarily transformed soil samples indicating higher bacterial biomass. Thus, a linear relationship was found between total amino acid content and the degree of secondary transformation of peat soils.

Among the mineral substances that play a major role in plant nutrition, the most important substance is nitrogen, which is available to plants in the mineral forms (ammonium and nitrates) and organic (amino acids, amines, amides, alkaloids, etc.). Nitrogen is also important for the ‘synthesis of enzymes’, as it is a component of enzymes that catalyze biochemical reactions in plants and has an indirect role in all enzymatic reactions of biosynthesis or decomposition of organic matter. Due to this significance, many authors study the content of nitrogen under his various forms in order to determine the most suitable content for a sustainable crop regarding the species. This chapter discusses research conducted in Romania, in eight blueberry plantations from the north-west region of the country. The purpose of the study was to determine the content of nitrogen, ammonium and nitrates under blueberry cultivation. The results were conducted in 2016–2017 and have a significant value for future studies and for future farmers as well because it answers many questions regarding the best way to cultivate this species, which is more and more harvested in Romania and also emphasises the importance of nitrogen for all agricultural landscape.

The aim of this study is to comprehensively assess the change in oxidoreductive enzyme activities, due to the potential in catalyzing oxidation and reduction reactions, as the basic processes on undrained and drained peat soils. On undrained peatlands, a significant decrease of enzyme activities was observed such as xanthine oxidase, urate oxidase, phenol oxidase, and peroxidase with an increase in depth. It was connected with significantly higher porosity values, hot water extractable organic carbon, and total organic nitrogen contents, ammonium and nitrate ions concentrations, and significantly lower ash and bulk density values in the upper layers. On drained peatlands, a significant increase of enzyme activities in depth was measured. Enzyme activities such as xanthine, urate, phenol oxidase, and peroxidase were documented to be effective as new indicators and tools for changes of the moorsh-forming process in association with the oscillation of the water table caused by the drainage of the peatlands.

The content of bounded amino acids in six entomopathogenic fungi was identified and determined. Analyzing the elements characterizing the pathogenicity of individual species of fungi based on infectivity criteria, ranges of infected hosts, and the ability to induce epizootics, these can be ranked in the following order: Isaria farinosa, Isaria tenuipes, Isaria fumosorose, Lecanicillium lecanii, Conidiobolus coronatus, Isaria coleopterorum. These fungi represent two types of Hyphomycetales-Paecilomyces Bainier and Verticillium Nees ex Fr. and one type of Entomophtorales-Conidiobolus Brefeld. Our study indicates that there are significant quantitative and qualitative differences of bounded amino acids in the entomopathogenic fungal strains contained in the mycelium between high and low pathogenicity strains. The richest composition of bounded amino acids has been shown in the mycelium of the Isaria farinosa strain, which is one of the most commonly presented pathogenic fungi in this group with a very wide range of infected hosts and is the most frequently recorded in nature as an important factor limiting the population of insects.

The agricultural use of peatlands, the stabilization of the substrate for building or road construction or for increasing the capacity of soil to support heavy machinery for industrial activities (peat and petroleum extraction), harvesting to provide peat for energy, and the growing media and initiation of chemical processes must be preceded by drainage. As a consequence of drainage, peat underwent an irreversible conversion into moorsh (secondary transformation of the peat). The object of the study was to investigate comparatively the organic matter composition and molecular structure of humic acids (HAs) in the raised bog, fen, and peat-moorsh soils developed in various compositions of botanical cover, peat-forming species, and oxic and anoxic conditions as a result of the oscillation of ground water during drainage as well as to evaluate the vulnerability of soil organic matter (SOM) to decomposition. Drainage was shown to be the principal factor causing the various chemical compositions and physicochemical properties of HAs. Large and significant differences in chemical composition of peat and the properties of HAs were found to be related to the degree of decomposition. The HAs from drained peatlands were less chemically mature. In contrast, the HAs from fen and raised bog were found to be more mature than that of the corresponding drained peatlands. The above findings showed the distinguishable structure of HAs within the soil profile created by the plant residue biodegradation and formed in both oxic and anoxic conditions. The analytical methods of thermal analysis together with the optical densities and paramagnetic behaviour are suitable and effective tools for studying structure–property relationships characterizing the origin and formation process of HAs in various environmental conditions.

Indole-3-acetic acid (IAA) is one of the most important auxin/phytohormones for plant growth. The effect of peat botanical composition of various vegetation cover and peat-forming species at 13 sampling points located in fens, bogs and drained peatlands on the content of IAA, hot water extractable organic carbon (CHWE), total organic carbon (TOC), total nitrogen (TN) and C/N quotient was assessed. The objective of this study was to analyse comparatively the quantities of IAA, TOC, CHWE, TN and C/N in peats of varying genesis with respect to the peculiarities of their origin due to the botanical composition of vegetation cover and peat-forming species. A high content of IAA, CHWE and TN was found in the top layers of the peatlands, indicating the formation of IAA mainly by the roots of peat-forming species and rhizosphere bacteria, because of the rich supplies of chemical and biochemical compounds exuded from the roots. Drainage of the peatlands did not have a significant effect on the amounts of IAA and TOC, but contributed to the release of large amounts of CHWE (mainly representative of labile carbon). High TOC contents and C/N quotients in deeper layers of the peat deposits indicated a decline in the rate of soil organic matter (SOM) mineralisation and accumulation of the recalcitrant fraction. Varying C/N quotients of peat-forming species may reflect the initial botanical composition of the vegetation cover or peat-forming species, or differences in the degree of decomposition and/or TN content of the peats.

The aim of the study was to evaluate the dynamics of organic matter and mineral components on the basis of botanical composition, peat species, and physical, chemical and biochemical properties in the acrotelm (0–50 cm) and catotelm (50–100 cm) of 19 Sphagnum- and Carex-dominated organic soils. The botanical composition and structure of 19 Baltic-type raised bog and fen sites in Poland and Siberia (Russia) were investigated. Principal component analysis (PCA) was used for the classification of 18 physical, chemical, biological and biochemical factors in the acrotelm (0–50 cm) and catotelm (50–100 cm). These factors affect the dynamics of organic matter transformation in Sphagnum- and Carex-dominated peat soils. The relative physical, chemical, biological and biochemical properties indicate that oxidation and polymerisation processes, along with the formation of resistant compounds and a lower rate of decomposition, are more prevalent in Sphagnum- than in Carex-dominated organic soils.

The Typic Hapludalfs soils under two old shelterbelts (200 years old) Robinia pseudacacia and Crataegus monogyna, multi species of trees (young shelterbelt - 20 years old) and neighbouring cultivated fields were investigated. The function of shelterbelts of different age and plant composition in agricultural landscape and estimation of biochemical and chemical soil conditions for the decrease of greenhouse gases release from soil to the atmosphere was the aim of the research. In soils under shelterbelts were estimated activities of several enzymes participating in the oxidation-reduction processes, ferric and ferrous ions and the evolutions of gases like N₂, N₂O, CO₂, and CH₄. The soils under old shelterbelts characterized higher peroxidase activity than in young shelterbelt and adjoining cultivated fields. However, no significant differences were observed for nitrate reductase activity between old and young shelterbelts. There were proved differences between emission of N₂O in soils under shelterbelts and in adjoining cultivated fields. Furthermore, it was observed significant effect of the young shelterbelt on the decrease of carbon dioxide release than in the adjoining cultivated field. The manipulation of the landscape through the introduction of shelterbelts of different age and the composition of plants leads to the modification of biogeochemical soil conditions for N₂O and N₂ formation and finally decrease of the greenhouse gases evolution from soils to the atmosphere. Thus the creation of new shelterbelts is favourable factor for agricultural landscape.