Possibilities of plant nutrient recycling in energy grass plantations = Augu barības elementu reciklācijas iespējas enerģētisko zālaugu plantācijās

To develop the scientific work, field trials were performed at the Research Institute of Agronomy of the Latvia University of Life Sciences and Technologies, in Skriveri in the time period from 2012 to 2016. Hypothesis of the thesis By using by-products of bioenergy production in fertilisation - fermentation residues or digestate and wood ash, it is possible to partially cover the requirements of energy grasses for nutrients, as well as to ensure their reuse. The aim of the thesis To find out the possibilities of growing reed canary grass (Phalaris arundinacea L.) 'Bamse' and festulolium (× Festulolium pabulare) 'Felina' for energy production by using bioenergy production by-products in fertilisation – fermentation residues or digestate and wood ash, as well as to study possibilities of plant nutrient reuse in the system: soil – plants – digestate / ash – soil – plants. Research tasks 1. To evaluate digestate and wood ash as energy grasses fertilisers. 2. To find out the optimal norm and the regime of use of digestate in reed canary grass fertilisation. 3. To study the nitrogen, phosphorus, potassium circulation cycle in the system: soil – plants – digestate / ash – soil – plants. 4. To perform economic evaluation of reed canary grass and festulolium fertilisation. The structure of the research paper Chapter 1 - The literature review includes five subchapters. The chapter provides a brief overview of bioenergy production technologies, examines perennial grasses in the context of bioenergy production, evaluates agrotechnical measures to ensure adequate grass biomass yield and quality for biogas and fuel feedstock production, examines plant nutrient circulation in bioenergy crop production systems, and provides agronomic assessment of by-product – digestate and ash fertiliser for use in energy grass plantations. Chapter 2 - Materials and Methods includes two subchapters. The chapter describes the methodology of test establishment, the studied material, the observations and analyzes performed, describes the meteorological conditions and describes the statistical analysis of data. Chapter 3 - The results and discussion include six subsections. The chapter analyzes the obtained results on reed canary grass and festulolium yield and changes in yield structure and quality due to the use of different fertilisers, norms and regimes, performing grassland dry matter yield inventory by mowing once and twice a year. The remove of plant nutrients from soil with dry matter yield, as well as changes in soil agrochemical parameters due to fertilisation were evaluated. An economic evaluation of reed canary grass and festulolium fertilisation has been performed. The conclusions include answers to the research tasks. The paper contains 34 tables, 41 figures, 53 annexes and 353 scientific source references.

Phytotoxic effects of essential oils from Nepeta glocephalata Rech.f. and N. ispahanica Boiss. on se-lected weed species

<p class="042abstractstekst">In the present study the bioherbicidal activity of essential oils hydrodistilled from <em>Nepeta glocephalata </em>Rech.f and <em>N</em>. <em>ispahanica</em> Boiss were investigated on four weed species (barnyard grass (<em>Echinochloa crus-galli</em> (L.) Beauv), redroot pigweed (<em>Amaranthus retroflexus </em>L.), lambsquarters (<em>Chenopodium album </em>L.) and canary grass (<em>Phalaris canariensis </em>L.)). A total of 37 components were identified from the essential oils of <em>N. glocephalata and N. ispahanica</em> constituting approximately 98.61 % and 96.1 % of the oils, respectively. In laboratory bioassay different concentrations (0, 1, 2, 4 and 8 μl ml^-1) of two <em>Nepeta </em>essential oils on germination, root and shoot length were studied. Results showed by increasing the concentration of oils, all studied traits of the weeds were decreased compared with control. In a glass house bioassay post-emergence application of <em>Nepeta</em> essential oils (1.25 %, 2.5 %, 5 % and 10 %, v/v) on 3-week-old weed plants caused visible injury (7-days after spray) ranging from chlorosis to necrosis of plant weeds. In foliar application under glasshouse conditions, both<em> Nepeta</em> essential oils reduced the seedling dry mass and concentrations of chlorophyll a chlorophyll b. The study concludes that <em>Nepeta</em> essential oils have phytotoxic effects and could be used as bioherbicides but the selectivity of these compounds should be considered also.</p>

Evaluating reed canary grass samples for reclamation of coal dumps

One reliable way to restore eroded soils and technogenic land is to reclaim it by sowing perennial grasses. Samples of reed canary grass suitable for reclamation of coal dumps in the Kemerovo region have been studied and identified. Experimental work was carried out in the Tomsk region (5811 N, 8300 E) during the period of 2017-2020. The research subjects are represented by samples of reed canary grass taken in 2016. A nursery of study samples suitable for reclamation of coal dumps was laid in 2017 with six numbers - KM-1, KM-2, KM-3, KM-4, KM-5 (Tomsk region), the variety Vityaz (Tomsk region) was used as a standard. The soils of the experimental plots were sod-podzolic acidic loamy sandy loam and loamy with a humus content of no more than 2% in the arable horizon. When evaluating the samples, the main attention is paid to studying the traits and properties that limit their cultivation under taiga conditions: grass density, plant height, foliage, winter hardiness, lodging resistance, seed productivity, green mass yield, resistance to the most common diseases. Over a 3-year study of selections of reed canary grass based on a set of the main economically important traits, the KM-5 sample has been identified. This specimen has a complex of valuable features in creating an adaptive variety suitable for reclamation of coal dumps (foliage - 61.4%, green matter yield - 38.5 t/ha, dry matter - 11.9, seeds - 0.21 t/ha). The selected number has annual reliable additions to the standard in terms of green matter yield of 8.5 t/ha, dry matter yield of 3.3, and seed yield of 0.04 t/ha. Samples KM-1, KM-5 showed high resistance to these diseases: helminthosporiosis - 6.0-6.1%, septoriosis - 2.6-4.2%.

Short communication: A predictive model for the time course of seedling emergence of Phalaris brachystachys (short-spiked canary grass) in wheat fields

Aim of study: A predictive model of the seedling emergence pattern of Phalaris brachystachys Link (short-spiked canary grass) was developed, aimed to contribute to support a more efficient management of this troublesome, competitive weed in winter cereal crops around its native Mediterranean range and in different areas of the world where it is introduced. Area of study: Southern (Andalusia) and northern Spain (Navarra). Material and methods: A model describing the emergence pattern of P. brachystachys in cereal fields based on accumulation of hydrothermal time in soil was developed and validated. For model development, cumulative emergence data were obtained in an experimental field, while an independent validation of the model was conducted with data collected in two commercial wheat fields from climatically contrasting regions of Spain. Main results: The relationship between cumulative emergence and cumulative hydrothermal time (CHT) was well described by a Logistic model. According to model predictions, 50% and 95% seedling emergence takes place at 108 and 160 CHT above base water potential for seed germination, respectively. The model accurately predicted the seedling emergence time course of P. brachystachys in the two commercial wheat fields (R2 ≥ 0.92). Research highlights: This model is a new tool that may be useful to improve the timing of control measures to maximize efficiency in reducing P. brachystachys infestations in cereal crops.

Reed Canary Grass for Energy in Sweden: Yields, Land-Use Patterns, and Climatic Profile

Research Highlights: (1) Reed canary grass (RCG) is analysed in Sweden compared to willow and poplar for 2001–2020. (2) Each crop presents a different land-use and climatic profile. (3) Average yield records of RCG are similar to willow and poplar. (4) There are divergences between trial-based and commercial yields. (5) Existing land-use change patterns suggest meadow > RCG and RCG > cereal. (6) RCG land area is very sensitive to policy incentives. Background and objectives: RCG is an alternative crop for biomass-to-energy due to high yield and frost tolerance. We assess the cultivation in Sweden by using an extensive compilation of data, with emphasis on the extent of the cultivation, climatic profile, land-use patterns, and productivity. Material and methods: RCG plantations are analysed for 2001–2020. A geostatistical analysis is performed to characterize where it is cultivated and the land uses associated. Climatic, productivity, and yield profiles are compared to willow and poplar plantations from experiments and from commercial plantations. Results: The results show that the cultivation of RCG expanded after 2005, with a maximum of 800 ha in 2009, to then decrease to the current levels of about 550 ha. It is mainly grown in colder climatic areas, with lower agricultural productivity than willow and poplar. Mean yields from trials are 6 oven dry tonnes (odt) ha−1 year−1; commercial yields are 3.5 odt ha−1 year−1. RCG replaces meadow land and then is replaced by cereals when abandoned. Conclusions: RCG is an interesting alternative with similar yields (commercial and trials) as other energy crops, but its success is more sensitive to policy incentives.

Biomass Yield of Selected Herbaceous and Woody Industrial Crops across Marginal Agricultural Sites with Shallow Soil

Agricultural land in Europe is affected by low rooting depth (LRD) on 27.9 Mha. This marginal agricultural land can potentially be used to grow industrial crops without directly threatening food security or biodiversity conservation. However, little is known about the yield performance of industrial crops at LRD conditions. This study therefore compiles and discusses the meaningful data available in scientific literature. Twelve relevant industrial crops were identified for Europe. Currently, robust information on good growth suitability for LRD conditions is available for only one industrial crop, namely reed canary grass (RCG). Because this information was taken from field trial results from a single site, it remains unclear what role other growing conditions such as soil quality and climate play on both the yield level and the biomass quality of RCG under LRD conditions. These uncertainties about the quantitative as well as qualitative performance of industrial crop cultivation on marginal agricultural land characterized by LRD represent a major agronomic knowledge gap. Here, more knowledge needs to be compiled through both expanded crop science activities and improved international information exchange to make more optimal use of the large LRD areas available for the transition to a bioeconomy.

The influence of oil pollution on the growth and development of phleum pratense, festuca pratensis, phalaris canariensis

Purpose of the study: to study the effect of oil pollution on the morphological parameters of cereal grasses: canary grass, timothy grass and meadow fescue. Tasks: assessment of the impact of oil pollution of soils on seed germination, growth and development of the studied species by morphological parameters; analysis of the species variability of the studied indicators. Oil-contaminated high-moor peat was used as a substrate. Objects of research: seeds of cereal grasses: meadow timothy Phleum pratense L, 1753, meadow fescue Festuca pratensis Huds, canary grass Phalaris canariensis. Evaluation of the effect of oil-contaminated soil was carried out on the basis of changes in seed germination and morphological parameters: plant mass, leaf length, length and number of roots. The experimental results were processed by the method of variation statistics. As a result of studying the effect of oil-contaminated peat on seed germination, it was found that in the variants of the experiment with the minimum oil content, no differences were noted with the control values. The maximum concentration of oil (10,000 mg / kg) reduced seed germination by 924%. With an increase in the oil content in the soil, the morphometric parameters of all the studied species of cereal grasses also decreased. The greatest differences in the studied test functions, in comparison with the control variant, were noted in canary grass, the smallest in meadow fescue.

Cultivation of Gal?ga Orient?lis in the Upper Volga of non-chernozem zone

Field studies were carried out at the Gubino reclamation facility located at the experimental base of VNIIMZ - a branch of the Federal Research Centre V.V. Dokuchaev Soil Science Institute in 2015-2019. We studied promising high-yielding varieties of legumes - gal?ga orient?lis, cereal rhizome grasses - awnless brome grass, canary grass and highly productive of loose shrub grass of meadow timothy. Studies have established that in the legume-cereal hay stands, the share of the gal?ga orient?lis was 18-83%. The share gal?ga orient?lis variety Gale ranged from 19 to 75%, variety Yubilyar from 18 to 79% and variety Krivich from 25 to 83%. On average, over the years of research, with two-fold mowing, the productivity of the gal?ga orient?lis and its mixtures with cereal grasses was 5.9-8.0 t / ha dry weight. The cereal grass mixture with two-cut use provided a dry matter yield at the level of 5.4-7.2 t / ha. The highest level of protein nutritional value was noted in the herbage of the gal?ga orient?lis variety Krivich 17-18%. The yield of green mass of legume-cereal hay herbage was 41.5-56.0 t / ha. Analysis of the dynamics of the density of the gal?ga orient?lis showed that the most dense was variety Krivich in single-species sowing - up to 166 pcs / m2. It was found that among the varieties of the legume component, the tallest, on average, over a five-year study were noted above-ground shoots of the gal?ga orient?lis variety Krivich - up to 117 cm. The gal?ga orient?lis had a high leafiness, the percentage of its leaves was 54-55%. In general, according to the options, the percentage of leaf apparatus in clean crops was 52-56%, in mixed crops - 48-57%. The output of fodder units was 4.7-6.8 thousand / ha.

The Influence of Lime Material and Nitrogen Fertilization on Reed Canary Grass Productivity, Plant Quality and Environmental Impact of Using Biomass for Energy Purposes

A field experiment with reed canary grass (Phalaris arundinacea L.) was carried out at LAMMC Vėžaičiai Branch (Western Lithuania) in 2010–2016 with the aim to evaluate the impact of liming and nitrogen on grass productivity, biomass chemical content and energetic parameters of the pellets. The site soil is the natural acidic loam Retisol (pH 4.2–4.6). Reed canary grass productivity was significantly affected by the year of growing and nitrogen fertilization. The average annual dry matter (DM) yield varied from 5442 to 11,114 t ha−1. The highest yields were obtained using the annual rate of 120 kg ha−1 N (nitrogen) fertilizers. Soil liming had a negligible effect on biomass productivity. Nitrogen utilization efficiency (NUE) varied greatly depending on the growing year and N fertilization rate. After analyzing the properties of reed canary grass and wood sawdust granules, it was found that the granules obtained a high density exceeding 1000 kg m−3 DM. The lowest calorific value of reed canary grass pellets was found to be quite high—17.4 MJ kg−1 DM. All harmful emissions did not exceed the permissible values. Summarizing the results, it can be stated that reed canary grass pellets may be recommended for burning in domestic boilers.